4.5V to 40V Input Automotive MAX15004A/B-MAX15005A/B Flyback/Boost/SEPIC Power-Supply Controllers

4.5V to 40V Input Automotive MAX15004A/B-MAX15005A/B Flyback/Boost/SEPIC Power-Supply Controllers
EVALUATION KIT AVAILABLE
MAX15004A/B-MAX15005A/B
4.5V to 40V Input Automotive
Flyback/Boost/SEPIC
Power-Supply Controllers
General Description
Benefits and Features
The MAX15004A/B/MAX15005A/B high-performance,
current-mode PWM controllers operate at an automotive input voltage range from 4.5V to 40V (load dump).
The input voltage can go down as low as 2.5V after
startup if VCC is supplied by an external bias voltage.
The controllers integrate all the building blocks necessary for implementing fixed-frequency isolated/nonisolated power supplies. The general-purpose boost,
flyback, forward, and SEPIC converters can be
designed with ease around the MAX15004/MAX15005.
The current-mode control architecture offers excellent
line-transient response and cycle-by-cycle current limit
while simplifying the frequency compensation.
Programmable slope compensation simplifies the
design further. A fast 60ns current-limit response time,
low 300mV current-limit threshold makes the controllers suitable for high-efficiency, high-frequency DCDC converters. The devices include an internal error
amplifier and 1% accurate reference to facilitate the
primary-side regulated, single-ended flyback converter
or nonisolated converters.
An external resistor and capacitor network programs
the switching frequency from 15kHz to 500kHz (1MHz for
the MAX15005A/B). The MAX15004A/B/MAX15005A/B
provide a SYNC input for synchronization to an external
clock. The maximum FET-driver duty cycle for the
MAX15004A/B is 50%. The maximum duty cycle can be
set on the MAX15005A/B by selecting the right combination of RT and CT.
• Wide Supply Voltage Range Meets Automotive
The input undervoltage lockout (ON/OFF) programs
the input-supply startup voltage and can be used to
shutdown the converter to reduce the total shutdown
current down to 10µA. Protection features include
cycle-by-cycle and hiccup current limit, output overvoltage protection, and thermal shutdown.
Ordering Information
The MAX15004A/B/MAX15005A/B are available in
space-saving 16-pin TSSOP and thermally enhanced
16-pin TSSOP-EP packages. All devices operate over
the -40°C to +125°C automotive temperature range.
Applications
• Automotive
• Vacuum Fluorescent Display (VFD) Power Supply
• Isolated Flyback, Forward, Nonisolated SEPIC, Boost
Converters
Pin Configurations appear at end of data sheet.
19-0723; Rev 4; 1/15
Power-Supply Operating Requirement Including
"Cold Crank" Conditions
• 4.5V to 40V Operating Input Voltage Range
• Operates Down to 2.5V (with Bootstrapped
VCC Bias)
• Control Architecture Offers Excellent Performance
While Simplifying the Design
• Current-Mode Control
• 300mV, 5% Accurate Current-Limit Threshold
Voltage
• Programmable Slope Compensation
• 50% (MAX15004) or Adjustable (MAX15005)
Maximum Duty Cycle
• Accurate, Adjustable Switching Frequency and
Synchronization Avoids Interference with Sensitive
Radio Bands
• Switching Frequency Adjustable from 15kHz to
500kHz (1MHz for the MAX15005A/B)
• RC Programmable 4% Accurate Switching
Frequency
• External Frequency Synchronization
• Built-In Protection Capability for Improved System
Reliability
• Cycle-by-Cycle and Hiccup Current-Limit Protection
• Overvoltage and Thermal-Shutdown Protection
• -40°C to +125°C Automotive Temperature Range
• AEC-Q100 Qualified
PART
PIN-PACKAGE
MAX DUTY CYCLE
MAX15004AAUE+
16 TSSOP-EP*
MAX15004AAUE/V+
16 TSSOP-EP*
50%
50%
MAX15004BAUE+
16 TSSOP
50%
MAX15004BAUE/V+
16 TSSOP
MAX15005AAUE+
16 TSSOP-EP*
Programmable
50%
MAX15005AAUE/V+
16 TSSOP-EP*
Programmable
MAX15005BAUE+
16 TSSOP
Programmable
MAX15005BAUE/V+
16 TSSOP
Programmable
Note: All devices are specified over the -40°C to +125°C
temperature range.
+Denotes a lead(Pb)-free/RoHS-compliant package.
/V denotes an automotive qualified part.
*EP = Exposed pad.
4.5V to 40V Input Automotive
Flyback/Boost/SEPIC
Power-Supply Controllers
MAX15004A/B-MAX15005A/B
Absolute Maximum Ratings
IN to SGND.............................................................-0.3V to +45V
IN to PGND.............................................................-0.3V to +45V
ON/OFF to SGND ........................................-0.3V to (VIN + 0.3V)
OVI, SLOPE, RTCT, SYNC, SS, FB, COMP,
CS to SGND .........................................-0.3V to (VREG5 + 0.3V)
VCC to PGND..........................................................-0.3V to +12V
REG5 to SGND .........................................................-0.3V to +6V
OUT to PGND .............................................-0.3V to (VCC + 0.3V)
SGND to PGND .....................................................-0.3V to +0.3V
VCC Sink Current (clamped mode) .....................................35mA
OUT Current (< 10μs transient) ..........................................±1.5A
Continuous Power Dissipation* (TA = +70°C)
16-Pin TSSOP-EP (derate 21.3mW/°C
above +70°C)..............................................................1702mW
16-Pin TSSOP (derate 9.4mW/°C above +70°C) ..........754mW
Operating Junction Temperature Range ...........-40°C to +125°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-60°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow) .......................................+260°C
*As per JEDEC51 Standard, Multilayer Board.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
Electrical Characteristics
(VIN = 14V, CIN = 0.1μF, CVCC = 0.1μF // 1μF, CREG5 = 1μF, VON/OFF = 5V, CSS = 0.01μF, CSLOPE = 100pF, RT = 13.7kΩ, CT =
560pF, VSYNC = VOVI = VFB = VCS = 0V, COMP = unconnected, OUT = unconnected. TA = TJ = -40°C to +125°C, unless otherwise
noted. Typical values are at TA = +25°C. All voltages are referenced to PGND, unless otherwise noted.) (Note 1) (Figure 5)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
POWER SUPPLY
Input Supply Range
VIN
Operating Supply Current
IQ
4.5
VIN = 40V, fOSC = 150kHz
40.0
V
2
3.1
mA
1.23
1.40
ON/OFF CONTROL
Input-Voltage Threshold
VON
Input-Voltage Hysteresis
VHYST-ON
VON/OFF rising
Input Bias Current
IB-ON/OFF
VON/OFF = 40V
Shutdown Current
ISHDN
VON/OFF = 0V
VVCC
IVCC = 0 to 20mA (sourcing)
1.05
75
V
mV
0.5
μA
10
20
μA
7.4
7.60
INTERNAL 7.4V LDO (VCC)
Output (VCC) Voltage Set Point
Line Regulation
UVLO Threshold Voltage
VUVLO-VCC
UVLO Hysteresis
VHYST-UVLO
Dropout Voltage
Output Current Limit
Internal Clamp Voltage
7.15
VIN = 8V to 40V
VCC rising
1
3.15
3.75
500
VIN = 4.5V, IVCC = 20mA (sourcing)
IVCC-ILIM
3.5
0.25
IVCC sourcing
VVCC-CLAMP IVCC = 30mA (sinking)
V
mV/V
V
mV
0.5
45
V
mA
10.0
10.4
10.8
V
4.75
4.95
5.05
V
INTERNAL 5V LDO (REG5)
Output (REG5) Voltage Set Point
VREG5
VCC = 7.5V, IREG5 = 0 to 15mA (sourcing)
Line Regulation
VCC = 5.5V to 10V
Dropout Voltage
VCC = 4.5V, IREG5 = 15mA (sourcing)
Output Current Limit
www.maximintegrated.com
IREG5-ILIM
IREG5 sourcing
2
0.25
32
mV/V
0.5
V
mA
Maxim Integrated | 2
4.5V to 40V Input Automotive
Flyback/Boost/SEPIC
Power-Supply Controllers
MAX15004A/B-MAX15005A/B
Electrical Characteristics (continued)
(VIN = 14V, CIN = 0.1μF, CVCC = 0.1μF // 1μF, CREG5 = 1μF, VON/OFF = 5V, CSS = 0.01μF, CSLOPE = 100pF, RT = 13.7kΩ, CT =
560pF, VSYNC = VOVI = VFB = VCS = 0V, COMP = unconnected, OUT = unconnected. TA = TJ = -40°C to +125°C, unless otherwise
noted. Typical values are at TA = +25°C. All voltages are referenced to PGND, unless otherwise noted.) (Note 1) (Figure 5)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
1000
kHz
OSCILLATOR (RTCT)
Oscillator Frequency Range
fOSC
fOSC = 2 x fOUT for MAX15004A/B,
fOSC = fOUT for MAX15005A/B
15
RTCT Peak Trip Level
VTH,RTCT
0.55 x VREG5
V
RTCT Valley Trip Level
VTL,RTCT
0.1 x VREG5
V
RTCT Discharge Current
IDIS,RTCT
Oscillator Frequency Accuracy
(Note 2)
VRTCT = 2V
1.30
1.33
-4
+4
RT = 13.7kΩ, CT = 560pF,
fOSC (typ) = 150kHz
-4
+4
RT = 21kΩ, CT = 100pF,
fOSC (typ) = 500kHz
-5
+5
RT = 7kΩ, CT = 100pF,
fOSC (typ) = 1MHz
-7
+7
Minimum On-Time
DMAX
tON-MIN
SYNC Lock-In Frequency Range
(Note 4)
VIH-SYNC
SYNC Low-Level Voltage
VIL-SYNC
ISYNC
50
78.5
VIN = 14V
RT = 13.7kΩ, CT = 560pF,
fOSC (typ) = 150kHz
SYNC High-Level Voltage
SYNC Input Current
MAX15005A/B,
RT = 13.7kΩ, CT = 560pF,
fOSC (typ) = 150kHz
81.5
110
170
ns
200
%fOSC
102
V
-0.5
SYNC Minimum Input Pulse Width
%
80
2
VSYNC = 0 to 5V
mA
%
MAX15004A/B
Maximum PWM Duty Cycle
(Note 3)
1.36
RT = 13.7kΩ, CT = 4.7nF,
fOSC (typ) = 18kHz
0.8
V
+0.5
μA
50
ns
ERROR AMPLIFIER/SOFT-START
Soft-Start Charging Current
ISS
SS Reference Voltage
VSS
VSS = 0V
8
15
21
μA
1.215
1.228
1.240
V
SS Threshold for HICCUP Enable
VSS rising
FB Regulation Voltage
VREF-FB
COMP = FB,
ICOMP = -500μA to +500μA
1.215
FB Input Offset Voltage
VOS-FB
COMP = 0.25V to 4.5V,
ICOMP = -500μA to +500μA,
VSS = 0 to 1.5V
-5
FB Input Current
COMP Sink Current
www.maximintegrated.com
VFB = 0 to 1.5V
ICOMP-SINK
VFB = 1.5V, VCOMP = 0.25V
1.1
1.228
-300
3
V
1.240
V
+5
mV
+300
5.5
nA
mA
Maxim Integrated | 3
4.5V to 40V Input Automotive
Flyback/Boost/SEPIC
Power-Supply Controllers
MAX15004A/B-MAX15005A/B
Electrical Characteristics (continued)
(VIN = 14V, CIN = 0.1μF, CVCC = 0.1μF // 1μF, CREG5 = 1μF, VON/OFF = 5V, CSS = 0.01μF, CSLOPE = 100pF, RT = 13.7kΩ, CT =
560pF, VSYNC = VOVI = VFB = VCS = 0V, COMP = unconnected, OUT = unconnected. TA = TJ = -40°C to +125°C, unless otherwise
noted. Typical values are at TA = +25°C. All voltages are referenced to PGND, unless otherwise noted.) (Note 1) (Figure 5)
PARAMETER
COMP Source Current
SYMBOL
ICOMPSOURCE
CONDITIONS
VFB = 1V, VCOMP = 4.5V
COMP High Voltage
VOH-COMP
VFB = 1V, ICOMP = 1mA (sourcing)
COMP Low Voltage
VOL-COMP
VFB = 1.5V, ICOMP = 1mA (sinking)
Open-Loop Gain
MIN
TYP
1.3
2.8
mA
VREG5
- 0.5
VREG5
- 0.2
V
0.1
MAX
0.25
UNITS
V
AEAMP
100
UGFEAMP
1.6
MHz
PMEAMP
75
degrees
COMP Positive Slew Rate
SR+
0.5
V/μs
COMP Negative Slew Rate
SR-
-0.5
V/μs
Unity-Gain Bandwidth
Phase Margin
dB
PWM COMPARATOR
Current-Sense Gain
ACS-PWM
ΔVCOMP/ΔVCS (Note 5)
PWM Propagation Delay to OUT
tPD-PWM
CS = 0.15V, from VCOMP falling edge:
3V to 0.5V to OUT falling (excluding
leading-edge blanking time)
PWM Comparator Current-Sense
Leading-Edge Blanking Time
tCS-BLANK
2.85
3
3.15
V/V
60
ns
50
ns
CURRENT-LIMIT COMPARATOR
Current-Limit Threshold Voltage
VILIM
Current-Limit Input Bias Current
IB-CS
ILIMIT Propagation Delay to OUT
tPD-ILIM
ILIM Comparator Current-Sense
Leading-Edge Blanking Time
tCS-BLANK
290
OUT= high, 0 ≤ VCS ≤ 0.3V
305
-2
From CS rising above VILIM (50mV
overdrive) to OUT falling (excluding
leading-edge blanking time)
Number of Consecutive ILIMIT
Events to HICCUP
317
mV
+2
μA
60
ns
50
ns
7
HICCUP Timeout
Clock
periods
512
SLOPE COMPENSATION (Note 6)
Slope Capacitor Charging
Current
ISLOPE
VSLOPE = 100mV
Slope Compensation
CSLOPE = 100pF
Slope Compensation Tolerance
(Note 2)
CSLOPE = 100pF
Slope Compensation Range
www.maximintegrated.com
9.8
10.5
11.2
25
-4
mV/μs
+4
CSLOPE = 22pF
110
CSLOPE = 1000pF
2.5
μA
%
mV/μs
Maxim Integrated | 4
4.5V to 40V Input Automotive
Flyback/Boost/SEPIC
Power-Supply Controllers
MAX15004A/B-MAX15005A/B
Electrical Characteristics (continued)
(VIN = 14V, CIN = 0.1μF, CVCC = 0.1μF // 1μF, CREG5 = 1μF, VON/OFF = 5V, CSS = 0.01μF, CSLOPE = 100pF, RT = 13.7kΩ, CT =
560pF, VSYNC = VOVI = VFB = VCS = 0V, COMP = unconnected, OUT = unconnected. TA = TJ = -40°C to +125°C, unless otherwise
noted. Typical values are at TA = +25°C. All voltages are referenced to PGND, unless otherwise noted.) (Note 1) (Figure 5)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
OUTPUT DRIVER
ROUT-N
VCC = 8V (applied externally),
IOUT = 100mA (sinking)
1.7
3.5
ROUT-P
VCC = 8V (applied externally),
IOUT = 100mA (sourcing)
3
5
Driver Output Impedance
Driver Peak Output Current
IOUT-PEAK
Ω
COUT = 10nF, sinking
1000
COUT = 10nF, sourcing
750
mA
OVERVOLTAGE COMPARATOR
Overvoltage Comparator Input
Threshold
Overvoltage Comparator
Hysteresis
Overvoltage Comparator Delay
OVI Input Current
VOV-TH
VOVI rising
1.20
VOV-HYST
TDOVI
IOVI
From OVI rising above 1.228V to OUT
falling, with 50mV overdrive
VOVI = 0 to 5V
1.228
1.26
V
125
mV
1.6
μs
-0.5
+0.5
μA
THERMAL SHUTDOWN
Shutdown Temperature
TSHDN
Thermal Hysteresis
THYST
Temperature rising
160
o
C
15
o
C
Note 1: 100% production tested at +125°C. Limits over the temperature range are guaranteed by design.
Note 2: Guaranteed by design; not production tested.
Note 3: For the MAX15005A/B, DMAX depends upon the value of RT. See Figure 3 and the Oscillator Frequency/External
Synchronization section.
Note 4: The external SYNC pulse triggers the discharge of the oscillator ramp. See Figure 2. During external SYNC, DMAX = 50% for
the MAX15004A/B; for the MAX15005A/B, there is a shift in DMAX with fSYNC/fOSC ratio (see the Oscillator Frequency/
External Synchronization section).
Note 5: The parameter is measured at the trip point of latch, with 0 ≤ VCS ≤ 0.3V, and FB = COMP.
Note 6: Slope compensation = (2.5 x 10-9)/CSLOPE mV/μs. See the Applications Information section.
www.maximintegrated.com
Maxim Integrated | 5
4.5V to 40V Input Automotive
Flyback/Boost/SEPIC
Power-Supply Controllers
MAX15004A/B-MAX15005A/B
Typical Operating Characteristics
VIN = 14V, CIN = 0.1μF, CVCC = 0.1μF // 1μF, CREG5 = 1μF, VON/OFF = 5V, CSS = 0.01μF, CSLOPE = 100pF, RT = 13.7kΩ,
CT = 560pF. TA = +25°C, unless otherwise noted.)
VIN SUPPLY CURRENT (ISUPPLY)
vs. OSCILLATOR FREQUENCY (fOSC)
22
19
16
13
10
4
1
110
135
6.0
5.5
5.0
10
15 20 25 30 35
VIN SUPPLY VOLTAGE (V)
40
10.50
10.25
10.00
9.75
9.50
9.25
9.00
8.75
8.50
8.25
8.00
7.75
7.50
7.25
7.00
VCC CLAMP VOLTAGE (V)
IVCC = 20mA
6.5
5
45
0.25
0.23
0.20
0.18
0.15
0.13
0.10
0.08
0.05
0.03
0
TA = +125°C
TA = +135°C
TA = +25°C
TA = +25°C
TA = -40°C
TA = +135°C
TA = +125°C
149
2
4
6
8
10
IREG5 (mA)
www.maximintegrated.com
12
14
MAX15004 toc03
40
45
IREG5 = 1mA (SOURCING)
4.950
4.925
4.900
4.875
4.850
4.825
4.800
4.775
IREG5 = 15mA (SOURCING)
OSCILLATOR FREQUENCY (fOSC)
vs. VIN SUPPLY VOLTAGE
OSCILLATOR FREQUENCY (fOSC)
vs. RT/CT
RT = 13.7kΩ
CT = 560pF
MAX15005
TA = +25°C
TA = -40°C
145
144
143
TA = +125°C
TA = +135°C
1000
CT = 100pF
CT = 220pF
CT = 560pF
CT = 1000pF
100
CT = 1500pF
CT = 2200pF
CT = 3300pF
140
0
5.000
4.975
141
TA = -40°C
20 25 30 35
SUPPLY VOLTAGE (V)
5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0 10.5
VCC VOLTAGE (V)
147
142
15
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30
VCC CURRENT SINK (mA)
148
146
10
4.750
4.725
4.700
150
OSCILLATOR FREQUENCY (kHz)
VCC = 4.5
VIN = VON/OFF
MAX15004 toc07
REG5 DROPOUT VOLTAGE
vs. IREG5
0.30
0.28
TA = -40°C
REG5 OUTPUT VOLTAGE
vs. VCC VOLTAGE
REG5 OUTPUT VOLTAGE (V)
MAX15004 toc04
7.5
7.0
TA = +25°C
VCC CLAMP VOLTAGE
vs. VCC CURRENT SINK (IVCC)
VCC OUTPUT VOLTAGE
vs. VIN SUPPLY VOLTAGE
IVCC = 0mA
IVCC = 1mA
TA = +135°C
5
10 60 110 160 210 260 310 360 410 460 510
FREQUENCY (kHz)
OSCILLATOR FREQUENCY (kHz)
10
35
60
85
TEMPERATURE (°C)
MAX15004 toc05
-15
MAX15004 toc08
-40
VCC OUTPUT VOLTAGE (V)
COUT = 0nF
7
20
10
0
REG5 LDO DROPOUT VOLTAGE (V)
COUT = 10nF
MAX15004 toc06
25
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
MAX15004 toc09
VIN SUPPLY CURRENT (mA)
28
MAX15005
VIN = 14V
CT = 220pF
VIN SHUTDOWN SUPPLY CURRENT (μA)
31
SHUTDOWN SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX15004 toc02
120
110
100
90
80
70
60
50
40
30
MAX15004 toc01
VIN UVLO HYSTERESIS (mV)
VIN UVLO HYSTERESIS
vs. TEMPERATURE
10
5.5 10.5 15.5 20.5 25.5 30.5 35.5 40.5 45.5
VIN SUPPLY VOLTAGE (V)
1
10
100
1000
RT (kΩ)
Maxim Integrated | 6
4.5V to 40V Input Automotive
Flyback/Boost/SEPIC
Power-Supply Controllers
MAX15004A/B-MAX15005A/B
Typical Operating Characteristics (continued)
(VIN = 14V, CIN = 0.1μF, CVCC = 0.1μF // 1μF, CREG5 = 1μF, VON/OFF = 5V, CSS = 0.01μF, CSLOPE = 100pF, RT = 13.7kΩ,
CT = 560pF. TA = +25°C, unless otherwise noted.)
85
80
CT = 2200pF
65
CT = 1500pF
60
CT = 1000pF
55
CT = 560pF
52
51
50
49
48
47
46
CT = 220pF
50
100
OUTPUT FREQUENCY (kHz)
1000
GAIN (dB)
65
55
-15
10
35
60
85
TEMPERATURE (°C)
110
75
73
71
69
135
-40
CRTCT = 220pF
RRTCT = 10kΩ
fOSC = fOUT = 418kHz
GAIN
1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0
fSYNC/fOSC RATIO
OVI TO OUT DELAY THROUGH
OVERVOLTAGE COMPARATOR
110
135
MAX15004 toc15
90
300
260
220
180
PHASE
VCS OVERDRIVE = 50mV
80
140
70
60
VCS OVERDRIVE = 190mV
50
40
30
20
10
0
-10
50
10
35
60
85
TEMPERATURE (°C)
100
340
90
80
70
60
50
40
30
20
-15
CS-TO-OUT DELAY vs. TEMPERATURE
MAX15004 toc14
110
100
MAX15004 toc13
MAXIMUM DUTY CYCLE (%)
CT = 560pF
RT = 10kΩ
fOSC = fOUT = 180kHz
70
60
77
ERROR AMPLIFIER OPEN-LOOP GAIN
AND PHASE vs. FREQUENCY
MAX15005
75
79
65
-40
MAXIMUM DUTY CYCLE
vs. fSYNC/fOSC RATIO
80
81
67
45
10
MAX15004 toc12
53
CT = 560pF
RT = 13.7kΩ
fOSC = fOUT = 150kHz
83
PHASE (DEGREES)
70
CT = 3300pF
85
CS-TO-OUT DELAY (ns)
75
fOUT = 75kHz
54
MAXIMUM DUTY CYCLE (%)
90
55
MAX15004 toc11
MAXIMUM DUTY CYCLE (%)
MAX15004 toc10
CT = 100pF
95
MAXIMUM DUTY CYCLE (%)
100
MAX15005 MAXIMUM DUTY CYCLE
vs. TEMPERATURE
MAX15004 MAXIMUM DUTY CYCLE
vs. TEMPERATURE
MAX15005 MAXIMUM DUTY CYCLE
vs. OUTPUT FREQUENCY (fOUT)
100
60
0.1
1
10
100 1k 10k 100k 1M 10M
FREQUENCY (Hz)
DRIVER OUTPUT PEAK SOURCE
AND SINK CURRENT
0
-40
-15
10
35
60
85
TEMPERATURE (°C)
110
135
POWER-UP SEQUENCE THROUGH VIN
MAX15004 toc17
MAX15004 toc16
10
MAX15004 toc18
COUT = 10nF
VOUT
5V/div
VOUT
VOVI
VIN
10V/div
VCC
5V/div
VON/OFF = 5V
VOUT
2V/div
REG5
5V/div
IOUT
1A/div
VOVI
500mV/div
VOUT
5V/div
1μs/div
www.maximintegrated.com
400ns/div
2ms/div
Maxim Integrated | 7
4.5V to 40V Input Automotive
Flyback/Boost/SEPIC
Power-Supply Controllers
MAX15004A/B-MAX15005A/B
Typical Operating Characteristics (continued)
(VIN = 14V, CIN = 0.1μF, CVCC = 0.1μF // 1μF, CREG5 = 1μF, VON/OFF = 5V, CSS = 0.01μF, CSLOPE = 100pF, RT = 13.7kΩ,
CT = 560pF. TA = +25°C, unless otherwise noted.)
POWER-DOWN SEQUENCE
THROUGH ON/OFF
POWER-UP SEQUENCE
THROUGH ON/OFF
POWER-DOWN SEQUENCE THROUGH VIN
MAX15004 toc21
MAX15004 toc20
MAX15004 toc19
VON/OFF = 5V
ON/OFF
5V/div
VIN
10V/div
ON/OFF
5V/div
VCC
5V/div
VCC
5V/div
VCC
5V/div
REG5
5V/div
REG5
5V/div
REG5
5V/div
VOUT
5V/div
VOUT
5V/div
VOUT
5V/div
400ms/div
1ms/div
4ms/div
LINE TRANSIENT FOR VIN STEP
FROM 14V TO 40V
LINE TRANSIENT FOR VIN STEP
FROM 14V TO 5.5V
MAX15004 toc23
MAX15004 toc22
VIN
10V/div
VCC
5V/div
VIN
20V/div
VCC
5V/div
REG5
5V/div
REG5
5V/div
VOUT
5V/div
VOUT
5V/div
100μs/div
100μs/div
HICCUP MODE FOR FLYBACK CIRCUIT
(FIGURE 7)
DRAIN WAVEFORM IN
FLYBACK CONVERTER (FIGURE 7)
MAX15004 toc25
MAX15004 toc24
ILOAD = 10mA
VCS
200mV/div
10V/div
VANODE
1V/div
ISHORT
500mA/div
10ms/div
www.maximintegrated.com
4μs/div
Maxim Integrated | 8
4.5V to 40V Input Automotive
Flyback/Boost/SEPIC
Power-Supply Controllers
MAX15004A/B-MAX15005A/B
Pin Description
PIN
NAME
FUNCTION
1
IN
2
ON/OFF
3
OVI
4
SLOPE
5
N.C.
No Connection. Not internally connected.
6
RTCT
Oscillator-Timing Network Input. Connect a resistor from RTCT to REG5 and a capacitor from RTCT to SGND to
set the oscillator frequency (see the Oscillator Frequency/External Synchronization section).
7
SGND
Signal Ground. Connect SGND to SGND plane.
8
SYNC
External-Clock Synchronization Input. Connect SYNC to SGND when not using an external clock.
Input Power Supply. Bypass IN with a minimum 0.1μF ceramic capacitor to PGND.
ON/OFF Input. Connect ON/OFF to IN for always-on operation. To externally program the UVLO threshold of the
IN supply, connect a resistive divider between IN, ON/OFF, and SGND. Pull ON/OFF to SGND to disable the
controller.
Overvoltage Comparator Input. Connect a resistive divider between the output of the power supply, OVI, and
SGND to set the output overvoltage threshold.
Programmable Slope Compensation Capacitor Input. Connect a capacitor (CSLOPE) to SGND to set the amount
of slope compensation.
Slope compensation = (2.5 x 10-9) / CSLOPE mV/μs with CSLOPE in farads.
9
SS
Soft-Start Capacitor Input. Connect a capacitor from SS to SGND to set the soft-start time interval.
10
FB
Internal Error-Amplifier Inverting Input. The noninverting input is internally connected to SS.
11
COMP
12
CS
13
REG5
14
PGND
15
OUT
Gate Driver Output. Connect OUT to the gate of the external n-channel MOSFET.
16
VCC
7.4V Low-Dropout Regulator Output—Driver Power Source. Bypass VCC with 0.1μF and 1μF or higher ceramic
capacitors to PGND.
—
EP
Error-Amplifier Output. Connect the frequency compensation network between FB and COMP.
Current-Sense Input. The current-sense signal is compared to a signal proportional to the error-amplifier output
voltage.
5V Low-Dropout Regulator Output. Bypass REG5 with a 1μF ceramic capacitor to SGND.
Power Ground. Connect PGND to the power ground plane.
Exposed Pad (MAX15004A/MAX15005A only). Connect EP to the SGND plane to improve thermal performance.
Do not use the EP as an electrical connection.
www.maximintegrated.com
Maxim Integrated | 9
4.5V to 40V Input Automotive
Flyback/Boost/SEPIC
Power-Supply Controllers
MAX15004A/B-MAX15005A/B
Functional Diagram
IN 1
MAX15004A/B
MAX15005A/B
PREREGULATOR
1.228V
OFF
OFF
16 VCC
7.4V LDO
REG
10.5V
30mA
CLAMP
ON/OFF 2
ON/OFF
COMP
3.5V
UVLO
REFERENCE
UVB
DRIVER
15 OUT
14 PGND
VCC
THERMAL
SHUTDOWN
SET
RESET
OV-COMP
OVI 3
UVB
ILIMIT
COMP
5V LDO
REG
13 REG5
50ns
LEAD
DELAY
12 CS
0.3V
1.228V
PWMCOMP
R
OVRLD
SLOPE 4
SLOPE
COMPENSATION
2R
RTCT 6
OSCILLATOR
11 COMP
SS_OK
CLK
10 FB
SGND 7
RESET
SYNC 8
7
CONSECUTIVE
EVENTS
COUNTER
EAMP
1.228V
9 SS
REF-AMP
OVRLD
www.maximintegrated.com
Maxim Integrated | 10
MAX15004A/B-MAX15005A/B
Detailed Description
The MAX15004A/B/MAX15005A/B are high-performance, current-mode PWM controllers for wide inputvoltage range isolated/nonisolated power supplies.
These controllers are for use as general-purpose boost,
flyback, and SEPIC controllers. The input voltage range
of 4.5V to 40V makes it ideal in automotive applications
such as vacuum fluorescent display (VFD) power supplies. The internal low-dropout regulator (VCC regulator) enables the MAX15004A/B/MAX15005A/B to
operate directly from an automotive battery input. The
input operating range can be as low as 2.5V when an
external source (e.g. bootstrap winding output) is
applied at the VCC input. The 2.5V to 40V input voltage
range allows device operation from cold crank to automotive load dump.
The undervoltage lockout (ON/OFF) allows the devices
to program the input-supply startup voltage and ensures
predictable operation during brownout conditions.
The devices contain two internal regulators, VCC and
REG5. The VCC regulator output voltage is set at 7.4V
and REG5 regulator output voltage at 5V ±2%. The
VCC output includes a 10.4V clamp that is capable of
sinking up to 30mA current. The input undervoltage
lockout (UVLO) circuit monitors the VCC voltage and
turns off the converter when the VCC voltage drops
below 3.5V (typ). See the Internal Regulators VCC and
REG5 section for a method to obtain lower than 4.5V
input operation with the MAX15004/MAX15005.
An external resistor and capacitor network programs
the switching frequency from 15kHz to 500kHz. The
MAX15004A/B/MAX15005A/B provide a SYNC input for
synchronization to an external clock. The OUT (FET-driver output) duty cycle for the MAX15004A/B is 50%.
The maximum duty cycle can be set on MAX15005A/B
by selecting the right combination of RT and CT. The
RTCT discharge current is trimmed to 2%, allowing
accurate setting of the duty cycle for the MAX15005.
An internal slope-compensation circuit stabilizes the
current loop when operating at higher duty cycles and
can be programmed externally.
The MAX15004/MAX15005 include an internal error
amplifier with 1% accurate reference to regulate the
output in nonisolated topologies using a resistive
divider. The internal reference connected to the noninverting input of the error amplifier can be increased in a
controlled manner to obtain soft-start. A capacitor connected at SS to ground programs soft-start to reduce
inrush current and prevent output overshoot.
The MAX15004/MAX15005 include protection features
like hiccup current limit, output overvoltage, and thermal
www.maximintegrated.com
4.5V to 40V Input Automotive
Flyback/Boost/SEPIC
Power-Supply Controllers
shutdown. The hiccup current-limit circuit reduces the
power delivered to the electronics powered by the
MAX15004/MAX15005 converter during severe fault conditions. The overvoltage circuit senses the output using
the path different from the feedback path to provide
meaningful overvoltage protection. During continuous
high input operation, the power dissipation into the
MAX15004/MAX15005 could exceed its limit. Internal
thermal shutdown protection safely turns off the converter
when the junction heats up to 160°C.
Current-Mode Control Loop
The advantages of current-mode control overvoltagemode control are twofold. First, there is the feed-forward characteristic brought on by the controller’s ability
to adjust for variations in the input voltage on a cycleby-cycle basis. Secondly, the stability requirements of
the current-mode controller are reduced to that of a single-pole system unlike the double pole in voltage-mode
control.
The MAX15004/MAX15005 offer peak current-mode
control operation to make the power supply easy to
design with. The inherent feed-forward characteristic is
useful especially in an automotive application where the
input voltage changes fast during cold-crank and load
dump conditions. While the current-mode architecture
offers many advantages, there are some shortcomings.
For higher duty-cycle and continuous conduction mode
operation where the transformer does not discharge
during the off duty cycle, subharmonic oscillations
appear. The MAX15004/MAX15005 offer programmable
slope compensation using a single capacitor. Another
issue is noise due to turn-on of the primary switch that
may cause the premature end of the on cycle. The current-limit and PWM comparator inputs have leadingedge blanking. All the shortcomings of the
current-mode control are addressed in the MAX15004/
MAX15005, making it ideal to design for automotive
power conversion applications.
Internal Regulators VCC and REG5
The internal LDO converts the automotive battery voltage input to a 7.4V output voltage (VCC). The VCC output is set at 7.4V and operates in a dropout mode at
input voltages below 7.5V. The internal LDO is capable
of delivering 20mA current, enough to provide power to
internal control circuitry and the gate drive. The regulated VCC keeps the driver output voltage well below the
absolute maximum gate voltage rating of the MOSFET
especially during the double battery and load dump
conditions. An auxiliary winding output can be fed to
the VCC output once the power supply is turned on.
The bootstrap winding is not necessary for proper
Maxim Integrated | 11
MAX15004A/B-MAX15005A/B
operation of the power supply; however, to reduce the
power dissipation of the internal LDO, it can be disabled by applying an external voltage higher than 7.4V
at VCC (LDO output). The LDO then stops drawing current from IN, thereby reducing the power dissipation in
the IC. The VCC voltage is clamped to 10.4V with 30mA
current sink in case there is a higher voltage at the bias
winding. This feature is useful in applications with continuous higher input voltage.
The second 5V LDO regulator from VCC to REG5 provides power to the internal control circuits. This LDO can
also be used to source 15mA of external load current.
Bypass VCC and REG5 with a parallel combination of
1μF and 0.1μF low-ESR ceramic capacitors. Additional
capacitors (up to 22μF) at VCC can be used although
they are not necessary for proper operation of the
MAX15004/MAX15005.
Startup Operation/UVLO/ON/OFF
The MAX15004A/B/MAX15005A/B feature two undervoltage lockouts (UVLO). The internal UVLO monitors
the VCC-regulator and turns on the converter once VCC
rises above 3.5V. The internal UVLO circuit has about
0.5V hysteresis to avoid chattering during turn-on. Once
the power is on and the bootstrapped voltage feeds
VCC, IN voltage can drop below 4V. This feature provides operation at a cold-crank voltage as low as 2.5V.
An external undervoltage lockout can be achieved by
controlling the voltage at the ON/OFF input. The
ON/OFF input threshold is set at 1.23V (rising) with
75mV hysteresis.
Before any operation can commence, the ON/OFF voltage must exceed the 1.23V threshold.
Calculate R1 in Figure 1 by using the following formula:
⎛ V
⎞
R1 = ⎜ ON − 1⎟ × R2
⎝ VUVLO
⎠
where VUVLO is the ON/OFF’s 1.23V rising threshold,
and VON is the desired input startup voltage. Choose
an R2 value in the 100kΩ range. The UVLO circuits
keep the PWM comparator, ILIM comparator, oscillator,
and output driver shut down to reduce current consumption (see the Functional Diagram). The ON/OFF
input can be used to disable the MAX15004/MAX15005
and reduce the standby current to less than 20μA.
Soft-Start
The MAX15004/MAX15005 are provided with an externally adjustable soft-start function, saving a number of
external components. The SS is a 1.228V reference
bypass connection for the MAX15004A/B/MAX15005A/B
www.maximintegrated.com
4.5V to 40V Input Automotive
Flyback/Boost/SEPIC
Power-Supply Controllers
VIN
MAX15004A/B
MAX15005A/B
R1
ON/OFF
1.23V
R2
Figure 1. Setting the MAX15004A/B/MAX15005A/B
Undervoltage Lockout Threshold
and also controls the soft-start period. At startup, after
VIN is applied and the UVLO thresholds are reached,
the device enters soft-start. During soft-start, 15μA is
sourced into the capacitor (CSS) connected from SS to
GND causing the reference voltage to ramp up slowly.
The HICCUP mode of operation is disabled during softstart. When VSS reaches 1.228V, the output as well as
the HICCUP mode become fully active. Set the soft-start
time (tSS) using following equation:
t SS =
1. 23(V) × C SS
15 × 10 − 6 ( A )
where tSS is in seconds and CSS is in farads.
The soft-start programmability is important to control the
input inrush current issue and also to avoid the
MAX15004/MAX15005 power supply from going into the
unintentional hiccup during the startup. The required
soft-start time depends on the topology used, currentlimit setting, output capacitance, and the load condition.
Oscillator Frequency/
External Synchronization
Use an external resistor and capacitor at RTCT to program the MAX15004A/B/MAX15005A/B internal oscillator
frequency from 15kHz to 1MHz. The MAX15004A/B output switching frequency is one-half the programmed
oscillator frequency with a 50% maximum duty-cycle
limit. The MAX15005A/B output switching frequency is
the same as the oscillator frequency. The RC network
connected to RTCT controls both the oscillator frequency
and the maximum duty cycle. The CT capacitor charges
and discharges from (0.1 x VREG5) to (0.55 x VREG5). It
charges through RT and discharges through an internal
trimmed controlled current sink. The maximum duty
cycle is inversely proportional to the discharge time
Maxim Integrated | 12
4.5V to 40V Input Automotive
Flyback/Boost/SEPIC
Power-Supply Controllers
MAX15004A/B-MAX15005A/B
(tDISCHARGE). See Figures 3a and 3b for a coarse selection of capacitor values for a given switching frequency
and maximum duty cycle and then use the following
equations to calculate the resistor value to fine-tune the
switching frequency and verify the worst-case maximum
duty cycle.
t CHARGE =
t DISCHARGE =
D MAX
fOSC
The MAX15004A/B is a 50% maximum duty-cycle part,
while the MAX15005A/B is 100% maximum duty-cycle
part.
fOUT =
1
f
2 OSC
for the MAX15004A/B and
t
RT = CHARGE
0. 7 × CT
2. 25(V) × RT × CT
fOUT = fOSC
(1. 33 × 10 − 3 (A) × RT) − 3. 375(V)
for the MAX15005A/B.
1
⎧
...................Us e This Equation If fOSC ≤ 500kHz
⎪t
⎪ CHARGE + t DISCHARGE
fOSC = ⎨
1
⎪
.......Use This Equation If fOSC > 500k Hz
⎪⎩ t CHARGE + t DISCHA R GE + 160ns
where fOSC is the oscillator frequency, RT is a resistor
connected from RTCT to REG5, and CT is a capacitor
connected from RTCT to SGND. Verify that the oscillator frequency value meets the target. Above calculations could be repeated to fine-tune the switching
frequency.
The MAX15004A/B/MAX15005A/B can be synchronized
using an external clock at the SYNC input. For proper
frequency synchronization, SYNC’s input frequency must
be at least 102% of the programmed internal oscillator
frequency. Connect SYNC to SGND when not using an
external clock. A rising clock edge on SYNC is interpreted as a synchronization input. If the SYNC signal is lost,
the internal oscillator takes control of the switching rate,
returning the switching frequency to that set by RC network connected to RTCT. This maintains output regulation even with intermittent SYNC signals.
MAX15004A/B (DMAX = 50%)
WITH SYNC
INPUT
WITHOUT
SYNC INPUT
RTCT
CLKINT
SYNC
OUT
D = 50%
D = 50%
MAX15005A/B (DMAX = 81%)
WITH SYNC
INPUT
WITHOUT
SYNC INPUT
RTCT
CLKINT
SYNC
OUT
D = 81.25%
D = 80%
Figure 2. Timing Diagram for Internal Oscillator vs. External SYNC and DMAX Behavior
www.maximintegrated.com
Maxim Integrated | 13
MAX15004A/B-MAX15005A/B
4.5V to 40V Input Automotive
Flyback/Boost/SEPIC
Power-Supply Controllers
OSCILLATOR FREQUENCY (fOSC)
vs. RT/CT
MAX15005 MAXIMUM DUTY CYCLE
vs. OUTPUT FREQUENCY (fOUT)
1000
100
OSCILLATOR FREQUENCY (kHz)
MAXIMUM DUTY CYCLE (%)
CT = 100pF
CT = 100pF
95
90
85
80
75
CT = 3300pF
70
CT = 2200pF
65
CT = 1500pF
60
CT = 1000pF
55
CT = 220pF
CT = 560pF
CT = 1000pF
100
CT = 1500pF
CT = 2200pF
CT = 560pF
CT = 3300pF
CT = 220pF
10
50
10
100
OUTPUT FREQUENCY (kHz)
1000
1
10
100
1000
RT (kΩ)
Figure 3a. MAX15005 Maximum Duty Cycle vs. Output
Frequency.
Figure 3b. Oscillator Frequency vs. RT/CT
n-Channel MOSFET Driver
Slope Compensation
OUT drives the gate of an external n-channel MOSFET.
The driver is powered by the internal regulator (VCC),
internally set to approximately 7.4V. If an external voltage
higher than 7.4V is applied at VCC (up to 10V), it appears
as the peak gate drive voltage. The regulated VCC voltage keeps the OUT voltage below the maximum gate
voltage rating of the external MOSFET. OUT can source
750mA and sink 1000mA peak current. The average current sourced by OUT depends on the switching frequency and total gate charge of the external MOSFET.
Error Amplifier
The MAX15004A/B/MAX15005A/B include an internal
error amplifier. The noninverting input of the error
amplifier is connected to the internal 1.228V reference
and feedback is provided at the inverting input. High
100dB open-loop gain and 1.6MHz unity-gain bandwidth allow good closed-loop bandwidth and transient
response. Moreover, the source and sink current capability of 2mA provides fast error correction during the
output load transient. For Figure 5, calculate the powersupply output voltage using the following equation:
⎛
R ⎞
VOUT = ⎜ 1 + A ⎟ VREF
RB ⎠
⎝
where VREF = 1.228V. The amplifier’s noninverting input
is internally connected to a soft-start circuit that gradually increases the reference voltage during startup. This
forces the output voltage to come up in an orderly and
well-defined manner under all load conditions.
www.maximintegrated.com
The MAX15004A/B/MAX15005A/B use an internal ramp
generator for slope compensation. The internal ramp
signal resets at the beginning of each cycle and slews
at the rate programmed by the external capacitor connected to SLOPE. The amount of slope compensation
needed depends on the downslope of the current
waveform. Adjust the MAX15004A/B/MAX15005A/B
slew rate up to 110mV/μs using the following equation:
Slope compensation (mV μ s) =
2. 5 × 10 − 9 (A)
C SLOPE
where CSLOPE is the external capacitor at SLOPE in
farads.
Current Limit
The current-sense resistor (RCS), connected between
the source of the MOSFET and ground, sets the current
limit. The CS input has a voltage trip level (V CS) of
305mV. The current-sense threshold has 5% accuracy.
Set the current-limit threshold 20% higher than the peak
switch current at the rated output power and minimum
input voltage. Use the following equation to calculate
the value of RS:
RS =
VCS
IPRI
where IPRI is the peak current that flows through the
MOSFET at full load and minimum VIN.
Maxim Integrated | 14
4.5V to 40V Input Automotive
Flyback/Boost/SEPIC
Power-Supply Controllers
MAX15004A/B-MAX15005A/B
When the voltage produced by this current (through the
current-sense resistor) exceeds the current-limit comparator threshold, the MOSFET driver (OUT) quickly terminates the on-cycle. In most cases, a short-time
constant RC filter is required to filter out the leadingedge spike on the sense waveform. The amplitude and
width of the leading edge depends on the gate capacitance, drain capacitance (including interwinding capacitance), and switching speed (MOSFET turn-on time).
Set the RC time constant just long enough to suppress
the leading edge. For a given design, measure the leading spike at the highest input and rated output load to
determine the value of the RC filter.
The low 305mV current-limit threshold reduces the
power dissipation in the current-sense resistor. The current-limit threshold can be further reduced by adding
an offset to the CS input from REG5 voltage. Do not
reduce the current-limit threshold below 150mV as it
may cause noise issues. See Figure 4. For a new value
of the current-limit threshold (VCS-LOW), calculate the
value of R1 using the following equation.
Applications Information
Boost Converter
The MAX15004A/B/MAX15005A/B can be configured
for step-up conversion. The boost converter output can
be fed back to VCC (see Figure 5) so that the controller
can function even during cold-crank input voltage
(≤ 2.5V). Use a Schottky diode (DVIN) in the VIN path to
avoid backfeeding the input source. A current-limiting
resistor (RVCC) is also needed from the boost converter
output to VCC depending upon the boost converter output voltage. The total current sink into VCC must be limited to 30mA. Use the equations in the following
sections to calculate R VCC , inductor (L MIN ), input
capacitor (C IN), and output capacitor (C OUT) when
using the converter in boost operation.
Inductor Selection in Boost Configuration
Using the following equation, calculate the minimum
inductor value so that the converter remains in continuous mode operation at minimum output current (IOMIN).
4. 75 × R CS
R1 =
0. 290 − VCS − Low
L MIN =
VIN 2 × D × η
2 × fOUT × VOUT × IOMIN
where:
VIN
D=
VOUT + VD − VIN
VOUT + VD − VDS
and
REG5
MAX15004A/B
MAX15005A/B
IOMIN = (0.1 × IO ) to (0.25 × IO )
N
R1
RCS
0.3V
CURRENT-LIMIT
COMPARATOR
CCS
RS
The higher value of IOMIN reduces the required inductance; however, it increases the peak and RMS currents
in the switching MOSFET and inductor. Use IOMIN from
10% to 25% of the full load current. The VD is the forward voltage drop of the external Schottky diode, D is
the duty cycle, and VDS is the voltage drop across the
external switch. Select the inductor with low DC resistance and with a saturation current (ISAT) rating higher
than the peak switch current limit of the converter.
Figure 4. Reducing Current-Sense Threshold
www.maximintegrated.com
Maxim Integrated | 15
4.5V to 40V Input Automotive
Flyback/Boost/SEPIC
Power-Supply Controllers
MAX15004A/B-MAX15005A/B
VIN
DVIN
CIN
CREG5
0.1μF
CVIN
1μF
1
13
REG5
RT
IN
L
RVCC
VOUT
18V
D3
DVCC
VCC
16
COUT
CVCC
4.7μF
6
RTCT
CT
MAX15004A/B
MAX15005A/B
OUT
CFF
CS
RF
CF
11
10
COMP
15
Q
RCS
12
RA
CCS
RS
FB
SLOPE
SS
PGND
9
4
CSLOPE
RB
CSS
Figure 5. Application Schematic
Input Capacitor Selection in Boost Configuration
The input current for the boost converter is continuous
and the RMS ripple current at the input capacitor is low.
Calculate the minimum input capacitor value and maximum ESR using the following equations:
C IN =
Δ IL × D
4 × fOUT × Δ VQ
ESR =
Δ VESR
Δ IL
capacitor discharge and ΔVESR is the contribution due
to ESR of the capacitor. Assume the input capacitor ripple contribution due to ESR (ΔVESR) and capacitor discharge (ΔVQ) is equal when using a combination of
ceramic and aluminum capacitors. During the converter turn-on, a large current is drawn from the input
source especially at high output to input differential.
The MAX15004/MAX15005 are provided with a programmable soft-start, however, a large storage capacitor at the input may be necessary to avoid chattering
due to finite hysteresis.
Output Capacitor Selection in Boost
Configuration
where:
Δ IL =
(VIN − VDS ) × D
L × fOUT
VDS is the total voltage drop across the external MOSFET plus the voltage drop across the inductor ESR. ΔIL
is peak-to-peak inductor ripple current as calculated
above. ΔVQ is the portion of input ripple due to the
www.maximintegrated.com
For the boost converter, the output capacitor supplies
the load current when the main switch is on. The
required output capacitance is high, especially at higher
duty cycles. Also, the output capacitor ESR needs to be
low enough to minimize the voltage drop due to the ESR
while supporting the load current. Use the following
equations to calculate the output capacitor, for a specified output ripple. All ripple values are peak-to-peak.
Maxim Integrated | 16
MAX15004A/B-MAX15005A/B
Δ VESR
ESR =
IO
I × D MAX
C OUT = O
Δ VQ × fOUT
IO is the load current, ΔVQ is the portion of the ripple due
to the capacitor discharge, and ΔVESR is the contribution
due to the ESR of the capacitor. DMAX is the maximum
duty cycle at the minimum input voltage. Use a combination of low-ESR ceramic and high-value, low-cost aluminum capacitors for lower output ripple and noise.
Calculating Power Loss in Boost Converter
The MAX15004A/MAX15005A devices are available in
a thermally enhanced package and can dissipate up to
1.7W at +70°C ambient temperature. The total power
dissipation in the package must be limited so that the
junction temperature does not exceed its absolute maximum rating of +150°C at maximum ambient temperature; however, Maxim recommends operating the
junction at about +125°C for better reliability.
The average supply current (IDRIVE-GATE) required by
the switch driver is:
IDRIVE − GATE = Q g × fOUT
where Qg is total gate charge at 7.4V, a number available from MOSFET datasheet.
The supply current in the MAX15004A/B/MAX15005A/B
is dependent on the switching frequency. See the
Typical Operating Characteristics to find the supply
current ISUPPLY of the MAX15004A/B/MAX15005A/B at
a given operating frequency. The total power dissipation (PT) in the device due to supply current (ISUPPLY)
and the current required to drive the switch (IDRIVEGATE) is calculated using following equation.
PT = VINMAX × (I SUPPLY + IDRIVE − GATE )
MOSFET Selection in Boost Converter
The MAX15004A/B/MAX15005A/B drive a wide variety of
n-channel power MOSFETs. Since VCC limits the OUT
output peak gate-drive voltage to no more than 11V, a
12V (max) gate voltage-rated MOSFET can be used without an additional clamp. Best performance, especially at
low-input voltages (5VIN), is achieved with low-threshold
n-channel MOSFETs that specify on-resistance with a
gate-source voltage (VGS) of 2.5V or less. When selecting
the MOSFET, key parameters can include:
1) Total gate charge (Qg).
www.maximintegrated.com
4.5V to 40V Input Automotive
Flyback/Boost/SEPIC
Power-Supply Controllers
2) Reverse-transfer capacitance or charge (CRSS).
3) On-resistance (RDS(ON)).
4) Maximum drain-to-source voltage (VDS(MAX)).
5) Maximum gate frequencies threshold voltage
(VTH(MAX)).
At high switching, dynamic characteristics (parameters 1
and 2 of the above list) that predict switching losses
have more impact on efficiency than RDS(ON), which predicts DC losses. Qg includes all capacitances associated with charging the gate. The VDS(MAX) of the selected
MOSFET must be greater than the maximum output voltage setting plus a diode drop. The 10V additional margin
is recommended for spikes at the MOSFET drain due to
the inductance in the rectifier diode and output capacitor
path. In addition, Qg helps predict the current needed to
drive the gate at the selected operating frequency when
the internal LDO is driving the MOSFET.
Slope Compensation in Boost Configuration
The MAX15004A/B/MAX15005A/B use an internal ramp
generator for slope compensation to stabilize the current
loop when operating at duty cycles above 50%. It is
advisable to add some slope compensation even at lower
than 50% duty cycle to improve the noise immunity. The
slope compensations should be optimized because too
much slope compensation can turn the converter into the
voltage-mode control. The amount of slope compensation
required depends on the downslope of the inductor current when the main switch is off. The inductor downslope
depends on the input to output voltage differential of the
boost converter, inductor value, and the switching frequency. Theoretically, the compensation slope should be
equal to 50% of the inductor downslope; however, a little
higher than 50% slope is advised.
Use the following equation to calculate the required
compensating slope (mc) for the boost converter:
mc =
(VOUT
−
VIN ) × R S × 10 − 3
( mV μs )
2L
The internal ramp signal resets at the beginning of
each cycle and slews at the rate programmed by the
external capacitor connected to SLOPE. Adjust the
MAX15004A/B/MAX15005A/B slew rate up to 110mV/μs
using the following equation:
C SLOPE =
2. 5 × 10 − 9
mc(mV μ s)
where CSLOPE is the external capacitor at SLOPE in
farads.
Maxim Integrated | 17
MAX15004A/B-MAX15005A/B
Selecting VCC Resistor (RVCC)
The VCC external supply series resistor should be sized
to provide enough average current from VOUT to drive
the external MOSFET (IDRIVE) and ISUPPLY. The VCC is
clamped internally to 10.4V and capable of sinking
30mA current. The VCC resistor must be high enough to
limit the VCC sink current below 30mA at the highest
output voltage. Maintain the VCC voltage to 8V while
feeding the power from VOUT to VCC. For a regulated
output voltage of VOUT, calculate the RVCC using the
following equation:
R VCC =
(VOUT − 8)
(I SUPPLY + IDRIVE )
See Figure 5 and the Power Dissipation section for the
values of ISUPPLY and IDRIVE.
Flyback Converter
The choice of the conversion topology is the first stage
in power-supply design. The topology selection criteria
include input voltage range, output voltage, peak currents in the primary and secondary circuits, efficiency,
form factor, and cost.
For an output power of less than 50W and a 1:2 input
voltage range with small form factor requirements, the
flyback topology is the best choice. It uses a minimum
of components, thereby reducing cost and form factor.
The flyback converter can be designed to operate
either in continuous or discontinuous mode of operation. In discontinuous mode of operation, the transformer core completes its energy transfer during the
off-cycle, while in continuous mode of operation, the
next cycle begins before the energy transfer is complete. The discontinuous mode of operation is chosen
for the present example for the following reasons:
• It maximizes the energy storage in the magnetic
component, thereby reducing size.
• Simplifies the dynamic stability compensation design
(no right-half plane zero).
• Higher unity-gain bandwidth.
A major disadvantage of discontinuous mode operation
is the higher peak-to-average current ratio in the primary
and secondary circuits. Higher peak-to-average current
means higher RMS current, and therefore, higher loss
and lower efficiency. For low-power converters, the
advantages of using discontinuous mode easily surpass
the possible disadvantages. Moreover, the drive capability of the MAX15004/MAX15005 is good enough to drive
a large switching MOSFET. With the presently available
MOSFETs, power output of up to 50W is easily achiev-
www.maximintegrated.com
4.5V to 40V Input Automotive
Flyback/Boost/SEPIC
Power-Supply Controllers
able with a discontinuous mode flyback topology using
the MAX15004/MAX15005 in automotive applications.
Transformer Design
Step-by-step transformer specification design for a discontinuous flyback example is explained below.
Follow the steps below for the discontinuous mode
transformer:
Step 1) Calculate the secondary winding inductance
for guaranteed core discharge within a minimum off-time.
Step 2) Calculate primary winding inductance for sufficient energy to support the maximum load.
Step 3) Calculate the secondary and bias winding
turns ratios.
Step 4) Calculate the RMS current in the primary and
estimate the secondary RMS current.
Step 5) Consider proper sequencing of windings and
transformer construction for low leakage.
Step 1) As discussed earlier, the core must be discharged during the off-cycle for discontinuous mode
operation. The secondary inductance determines the
time required to discharge the core. Use the following
equations to calculate the secondary inductance:
LS ≤
( VOUT + VD ) × (D OFFMIN ) 2
2 × IOUT × fOUT(MAX)
t OFF
D OFF =
t ON + t OFF
where:
DOFFMIN = minimum DOFF.
VD = secondary diode forward voltage drop.
IOUT = maximum output rated current.
Step 2) The rising current in the primary builds the
energy stored in the core during on-time, which is then
released to deliver the output power during the off-time.
Primary inductance is then calculated to store enough
energy during the on-time to support the maximum output power.
LP =
D=
VINMIN 2 × D MAX 2 × η
2 × POUT × fOUT(MAX)
t ON
t ON + t OFF
DMAX = Maximum D.
Maxim Integrated | 18
MAX15004A/B-MAX15005A/B
4.5V to 40V Input Automotive
Flyback/Boost/SEPIC
Power-Supply Controllers
Step 3) Calculate the secondary to primary turns ratio
(NSP) and the bias winding to primary turns ratio (NBP)
using the following equations:
spike. The MOSFET’s absolute maximum VDS rating
must be higher than the worst-case (maximum input
voltage and output load) drain voltage.
NS
=
NP
⎡N
⎤
VDSMAX = VINMAX + ⎢ P × (VOUT + VD ) ⎥ + VSPIKE
N
⎢⎣ S
⎥⎦
N SP =
LS
LP
and
N BP =
N BIAS
11. 7
=
NP
VOUT + 0 . 35
The forward bias drops of the secondary diode and the
bias rectifier diode are assumed to be 0.35V and 0.7V,
respectively. Refer to the diode manufacturer’s
datasheet to verify these numbers.
Step 4) The transformer manufacturer needs the RMS
current maximum values in the primary, secondary, and
bias windings to design the wire diameter for the different windings. Use only wires with a diameter smaller
than 28AWG to keep skin effect losses under control.
To achieve the required copper cross-section, multiple
wires must be used in parallel. Multifilar windings are
common in high-frequency converters. Maximum RMS
currents in the primary and secondary occur at 50%
duty cycle (minimum input voltage) and maximum output power. Use the following equations to calculate the
primary and secondary RMS currents:
POUT
D MAX
IPRMS =
×
0. 5 × D MAX × η × VINMIN
3
I SRMS =
IOUT
0. 5 × D OFFMAX
D OFFMAX
3
The bias current for most MAX15004/MAX15005 applications is about 20mA and the selection of wire depends
more on convenience than on current capacity.
Step 5) The winding technique and the windings
sequence is important to reduce the leakage inductance spike at switch turn-off. For example, interleave
the secondary between two primary halves. Keep the
bias winding close to the secondary, so that the bias
voltage tracks the output voltage.
MOSFET Selection
MOSFET selection criteria include the maximum drain
voltage, peak/RMS current in the primary and the maximum-allowable power dissipation of the package without exceeding the junction temperature limits. The
voltage seen by the MOSFET drain is the sum of the
input voltage, the reflected secondary voltage through
transformer turns ratio and the leakage inductance
www.maximintegrated.com
Lower maximum V DS requirement means a shorter
channel, lower RDS-ON, lower gate charge, and smaller
package. A lower NP/NS ratio allows a low VDSMAX
specification and keeps the leakage inductance spike
under control. A resistor/diode/capacitor snubber network can be also used to suppress the leakage inductance spike.
The DC losses in the MOSFET can be calculated using
the value for the primary RMS maximum current.
Switching losses in the MOSFET depend on the operating frequency, total gate charge, and the transition loss
during turn-off. There are no transition losses during
turn-on since the primary current starts from zero in the
discontinuous conduction mode. MOSFET derating
may be necessary to avoid damage during system
turn-on and any other fault conditions. Use the following
equation to estimate the power dissipation due to the
power MOSFET:
PMOS = (1 . 4 × R DSON × I 2 PRMS ) + (Q g × VIN × fOUTMAX ) +
× I × t OFF × fOUTMAX
V
)
( I NMAX PK
4
× VDS 2 × fOUTMAX
C
+ DS
2
where:
Qg = Total gate charge of the MOSFET (C) at 7.4V
VIN = Input voltage (V)
tOFF = Turn-off time (s)
CDS = Drain-to-source capacitance (F)
Output Filter Design
The output capacitance requirements for the flyback
converter depend on the peak-to-peak ripple acceptable at the load. The output capacitor supports the load
current during the switch on-time. During the off-cycle,
the transformer secondary discharges the core replenishing the lost charge and simultaneously supplies the
load current. The output ripple is the sum of the voltage
drop due to charge loss during the switch on-time and
the ESR of the output capacitor. The high switching frequency of the MAX15004/MAX15005 reduces the
capacitance requirement.
Maxim Integrated | 19
MAX15004A/B-MAX15005A/B
An additional small LC filter may be necessary to suppress the remaining low-energy high-frequency spikes.
The LC filter also helps attenuate the switching frequency ripple. Care must be taken to avoid any compensation problems due to the insertion of the additional LC
filter. Design the LC filter with a corner frequency at more
than a decade higher than the estimated closed-loop,
unity-gain bandwidth to minimize its effect on the phase
margin. Use 1μF to 10μF low-ESR ceramic capacitors
and calculate the inductance using following equation:
L≤
1
4 × 10 3 × fc 2 × C
where fC = estimated converter closed-loop unity-gain
frequency.
SEPIC Converter
The MAX15004A/B/MAX15005A/B can be configured
for SEPIC conversion when the output voltage must be
lower and higher than the input voltage when the input
voltage varies through the operating range. The dutycycle equation:
VO
D
=
VIN 1 − D
indicates that the output voltage is lower than the input
for a duty cycle lower than 0.5 while VOUT is higher
than the input at a duty cycle higher than 0.5. The
inherent advantage of the SEPIC topology over the
boost converter is a complete isolation of the output
from the source during a fault at the output. For the
MAX15004/MAX15005, the SEPIC converter output can
be fed back to VCC (Figure 6), so that the controller can
function even during cold-crank input voltage (≤ 2.5V).
Use a Schottky diode (DVIN) in the VIN path to avoid
backfeeding the input source. A current-limiting resistor
(RVCC) is also needed from the output to VCC depending upon the converter output voltage. The total VCC
current sink must be limited to 25mA. See the Selecting
VCC Resistor (RVCC) section to calculate the optimum
value of the VCC resistor.
The SEPIC converter design includes sizing of inductors, a MOSFET, series capacitance, and the rectifier
diode. The inductance is determined by the allowable
www.maximintegrated.com
4.5V to 40V Input Automotive
Flyback/Boost/SEPIC
Power-Supply Controllers
ripple current through all the components mentioned
above. Lower ripple current means lower peak and RMS
currents and lower losses. The higher inductance value
needed for a lower ripple current means a larger-sized
inductor, which is a more expensive solution. The inductors L1 and L2 can be independent, however, winding
them on the same core reduces the ripple currents.
Calculate the maximum duty cycle using the following
equation and choose the RT and CT values accordingly
for a given switching frequency (see the Oscillator
Frequency/External Synchronization section).
⎡
⎤
VOUT + VD
D MAX = ⎢
⎥
⎣ VIN−MIN + VOUT + VD − (VDS + VCS ) ⎦
where VD is the forward voltage of the Schottky diode,
V CS (0.305V) is the current-sense threshold of the
MAX15004/MAX15005, and VDS is the voltage drop
across the switching MOSFET during the on-time.
Inductor Selection in SEPIC Converter
Use the following equations to calculate the inductance
values. Assume both L1 and L2 are equal and that the
inductor ripple current (ΔIL) is equal to 20% of the input
current at nominal input voltage to calculate the inductance value.
⎡V
× D MAX
L = L 1 = L2 = ⎢ IN−MIN
2
×
f
OUT × Δ IL
⎣
⎡ 0 . 2 × IOUT −MAX × D MAX
Δ IL = ⎢
(1 − D MAX ) × η
⎣
⎤
⎥
⎦
⎤
⎥
⎦
where fOUT is the converter switching frequency and η
is the targeted system efficiency. Use the coupled
inductors MSD-series from Coilcraft or PF0553-series
from Pulse Engineering, Inc. Make sure the inductor
saturating current rating (ISAT) is 30% higher than the
peak inductor current calculated using the following
equation. Use the current-sense resistor calculated
based on the ILPK value from the equation below (see
the Current Limit section).
⎡I
⎤
× D MAX
ILPK = ⎢ OUT −MAX
+ IOUT −MAX + Δ IL ⎥
⎣ (1 − D MAX ) × η
⎦
Maxim Integrated | 20
4.5V to 40V Input Automotive
Flyback/Boost/SEPIC
Power-Supply Controllers
MAX15004A/B-MAX15005A/B
MOSFET, Diode, and Series Capacitor Selection
in a SEPIC Converter
For the SEPIC configuration, choose an n-channel
MOSFET with a VDS rating at least 20% higher than the
sum of the output and input voltages. When operating
at a high switching frequency, the gate charge and
switching losses become significant. Use low gatecharge MOSFETs. The RMS current of the MOSFET is:
IMOS −RMS (A) =
The series capacitor should be chosen for minimum ripple voltage (ΔVCP) across the capacitor. We recommend
using a maximum ripple ΔVCP to be 5% of the minimum
input voltage (VIN-MIN) when operating at the minimum
input voltage. The multilayer ceramic capacitor X5R and
X7R series are recommended due to their high ripple
current capability and low ESR. Use the following equation to calculate the series capacitor CP value.
⎡I
× D MAX ⎤
CP = ⎢ OUT −MAX
⎥
⎣ Δ VCP × fOUT
⎦
⎡ (ILPK ) 2 + (ILDC ) 2 + (ILPK × ILDC ) ⎤ × D MAX
⎣
⎦
3
where ILDC = (ILPK - ΔIL).
Use Schottky diodes for higher conversion efficiency.
The reverse voltage rating of the Schottky diode must
be higher than the sum of the maximum input voltage
(VIN-MAX) and the output voltage. Since the average
current flowing through the diode is equal to the output
current, choose the diode with forward current rating of
IOUT-MAX. The current sense (RS) can be calculated
using the current-limit threshold (0.305V) of
MAX15004/MAX15005 and ILPK. Use a diode with a forward current rating more than the maximum output current limit if the SEPIC converter needs to be output
short-circuit protected.
where ΔVCP is 0.05 x VIN-MIN.
For a further discussion of SEPIC converters, go to
http://pdfserv.maxim-ic.com/en/an/AN1051.pdf.
Power Dissipation
The MAX15004/MAX15005 maximum power dissipation
depends on the thermal resistance from the die to the
ambient environment and the ambient temperature. The
thermal resistance depends on the device package,
PCB copper area, other thermal mass, and airflow.
Calculate the temperature rise of the die using following
equation:
TJ = TC + (PT x θJC)
or
0. 305
R CS =
ILPK
Select R CS 20% below the value calculated above.
Calculate the output current limit using the following
equation:
⎡ D
IOUT −LIM = ⎢
× (ILPK
⎣ (1 − D)
−
⎤
Δ IL ) ⎥
⎦
where D is the duty cycle at the highest input voltage
(VIN-MAX).
www.maximintegrated.com
TJ = TA + (PT x θJA)
where θJC is the junction-to-case thermal impedance
(3°C/W) of the 16-pin TSSOP-EP package and PT is
power dissipated in the device. Solder the exposed
pad of the package to a large copper area to spread
heat through the board surface, minimizing the case-toambient thermal impedance. Measure the temperature
of the copper area near the device (TC) at worst-case
condition of power dissipation and use 3°C/W as θJC
thermal impedance. The case-to-ambient thermal
impedance (θJA) is dependent on how well the heat is
transferred from the PCB to the ambient. Use a large
copper area to keep the PCB temperature low. The θJA
is 38°C/W for TSSOP-16-EP and 90°C/W for TSSOP-16
package with the condition specified by the JEDEC51
standard for a multilayer board.
Maxim Integrated | 21
4.5V to 40V Input Automotive
Flyback/Boost/SEPIC
Power-Supply Controllers
MAX15004A/B-MAX15005A/B
VIN
2.5V TO 16V
L1
L11 = L22 = 7.5μH
C7
6.8μF
VOUT
(8V/2A)
D2
STP745G
D1
LL4148
VOUT
R5
10Ω
1
IN
VCC
C4
22μF
D3
BAT54C
C1
6.8μF
16
C2
6.8μF
C5
22μF
C6
22μF
C3
6.8μF
CVCC
1μF
C1
100nF
MAX15005A/B
2
ON
ON/OFF
OFF
OUT
3
REG5
REG5
5
RT
15kΩ
6
14
SLOPE
CSLOPE
47pF
REG5
STD20NF06L
OVI
PGND
4
RG
1Ω
15
13
C10
1μF
N.C.
RTCT
CS
RCS
100Ω
12
CCS
100pF
CT
150pF
7
SGND
COMP
SYNC
8
RS
0.025Ω
11
R3
1.8kΩ
SYNC
RSYNC
10kΩ
FB
SS
10
C3
47nF
VOUT
C4
680pF
R2
15kΩ
R1
2.7kΩ
9
CSS
150nF
EP
Figure 6. SEPIC Application Circuit
www.maximintegrated.com
Maxim Integrated | 22
MAX15004A/B-MAX15005A/B
Layout Recommendations
Typically, there are two sources of noise emission in a
switching power supply: high di/dt loops and high dv/dt
surfaces. For example, traces that carry the drain current often form high di/dt loops. Similarly, the heatsink
of the MOSFET connected to the device drain presents
a dv/dt source; therefore, minimize the surface area of
the heatsink as much as possible. Keep all PCB traces
carrying switching currents as short as possible to minimize current loops. Use a ground plane for best results.
Careful PCB layout is critical to achieve low switching
losses and clean, stable operation. Refer to the
MAX15005 EV kit data sheet for a specific layout example. Use a multilayer board whenever possible for better noise immunity. Follow these guidelines for good
PCB layout:
1) Use a large copper plane under the package and
solder it to the exposed pad. To effectively use this
copper area as a heat exchanger between the PCB
and ambient, expose this copper area on the top
and bottom side of the PCB.
2) Do not connect the connection from SGND (pin 7)
to the EP copper plane underneath the IC. Use midlayer-1 as an SGND plane when using a multilayer
board.
www.maximintegrated.com
4.5V to 40V Input Automotive
Flyback/Boost/SEPIC
Power-Supply Controllers
3) Isolate the power components and high-current
path from the sensitive analog circuitry.
4) Keep the high-current paths short, especially at the
ground terminals. This practice is essential for stable, jitter-free operation.
5) Connect SGND and PGND together close to the
device at the return terminal of VCC bypass capacitor. Do not connect them together anywhere else.
6) Keep the power traces and load connections short.
This practice is essential for high efficiency. Use
thick copper PCBs (2oz vs. 1oz) to enhance fullload efficiency.
7) Ensure that the feedback connection to FB is short
and direct.
8) Route high-speed switching nodes away from the
sensitive analog areas. Use an internal PCB layer
for SGND as an EMI shield to keep radiated noise
away from the device, feedback dividers, and analog bypass capacitors.
9) Connect SYNC pin to SGND when not used.
Maxim Integrated | 23
4.5V to 40V Input Automotive
Flyback/Boost/SEPIC
Power-Supply Controllers
MAX15004A/B-MAX15005A/B
Typical Operating Circuits
R7
510Ω
VIN
(5.5V TO 16V)
C1
330μF
50V
C11
2200pF
100V
R16
10Ω
R17
100kΩ
1%
C2
0.1μF
50V
VCC
VGRID
(60V/12mA)
C15
22μF
60V
16
C3
1μF
16V
R9
NU
C14
NU
R10
36kΩ
FILAMENT+
(3V/650mA)
ON/OFF
VIN
R11
182kΩ
1%
OUT
3
C4
100pF
15
C16
330μF
6.3V
R15
100Ω
R3
50Ω
N
FILAMENTC17
2.2μF
10V
OVI
PGND
4
14
D5
REG5
SLOPE
REG5
13
C10
1μF
R1
8.45kΩ
1%
5
6
7
CS
RTCT
12
C9
560pF
R6
0.06Ω
1%
SGND
COMP
8
R5
1kΩ
N.C.
C5
1200pF
R19
10kΩ
D2
D4
R12
12.1kΩ
1%
REG5
C13
10μF
200V
R8
100kΩ
D1
MAX15005A/B
2
R18
47.5kΩ
1%
IN
VANODE
(110V/55mA)
D2
R2
560Ω
C18
4700pF
100V
1
C12
220pF
11
R2
402kΩ
1%
SYNC
1
JU1
2
FB
SS
EP
10
C6
4700pF
9
C8
0.1μF
VANODE
C7
47pF
R13
118kΩ
1%
R14
1.3kΩ
1%
Figure 7. VFD Flyback Application Circuit
www.maximintegrated.com
Maxim Integrated | 24
4.5V to 40V Input Automotive
Flyback/Boost/SEPIC
Power-Supply Controllers
MAX15004A/B-MAX15005A/B
Typical Operating Circuits (continued)
VIN
(4.5V TO 16V)
C1
10μF
25V
L1
10μH/IHLP5050
VISHAY
1
C11
0.1μF
IN
VCC
16
C10
1μF/16V
CERAMIC
MAX15005A/B
D1
B340LB
R11
301kΩ
2
R10
100kΩ
R8
153kΩ
OUT
3
PGND
C2
100pF
REG5
R1
5Ω
15
Q
Si736DP
OVI
R9
10kΩ
4
C6
56μF/25V
SVP-SANYO
ON/OFF
VOUT
VOUT
(18V/2A)
14
REG5
SLOPE
REG5
13
C10
1μF
5
R2
13kΩ
6
CS
RTCT
12
C4
100pF
C3
180pF
7
R4
0.025Ω
SGND
COMP
SYNC
8
R3
1kΩ
N.C.
11
R5
100kΩ
SYNC
1
JU1
2
FB
SS
EP
10
C9
0.1μF
9
C7
0.1μF
VOUT
C8
330pF
R6
136kΩ
R7
10kΩ
Figure 8. Boost Application Circuit
www.maximintegrated.com
Maxim Integrated | 25
MAX15004A/B-MAX15005A/B
4.5V to 40V Input Automotive
Flyback/Boost/SEPIC
Power-Supply Controllers
Pin Configurations
TOP VIEW
+
+
IN 1
16 VCC
IN 1
16 VCC
ON/OFF 2
15 OUT
ON/OFF 2
15 OUT
OVI 3
SLOPE 4
N.C. 5
13 REG5
SLOPE 4
SGND 7
EP
PROCESS: BiCMOS
12 CS
RTCT 6
11 COMP
10 FB
SGND 7
10 FB
9 SS
SYNC 8
9 SS
TSSOP
Package Information
For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a
“+”, “#”, or “-” in the package code indicates RoHS status only.
Package drawings may show a different suffix character, but the
drawing pertains to the package regardless of RoHS status.
PACKAGE
TYPE
www.maximintegrated.com
13 REG5
11 COMP
TSSOP-EP
Chip Information
14 PGND
MAX15004B
MAX15005B
N.C. 5
12 CS
RTCT 6
SYNC 8
OVI 3
14 PGND
MAX15004A
MAX15005A
PACKAGE
CODE
OUTLINE
NO.
LAND
PATTERN NO.
16 TSSOP
U16+2
21-0066
90-0117
16 TSSOP-EP
U16E+3
21-0108
90-0120
Maxim Integrated | 26
4.5V to 40V Input Automotive
Flyback/Boost/SEPIC
Power-Supply Controllers
MAX15004A/B-MAX15005A/B
Revision History
PAGES
CHANGED
REVISION
NUMBER
REVISION
DATE
0
1/07
1
11/07
Updated Features, revised equations on pages 13, 20, and 21, revised Figure 8 with
correct MOSFET, and updated package outline
2
12/10
Added MAX15005BAUE/V+ automotive part, updated Features, updated Package
Information, style edits
1–5, 9, 13, 21,
25–29
3
1/11
Added MAX15004AAUE/V+, MAX15004BAUE/V+, MAX15005AAUE/V+ automotive
parts to the Ordering Information
1
4
1/15
Updated Benefits and Features section
1
DESCRIPTION
Initial release
—
1, 13, 20, 21,
25, 28
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent
licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and
max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
© 2011 Maxim Integrated Products, Inc. | 27
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertisement