NXP UM10930

UM10930
SSL5251DB1332 LED driver
Rev. 1 — 10 November 2015
User manual
Document information
Info
Content
Keywords
SSL5251DB1332, SSL5251T, SSL5261AT, Solid-State Lighting (SSL),
low Total Harmonic Distortion (THD), high Power Factor, dimmable, linear,
Pulse-Width Modulation (PWM), single-stage buck-boost
Abstract
This user manual describes the NXP Semiconductors SSL5251DB1332
35 W LED driver demo board. The board is non-isolated and intended for
fixtures.
UM10930
NXP Semiconductors
SSL5251DB1332 LED driver
Revision history
Rev
Date
Description
v.1
20151110
first issue
Contact information
For more information, please visit: http://www.nxp.com
For sales office addresses, please send an email to: [email protected]
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1. Introduction
WARNING
Lethal voltage and fire ignition hazard
The non-insulated high voltages that are present when operating this product, constitute a
risk of electric shock, personal injury, death and/or ignition of fire.
This product is intended for evaluation purposes only. It shall be operated in a designated test
area by personnel qualified according to local requirements and labor laws to work with
non-insulated mains voltages and high-voltage circuits. This product shall never be operated
unattended.
This user manual describes the dimmable LED driver solution for fixtures with the
SSL5251T LED driver controller.
The board is an example of a buck-boost topology with the controller ICs placed at the
high side. The IC ground pin (pin 2) is the switching node.
The typical features of the single-stage buck-boost topology are:
• Low Total Harmonic Distortion (THD)
• Small bus capacitor and large output capacitor
• Fixed on-time with small modulation for low mains current harmonics
The circuit GND is equipotential with the LED module anode (LEDP). The LED module
anode (LEDN) is negative to GND.
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Fig 1.
DDD
Principal converter circuit diagram without DIM interface
The board provides three dimming interfaces that provide a minimum dim level of 10 %. A
DIP switch sets the interface:
• 1 V to 10 V analog dimming
• PWM dimming
• Trimmer (adjustable resistor)
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2. Safety warning
The SSL5251DB1332 demo board input is connected to the 230 V mains. Avoid touching
the board while it is connected to the mains voltage or when it is in operation. Isolated
housing is obligatory when used in uncontrolled, non-laboratory environments. Galvanic
isolation from the mains phase using a fixed or variable transformer is always
recommended. Figure 2 shows the symbols on how to recognize these devices.
019aab174
019aab173
a. Isolated
Fig 2.
UM10930
User manual
b. Not isolated
Variable transformer (variac) isolation symbols
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3. Specifications
Table 1.
SSL5251DB1332 specifications
Symbol
Parameter
Condition
Min
Typ
Max
Unit
Io = Io(max)
90
-
-
%
-
-
400
ms
General parameters

Efficiency
td(on)
turn-on delay
Input parameters
Pi(max)
maximum input power
Vo = 135 V
-
-
38
W
Pi(noload)
no load input power
Vo = Vo(ovp)
-
-
750
mW
Pi(stb)
standby input power
PWM dimming;
 = 100 %;
R33 = not mounted
-
-
250
mW
Vmains
mains voltage (RMS)
180
230
264
V (AC)
PF
power factor
Vo(max)
0.95
-
-
THD
total harmonic distortion
Vo(max)
-
-
10
%
fmains
mains frequency
45
50
65
Hz
Output parameters
Vo(ovp)
output overvoltage protection level no load
-
-
145
V
Vo(max)
maximum output voltage
normal operation
-
135
-
V
Vo(min)
minimum output voltage
normal operation
-
50
-
V
Io(max)
maximum output current
normal operation;
no dimming
-
260
-
mA
Io(min)
minimum output current
normal operation
-
0.1  Io(max)
-
mA
Io(ripple)
output current ripple
0.5 x Io(pp)/Io(avg)
-
35
-
%
PWM dimming interface
PWM
fPWM
PWM duty cycle
R33 = 11 M
0
100
-
%
R33 = not mounted
0
42
-
%
0.3
1
-
kHz
PWM frequency
1 V to 10 V dimming interface
Vdim
dim input control voltage
0
-
10
V
Rdim
dim input control resistance
0
-
470
k
Surge was tested up to 3.5 kV differential mode. No fails were observed.
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4. Board photograph
Fig 3.
SSL5251DB1332 demo board photograph
5. LED driver design
5.1 Design input
To simplify calculations, the assumption is that the converter on-time is constant during a
half mains cycle. The calculation of the buck-boost inductor is based on the following LED
driver design target. On the NXP Semiconductors website, a calculation tool is provided to
calculate the circuit.
Table 2.
Design target of the large signal parts
Symbol
Parameter

efficiency
P
Power
Vmains
mains voltage (RMS)
fmains
mains frequency
Vo(max)
maximum output voltage
Io(max)
minimum output current
fsw
switching frequency at peak of
typical mains
UM10930
User manual
Condition
Min
Typ
Max
Unit
-
100
-
%
-
35
W
180
230
280
V (AC)
-
50
-
Hz
normal operation
-
135
-
V
normal operation;
no dimming
-
260
-
mA
peak of Vmains(typ);
no dimming
-
70
-
kHz
Vo = 135 V; no dimming -
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SSL5251DB1332 LED driver
/
'EULGJH
a
VZLWFK
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&L
&R
/EE
LQGXFWRUFKDUJH
FXUUHQW
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FXUUHQW
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Fig 4.
DDD
Buck-boost LED driver large signal path
For low THD, the OverCurrent Protection (OCP) must not be reached at the peak of the
typical line voltage. The buck-boost inductance can be calculated with Equation 1:
2
2
2  V AC  V LED   t dead  f sw – 1 
L bb = ---------------------------------------------------------------------------------2
  I LED  f sw   V LED + 2  V AC 
(1)
The peak current is calculated with Equation 2:
2    I LED  V AC +   2  I LED  V LED
I peak = ----------------------------------------------------------------------------------------------2  V AC – 2  t dead  V AC  f sw
(2)
Where:
•
•
•
•
•
•
•
UM10930
User manual
Lbb = 1.016 mH; primary inductance value
Ipeak = 1.243 A; inductor peak current
tdead = 1 s; assumption of dead time until first valley
fsw = 70 kHz
VAC = 230 V
VLED = 135 V
ILED = 260 mA
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5.2 On-time control
The on-time of the SSL5251T controller is set with the voltage on pin COMP (VCOMP).
DDD
RQWLPH
—V
RQWLPH
Fig 5.
9&2039
SSL5251T on-time as function of VCOMP
The loop gain response of the converter is set with the capacitor C11 on the COMP pin.
The value of capacitor C11 is high enough to keep the on-time constant over a half mains
period. This type of control gives a low THD of the mains current. To optimize the THD
even more, the on-time is modulated with resistor R43. The resistor injects a
compensation current into resistor R6 and capacitor C8. The values of resistor R6 and
capacitor C8 must be kept constant. If no compensation with resistor R43 is required, the
resistor can be removed and resistor R6 can be shorted.
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UM10930
User manual
QF
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Fig 6.
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6:
DDD
COMP pin application
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5.3 OverCurrent Protection (OCP)
OCP is active at low-line and/or high-power conditions. When the OCP limit is reached,
the converter operates with a fixed peak current. When the OCP limit is not reached, the
converter operates with the on-time set by VCOMP. OCP reduces the THD performance, so
it is not desired at nominal line voltages.
In the SSL5251T, the OCP function uses the ISNS pin. The ISNS pin also senses the LED
current. NXP Semiconductors also provides the SSL5261AT with a special pin to sense
the LED current for more design freedom.
Two resistance values, ROCP1 and ROCP2 set the OCP level of the primary stroke.
• ROCP1 = R4 // R58 = 100 m //  = 100 m
• ROCP2 = R1 + (R59 // R60 // R61) = 0  + 1.8 // 1.8 // 1.8 = 1.8 / 3 = 0.6 
Remark: “//” indicates resistors in parallel.
ROCP1 and ROCP2 set the peak current according to Equation 3:
V i  ISNS max
1.2
I SW  max  = ------------------------------------- = --------------------- = 1.714
R OCP1 + R OCP2
0.1 + 0.6
(3)
Figure 7 shows the waveform at 230 V (AC) and at low line 180 V (AC). Although the
clipping occurs at low line, the THD is < 9 % and the class C mains harmonics are easily
met.
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a. Typical line voltage
(1) C1 = V(L, N) line voltage
(2) C2 = V(B+, GND) B+ voltage
(3) C3 = line current
(4) C4 = MOSFET drain current
b. Low line voltage
Fig 7.
UM10930
User manual
Typical and low line waveforms at Vo(max) and Io(max)
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5.4 Maximum output power
The integrated source switch feeds the primary stroke current through the SSL5251T IC.
So, the current through limit of the IC limits the LED driver maximum power.
To ensure lifetime, the following design constrains apply to pin SW current II(SW):
• Maximum RMS switch current = 380 mA
• Maximum peak switch current = 2.0 A
When modifying the circuit, II(SW) must comply with the specification. The MOSFET drain
current can easily be measured. This drain current also enters the SW pin.
(1) C1 = V(L,N) line voltage
(2) C2 = V(LEDP, LEDN) LED voltage
(3) C3 = LED current
(4) C4 = MOSFET drain current
Fig 8.
ISW (RMS) check waveforms at Vmains = 200 V (AC), Vo(max), and Io(max)
To increase the converter current by partly bypassing the internal source switch transistor
with an external PNP transistor (see Section 11.3), an additional circuit can be applied.
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5.5 Start-up
When the AC voltage is applied to the input, the VCC capacitor is charged to the VCC
start voltage and the IC starts switching. The output capacitor is charged and the LED
module starts to conduct when the LED forward voltage is reached in less than 300 ms.
(1) C1 = V(L, N) line voltage
(2) C2 = V(LEDP, LEDN) negative LED voltage
(3) C3 = LED current
(4) C4 = V(VCC, GND) VCC referenced to LEDP
Fig 9.
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User manual
Start-up at Vmains(typ), Vo(max) and Io(max)
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5.6 Output OverVoltage Protection (OVP)
When no LED module is connected or when the LED string is broken, the output capacitor
is protected against overvoltage.
(1) C1 = V(L, N) line voltage
(2) C2 = V(LEDP, LEDN) negative LED voltage
(3) C3 = LED current
(4) C4 = V(VCC, GND) VCC referenced to LEDP
Fig 10. Start-up at Vmains(typ) without LED module
The band gapped referenced OVP level in the IC sets the overvoltage level at the output
capacitors C4 and C5. The IC stops switching after three sequential overvoltage
protection cycles and a restart is initiated.
The ICC(dch) supply discharge current and VCC capacitor set the restart cycle timing. As a
result of the low load on the output capacitors, the output remains at the overvoltage level.
Resistor R46 sets the OVP level set to 145 V (DC).
V o  ovp  – V th  ovp 
R46 = R17  -----------------------------------------V th  ovp 
(4)
Where:
• Vo(ovp) = 145 V
• Vth(ovp) = 1.81 V
• R17 = 5.6 k
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5.7 Output short
During output short, the converter runs on very short on-times of 2 s and long off-times of
500 s. The IC temperature does not increase significantly during output short conditions.
(1) C1 = V(L, N) line voltage
(2) C2 = V(LEDP, LEDN) negative LED voltage
(3) C3 = LED current
(4) C4 = V(VCC, GND) VCC referenced to LEDP
Fig 11. Output short during start-up
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6. Performance measurement results
6.1 Mains input measurements
The mains input measurements are performed with an electronic load type 63115A in
LEDH mode with Rd = 20 .
Table 3.
Electronic load settings
Output
Unit
Vo (V)
V
Io (mA)
mA
Table 4.
Po1 = 100 %
Po2 = 50 %
Po3 = 50 %
Po4 = 25 %
135.0
67.5
135.0
67.5
260
260
130
130
Results measured at 230 V (AC)/50 Hz
Parameter
Unit
Po1 = 100 %
Po2 = 50 %
Po3 = 50 %
Po4 = 25 %
Pi
W
38.2
19.1
19.8
9.7

%
93.4
92.4
91.5
89
0.97231
0.90386
0.93045
0.81109
8.8
15.2
15.6
27.7
PF
THDi
%
6.2 Mains current harmonics compliance
To indicate IEC 61000-3-2 class C compliance at 230 V (AC), the mains current
harmonics are measured for several power levels.
Remark: For Po4, the input power is far below the 25 W, as specified in the IEC 61000-3-2
for class C equipment.
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NXP Semiconductors
UM10930
User manual
Table 5.
Mains current harmonics in % of fundamental
Load
PF
1
2
3
5
7
9
11
13
15
17
19
21
23
25
27
29
31
33
35
37
39
Po1
.97
100
0.1
6.7
2.6
2
2.3
1.6
1.7
1.2
1.2
0.9
0.8
0.6
0.5
0.4
0.3
0.4
0.4
0.4
0.4
0.4
Po2
.90
100
0.1
10.8
7.3
5.3
3.6
2.2
1.5
1.5
1.7
1.5
1.3
1
0.9
1
1
0.9
0.8
0.7
0.7
0.7
Po3
.93
100
0.1
9.6
5.8
4.5
4
3.1
2.8
2.2
1.7
1.4
1.2
1.2
1.1
1.2
0.9
1.2
0.9
0.9
0.9
0.6
Po4
.81
100
0.2
21.2
12.6
6.7
4.8
5
4
3.1
3
2.7
2.4
2.2
2.1
2
1.8
1.7
1.7
1.5
1.4
1.4
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(2) Blue: Po1 = 100 %
(3) Orange: Po2 = 50 %
(4) Gray: Po3 = 50 %
Fig 12. Mains current harmonics in % of fundamental
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(1) Red: Limit
SSL5251DB1332 LED driver
DDD
UM10930
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SSL5251DB1332 LED driver
The results comply with the limits as described in IEC 61000-3-2 for class C equipment.
Table 6.
IEC 61000-3-2 class C limits of harmonic current as percentage of fundamental
Harmonic order n
Limit
2
2%
3
30 % * PF
5
10 %
7
7%
9
5%
11  n  (odd harmonic only)
3%
DDD
(IILFLHQF\
9R9
(1) Vmains = 180 V (AC)
(2) Vmains = 230 V (AC)
(3) Vmains = 270 V (AC)
Fig 13. Efficiency at Io(max) and 1 V to 10 V dimming interface
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DDD
7+'
9R9
(1) Vmains = 180 V (AC)
(2) Vmains = 230 V (AC)
(3) Vmains = 270 V (AC)
Fig 14. THD at Io(max) versus Vo
DDD
7+'
P
P
P
P
P
P
,R$
P
(1) Vo = 50 V
(2) Vo = 60 V
(3) Vo = 80 V
(4) Vo = 100 V
(5) Vo = 135 V
Fig 15. THD versus Io at 230 V (AC) for several dim levels
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7. Dimming
The SSL5251T in buck-boost low-THD configuration has a dimming range from
10 % to 100 % output current. Below 10 % output current, dimming flicker can be visible.
7.1 DIM input interface
The dimming interface inputs on the board connect to the anode of the bridge rectifier.
The SSL5251T connects to the switch node of the buck-boost converter. The dimming
interface on the board translates the DIM signal at the PCB input to the DIM pin voltage
which is referenced to the switching node. The DIM pin input voltage determines the
average output current of the buck-boost stage.
A circuit is used to transform the dim input signal to an average signal on node DIMRC.
The absolute voltage of DIMRC is relatively large compared to the average voltage across
the inductor. The average voltage across an ideal inductor is 0 V. However, due to the
converter current and the resistive impedance of the inductor there is a small average
voltage across the inductor.
Close to the DIM pin the DIMRC signal is attenuated to meet the voltage range of the DIM
pin. To average the DIM pin voltage, capacitor C12 is also required. R33 sets the
minimum DIM pin voltage and therefore the minimum output current. The minimum dim
level is very accurate because the internal VCC clamp of the SSL5251T is band gap
referenced.
7.2 1 V to 10 V dimming interface
The 1 V to 10 V dimming interface transformer L5 (2  10 mH) realizes the basic
insulation required for the 1 V to 10 V dimming input.
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Fig 16. 1 V to 10 V dimming interface circuit diagram
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When capacitor C20 is discharged, a current is fed through the transformer and diode D8.
The 1 V to 10 V voltage or diode D7 clamps the voltage between pins 1 and 4 of L5.
Because of the 1:1 turn ratio, the voltage between pins 2 and 3 equals the voltage
between pins 1 and 4. The reverse voltage rating of diodes D5 and D8 must meet the
ringing on the transformer pins that occur when capacitor C20 is charged.
Diode D4 feeds the control voltage to node DIMRC. Diode D4 must be a low-leakage type
because the impedance on the DIM pin is very high. A normal diode on position D4
causes an inaccurate DIM pin voltage.
7.2.1 1 V to 10 V dimming curve
The voltage at the 1 V to 10 V dimming input sets the output current according the
measured curve below.
DDD
,R
$
9',09
Fig 17. 1 V to 10 V dim voltage versus output current measurement
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7.2.2 Line and load regulation
Figure 18 shows the line and load regulation at Io(max) for various output voltages and
mains voltages.
DDD
P
,RPD[
$
P
P
P
P
P
P
9R9
(1) Vmains = 180 V (AC)
(2) Vmains = 230 V (AC)
(3) Vmains = 270 V (AC)
Fig 18. 1 V to 10 V dimming: line and load regulation at Io(max)
Figure 19 shows the line and load regulation at Io(min) for various output voltages and
mains voltages.
DDD
P
,RPLQ
$
P
P
P
P
P
P
9R9
(1) Vmains = 180 V (AC)
(2) Vmains = 230 V (AC)
(3) Vmains = 270 V (AC)
Fig 19. 1 V to 10 V dimming line and load regulation at Io(min)
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7.3 PWM dimming interface
A 3.3 V or 5 V PWM signal can be applied to the PWM input. If the input is open or 0 V
(duty cycle = 0 %) is applied, the output current is maximum.
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7.3.1 PWM dimming curve
Figure 21 shows the relationship between duty cycle at the PWM dim input connector and
the output current. When  = 0 %, the output current is maximum. When  = 100 %, the
output current is minimum. The current through resistor R33 sets the minimum value.
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Fig 21. Duty cycle versus output current measurements
The default PCB includes R33 = 10 M. However, resistor R33 can be omitted:
• Resistor R33 mounted:  = 100 % = minimum output current
• Resistor R33 open:  = 100 % = SSL5251T switching disabled
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When the minimum current is not set (R33 = not mounted):
• To avoid flickering, the duty cycle must remain < 40 % for an output current > 10 %
• When the duty cycle is set to 100 %, the DIM pin is pulled down and the controller is
not switching.
7.4 Trimmer interface
To set the output current, a potentiometer (adjustable resistor or trimmer) can be used.
Figure 22 shows an implementation where the adjustable resistor is referenced to the low
side of the bridge rectifier. The advantage is a low EMI emission of the large metal casing
of an adjustable resistor.
This circuit is not isolated. The safety isolation must be done with plastic housing and a
plastic control shaft.
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Fig 22. Trimmer dimming interface circuit diagram
Resistor R33 sets the minimum output current, which is 10 % of Io(max). The line and load
regulation of trimmer dimming is comparable with the PWM dimming interface.
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7.5 ElectroMagnetic Interference (EMI) prescan results
7.5.1 Conducted
a. Line
b. Neutral
Fig 23. EMI conducted emission prescan results at 230 V AC)
7.5.2 Radiated
Fig 24. EMI radiated emission prescan results at 230 V (AC)
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8. Schematic
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Rev. 1 — 10 November 2015
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UM10930
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UM10930
NXP Semiconductors
SSL5251DB1332 LED driver
9. Bill Of Materials (BOM)
Table 7.
SSL5251DB1332 demo board BOM
Reference
Description and values
Part number
Manufacturer
BD1
bridge rectifier; 600 V; 800 mA
B6S-G
Comchip Tech
C1
capacitor; 100 nF; 20 %; 440 V (AC);
PP; X1
BFC233810104
Vishay
C4; C5
capacitor; 180 F; 20 %; 200 V; ALU;
THT
UCY2D181MHD3
Nichicon
C8
capacitor; 47 nF; 10 %; 50 V; X7R;
0603
-
-
C11
capacitor; 150 nF; 10 %; 50 V; X7R;
0603
-
-
C12; C13;
C17
capacitor; 10 nF; 10 %; 50 V; X7R;
0603
-
-
C14
capacitor; 330 nF; 10 %; 450 V; PP;
THT
B32672Z4334K000
EPCOS
C15
capacitor; 100 nF; 10 %; 100 V; X7R;
0603
GRM188R72A104K
Murata
C18
capacitor; 470 nF; 10 %; 50 V; X7R;
0603
-
-
C20
capacitor; 15 pF; 5 %; 630 V; C0G;
1206
GRM31A5C2J150J
Murata
C23
capacitor; 2.2 F; 10 %; 25 V; X7R;
0805
GRM21BR71E225K
Murata
C24
capacitor; 100 nF; 5 %; 450 V; PP; THT ECWF2W104JAQ
Panasonic
C25
capacitor; 3.3 nF; 10 %; 50 V; X7R;
0603
-
-
D1
diode; 600 V; 3 A; SMC
ES3J
Fairchild
D3; D5; D8
diode; 100 V; 250 mA
BAS316
NXP Semiconductors
D4
diode; 85 V; 200 mA
BAS416
NXP Semiconductors
D7
diode; Zener; 12 V; 200 mA
BZX84-C12
NXP Semiconductors
D11
diode; TVS; 44 V; 5 A
PESD15VL1BA
NXP Semiconductors
D13
diode; Zener; 16 V; 250 mA
BZT52H-B16
NXP Semiconductors
D14
diode; TVS; Unidirectional; 440 V;
600 mA
SMAJ440A
Littelfuse
D15
diode; Zener; 2.7 V; 250 mA
BZT52H-B2V7
NXP Semiconductors
D16
diode; 1 kV; 1 A
UF4007
Vishay
F1
fuse; slow bow; 2 A
SS-5H-2A-APH
Cooper Bussmann
FB1
ferrite bead; 330 ; 1.5 A; 0805
BLM21PG331SN1D
Murata
L1; L4
inductor; 1 mH; 500 mA
768772102
Würth Elektronik
L3
inductor; 1 mH; 2 A
750315481
Würth Elektronik
L5
transformer; 10 mH; 1:1
750311081
Würth Elektronik
Q1
MOSFET-N; 650 V; 4.5 A
IPS65R950C6AKM
Infineon
Q2
transistor; NPN; 65 V; 100 mA
BC846B
NXP Semiconductors
R2
resistor; VDR; 275 V; 63 J
VDRS10P275BSE
Vishay
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Table 7.
SSL5251DB1332 demo board BOM …continued
Reference
Description and values
Part number
Manufacturer
R4
resistor; 0.1 ; 1 %; 100 ppm; 1206
RL73H2BR10FTD
TE Connectivity
R5
resistor; 470 ; 1 %; 250 mW; 1206
-
-
R6
resistor; 2.2 k; 1 %; 63 mW; 0603
-
-
R8
resistor; 430 k; 1 %; 63 mW; 0603
-
-
R17
resistor; 5.6 k; 1 %; 63 mW; 0603
-
-
R24
resistor; 1 ; 5 %; 3 W; THT
WHS3-1RJA1
Welwyn Components
R32
resistor; trimmer; 10 M; 30 %; THT
CB10LV106N
TE Connectivity
R33
resistor; 10 M; 1 %; 100 mW; 0603
RC0603FR-0710ML
Yageo
R35; R40
resistor; 330 k; 1 %; 63 mW; 0603
-
-
R36; R39
resistor; 10 k; 1 %; 63 mW; 0603
-
-
R41
resistor; 470 kW; 1 %; 500 V; 1206
RCV1206470KFKEA
Vishay
R42; R43
resistor; 2 M; 1 %; 500 V; 1206
LHVC1206-2MFT5
Welwyn Components
R44
resistor; 562 k; 1 %; 500 V; 1206
ERJP08F5623V
Panasonic
R45
resistor; 100 k; 1 %; 500 V; 1206
LHVC1206-100KFT5
Welwyn Components
R46
resistor; 442 k; 1 %; 500 V; 1206
ERJP08F4423V
Panasonic
R48; R62
resistor; 100 ; 1 %; 63 mW; 0603
-
-
R50
resistor; 47 k; 1 %; 63 mW; 0603
-
-
R52
resistor; 47 k; 1 %; 500 V; 1206
ERJ-P08J473V
Panasonic
R56
resistor; 0 ; 1206
-
-
S59; R60;
R61
resistor; 1.8 ; 1 %; 100 ppm; 1206
CRCW12061R80FK
Vishay
S1
switch; DIP; DPDT; slide; 4-way
SCS-4-023
ERG Components
U1
SSL5251T dimmable LED driver
SSL5251T
NXP Semiconductors
X1
connector; mains inlet
770W-X2-10
Qualtek
X2
connector; terminal block; 5.08 mm
1508060000
Weidmüller
X3; X4
connector; terminal block; 2-way;
5.0 mm
691312710002
Würth Elektronik
Table 8.
SSL5251DB1332 demo board: parts not mounted
Reference
Description and values
Part number
Manufacturer
C16
capacitor; 10 nF; 10 %; 100 V; X7R;
0603
-
-
C21
capacitor; 100 nF; 10 %; 100 V; X7R;
0805
-
-
C22
capacitor; 2.2 F; 10 %; 25 V; X7R;
0805
GRM21BR71E225K
Murata
C26
capacitor; 470 pF; 10 %; 250 V; X7R;
0603
GRM188R72E471K
Murata
D9; D12
diode; 100 V; 250 mA
BAS316
NXP Semiconductors
D10
diode; Zener; 6.2 V; 300 mA
BZX384-C6V2
NXP Semiconductors
Q5
transistor; NPN; 160 V; 600 mA
2N5551
Fairchild
Q6
MOSFET-N; 650 V; 4.5 A
IPS65R950C6AKMA
Infineon
R53
resistor; 1 k; 1 %; 63 mW; 0603
-
-
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Table 8.
SSL5251DB1332 demo board: parts not mounted …continued
Reference
Description and values
Part number
Manufacturer
R54
resistor; 100 k; 1 %; 250 mW; 500 V;
1206
LHVC1206-100KFT5
Welwyn Components
R55
resistor; 22 ; 1 %; 63 mW; 0603
-
-
R58
resistor; jumper; 0 ; 250 mW; 1206
-
-
R63
resistor; 4.7 k; 1 %; 63 mW; 0603
-
-
X5
header; straight; 1  5-way; 2.54 mm
22-28-4050
Molex
10. PCB layout
a. Top
b. Bottom
Fig 26. PCB layout and component placement
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11. Board adjustments
This section offers some suggestions for changing the board.
11.1 Standby power reduction
The standby power (VDIM = 0 V) can easily be reduced from 233 mW to 105 mW by
connecting resistor R44 before the bridge.
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Fig 27. Alternative connection of R44 to reduce standby power
In smart fixtures that include a microcontroller, a switchable current source circuit can be
added for switching the buck-boost converter on and off. The standby power can be
reduced to 81 mW.
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11.2 Reducing number of surge components
When lowering the surge requirements, remove the following parts one-by-one until the
surge robustness requirements are met with a minimal number of parts:
1. Bridge voltage clamp diode D14 (SMAJ440A)
2. Reverse IC bypass diode D16 (UF4006)
3. EMI choke bidirectional clamp diode D11 (PESD15VL1BA)
4. ISNS clamp Zener diode D15 (2.7 V)
5. Input metal oxide (voltage-dependent) varistor R2 (VDRS10P275BSE)
Leave diode D13 (SW pin protection) in the application. This diode prevents that the VCC
pin is charged above its maximum rating.
11.3 Partly bypass the SW pin current with an external PNP transistor
The SW pin current can be reduced by adding a PNP transistor in parallel with the internal
transistor at the SW pin. A small resistor is also required between the emitter and the
base. The large signal current partly flows through the IC, which is useful when more
output power is required. The accuracy of the OCP is maintained.
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Fig 29. External PNP transistor in parallel with SW pin transistor
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12. Abbreviations
Table 9.
Abbreviations
Acronym
Description
AC
Alternating Current
ALU
ALUminum
EMI
ElectroMagnetic Interference
LED
Light-Emitting Diode
MOSFET
Metal-Oxide-Semiconductor Field-Effect Transistor
OCP
OverCurrent Protection
OVP
OverVoltage Protection
PWM
Pulse-Width Modulation
RMS
Root Mean Square
SSL
Solid-State Lighting
THD
Total Harmonic Distortion
THT
Through Hole Technology
VDR
Voltage Dependent Resistor
13. References
UM10930
User manual
[1]
SSL5231T data sheet — Mains dimmable buck-boost LED driver IC;
2015, NXP Semiconductors
[2]
SSL5261AT data sheet — Mains dimmable LED driver IC;
2015, NXP Semiconductors
[3]
SSL5251T data sheet — Mains dimmable buck-boost LED driver IC;
2015, NXP Semiconductors
[4]
AN11702 application note — SSL525XT buck-boost controller;
2015, NXP Semiconductors
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14. Legal information
14.1 Definitions
Draft — The document is a draft version only. The content is still under
internal review and subject to formal approval, which may result in
modifications or additions. NXP Semiconductors does not give any
representations or warranties as to the accuracy or completeness of
information included herein and shall have no liability for the consequences of
use of such information.
NXP Semiconductors does not accept any liability related to any default,
damage, costs or problem which is based on any weakness or default in the
customer’s applications or products, or the application or use by customer’s
third party customer(s). Customer is responsible for doing all necessary
testing for the customer’s applications and products using NXP
Semiconductors products in order to avoid a default of the applications and
the products or of the application or use by customer’s third party
customer(s). NXP does not accept any liability in this respect.
Export control — This document as well as the item(s) described herein
may be subject to export control regulations. Export might require a prior
authorization from competent authorities.
14.2 Disclaimers
Limited warranty and liability — Information in this document is believed to
be accurate and reliable. However, NXP Semiconductors does not give any
representations or warranties, expressed or implied, as to the accuracy or
completeness of such information and shall have no liability for the
consequences of use of such information. NXP Semiconductors takes no
responsibility for the content in this document if provided by an information
source outside of NXP Semiconductors.
In no event shall NXP Semiconductors be liable for any indirect, incidental,
punitive, special or consequential damages (including - without limitation - lost
profits, lost savings, business interruption, costs related to the removal or
replacement of any products or rework charges) whether or not such
damages are based on tort (including negligence), warranty, breach of
contract or any other legal theory.
Notwithstanding any damages that customer might incur for any reason
whatsoever, NXP Semiconductors’ aggregate and cumulative liability towards
customer for the products described herein shall be limited in accordance
with the Terms and conditions of commercial sale of NXP Semiconductors.
Right to make changes — NXP Semiconductors reserves the right to make
changes to information published in this document, including without
limitation specifications and product descriptions, at any time and without
notice. This document supersedes and replaces all information supplied prior
to the publication hereof.
Suitability for use — NXP Semiconductors products are not designed,
authorized or warranted to be suitable for use in life support, life-critical or
safety-critical systems or equipment, nor in applications where failure or
malfunction of an NXP Semiconductors product can reasonably be expected
to result in personal injury, death or severe property or environmental
damage. NXP Semiconductors and its suppliers accept no liability for
inclusion and/or use of NXP Semiconductors products in such equipment or
applications and therefore such inclusion and/or use is at the customer’s own
risk.
Applications — Applications that are described herein for any of these
products are for illustrative purposes only. NXP Semiconductors makes no
representation or warranty that such applications will be suitable for the
specified use without further testing or modification.
Customers are responsible for the design and operation of their applications
and products using NXP Semiconductors products, and NXP Semiconductors
accepts no liability for any assistance with applications or customer product
design. It is customer’s sole responsibility to determine whether the NXP
Semiconductors product is suitable and fit for the customer’s applications and
products planned, as well as for the planned application and use of
customer’s third party customer(s). Customers should provide appropriate
design and operating safeguards to minimize the risks associated with their
applications and products.
Evaluation products — This product is provided on an “as is” and “with all
faults” basis for evaluation purposes only. NXP Semiconductors, its affiliates
and their suppliers expressly disclaim all warranties, whether express, implied
or statutory, including but not limited to the implied warranties of
non-infringement, merchantability and fitness for a particular purpose. The
entire risk as to the quality, or arising out of the use or performance, of this
product remains with customer.
In no event shall NXP Semiconductors, its affiliates or their suppliers be liable
to customer for any special, indirect, consequential, punitive or incidental
damages (including without limitation damages for loss of business, business
interruption, loss of use, loss of data or information, and the like) arising out
the use of or inability to use the product, whether or not based on tort
(including negligence), strict liability, breach of contract, breach of warranty or
any other theory, even if advised of the possibility of such damages.
Notwithstanding any damages that customer might incur for any reason
whatsoever (including without limitation, all damages referenced above and
all direct or general damages), the entire liability of NXP Semiconductors, its
affiliates and their suppliers and customer’s exclusive remedy for all of the
foregoing shall be limited to actual damages incurred by customer based on
reasonable reliance up to the greater of the amount actually paid by customer
for the product or five dollars (US$5.00). The foregoing limitations, exclusions
and disclaimers shall apply to the maximum extent permitted by applicable
law, even if any remedy fails of its essential purpose.
Safety of high-voltage evaluation products — The non-insulated high
voltages that are present when operating this product, constitute a risk of
electric shock, personal injury, death and/or ignition of fire. This product is
intended for evaluation purposes only. It shall be operated in a designated
test area by personnel that is qualified according to local requirements and
labor laws to work with non-insulated mains voltages and high-voltage
circuits.
The product does not comply with IEC 60950 based national or regional
safety standards. NXP Semiconductors does not accept any liability for
damages incurred due to inappropriate use of this product or related to
non-insulated high voltages. Any use of this product is at customer’s own risk
and liability. The customer shall fully indemnify and hold harmless NXP
Semiconductors from any liability, damages and claims resulting from the use
of the product.
Translations — A non-English (translated) version of a document is for
reference only. The English version shall prevail in case of any discrepancy
between the translated and English versions.
14.3 Trademarks
Notice: All referenced brands, product names, service names and trademarks
are the property of their respective owners.
GreenChip — is a trademark of NXP Semiconductors N.V.
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15. Contents
1
2
3
4
5
5.1
5.2
5.3
5.4
5.5
5.6
5.7
6
6.1
6.2
7
7.1
7.2
7.2.1
7.2.2
7.3
7.3.1
7.4
7.5
7.5.1
7.5.2
8
9
10
11
11.1
11.2
11.3
12
13
14
14.1
14.2
14.3
15
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Safety warning . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Board photograph . . . . . . . . . . . . . . . . . . . . . . . 6
LED driver design . . . . . . . . . . . . . . . . . . . . . . . 6
Design input . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
On-time control . . . . . . . . . . . . . . . . . . . . . . . . . 8
OverCurrent Protection (OCP) . . . . . . . . . . . . . 9
Maximum output power . . . . . . . . . . . . . . . . . 11
Start-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Output OverVoltage Protection (OVP) . . . . . . 13
Output short . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Performance measurement results . . . . . . . . 15
Mains input measurements. . . . . . . . . . . . . . . 15
Mains current harmonics compliance . . . . . . . 15
Dimming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
DIM input interface . . . . . . . . . . . . . . . . . . . . . 19
1 V to 10 V dimming interface . . . . . . . . . . . . 19
1 V to 10 V dimming curve . . . . . . . . . . . . . . . 20
Line and load regulation . . . . . . . . . . . . . . . . . 21
PWM dimming interface . . . . . . . . . . . . . . . . . 22
PWM dimming curve. . . . . . . . . . . . . . . . . . . . 22
Trimmer interface . . . . . . . . . . . . . . . . . . . . . . 23
ElectroMagnetic Interference (EMI) prescan
results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Conducted . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Radiated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Bill Of Materials (BOM) . . . . . . . . . . . . . . . . . . 26
PCB layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Board adjustments . . . . . . . . . . . . . . . . . . . . . 29
Standby power reduction . . . . . . . . . . . . . . . . 29
Reducing number of surge components. . . . . 30
Partly bypass the SW pin current with an
external PNP transistor. . . . . . . . . . . . . . . . . . 30
Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . 31
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Legal information. . . . . . . . . . . . . . . . . . . . . . . 32
Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Disclaimers . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Trademarks. . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Please be aware that important notices concerning this document and the product(s)
described herein, have been included in section ‘Legal information’.
© NXP Semiconductors N.V. 2015.
All rights reserved.
For more information, please visit: http://www.nxp.com
For sales office addresses, please send an email to: [email protected]
Date of release: 10 November 2015
Document identifier: UM10930