Manuel for 12V High Side Battery Sensor Reference Design

Manuel for 12V High Side Battery Sensor Reference Design
Manuel for 12V High Side Battery Sensor Reference Design
Purpose of this reference design is to sense current and voltage of a 12V battery as well
as the temperature of the PCB. From these measurements battery charge is counted
(Coulomb counter) and battery impedance is calculated whenever load current change is >
5A.
This sensor supports both, normal measurement mode 1 as well as low power standby
mode 1 (see AS8510 / AS8525 data sheet) were the sensor wakes up at 5s time interval to
perform a current measurement and threshold comparison.
The sensors are not calibrated and response differs due to initial spread of shunt
resistance, gain, attenuator ratio and temperature sensor!
Specifications:
 Temperature range: -40°C to +125°C
 Pre programmed current measurement range: +/-400A, can be adjusted through
gain setting menue
 Supply range 6V – 18V. Limited towards low supply by LIN interface. Works down
to typ 4,5V at room temperature from experience.
 Accuracy for current measurement after system calibration: Typ. +/-0,2% over
entire signal and temperature range except were quantization gets dominant at low
current readings. In addition there is a common mode error of 0,05%/V when
battery voltage changes. This error can be canceled by software as for each
current measurement there is a synchronized voltage measurement.
 Accuracy for voltage measurement after system calibration: Typ +/- 0,1% for -20 to
+65°C. Could be improved by software correction of ADC reference drift through
internal temperature sensor.
 Accuracy for temperature measurement after single point calibration: +/-3° for -20°
to +65°
 Linearity: better 0,01%
 Offset: < +/- 1 LSB
 Current consumption of the sensor slave in standby mode: 100 uA typical
 Sensor current consumption in Normal mode: 8 mA
 Maximum voltage in load dump condition for 500 ms: 42V
 Withstands ISO pulses
 Reverse polarity protected
 LIN 2.1 interface - conformance and EMC tested, go to sleep and wake through
LIN instruction
 Controller type MB96F315, 128 + 32 kB of flash memory
page 1/9
The sensor system consists of the shunt sensor module as a LIN slave, The LIN master
with LIN and USB controller as well as the GUI software which is available from AS8510
demo board download area.
The sensor need to be connected to 12V, GND and through LIN bus, the master need to
be connected through USB cable to laptop USB port. After starting the application and
pressing the connect button, the read button can be clicked and sensor starts to measure.
Software:
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Download .net Framework and software:
http://www.ams.com/eng/Support/Design-Resources/Demoboards/DataConverters/Data-Acquisition-Front-End/AS8510-DK
Install both
Connect the USB/LIN Board via USB
Windows will ask for a new driver for the device this driver is in the installation
folder of the software in the driver subdirectory
After installation check which com port was associated with the new device in the
device manager
Start the demo software
Power the demo Board according to the following picture:
GND
Battery +12V
Load
USB
page 2/9


Select the correct com port (normally it should already be pre-selected) and click
the connect button (grey plug)
The LIN Tab will open automatically

You can start the measurement with the read button
page 3/9

You can save the measurement data with the save button. File format is .csv which
is easily opened in for example in Excel
page 4/9
The columns in the table are as follows:
 Current
[mA]
 Voltage
[mV]
 Charge integration value
 Impedance
[mΩ]
 Temperature
[°C]
 Check value
In addition the charge sum is displayed in the small charge box at top the graphic display
in [mAh]. The temperature in the right box is also updated automatically. The graphic
display allows seamless zoom and scrolling even while the measurement is active. With a
right click you can open a menu which lets you save and navigate through the graphics.
Buttons:
 Read: Starts the measurement
 Stop: Stops the measurement
 Clear: Resets the table and the graphic window as well as the charge counter
 Standby: If the sensor is in stop mode it will send the whole demo board into
standby. You will only be able to see a difference in current consumption otherwise
there is no indication of the change to standby mode
 Save: Saves the whole left table into a .csv file
 Temp: Will initialize a single temperature measurement. The temperature will be
displayed in RAW format
 Gain: With this dropdown menu you can adjust the internal gain of the ADC. It will
have an effect on noise and offset. You should only change the gain setting while
the ADC is in stop mode.
LIN Interface description:
The LIN message consists of Sync Break Sync Field Identifier data fields and checksum.
Our implementation will accept Sync and break Fields but it has a preconfigured Datarate
of 19200Baud.
It will recognize the following Identifiers:
 1:
Will prompt a 4 byte standard frame request in the following format
Voltage [2byte] Current [2byte]
 2
Will prompt a 14 byte extended frame request in the following format
Voltage [2byte] Current [3byte] Charge_sum [4byte] Impedance [2byte]
Temperature [2byte] Status [1byte]

Anything else will be treated as a normal command. The commands are listed
below. They have to be terminated by one of the following characters: “\n” “\r” “:” 0
page 5/9
Serial Interface description:
The USB2LIN Board communicates to the PC via a virtual COM port. This Interface hast
three distinct commands:
 t#:
Will transmit the character following t over the LIN interface
o t1:
Do a single voltage and current read
o t2:
Do a single temperature read
o t3:
Do a continuous read of all parameters
o t4:
Stop continuous read
o t5:
Reset all registers
o t6:
Goto Standby + keep measuring
o t7:
Goto Standby
o ta:
activate UART interface
115200kbps 8N1
o tb:
Set GAIN 5
o tc:
Set GAIN 25
o td:
Set GAIN 50
o te:
Set GAIN 100
o tf
Set RAW data mode
 r:
Will do a read of current and voltage
 q:
Will do an extended read with all the measurements available.
Message format is:
Voltage [2byte] Current [2byte] Charge_sum [4byte] Impedance [2byte]
Temperature [2byte] Status [1byte]
page 6/9
Schematic:
Board layout:
Sensor board is double sided FR4
PCB dimension 39 x 17 mm
page 7/9
BOM:
Item
Quantity
Reference
Part
farnell-nr
C2,C5,C8,C10
C3,C6,C11,C12
C1,C4,C7,C9
D1
D2
J4
J5
J6
R4,R5,R6,R10
R7
R8,R9
U1
U2
U3
220nF
100nF
10uF
DIODE
Sup Diode
PROG_JMP
PROG
LIN_CON
1K
10K
100R
AS8510
AS8525
MB96F615
1759019
1759017RL
1833825
1469425RL
1189316
stiftleiste
stiftleiste
stiftleiste
9330380
1469749
9330364
AMS
AMS
fujitsu direkt
2
3
4
5
6
9
10
11
12
13
14
15
16
17
4
4
4
1
1
1
1
1
4
1
2
1
1
1
18
1 U4
Ceramic 4MHz
1448125
19
1 Shunt
100µOhm, 5%
Vishay WSBS5012L1000JK
The reference design is clocked by an 4 MHz ceramic resonator to achieve highest
accuracy in Coulomb counting over entire temperature range. AS8510 internal precision
RC oscillator is disabled.
page 8/9
Copyright notice
© ams AG, 2008-2012. Austria-Europe. Trademarks Registered ®. All rights reserved. The material
herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written
consent of the copyright owner.
All products and companies mentioned are trademarks or registered trademarks of their respective
companies.
Disclaimer
Devices sold by ams AG are covered by the warranty and patent indemnification provisions appearing
in its Term of Sale. ams AG makes no warranty, express, statutory, implied, or by description
regarding the information set forth herein or regarding the freedom of the described devices from
patent infringement. ams AG reserves the right to change specifications and prices at any time and
without notice. Therefore, prior to designing this product into a system, it is necessary to check with
ams AG for current information. This product is intended for use in normal commercial applications.
Applications requiring extended temperature range, unusual environmental requirements, or high
reliability applications, such as military, medical life-support or life-sustaining equipment are
specifically not recommended without additional processing by ams AG for each application. For
shipments of less than 100 parts the manufacturing flow might show deviations from the standard
production flow, such as test flow or test location.
The information furnished here by ams AG is believed to be correct and accurate. However, ams AG
shall not be liable to recipient or any third party for any damages, including but not limited to personal
injury, property damage, loss of profits, loss of use, interruption of business or indirect, special,
incidental or consequential damages, of any kind, in connection with or arising out of the furnishing,
performance or use of the technical data herein. No obligation or liability to recipient or any third
party shall arise or flow out of ams AG rendering of technical or other services.
Contact Information
Headquarters
ams
Tobelbaderstrasse 30
A-8141 Unterpremstaetten, Austria
Tel : +43 (0) 3136 500 0
Fax : +43 (0) 3136 525 01
www.ams.com
page 9/9
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