Automotive eCall Power Supply Reference Design with Low Intermediate Voltage


Design files


This reference design includes a complete power management solution for a standalone emergency call (eCall) system in an automotive environment. The circuit is supplied directly from the car battery rail. It also manages a backup battery to power the eCall system while the car battery rail is not available. It includes power path management which routes the available power rail directly to four DC/DC converters which are supplying the required functional blocks of the eCall system. The solution is optimized to operate at maximum efficiency while powered from the backup battery.



  • Complete power solution for an automotive eCall system
  • Operating input voltage range up to 40V
  • Provides supply voltage for all required eCall functional blocks
  • Up to 87% total efficiency while operating at backup power
  • Up to 90% total efficiency in standby at backup power
  • All DC/DC converters used can operate at switching frequencies above 2MHz


Output voltage options PMP9769.1 PMP9769.2 PMP9769.3 PMP9769.4
Vin (Min) (V) 5 5 5 5
Vin (Max) (V) 40 40 40 40
Vout (Nom) (V) 3.8 1.8 5 9
Iout (Max) (A) 2 1 1 1
Output Power (W) 7.6 1.8 5 9
Isolated/Non-Isolated Non-Isolated Non-Isolated Non-Isolated Non-Isolated
Input Type DC DC DC DC
Topology Buck Boost- Integrated Switch Buck- Integrated Switch Buck Boost- Integrated Switch Boost- Integrated Switch
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A fully assembled board has been developed for testing and performance validation only, and is not available for sale.

Design files & products

Design files

Download ready-to-use system files to speed your design process.


Test results for the reference design, including efficiency graphs, test prerequisites and more


Detailed schematic diagram for design layout and components


Complete listing of design components, reference designators, and manufacturers/part numbers


Design file that contains information on physical board layer of design PCB

TIDRKC6.PDF (1151 K)

PCB layer plot file used for generating PCB design layout


Includes TI products in the design and potential alternatives.

AC/DC & DC/DC converters (integrated FET)

LM43603-Q1Automotive Qualified 3.5V to 36V, 3A Synchronous Step-Down Voltage Converter

Data sheet: PDF | HTML
AC/DC & DC/DC converters (integrated FET)

TPS61175-Q13-A, 40-V high voltage boost converter with soft-start and programmable switching frequency

Data sheet: PDF | HTML
AC/DC & DC/DC converters (integrated FET)

TPS62290-Q1Automotive 2.3V to 6V, 2.25MHz Fixed Frequency 1A Buck Converter in 2x2mm SON/TSOT23 Package

Data sheet: PDF | HTML
AC/DC & DC/DC converters (integrated FET)

TPS63020-Q1High Efficiency Automotive Single Inductor Buck-Boost Converter with 4A Switch

Data sheet: PDF | HTML
Battery charger ICs

BQ250711-cell, 1-A, Li-ion linear battery charger with 50mA LDO

Data sheet: PDF | HTML
Battery fuel gauges

BQ28Z610Battery fuel gauge with integrated protector for 1-2 series packs

Data sheet: PDF | HTML
Battery fuel gauges

BQ28Z610-R1Battery fuel gauge with integrated protector for 1-2 series packs

Data sheet: PDF | HTML
Battery fuel gauges

BQ28Z620 Battery fuel gauge with integrated protector for 1-series to 2 series packs with 1.2-V I/O

Data sheet: PDF | HTML

TL331-Q1Automotive Catalog Single Differential Comparator

Data sheet: PDF | HTML

CSD16412Q5A25-V, N channel NexFET™ power MOSFET, single SON 5 mm x 6 mm, 16 mOhm

Data sheet: PDF

CSD25402Q3A-20-V, P channel NexFET™ power MOSFET, single SON 3 mm x 3 mm, 8.9 mOhm

Data sheet: PDF | HTML
Speaker amps

TAS5421-Q1Automotive, 22-W, 1-ch, 4.5- to 18-V analog input class-D audio amplifier w/ I2C diag, load dump

Data sheet: PDF | HTML

Technical documentation

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Type Title Date
Technical article A complete low-voltage backup battery solution for eCall systems PDF | HTML Mar. 05, 2016
Test report PMP9769 Test Results Jan. 13, 2016

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