Automotive Brushed-Motor Ripple Counter Reference Design for Sensorless Position Measurement


Design files


The demand to retain memory on the position of the seat, window, sliding door, mirror, lift-gate, and others driven by that motor has increased as small motors within the modern automotive vehicle continue to evolve. Existing solutions utilize multiple magnetic sensors attached to the body of a motor to provide a feedback loop to the motor control module. A sensorless approach provides redundancy for existing solutions and, in some cases, removes the requirement for motors with sensors attached. The sensorless approach has become increasingly popular through the implementation of an in-line, current-sense signal-conditioning circuit. This reference design provides a solution that is easily modifiable for many automotive motor systems that control position measurement.

  • Configurable for many DC motor solutions
  • -14V to 80V wide common mode input range for in-line motor current sensing
  • Operational for typical 9V to 18V battery supply
  • Simple interfacing with MSP430™ LaunchPad™ Development Kit for digital capture
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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.

TIDUD30A.PDF (5848 K)

Reference design overview and verified performance test data


Detailed schematic diagram for design layout and components


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


Detailed overview of design layout for component placement


Files used for 3D models or 2D drawings of IC components


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


PCB layer plot file used for generating PCB design layout


Includes TI products in the design and potential alternatives.


LMV7275-Q1Automotive-grade, micropower, single comparator

Data sheet: PDF | HTML
Current sense amplifiers analog output

INA240-Q1AEC-Q100, -4 to 80V, bi-directional, ultra-precise current sense amplifier w/ enhanced pwm rejection

Data sheet: PDF | HTML
General-purpose op amps

TLV2316-Q1Automotive-grade, dual, 5.5-V, 10-MHz, RRIO operational amplifier

Data sheet: PDF | HTML
Linear & low-dropout (LDO) regulators

TPS7B69-Q1Automotive 150-mA, off-battery (40-V), high-PSRR, low-IQ, low-dropout voltage regulator

Data sheet: PDF | HTML

Technical documentation

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Type Title Date
* Design guide Automotive Brushed-Motor Ripple Counter Ref Design for Sensorless Measurement (Rev. A) Jun. 14, 2018
Technical article The seat remembers: Brushed DC motor ripple counting drives innovation in full-featured memory seats Aug. 16, 2017

Related design resources

Hardware development

MSP-EXP430FR6989 MSP430FR6989 LaunchPad™ development kit

Reference designs

TIDA-01330 Automotive 2-Axis Power Seat Brushed DC Motor Drive Reference Design

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