Automotive H-bridge motor driver makes 12V brushed motor control easy

July 9, 2026

The VNH9045AQ from STMicroelectronics integrates a full H-bridge, current sensing, diagnostics and protection functions, giving engineers a compact route to 12V automotive motor control with reduced external circuitry.

When the power stage and protection are in one chip it saves board space, design work and fault management. The VNH9045AQ has two high-side drivers and two low-side switches in an integrated H-bridge. This is for motor control on 12V systems.

 

The VNH9045AQ works well in cars and other vehicles. The motor driver is good to go because it meets the AEC-Q100 standard and it is also ready for ISO 26262. The motor driver works with 3V complementary metal-oxide-semiconductor (CMOS) logic inputs. The motor driver operates from 4V to 28V, and can handle a transient supply voltage of 36V. Speed control is supported with pulse-width modulation up to 25kHz. When the motor driver is not being used the standby current is a really low at 1µA, at 25°C.

 

The VNH9045AQ offers protection which includes under-voltage shutdown, over-voltage clamp, thermal shutdown and cross-conduction protection. It also limits current and power and protects against loss of ground and loss of supply voltage. The outputs are protected against short-to-ground and short-to-supply voltage events. The side current limit is 23A to 46A and low-side shutdown current is 28A to 56A.

 

The chip also has built-in monitoring and diagnostics. The multisense pin gives analog motor feedback, chip temperature warning and fault reporting. A dedicated feedback pin reports the actual voltage state of one motor output terminal back to the microcontroller, allowing the system to verify correct H-bridge switching for safety monitoring. In the off state these pins also support load and short to supply voltage checks before the motor starts.

 

The quad flat no-lead (QFN) 6mm x 6mm triple pad 26+2L package helps with layout performance. The package uses three exposed islands for heat dissipation. ST also provides a six-layer printed circuit board (PCB) reference layout and thermal data.

Features

  • Monitoring functions:
    • Analog motor current feedback
    • Chip temperature monitoring
  • Diagnostic functions:
    • Output short-to-ground
    • Thermal shutdown
    • Off-state open-load
    • High-side power limitation
    • Low-side over-current shutdown
    • Output short-to-supply voltage
  • Half-bridge operation
  • Operating junction temperature range: -40°C to 150°C
  • AEC-Q100 qualified
  • ISO 26262 ready

Applications

  • Motor control automotive applications supplied by 12V board-net
STMicroelectronics — VNH9045AQTR H-Bridge Motor Driver

Evaluation Board

Part Number: EV-VNH9045AQ

The EV-VNH9045AQ board from STMicroelectronics is, for evaluating the VNH9045AQ motor driver. The board is preassembled with the external parts. It allows connection of the load, power supply and microcontroller.

 

The board supports control and diagnostic functions. This makes it easy to test direction control, pulse-width modulation, current feedback and diagnostics.

 

The board also supports development. It provides connectivity and some thermal heat-sinking for prototyping. The board uses a 4-layer FR4 PCB measuring 65.74mm x 93.13mm.

FTM Board Club

Sign up for access to exclusive development boards, an essential tool for many innovative design projects.

*Available to pre-qualified EMEA customers only.

Tags

Related Articles

STMicroelectronics — STM32G4 Microcontrollers
STMicroelectronics’ STM32G4 microcontrollers provide a combination of high processor throughput, generous...
Read More
NIC Components — NPDC Radial Film DC-link Capacitors
Radial film DC-link capacitors provide high reliability and stability...
Read More
Infineon — PSOC Control C3 Microcontroller
Secure MCU’s high-quality signal-processing eases design of EV chargers...
Read More

Subscribe to our newsletters

Subscribe to Future Electronics

Get access to the latest product information, technical analysis, design notes and more

Choose your region