Brushed DC Motor Driver with Internal Current Sense

The DRV8871 is a brushed-DC motor driver for printers, appliances, industrial equipment, and other small machines. Two logic inputs control the H-bridge driver, which consists of four N-channel MOSFETs that can control motors bi-directionally with up to 3.6-A peak current. The inputs can be pulse-width modulated (PWM) to control motor speed, using a choice of current-decay modes. Setting both inputs low enters a low-power sleep mode.

The DRV8871 has advanced current regulation circuitry that does not use an analog voltage reference or external sense resistor. This novel solution uses a standard low-cost, low-power resistor to set the current threshold. The ability to limit current to a known level can significantly reduce the system power requirements and bulk capacitance needed to maintain stable voltage, especially for motor start-up and stall conditions.

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December'15/January 2016