DRV8828

SLVSA11G – OCTOBER 2009 – REVISED NOVEMBER 2015

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7.3.6.1 Overcurrent Protection (OCP)

An analog current limit circuit on each FET limits the current through the FET by removing the gate drive. If this

analog current limit persists for longer than the OCP time, all FETs in the H-bridge will be disabled and the

nFAULT pin will be driven low. The device will remain disabled until either nRESET pin is applied, or VM is

removed and re-applied.

Overcurrent conditions on both high and low side devices; i.e., a short to ground, supply, or across the motor

winding will all result in an overcurrent shutdown. Note that overcurrent protection does not use the current sense

circuitry used for PWM current control, and is independent of the ISENSE resistor value or VREF voltage.

7.3.6.2 Thermal Shutdown (TSD)

If the die temperature exceeds safe limits, all FETs in the H-bridge will be disabled and the nFAULT pin will be

driven low. Once the die temperature has fallen to a safe level operation will automatically resume.

7.3.6.3 Undervoltage Lockout (UVLO)

If at any time the voltage on the VM pins falls below the undervoltage lockout threshold voltage, all circuitry in the

device will be disabled and internal logic will be reset. Operation will resume when VM rises above the UVLO

threshold.

7.4 Device Functional Modes

7.4.1 nRESET and nSLEEP Operation

The nRESET pin, when driven active low, resets the internal logic. It also disables the H-bridge drivers. All inputs

are ignored while nRESET is active. The nRESET pin has an internal pulldown resistor of 100 k

Ω. The nSLEEP

pin has an internal pulldown resistor of 1 M

Ω.

Driving nSLEEP low will put the device into a low power sleep state. In this state, the H-bridge is disabled, the

gate drive charge pump is stopped, the V3P3OUT regulator is disabled, and all internal clocks are stopped. In

this state all inputs are ignored until nSLEEP returns inactive high. When returning from sleep mode, some time

(approximately 1 ms) needs to pass before the motor driver becomes fully operational.

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