DRV8821

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SLVS912E – JANUARY 2009 – REVISED AUGUST 2010

Protection Circuits

The DRV8821 is fully protected against undervoltage, overcurrent and overtemperature events.

Overcurrent Protection (OCP)

All of the drivers in DRV8821 are protected with an OCP (Over-Current Protection) circuit.

The OCP circuit includes an analog current limit circuit, which acts by removing the gate drive form each output

FET if the current through it exceeds a preset level. This circuit will limit the current to a level that is safe to

prevent damage to the FET.

A digital circuit monitors the analog current limit circuits. If any analog current limit condition exists for longer than

a preset period, all drivers in the device will be disabled.

The device is re-enabled upon the removal and re-application of power at the VM pins.

Thermal Shutdown (TSD)

If the die temperature exceeds safe limits, all drivers in the device will be shut down.

The device will remain disabled until the die temperature has fallen to a safe level. After the temperature has

fallen, the device may be re-enabled upon the removal and re-application of power at the VM pin.

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. Operation will resume when VM rises above the UVLO threshold. The indexer logic will

be reset to its initial condition in the event of an undervoltage lockout.

Shoot-Through Current Prevention

The gate drive to each FET in the H-bridge is controlled to prevent any cross-conduction (shoot through current)

during transitions.

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Product Folder Link(s): DRV8821