DRV8833 Datasheet, PDF (10/22 Pages) Texas Instruments – DUAL H-BRIDGE MOTOR DRIVER

DRV8833
SLVSAR1B – JANUARY 2011 – REVISED AUGUST 2011
www.ti.com
nSLEEP Operation
Driving nSLEEP low will put the device into a low power sleep state. In this state, the H-bridges are disabled, the
gate drive charge pump is stopped, all internal logic is reset, and all internal clocks are stopped. All inputs are
ignored until nSLEEP returns inactive high. When returning from sleep mode, some time (up to 1 ms) needs to
pass before the motor driver becomes fully operational. To make the board design simple, the nSLEEP can be
pulled up to the supply (VM). It is recommended to use a pullup resistor when this is done. This resistor limits the
current to the input in case VM is higher than 6.5 V. Internally, the nSLEEP pin has a 500-kΩ resistor to GND. It
also has a clamping zener diode that clamps the voltage at the pin at 6.5 V. Currents greater than 250 µA can
cause damage to the input structure. Hence the recommended pullup resistor would be between 20 kΩ and
75 kΩ.
Protection Circuits
The DRV8833 is fully protected against undervoltage, overcurrent and overtemperature events.
Overcurrent Protection (OCP)
An analog current limit circuit on each FET limits the current through the FET by limiting the gate drive. If this
analog current limit persists for longer than the OCP deglitch time, all FETs in the H-bridge will be disabled and
the nFAULT pin will be driven low. The driver will be re-enabled after the OCP retry period (t_OCP) has passed.
nFAULT becomes high again at this time. If the fault condition is still present, the cycle repeats. If the fault is no
longer present, normal operation resumes and nFAULT remains deasserted. Please note that only the H-bridge
in which the OCP is detected will be disabled while the other bridge will function normally.
Overcurrent conditions are detected independently 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, so functions even without presence of the
xISEN resistors.
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.
Undervoltage Lockout (UVLO)
If at any time the voltage on the VM pin falls below the undervoltage lockout threshold voltage, all circuitry in the
device will be disabled, and all internal logic will be reset. Operation will resume when VM rises above the UVLO
threshold. nFAULT is driven low in the event of an undervoltage condition.
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