ZHCSPH2 January 2022 DRV8251A
PRODUCTION DATA
The DRV8251A is an 8-pin device for driving brushed DC motors from a 4.5-V to 48-V supply rail. Two logic inputs control the H-bridge driver, which consists of four N-channel MOSFETs that have a typical RDS(on) of 450 mΩ (including one high-side and one low-side FET). A single power input, VM, serves as both device power and the motor winding bias voltage. The integrated charge pump of the device boosts VM internally and fully enhances the high-side FETs. Motor speed can be controlled with pulse-width modulation at frequencies between 0 to 200 kHz. The device enters a low-power sleep mode by bringing both inputs low.
The DRV8251A also integrates current sense feedback to a microcontroller using current mirrors on the low-side power MOSFETs. The IPROPI pin sources a small current that is proportional to the current in the MOSFETs. This current can be converted to a proportional voltage using an external resistor (RIPROPI). This integrated current sensing scheme out-performs traditional external shunt resistor sensing by providing current information even during the off-time slow decay recirculating period and removing the need for an external power shunt resistor. The integrated current regulation feature allows the device to limit the output current with a fixed off-time PWM chopping scheme. The VREF pin configures the current regulation level during motor operation to limit the load current.
A variety of integrated protection features protect the device in the case of a system fault. These include undervoltage lockout (UVLO), overcurrent protection (OCP), and overtemperature shutdown (TSD).