A DRV8701 full bridge mosfet driver provides the capabilities to drive the MOSFET gates at an appropriate voltage with acceptable switching speed, while also protecting them from being damaged from heating due to insufficient gate voltage, shoot-through, etc.
It also controls an indicator LED for signaling the fault modes the device is able to detect, such as motor overcurrent and driver undervoltage.
Finally, the driver also performs a current limiting function to avoid damaging the transistors. The current level is set via a low pass filtered PWM signal or by a onboard trimpot.
MOSFETs in H bridge configuration
The device utilizes four IRFB7546 MOSFETs. These transistors have a breakdown voltage of 60 V and a RDSon of 6.0 mOhm typically (a worst case resistance of 14.1 mOhm at 175 °C Tj) with a Vgs of 10 V.
Current LimitingCurrent limiting is accomplished by the driver by turning off the appropriate transistors by a voltage comparator sensing the voltage drop across RSENSE and comparing it to the voltage on LIM pin.
Motor side voltage
Motor side continuous current
Logic side input voltage
Current limit signal frequency
Ambient temperature for operation