The A3921 is used with N-channel power MOSFETsFull-bridge controllerIt is especially designed for automotive applications using high-power inductive loads such as DC brush motors.
Unique charge pump regulator provides complete (>10 V)Gate driversto handle battery voltages as low as 7 V and allow the A3921 to operate when the gate driver voltage drops to 5.5 V. The bootstrap capacitor is used to provide the above battery supply voltage required for the N-channel MOSFET. The high-side drive internal charge pump allows DC (100% duty cycle) operation.
Diodes or synchronous rectification can be used to put the full bridge in fast or slow delay mode. In slow delay mode, current freewheeling can pass through either a high-side or low-side FET. The resistor adjusts the inductive time, which saves the power FET from breakdown.
Integrated diagnostics indicate undervoltage, overtemperature, and power bridging faults, and can be configured to protect the power MOSFETs under most short-circuit conditions.
The A3921 is available in a 28-pin TSSOP power package with an exposed thermal pad (suffix LP). The package is lead (Pb) free with 100% matte tin leadframe plating.
- N-channel MOSFET full-bridge high-current gate driver
- High-side or low-side PWM switches
- The charge pump operates at low supply voltages
- The charge pump provides 100% PWM when fully charged
- Cross-conduction protection with adjustable inductive time
- 5.5 to 50 V supply voltage range
- Integrated 5 V regulator
- Diagnostic output
- Low current sleep mode