Dual Half-Bridge Piezoelectric Driver with Step-up DC-DC Converter

The FAN8841 is a single-chip piezoelectric actuator driver consisting of a step-up DC-DC converter with integrated 36 V boost switch and the dual half-bridge output stages. The step-up DC-DC converter operates in Critical Conduction Mode (CRM) in order to reduce switching loss at the DC-DC converter for high efficiency. It is optimized to work in a coupled-inductor configuration to provide output voltages in excess of 60 V. The step-up DC-DC converter has a soft-start capability that limits the inrush current during startup. Over-voltage protection and over-current protection are included. Under-voltage protection is used to disable the dual half-bridge gate driver when the step-up DC-DC converter output voltage is lower than the specified threshold voltage. The boost voltage is set using external resistors and analog voltage at the VCON pin and step-up current limit is programmable via the external resistor at the OCP pin. The output Half-bridge is integrated with 75 V P- and N-channel for the piezoelectric actuator driving. An open drain Fault-out (FO) signal indicates if an abnormal over-voltage has occurred.