FAN8841: 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.

Features

• Integrated Step-up Power Switch up to 36 V
• Wide Operating Voltage Range of 2.7 to 5.5 V
• Adjustable Step-up Output Voltage by V_CON
• Adjustable Step-up Switch Current Limit
• Zero Current Detector (ZCD)
• Internal Soft-Start
• Built-in Protection Circuit Piezo Actuator Driver
  • Under-Voltage Protection (UVP)
  • Over-Voltage Protection (OVP)
• Under-Voltage Protection (UVP)
• Over-Voltage Protection (OVP)
• Integrated Half-Bridge Switches (V_DS=75 V)
• Dual Half-Bridge Piezoelectric Driver
• Built-in Shutdown Function
• Small 4.0 mm × 4.0 mm MLP