An 80-V integrated boost converter for piezoelectric actuators in smartphones

Abstract

A boost converter for piezoelectric actuator driving system in haptic smartphones is proposed and implemented using a 0.35 mu m BCDMOS process. The designed boost converter generates extremely high output voltage from a low-voltage battery supply. The boost converter provides stable power for the piezoelectric actuator with the peak-current control technique. The minimum variation of the output ripple variation can be achieved by the designed current-sensing and peak-current control circuits. The supply voltage of the boost converter is 2.7-4.2 V and the maximum output voltage is up to 80 V. The complete piezoelectric actuator driving system consists of a serial interface, SRAM, and signal-shaping logic as well as the boost converter. It also includes the resistor-string digital-to-analog converter and high voltage piezoelectric actuator driver (PZ driver). The fabricated chip size is 2,100 x 2,200 mu m, including bonding pads.