A design of power managements IC with peak efficiency of 92.8 % step-up converter and peak efficiency of 93.8 % step-down converter for power transmitting unit of A4WP applications in 0.18 μm BCD

This paper presents a power managements IC for power transmitting unit (PTU) of magnetic resonant A4WP application. A high efficiency step-up converter with a programmable output is proposed to provide supply voltage to the external power amplifier with a peak power of 37.5 W. In order to implement the closed loop gain control function of the PTU with the power receiving unit, the duty cycle is controlled with the pulse width modulation signal from bluetooth low energy. The chip is fabricated using a 0.18 μm BCD process with high power MOSFET options, and the die area is 4000 μm × 4000 μm. The measured maximum power efficiency of the step-up converter and step-down converter is each 92.8 % at load current of 0.5 A and 93.8 % at load current of 0.3 A. The output voltage of the step-up converter ranges from 12 to 25 V and that of the step-down converter ranges from 3.3 and 5 V.