A 95% Efficiency Reusable Adaptive Time Control Bidirectional Buck Charge Converter for Wide Input Range Operation

A 95% efficiency reusable adaptive time control bidirectional buck charge converter for wide input range operation is presented in this brief. For keeping the switching frequency stable, a reusable adaptive time generator is proposed to improve the transient response and stability of the system. In the buck charging and reverse boost discharging mode, the circuit adopts adaptive off-time control and on-time control, respectively. In order to ensure that the converter can work over a wide input range in the above two working modes, a maximum voltage selection circuit is used to generate a stable high-voltage output signal as the power supply voltage of the system. The proposed bidirectional converter has been fabricated using 0.18- $\mathbf {\mathrm {\mu }}\text{m}$ BCD process. Measurement results show that the converter has good output accuracy. The switching frequency is centered at 750kHz with less than 1.5% variation when the input voltage is 4.5-14V in the buck mode and 2.6-4.5V in the boost mode. The maximum conversion efficiency is up to 95%. Its minimum input starting voltage can be as low as 2.6V.