带有无损电流检测的高效率可重构DC-DC变换器

Reconfigurable high-efficiency DC-DC converter with lossless current-sensing technique

为了提高便携式设备供电电源的效率,提出可重构的高效率DC-DC变换器.针对锂电池供电电源的特点,采用绿色模式控制策略将变换器自动重构成3种模式,以实现升压和降压功能,并减小功耗.在轻载条件下引入突发控制模式,以减小开关损耗,从而提高了效率.变换器在1.5μm BCD工艺下设计并流片,芯片面积为8.75mm^2.变换器的输入电压为2.7-4.2V,输出电压为3.3V.当输入电压接近3.3V时,该系统可以实现降压和升压的平滑过渡.在快速响应的电流模式控制中,提出基于Gm-C滤波器的无损电流检测技术,实现了无损、精准的电流检测.当负载在30mA和300mA之间跳变时,系统恢复时间小于100μs.在0-500mA的负载范围内,系统的效率能够保持在80%以上,最高可达94%.

A reconfigurable high-efficiency DC-DC converter was proposed in order to improve the power efficiency of portable electric devices. A green-mode control strategy was developed to adaptively configure the converter into three modes based on the properties of Li-ion battery in order to achieve seamless step- up/down voltage conversion and minimize power loss. A burst mode control strategy was adopted at light load to reduce switching loss, and the power efficiency was improved. This converter was designed and fabricated in 1.5 μm BCD process, with a total chip area of 8.75 mm^2. The input voltage can vary from 2.7 V to 4.2 V, and the output voltage is regulated at 3.3 V. The system can achieve seamless-transition between buck and boost when its input voltage approaches 3. 3 V. A zero consumption current-sensing technique based on Gm-C filter was proposed to achieve lossless and accurate current sensing in fast- response current-mode controller. The recovery time for the system was less than 100 gs when its load steps were between 30 mA and 300 mA. The power efficiency of the system can maintain above 80 % for 0- 500 mA load range, and the peak value can be 94%.