带轻载变频模式的升压式DC-DC转换器设计

分析了传统升压式DC-DC转换器在全负载范围内实现高电源转换效率的局限性,在此基础上,提出了一种轻载检测和自适应变频机制.该技术无需额外的芯片管脚和器件,即能使转换器在电感电流断续模式下精确检测出负载状况.将所设计的升压式DC-DC转换器在CZ6H0.35μm标准CMOS工艺条件下进行仿真.结果表明,当负载电流发生变化时,转换器能够根据负载检测值的大小自适应地进行跳频变换.在负载电流为1mA的条件下,电源转换效率达到82%.系统环路能够在全负载范围内保持良好的稳定性,当负载电流以1.5μA/20μs跳变时,最大下冲和上冲电压分别为300和200mV,恢复时间分别只需80和60μs,版图面积约为1.26mm2.

Design of Boost DC DC Converter withFrequency Hopping at Light Load

This paper analyzes the high power conversion efficiency limit at full load range of traditional boost DC DC converter. Based on the analysis, light load detector and adaptive frequency hopping mechanism are put forward. The proposed technique doesn’t need additional pad and device while the load condition can be accurately detected in the Discontinuous Conduction Mode (DCM) of inductor current. The proposed boost DC DC converter is simulated in the CZ6H 0.35μm standard CMOS process, and results show that the proposed converter can adaptively select control frequency according to the load detector. At the load condition of 1 mA, power conversion efficiency can be up to 82%. System feedback loop can keep well stable within a wide range of load variation. For a load step of 1.5μA/20μs, the circuit has a maximum undershoot of 300mV and a maximum overshoot of 200mV. The recovery time is only 80μs and 60μs respectively,and the layout area is about 1.26mm2.