一种多相DC-DC数字控制器的设计

分析了多相DC-DC变换器的均流环路小信号动态特性以及极限环振荡条件,提出一种基于平均电流的数字均流技术,并据此实现了一种多相DC-DC数字控制器。采用基于同步设计的均流控制电路和数字脉宽调制器实现电流均衡和相位交错。该多相DC-DC数字控制器芯片基于0.18μm CMOS工艺设计。仿真结果表明,在10~20 A阶跃负载电流下,输出过冲/下冲电压在20 mV以内,开关频率在0.5 MHz~2 MHz范围内可调整,均流误差从20.8%减小到5%以下。

Design of a Multi-Phase DC-DC Digital Controller

The small-signal dynamic characteristics of the current sharing loop and the limit-cycle oscillation condition of the digital multi-phase DC-DC converter were analyzed. A digital current sharing technology based on average current was proposed, and a multi-phase DC-DC digital controller was designed. A current sharing control circuit and a digital pulse width modulator(DPWM) based on the synchronous design were presented to achieve current balancing and interleave operation. The multi-phase DC-DC digital controller chip was designed in a 0.18μm CMOS process. The simulation results showed that under 10 A~20 A load transient, the overshoot/undershoot voltage was within 20 mV, the switching frequency was adjustable from 0.5 MHz to 2 MHz, and the current sharing error was reduced from 20.8% to less than 5%.