一种峰值电流控制模式中电流比较器的设计

本文设计了一种应用于同步降压型DC/DC集成开关稳压电源的电流比较器。其主要作用是检测电感的峰值电流,将其与设计所需的值进行比较,输出控制信号,以达到调节占空比的目的。电路设计采用电流镜、折叠式共源共栅等结构,实现了在峰值电流控制模式中的电流比较功能。采用SanyoHspice模型进行仿真后表明,在典型条件下,此电流比较器的差模增益超过100dB,共模增益大于180dB,电源抑制比达到160dB以上,满足各项设计指标要求,并显著提高了芯片的性能。

Current eomparator in peak-value-current-mode-control for DC/DC regulator

A novel current comparator for buck DC/DC regulator is presented in this paper.Its main role is to detect the peak inductor current,compares detected peak-value current of the inductor with the designed value,and outputs control signal in order to regulate the duty cycle.By using the structures such as current mirror,folded-cascode and so on,the function of comparison in peak-value-current-mode-control is realized.The simulation results by using Sanyo Hspice models show that the differential-mode and common-mode gain are over 100 dB and 180 dB respectively,PSRR is over 160 dB in typical conditions.The specifications are satisfied,and the characteristics of the chip are improved evidently.