高精度振荡器及峰值固定斜坡补偿电路设计

Design of a High Precision Oscillator and Peak Voltage Fixed Slope Compensation Circuit

设计了一款具有充放电电容的高性能振荡器。该振荡器基于0．5μmBCD工艺库，利用Cadence和Hspice软件，在芯片系统典型应用环境下仿真，得到的内同步振荡频率为500kHz，外部EN同步振荡频率为200kHz到2MHz；在3～5．5V电源电压．下及-40~125℃温度范围内，振荡器的频率偏移在±30以内，内部时钟CLK占空比偏移在±4％以内，补偿电压峰值偏移在4-8％以内。该振荡器性能良好，已成功应用于一款DC／DC降压开关电源芯片。

A high performance oscillator with charge and discharge capacitors was designed based on 0. 5 ~m BCD technology. Simulation under typical application environment of the chip system showed that the oscillator had an internal synchronous oscillating frequency of 500 kHz, an external synchronous oscillating frequency from 200 kHz to 2 MHz, a frequency offset within ±3%, a clock duty cycle shift within ± 4%, and a maximum compensation voltage variation within !8% in the temperature range between -40 ℃ to 125℃ when supply voltage changed from 3 V to 5. 5 V. The high performance oscillator has been successfully applied to the design of a DC/DC buck switching power supply IC.