中圖分類號：TN432 文獻標志碼：A DOI: 10.16157/j.issn.0258-7998.223029
中文引用格式： 曹楊，曹振吉，曹靚，等. 一種片外電容交叉充放電型振蕩電路設計[J]. 電子技術(shù)應用，2023，49(3)：77-81.
英文引用格式： Cao Yang，Cao Zhenji，Cao Liang，et al. An oscillator circuit with cross charge and discharge by off-chip capacitors[J]. Application of Electronic Technique，2023，49(3)：77-81.

An oscillator circuit with cross charge and discharge by off-chip capacitors

Abstract： CMOS Ring Oscillator has many advantages such as small layout area, large frequency range and easy integration. It is widely used in the DC-DC buck converter and electronic communication systems. On the basis of the traditional ring oscillator circuit, an independent charge and discharge control path is designed to realize a cross charge and discharge ring oscillator circuit, and a lower frequency oscillation period is obtained by externally connecting an off-chip capacitor. Based on 0.18 μm process, the circuit has been simulated with HSIM tool. After the back-end physical implementation, the layout of the oscillation occupies an area of 172 μm×76 μm. Using tools to extract parasitic parameters from the layout and conduct post-simulation, the simulation results indicates that with externally connecting an off-chip capacitor, and the power supply voltage in 3.3 V and temperature in 25℃, the oscillator has a clock period of 1.2 ms. With the power supply voltage changes in 2.7 V~5.5 V and temperature changes in -55℃~125℃, the frequency deviation is 5.83%.The circuit has been successfully applied in a power management chip.

Key words : ring oscillator；charge and discharge of capacitor；power management chip；clock