一种适用于BUCK型DC-DC芯片振荡器电路设计

Design of an oscillator circuit for BUCK type DC-DC chip

基于0.5μm UMC工艺库,设计了一款高性能振荡器,在电路的设计中加入延迟电路以改变输出频率的占空比,同时加入分频电路使得频率的输出更加多样化以满足不同的频率需求。利用Cadence和Hspice软件进行电路设计与仿真。结果显示,在系统典型应用环境下该振荡器内同步振荡频率为1.1 MHz;当温度在–40^+125℃变化时,输出频率随温度的变化率仅为4.5%;当电源电压在3.0~5.5 V变化时,输出频率的变化率仅为3.6%。该振荡器的性能良好,已成功应用于一款DC/DC降压电源管理芯片之中。

Based on 0.5μm UMC process, a high performance oscillator was designed. In the design of the circuit by adding the delay circuit could effectively change the duty cycle, also a divider circuit was joined to let the frequency of the output have more diversification, to meet the needs of different frequencies. Using Cadence for circuit design and Hspice software for circuit simulation, the oscillator was simulated. The results show that under the environment of typical applications in the chip system, the oscillator gets the internal synchronous oscillation frequency of 1.1 MHz; when the temperature at –40 – ＋125℃, the output frequency variation with temperature is only 4.5%; with the power supply voltage changes in 3.0–5.5 V, the change rate of the output frequency is 3.6%. The good performance of the oscillator has been successfully applied in a DC/DC step-down power-management chip.