适用于DC-DC开关电源的锯齿波振荡器设计

Design of sawtooth-wave oscillator for DC-DC switching power

基于恒流源技术设计了一种适合于DC-DC开关电源的锯齿波振荡器,并基于CSMC 0.5μm混合标准CMOS工艺对所设计电路进行了仿真验证。在4 V电源电压及27℃条件下,电路获得了振荡频率为246.61 kHz的锯齿波信号;当温度在0～70℃变化时,锯齿波信号振荡频率在244.14～247.4 kHz变化,最大偏差仅为±1%;当电源电压在3～6 V变化时,锯齿波信号振荡频率在245.94～247.89 kHz变化,最大偏差仅为±0.52%。仿真结果显示,该锯齿波振荡器具有非常好的线性度,适用于DC-DC开关电源。

A sawtooth-wave oscillator for DC-DC switching power is designed by adopting the technique of constant current source in this paper.The sawtooth-wave oscillator is designed and simulated in CSMC 0.5μm mixed-signal standard CMOS process.An oscillation signal of 246.61 kHz is achieved under the condition of 4 V power supply voltage and 27 ℃.When temperature changes from 0 ℃ to 70 ℃,the oscillation frequency of sawtooth-wave oscillator changes from 244.14 kHz to 247.40 kHz,and whose variation is within ±1%.When power supply voltage changes from 3 V to 6 V,the oscillation frequency of sawtooth-wave oscillator changes from 245.94 kHz to 247.89 kHz,and whose variation has only ±0.52%.Simulation results show that the designed sawtooth-wave oscillator has a well characteristic of linearity,so the sawtooth-wave oscillator is suited for DC-DC converters.