很多电路中都能看到三相VCO (压控振荡器)的应用,包括电源变换器与电子音乐合成器中用作控制源与调制源。曾有个设计实例描述了一个简单的三相VCO的电路原理(参考文献1)。原电路的输出仅有600 mV p-p,不能耐受大负载。特别是在低工作频率下电路只消耗很少工作电流时,为输出信号提供的交流耦合不能正常工作,并使负载问题恶化,电路的直流工作点会随频率而变 Many circuits can see the application of three-phase VCOs (voltage-controlled oscillators), including power converters and electronic music synthesizers as control and modulation sources. There was a design example describing the circuit theory of a simple three-phase VCO (Reference 1). The output of the original circuit is only 600 mV p-p, can not tolerate large loads. Especially when the circuit consumes only a small amount of operating current at low operating frequencies, the AC coupling provided for the output signal does not function properly and worsens the load problem. The dc operating point of the circuit changes with frequency