Pulse width modulation regulator control circuit having precise frequency and amplitude control

Abstract

A control circuit ( ) for a switch mode power converter having precise control of amplitude and frequency that does not exhibit overshoot error nor undershoot error during a fast charge cycle nor a fast discharge cycle, respectively. In a first embodiment, the control circuit ( ) does not exhibit undershoot error during a fast discharge cycle. The control circuit ( ) comprises an oscillator ( ) for providing a periodic carrier signal comprising a sawtooth wave output signal (V ). The oscillator ( ) includes a capacitor (C ) charged and discharged to the power supply voltage (V ) to provide the sawtooth wave output signal (V ). In addition, the oscillator ( ) includes a switching circuit ( ) coupled to the reference voltage level (V ). The control circuit ( ) further includes a gain circuit ( ) having a reference voltage input (V ), voltage input (V ) and an output (Out). The reference voltage input (V ) receives the reference voltage(V ). The voltage input (V ) connects to the capacitor (C ). The output (Out) of the gain circuit ( ) connects to the switching circuit ( ) to provide feedback proportional to the analog error signal related to the difference between the sawtooth wave output signal (V ) and the predetermined reference voltage level (V ).