Patent ID: 7471125
Filing Date: 2008-12-30
Classification: H03K

Abstract:
1. A sawtooth wave generating circuit for use in a sawtooth wave generating apparatus, the sawtooth wave generating apparatus comprising: a base frequency generating section and a frequency generation section which generates a reference signal having a predetermined frequency; a sawtooth wave forming section which generates a sawtooth wave based on the reference signal; a voltage comparator which compares a voltage value of the sawtooth wave generated by the sawtooth wave forming section with a predetermined voltage value; a phase comparator which compares a phase of the reference signal from the frequency generation section with a phase of an output signal outputted from the voltage comparator; and a low-pass filter which cuts out a high frequency component of an output signal from the phase comparator and feeds back the resulting signal to the sawtooth wave forming section, wherein the sawtooth wave generating circuit is provided in the sawtooth wave forming section for outputting a sawtooth wave output signal to generate the sawtooth wave, the sawtooth wave generating circuit including: wherein when the IGFET is turned off, a predetermined current flows into the capacitor to charge the capacitor to thereby output the sawtooth wave output signal.