Patent ID: 7285998

Claim:
A duty ratio adjusting circuit comprising: a differential buffer for producing a pulse signal according to a sine wave signal and a reference voltage; an inverter connected to said differential buffer for inverting the pulse signal to produce an inverted pulse signal; a low pass filter connected to said inverter for removing high frequency component from the inverted pulse signal to produce direct voltage; a first analog buffer connected to said low pass filter and having a high input impedance for producing a first buffered voltage substantially equal to the direct voltage supplied from said low pass filter; a second analog buffer having the same configuration as said first analog buffer for producing a second buffered voltage substantially equal to the reference voltage; a differential amplifying buffer connected to said first and said second buffers and said differential buffer for producing an output voltage according to the first and the second buffered voltages to supply the output voltage to said differential buffer and said second analog buffer as the reference voltage.