Patent ID: 7898311

Claim:
A phase shifting circuit, comprising: a first waveform generating circuit that receives a first signal and outputs a first waveform; a second waveform generating circuit that receives an inverted signal of the first signal, and outputs a second waveform; and a comparator that receives the first and second waveforms and outputs a signal having a predetermined phase difference from the first signal, wherein each of the first and second waveform generating circuits includes: a constant current circuit connected to a first power supply; a current mirror circuit including an output connected to an output terminal and used to flow a current between the output and a second power supply, the current being n times (n: a real number of 1 or more) a current flowing between an input of the current mirror circuit and the second power supply; a switching circuit that outputs a current to flow to the constant current circuit when an input signal to the first or second waveform generating circuit is on a first level to the output terminal, and outputs a current to flow to the constant current circuit when the input signal is on a second level to the current mirror circuit; and a capacitance connected between the output terminal and a fixed potential, wherein the predetermined phase difference depends on the n value of the current mirror circuit.