Patent ID: 7057417

Claim:
A voltage conversion circuit, comprising: an output pulse generator circuit that generates an output pulse signal having a constant pulse width and having a variable pulse period; and a voltage output unit determining an output voltage based on a ratio of the pulse width to the pulse period of the output pulse signal generated by the output pulse generator circuit, the output pulse generator circuit includes a reference pulse generator circuit that generates a reference pulse signal having a constant pulse width, a first delay circuit that delays the reference pulse signal by one predetermined unit time after another to generate a plurality of pulse signals and then selects and outputs one of the plurality of pulse signals, the first delay circuit thereby delaying by a predetermined time the reference pulse signal, and a second delay circuit that delays by an arbitrary time a pulse signal output from the first delay circuit, an output signal of the second delay circuit being fed out as the output pulse signal, wherein the second delay circuit comprises a plurality of arbitrary delay circuit portions connected in series, each portion selectively outputting one of a pulse signal fed thereto and a delayed pulse signal that is delayed for a predetermined time from that pulse signal fed thereto, and an output signal of a last-stage arbitrary delay circuit portion is fed out as an output signal of the second delay circuit.