To simplify a pulse width modulation circuit, save space, and reduce cost.
The pulse width modulation circuit 1 generates a pulse width modulation signal PWMout by allowing a first and a second capacitors C1, C2 to perform a charging action with electric current in proportion to voltage of audio signal eS and a discharging action with constant electric current in a relation to make them reverse actions for each other. A switch circuit for controlling charging actions of the first and second capacitors C1, C2 and a circuit configuration for generating charging current consisting of a differential amplifier circuit and a charging current generation circuit are made up in a same configuration, and are configured to share the differential amplifier circuit. Also, a switch circuit for controlling discharging actions of the first and second capacitors C1, C2 and a constant electric current for discharge are made up in a same configuration. In addition, electric sources of them are made up of two types of electric sources; +V and -V. Those allow for components sharing and reduction in the number of components.
SEKIYA MAMORU
| JP2008206128A | 2008-09-04 | |||
| JP2007336361A | 2007-12-27 | |||
| JP2007257279A | 2007-10-04 | |||
| JPH0440112A | 1992-02-10 |
Tatsuya Tanaka
Tsukasa Senba