Pulse width modulation circuit and switching amplifier using the same
US7456668B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 19, 2007 |
| Grant date | Nov 25, 2008 |
| Priority date | — |
| Expiry date | Oct 19, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F3/217
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A pulse width modulation circuit 1 of the present invention changes the voltage of a first integration circuit C1 during the first period T1 of the clock signal MCLK based on a current based on an audio signal eS, changes the voltage of the first integration circuit C1 based on a constant bias current in the opposite direction while changing the voltage of a second integration circuit C2 during the second period T2, and changes the voltage of the second integration circuit C2 based on the bias current during the third period T3. The amount of time from the start of the second period T2 until the voltage of the first integration circuit C1 reaches the reference voltage Vth is detected, and the amount of time from the start of the third period T3 until the voltage of the second integration circuit C2 reaches the reference voltage Vth is detected. The voltage of the first integration circuit C1 is kept at the reference voltage Vth from when the voltage of the first integration circuit C1 reaches the reference voltage Vth until the start of the third period T3, and the voltage of the second integration circuit C2 is kept at the reference voltage Vth from when the voltage of the second …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.