Triangular wave generating circuit used in a Class-D amplifier
US6791405B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 27, 2003 |
| Grant date | Sep 14, 2004 |
| Priority date | — |
| Expiry date | Mar 27, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2200/351
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
The integrating circuit of the triangular wave generating circuit includes an operational amplifier and a capacitor. Switch elements are alternatively turned ON and capacitors are alternatively recharged by the currents flowing in constant-current circuits thus obtaining a triangular wave on an output terminal. In this practice, when the voltage on the output terminal reaches ±1 V, comparator circuits (41, 42) and a flip-flop including NAND gates change over the switch elements. The currents flowing in the constant-current circuits are controlled depending on the current flowing in a load circuit. The current flowing in the load circuit is controlled by a PLL circuit including a phase comparator circuit, a loop filter, an LPF, an operational amplifier and an FET. This provides an output triangular wave having the same frequency as a clock pulse (CK).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.