Start-up circuit for self oscillating class D modulator
US6118336A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 30, 1998 |
| Grant date | Sep 12, 2000 |
| Priority date | — |
| Expiry date | Oct 30, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2200/276
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A class D modulator 100 is self oscillating. It includes an input stage 110, an operational amplifier 120, an integrator 130 and a pulse width modulator 140. A start-up generator 22 generates signals ENABLE and MUTE. The MUTE signal is connected to the input stage 110 to prevent any unwanted, initial sound. The ENABLE signal connects a start-up voltage source to the integrator 130 to set the initial voltage for integration. The ENABLE signal is coupled to a dead time control circuit 16 which controls the operation of the output power transistors 42, 44 to assure that the low side power transistor 44 is turned on before the high side transistor 42.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.