Frequency stabilization technique for self oscillating modulator
US7075803B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Nov 16, 2004 |
| Grant date | Jul 11, 2006 |
| Priority date | — |
| Expiry date | Jan 22, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2200/351
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
With self oscillating pulse width modulators, using a hysteretic comparator to change the output duty cycle according to the input signal, as often used for example for Class-D amplifiers or switching regulators, the frequency varies with output power and supply voltage. The disclosed invention presents a method to drastically reduce the frequency variation by introducing the combination of an analog and a digital feedback loop to shift the hysteretic threshold, ideally by providing a single absolute value, which is proportional to the pulse frequency and by alternating the polarity of shifting the hysteretic threshold, based on the actual output pulse phase.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.