PWM controller for resonant converters
US5680034A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 22, 1995 |
| Grant date | Oct 21, 1997 |
| Priority date | — |
| Expiry date | Sep 22, 2015 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B70/10
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A pulse width modulated controller controls a zero-voltage switching resonant power converter or inverter. The on time of the power switch (110) of the converter or inverter is varied by an error amplifier (280) such that the output voltage of the converter or inverter maintains proportionality to a reference voltage (290). The off time is terminated by a switch-voltage detector (320) when the voltage across the power switch (110) drops below a threshold voltage (330) due to the natural resonance of the external resonating capacitor (120) and inductors (130 and 150). In the first two embodiments of the invention, a single timing capacitor (260) is employed both for determining the on time and the off time. In two other embodiments, two timing capacitors (262 and 264) are employed for separately determining the maximum allowed off time and the variable on time. A cycle-by-cycle current limit circuit comprising a current sensor (605), a comparator (610), and an R-S latch (620) may be added to the circuits representing each of the embodiments. By incorporating a soft start subcircuit (775) and an overlap detector (710, 715, 20, 725), protection against overdissipation of the power swi…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.