Discontinuous mode PFC controller having a power saving modulator and operation method thereof
US6768655B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 3, 2003 |
| Grant date | Jul 27, 2004 |
| Priority date | — |
| Expiry date | Feb 22, 2023 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P80/10
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The present invention discloses a ZCS discontinuous mode PFC controller having a power saving modulator. The controller turns on through the feedback resistor and the parasitic diode of the controller, thus eliminating the need for a startup resistor. To achieve ZCS, the inductor current is released to zero, while the switching signal is off, before the next switching cycle starts. In order to decrease the switching frequency for light load conditions, an off-time delay is inserted right before the start of every switching cycle. The off-time delay is modulated to be the function of the feedback voltage and supply voltage. When the supply voltage is lower than the limit voltage, the off-time delay will decrease to inhibit the decrease of a switching frequency therefore prevents a low supply voltage. The switching frequency is decreased in accordance with the decrease of the load. Consequently, the switching losses and power consumption for light load and no load conditions are reduced.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.