Flyback power converter having a constant voltage and a constant current output under primary-side PWM control
US6862194B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 18, 2003 |
| Grant date | Mar 1, 2005 |
| Priority date | — |
| Expiry date | Sep 17, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M1/0006
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A primary-side flyback power converter supplies a constant voltage and a constant current output. To generate a well-regulated output voltage under varying load conditions, the power converter includes a PWM controller. The PWM controller generates a PWM signal to control a switching transistor in response to a flyback voltage detected from the first primary winding of the power supply transformer. To reduce power consumption, the flyback energy of the first primary winding is used as a DC power source for the PWM controller. The flyback voltage is sampled following a delay time to reduce interference from the inductance leakage of the transformer. To generate a more accurate DC output voltage, a bias current is pulled from the detection input to form a voltage drop across a detection resistor for compensating for the voltage drop of the output rectifying diode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.