Control of a startup circuit using a feedback pin of a PWM controller integrated circuit chip
US9812976B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | May 2, 2016 |
| Grant date | Nov 7, 2017 |
| Priority date | — |
| Expiry date | May 2, 2036 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M1/0009
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A power supply includes a control transistor that controls a primary winding of a transformer to induce current on a secondary winding of the transformer to generate an output voltage. A pulse width modulation (PWM) controller integrated circuit (IC) chip drives the control transistor through a gate pin. The PWM controller IC chip has a feedback pin that receives a feedback signal indicative of the output voltage. A high voltage (HV) startup transistor is controlled through the feedback pin. The HV startup transistor turns ON during startup to generate a supply voltage from current received from the input voltage of the power supply. The HV startup transistor turns OFF when the supply voltage reaches a startup voltage level that is sufficient to start the switching operation of the control transistor and thereby receive operating current from an auxiliary winding of the transformer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.