Temperature compensation of output diode in an isolated flyback converter
US9019727B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 18, 2012 |
| Grant date | Apr 28, 2015 |
| Priority date | — |
| Expiry date | Jun 27, 2033 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M3/335
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An isolated flyback converter having temperature compensation (TC) uses primary side sensing and an output diode, the output diode having a variable voltage drop related to its temperature. A feedback voltage VFB, proportional to the output voltage VOUT, in a feedback loop is compared to a fixed reference voltage VREF for setting a duty cycle of a power switch, wherein VFB is caused to approximately equal VREF. A TC circuit has a voltage source configured to generate a proportional-to-absolute-temperature voltage VPTAT, wherein VPTAT is at approximately VREF at a calibration temperature T0 and rises as a temperature exceeds T0. The voltage source is connected to the VFB node via a TC resistor RTC, so that at T0 no current flows through RTC. Therefore, the selection of the optimal RTC does not affect the selection of a scaling resistance for generating VFB. The current through RTC at elevated temperatures compensates VOUT.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.