Method and circuit for detecting faulty recirculation diode in a switched mode power supply
US5576615A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 22, 1994 |
| Grant date | Nov 19, 1996 |
| Priority date | — |
| Expiry date | Apr 22, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H9/047
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A circuit (10) and method for detecting a fault in a recirculation diode (13) in a switched power supply. The power supply has a switching transistor (12) that is turned on and off by a power supply control device (31), switchably applying a supply voltage (15) to an output (14). The recirculation diode (13) is connected between the output (14) and a reference potential (16). The circuit includes a sense resistor (11) in series between the supply voltage (15) and the switching transistor (12). A biasing element (25) is connected to clamp a current control element of the switching transistor (12) to the reference potential (16) when the switching transistor (12) is switched off so that a fault in the recirculation diode (13) results in a current flowing in the switching transistor (12). An amplifier (33) is connected across the sense resistor (11). The amplifier (33) has a variable gain (35) controlled by the power supply control device (31), a normal gain when the switching transistor (12) is turned on, but an increased gain when the switching transistor (12) would be normally turned off, to measure the current, if any, in the switching transistor (12) resulting from any faults in …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.