Non zero-voltage switching protection circuit
US5973943A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 27, 1998 |
| Grant date | Oct 26, 1999 |
| Priority date | — |
| Expiry date | Jul 27, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B41/2985
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A protection circuit for preventing non zero-voltage switching of a lamp resonant output circuit driven by upper and lower half-bridge switches. The protection circuit includes a sense resistor disposed between the lower half bridge switch and ground for developing a voltage corresponding to the current flowing through the lower switch. A comparator compares the voltage developed across the sense resistor against a fixed reference voltage and generates an output indicative of a non zero-voltage switching condition when the voltage across the sense resistor exceeds the fixed reference voltage. A latch is connected to the output of the comparator and generates a latch output signal which disables the generation of drive signals to the upper and lower switches in the event of a non zero-voltage switch condition.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.