Active clamp used to maintain proper current transformer operation
US5923548A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 28, 1997 |
| Grant date | Jul 13, 1999 |
| Priority date | — |
| Expiry date | Mar 28, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B70/10
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An active clamp used to maintain proper current transformer operation in a resonant transition converter circuit or any circuit having a wide range of reverse current present in a current transformer primary at the beginning of a power pulse. The active clamp is connected directly to a secondary of the current transformer and is placed in an active state for the duration of the "on" time of a switch associated with a particular current transformer. A diode, FET combination of the active clamp provides a path for current to flow when primary current is reversed or negative flow. Thereby only small amounts of voltage, and thus volt-seconds will be developed on the transformer during reverse primary current, in turn keeping the current transformer out of reverse saturation. A resistive-capacitive network allows the active clamp to use the circuit drive signal to place the active clamp in an on state.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.