Half-bridge DC to DC converter with low output current ripple
US5999433A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 12, 1998 |
| Grant date | Dec 7, 1999 |
| Priority date | — |
| Expiry date | Jan 12, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B70/10
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for maintaining relatively low ripple current in a dc-dc converter while minimizing the size of an inductive line filter utilizes a transformer having at least a pair of secondary windings in which the secondary windings are selected to have different numbers of winding turns depending on the specific design of the ideal duty factor at which the converter will be operated. In addition, the converter is provided with an active pre-load which establishes a continuous conduction current when load current is below some selected minimum value in order to provide control stability during light load conditions without converter oscillations. In an illustrated embodiment, the active pre-load circuit comprises a resistor connected in series with a transistor across the voltage output of the converter with the gate terminal of the transistor connected through a zener diode to the control circuit so that when the control voltage feedback signal drops to a selected low value, the transistor is biased into conduction to connect the resistor as a load to maintain a minimum load current. Alternatively, the transistor can be connected across one of the diodes in the transfor…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.