Method and apparatus for switching a synchronous DC/DC converter between a PWM mode of operation and a light-load mode of operation
US8030909B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 27, 2009 |
| Grant date | Oct 4, 2011 |
| Priority date | — |
| Expiry date | Apr 19, 2030 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B70/10
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A synchronous buck converter operates in a PWM mode of operation and switches to light-load mode of operation under a light-load condition. When operating in the light-load mode, the synchronous buck converter transitions between a burst mode and an idle mode of operation. In the burst mode of operation, the converter operates with a fixed but increased duty ratio, with respect to the PWM mode of operation, that installs additional energy in an output capacitor. In the idle mode of operation, the high-side and low-side transistors are each turned off. To maximize energy savings and to quickly transition back to the PWM mode of operation if the load increases, a limit as to the number of allowed switching cycles when bursting is imposed and a minimum ratio of the number of clock cycles when idling to the number of switching cycles when bursting is set. Additionally, a comparator is provided to detect a sudden step-increase in the load to quickly switch the converter back to the PWM mode of operation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.