Switching regulators having a synchronizable oscillator frequency with constant ramp amplitude
US5929620A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 7, 1996 |
| Grant date | Jul 27, 1999 |
| Priority date | — |
| Expiry date | Nov 7, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M1/0025
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Switching regulator circuits and methods are provided in which a voltage controlled oscillator circuit (VCO) is utilized to produce signals that turn ON a switch circuit. The VCO is itself controlled by a phase detector circuit that compares the output of the VCO to an external synchronization signal and locks the VCO to the external synchronization signal. The switching regulator circuits also include a slope compensation circuit that derives a slope compensation signal from an oscillator ramp signal produced by the VCO. The slope compensation signal is used to modify turning the switch circuit OFF when the duty cycle of the switch circuit exceeds a predetermined value. An alternate embodiment of the present invention includes a signal generation circuit in place of the phase detector circuit. The signal generation circuit applies a waveform to the VCO to vary the voltage oscillator circuit frequency, which causes a reduction in the amplitude of noise generated by the switching regulator circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.