Oscillator for generating a varying amplitude feed forward PFC modulation ramp
US5592128A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 30, 1995 |
| Grant date | Jan 7, 1997 |
| Priority date | — |
| Expiry date | Mar 30, 2015 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P80/10
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An oscillator for generating a varying amplitude feed forward power factor correction (PFC) modulation ramp signal includes a clock generating circuit and a ramp generating circuit. The PFC ramp signal generated by the ramp generating circuit is used within a power factor correction circuit of a switching mode power converter. The timing capacitor used within the ramp generating circuit is charged from the full wave rectified line input voltage so that the amplitude of the generated ramp output signal will follow the full wave rectified input signal, thereby maintaining the current loop bandwidth at a constant value and improving the transient response of the circuit. A one-shot circuit is coupled between the discharge transistor of the clock generating circuit and the discharge transistor of the ramp generating circuit for synchronizing the clock and ramp reference signals generated by the oscillator so that the frequency of the ramp reference signal is equal to the frequency of the clock signal. The one-shot circuit has a duty cycle which is always a fixed percentage of the period of the clock reference signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.