Phase synchronizing circuit with feedback to control charge pump
US5144156A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 17, 1991 |
| Grant date | Sep 1, 1992 |
| Priority date | — |
| Expiry date | Jun 17, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L2207/04
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
In a semiconductor phase synchronizing circuit, variations in specific frequency and damping factor due to unavoidable variations in manufacturing conditions are prevented so that variations in phase synchronizing characteristics from one product to another are reduced. A charge pump of the phase synchronizing circuit is provided with a proportional charging electric current source and a proportional discharging electric current source arranged to be in the form of a feedback loop and to pass to a loop filter charging/discharging electric currents which are proportional to a converted electric current (output electric current) of a V/I converting circuit. The proportional charging electric current source is a P-type MOSFET, while the proportional discharging electric current source is an N-type MOSFET. The charge pump is a current mirror circuit in front of which a current mirror circuit of the V/I converting circuit is disposed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.