High speed and low drift charge pump circuit
US5359299A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 21, 1993 |
| Grant date | Oct 25, 1994 |
| Priority date | — |
| Expiry date | Jan 21, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L7/0896
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A device for converting binary logic pulses into an output current and the output current being switchable between a positive and negative polarity. The device provides a charge pump circuit which is suitable for the phase-detector stage in a phase-locked loop (PLL) circuit. The charge pump circuit comprises an input stage for the "UP" binary logic pulses and a second stage for the "DOWN" binary logic pulses. The input stages comprise emitted-coupled transistor pairs. The circuit includes current sources and current sinks for generating the output current in the input stages in response to the binary logic pulses. The circuit features a pair of switch diodes coupled between the outputs of the input stages. The diodes form a commutator which controls the direction of the output current and the leakage current during the idle states. The circuit also includes a clamping circuit to limit the voltage swing across the switching diodes. The charge pump circuit according to the present invention exhibits a fast response time, a symmetrical response to the binary logic pulses, and virtually zero leakage current in the idle state. The charge pump circuit utilizes non-complimentary bipolar p…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.