Integrated dual charge pump power supply and RS-232 transmitter/receiver
US4777577A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 9, 1987 |
| Grant date | Oct 11, 1988 |
| Priority date | — |
| Expiry date | Nov 9, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D84/854
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A monolithic integrated circuit containing an inverting/non-inverting voltage doubler charge pump circuit is disclosed for converting a unipolar supply voltage to a bipolar supply voltage of a greater magnitude. The unipolar input voltage is placed across a first external transfer capacitor by a first set of MOS switches during a first time period. The unipolar input voltage source is placed in series with the first transfer capacitor and this series combination of voltages is placed across a first external reservoir capacitor by a second set of MOS switches during a second time period. The voltage appearing across the first external reservoir capacitor is placed on a second transfer capacitor during the first time period by a third set of MOS switches. The voltage across the second transfer capacitor is placed into a second external reservoir capacitor with its polarity inverted by a fourth set of MOS switches during the second time period. A dual-collector lateral junction transistor, formed during the conventional CMOS processing steps used to fabricate the MOS switches, is connected as voltage clamp between a ground potential and the two bipolar DC output lines of the power sup…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.