Charge/discharge control circuit and chargeable electric power source apparatus
US5998974A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 20, 1998 |
| Grant date | Dec 7, 1999 |
| Priority date | — |
| Expiry date | Nov 20, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02E60/10
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A charge/discharge control circuit has a voltage detector for detecting a voltage level of a secondary cell, a switch connected in series with the secondary cell, and a control circuit connected in parallel with the voltage detector for receiving and processing an output signal of the voltage detector and controlling an impedance of the switch. The voltage detector, the switch and the control circuit are integrated in a single substrate. In a preferred embodiment, the switch comprises an external connection terminal and a second terminal connected to the secondary cell, a first IGFET connected between the first and second terminals, a second IGFET connectected between the first terminal and a substrate electrode of the first IGFET, and a third IGFET connected between the second terminal and the substrate electrode of the first IGFET.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.