Power supply control for integrated circuit
US4451742A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 9, 1983 |
| Grant date | May 29, 1984 |
| Priority date | — |
| Expiry date | Dec 9, 2003 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S331/03
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A power supply control circuit (20) selectively provides power to an integrated circuit from either a primary power supply terminal (22), or through terminals (24, 26) connected to backup batteries. The voltage level of the primary power is monitored continuously and when it drops to a predetermined level one of the two backup batteries is substituted to power the integrated circuit in a power-down mode. The circuit (20) includes a level detector circuit (32) and a voltage reference circuit (98). In the power-down mode one battery is connected to power the integrated circuit and this battery is continuously monitored. When the voltage of the on-line battery drops to below a fixed level in comparison to off-line battery a control logic circuit (92) activates switches (56) to substitute the off-line battery for the on-line battery. Control logic circuitry (92) is provided to disconnect the control signals from the integrated circuit to prevent loss of stored information. Further the failure of one of the backup batteries is indicated by disabling a write enable signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.