Protection circuit for electronic devices
US6130813A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 11, 1999 |
| Grant date | Oct 10, 2000 |
| Priority date | — |
| Expiry date | Jan 11, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H11/005
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
For an electronic device having at least one power switch for each of two or more power sources such that the power switches can be selectively activated or deactivated depending on a signal supplied to them, a protection circuit having a current-sense circuit coupled to measure the current from the two or more power sources, and a latch for producing a switch deactivating signal and applying it to the switches in response to an over-current signal from the current-sense circuit can protect the switches and the electronic device from soft-short circuits and absolute short circuits. Bypass resistors coupled to the switches allow the electronic device to receive a small current ("pre-charge") before any of the switches are activated so that a comparator can test for the presence of various types of short circuits. Additionally, the precharging brings the electronic device to a higher voltage (as compared to no pre-charging) when one of the switches is activated, thereby helping to reduce in-rush currents. Blanking logic allows the protection circuit to tolerate certain in-rush currents by preventing the latch from triggering (e.g., supplying the latch with an under-current signal) fo…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.