Protective device for a power element of an integrated circuit
US4074334A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 17, 1976 |
| Grant date | Feb 14, 1978 |
| Priority date | — |
| Expiry date | Sep 17, 1996 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F1/52
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A protective device limiting the current flow through a power transistor 11 in a final stage of an integrated circuit comprises, as part of that circuit, a normally nonconductive shunt transistor 31 which is turned on by a monitoring transistor 22 whenever the collector current I and the collector-emitter voltage V.sub.CE of the power transistor reach values beyond a protective curve 52 plotted on a current/voltage diagram. The base-emitter circuit of the monitoring transistor 22 is connected across an output resistor R.sub.2, in series with the power transistor 11, via a diode 21 of logarithmic conduction characteristic, that diode being also connected across the power transistor in series with a voltage-sensing network. This network includes a voltage divider R.sub.3, R.sub.5 in series with a Zener diode 33, the voltage divider being connected in parallel with a switching transistor 35 whose base is tied to a tap of the divider.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.