Integrated circuit overvoltage protection circuit
US4005342A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 15, 1974 |
| Grant date | Jan 25, 1977 |
| Priority date | — |
| Expiry date | Nov 15, 1994 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D89/60
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An overvoltage protection circuit in an integrated circuit for increasing the breakdown voltage of the integrated circuit between first and second terminals thereof. Diode-connected transistors are connected in series between the first terminal and a resistor. The resistor is connected to the base of a first transistor having its emitter connected to the second terminal and its collector connected to the base of a second transistor having its emitter connected to the second terminal and its collector connected to the first terminal. If an overvoltage applied between the first and second terminals exceeds the sum of the emitter-base reverse breakdown voltages of the diode-connected transistors, current flows into the base of the first transistor, causing it to saturate, thereby preventing the emitter-base junction of the second transistor from being forward biased. The collector to emitter breakdown voltage of the second transistor is thereby increased.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.