Negative overvoltage protection circuit, in particular for output stages
US5182470A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 5, 1990 |
| Grant date | Jan 26, 1993 |
| Priority date | — |
| Expiry date | Oct 5, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H9/047
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An output stage with a protection circuit against negative overvoltage at its output terminal, having a transistor with collector output and with the emitter connected to a reference voltage line; a diode for protection against negative overvoltages present on the output is arranged between the collector and the output of the stage. In order to give the output of the stage a presettable minimum voltage level, the reference voltage line is set to a preset voltage which differs from the ground voltage. For this purpose, the circuit comprises an operational amplifier in a voltage-follower configuration, the output whereof is connected to the reference voltage line, a diode which is connected between the ground and the non-inverting terminal of the operational amplifier, and a current source which is connected between the non-inverting input of the operational amplifier and a negative supply line.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.