Voltage-clamped integrated circuit
US4975798A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 5, 1989 |
| Grant date | Dec 4, 1990 |
| Priority date | — |
| Expiry date | Sep 5, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H3/048
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An automobile alternator regulator integrated circuit having a voltage-supply or -sense node (6) for connection to an external voltage, and a voltage clamp comprising: a pnp bypass transistor (Q1) having a base electrode, an emitter electrode coupled to the node and a collector electrode coupled to ground; a resistor (R1) connected between the base electrode and the node; a Zener diode (Z1-Z4) connected between the base electrode and ground for enabling the bypass transistor when the voltage at the node exceeds a predetermined value, whereby the voltage at the node is clamped to a voltage no greater than the predetermined value; and a fuse (F1) connected between the node and the emitter electrode so as to provide a subsequently identifiable cause of failure if the fuse becomes blown due to excess voltage while allowing subsequent operation of the integrated circuit if the clamp means fails but another part of the integrated circuit remains functional.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.