Starting circuit with precise turn-off
US4333047A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 6, 1981 |
| Grant date | Jun 1, 1982 |
| Priority date | — |
| Expiry date | Apr 6, 2001 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S323/901
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A current control circuit which can be used to provide starting current during the build-up of an input voltage, and terminate the starting current when the input voltage has reached a predetermined level. The preferred embodiment employs three FETs and one bipolar transistor, located in a total of only two isolation pockets on an integrated circuit chip. The first FET, which is scaled to operate in its saturated region while the second FET is in its resistive region, transmits a current received from the second FET as an output starting current during the initial portion of the input voltage build-up. During this time the second FET holds the gate-source voltage of the first FET to a level less than its pinch-off voltage. The third FET has its gate and source terminals connected in parallel with the first FET, and its drain connected to the base of the bipolar transistor, which is also connected to shunt current away from the first FET when appropriately gated. When the input voltage reaches a predetermined amount, the gate-source voltage of the third FET is elevated to the pinch-off voltage of the first FET, turning that device off. At the same time the bipolar transistor is gate…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.