Saturation limiting system for a vertical, isolated collector PNP transistor and monolithically integrated structure thereof
US4887141A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 19, 1988 |
| Grant date | Dec 12, 1989 |
| Priority date | — |
| Expiry date | Oct 19, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S257/918
Abstract
The structure of a vertical PNP transistor with isolated collector is modified by forming a P-type diffusion outside the perimeter of a sinker collector diffusion to form an auxiliary collector capable of detecting the injection of current toward the substrate when the integrated transistor saturates. The current gathered by said auxiliary collector is used for activating a saturation limiting circuit formed by an NPN transistor which is switched-on when said said current gathered by said auxiliary collector reaches a threshold value and which in turn switches-on a PNP transistor having an emitter and a collector connected respectively to the emitter and to the base of the PNP vertical transistor with isolated collector for reducing the driving base current thereto.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.