Differential amplifier
US4612513A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 1, 1985 |
| Grant date | Sep 16, 1986 |
| Priority date | — |
| Expiry date | Mar 1, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2203/45604
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A first and a second transistor (T.sub.1, T.sub.2) whose emitters are connected to a common point (4) via first resistors (R.sub.1, R.sub.2), which common point is connected to the positive power-supply terminal via a current source (I.sub.1), form a differential amplifier to which an input signal (V.sub.i) is applied. In order to increase the slew rate the quiescent current through the first and the second transistor (T.sub.1, T.sub.2) is made to increase when the input voltage (V.sub.i) increases. This is achieved by means of a third transistor (T.sub.3) whose emitter is connected to the common point (4). The base of this transistor (T.sub.3) is connected to the tapping of a voltage divider which is arranged between the bases of the first and the second transistor (T.sub.1, T.sub.2) and which comprises second resistors (R.sub.3, R.sub.4). When the input voltage increases the transistor (T.sub.3) drains a continually decreasing portion of the current from the current source (I.sub.1).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.