Darlington transistor circuit
US4539492A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 27, 1983 |
| Grant date | Sep 3, 1985 |
| Priority date | — |
| Expiry date | Jan 27, 2003 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K17/04126
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A three-stage Darlington transistor circuit having a power transistor (T.sub.3), a driver transistor (T.sub.2) and an initial transistor (T.sub.1) is provided. The collectors of these three transistors are connected with one another, while the emitter of the driver transistor (T.sub.2) is connected to the base of the power transistor (T.sub.3), and the emitter of the initial transistor (T.sub.1) is connected to the base of the driver transistor (T.sub.2). Connected to the base of the driver transistor (T.sub.2) is a series circuit comprising a first resistor (R.sub.1), which is connected directly to this base, and a Zener diode (ZD), the anode of the Zener diode being connected with the resistor (R.sub.1); and a second resistor (R.sub.2); the second resistor (R.sub.2) is connected in parallel to the emitter-base path of the driver transistor (T.sub.2). Upon the attainment of a predetermined voltage at the cathode of the Zener diode (ZD), the driver transistor (T.sub.2) and the power transistor (T.sub.3) are switched ON. The temperature dependency of this switch-on voltage can be adjusted by varying the resistance ratio of these two resistors (R.sub.1, R.sub.2).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.