Sziklai couple

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Sziklai pair consisting of two complementary bipolar transistors Q 1 and Q 2 , which together act like an npn transistor
Sziklai pair consisting of two complementary bipolar transistors Q 1 and Q 2 , which together act like a pnp transistor

A Sziklai pair , also known as a complementary Darlington circuit , is an electronic circuit made up of two bipolar transistors similar to a Darlington circuit , in contrast to which two different bipolar transistors, one npn transistor and one pnp transistor , are used. The circuit is named after the American-Hungarian engineer George Clifford Sziklai , who developed it in 1953.

Functionality and properties

Two variants of a Sziklai pair are described in the literature. Depending on the arrangement of the npn and pnp transistors, the Sziklai pair acts as an npn or as a pnp transistor. By interconnecting the two complementary transistors, a higher current gain is achieved than with individual bipolar transistors.

The base-emitter voltage U BE , the voltage between the connections marked with B and E in the adjacent circuit diagram, is around 0.6 V for both variants - in contrast to the Darlington circuit with its base-emitter voltage of twice as high around 1.2 V. As with Darlington steps, the saturation voltage in the collector-emitter path U CE is around 0.6 V. In practical applications, a resistance in the range from 0.1 to 1 kΩ between the emitter and base of Q 2 switched to shorten the switch-off times for fast switching applications.

application

In terms of practical circuit technology, the Sziklai pair initially played a subordinate role compared to the Darlington stage, despite technical advantages, since two npn transistors of the Darlington circuit can be manufactured more easily on a common semiconductor substrate than a combination of npn and pnp transistor. Applications of the complementary Darlington pair are in the area of ​​bipolar, integrated amplifiers and their push-pull output stages .

literature

  • Paul Horowitz, Winfield Hill: The Art of Electronics . Cambridge University Press, 1989, ISBN 0-521-37095-7 , pp. 95 .

Web links

Individual evidence

  1. ↑ Patent US2762870 : Push-pull complementary type transistor amplifier. Filed May 28, 1953 , published September 11, 1956 , inventors: George C. Sziklai, Robert D. Lohman, Allen A. Barco. ‌
  2. ^ GC Sziklai: Symmetrical Properties of Transistors and Their Applications . In: Proceedings of the IRE . tape 41 , no. 6 , 1953, pp. 717-724 , doi : 10.1109 / JRPROC.1953.274250 .
  3. ↑ Ben Duncan: High Performance Audio Power Amplifiers . Newnes, 1996, ISBN 0-7506-2629-1 , pp. 90 .