CIRCUITO LOGICO DIGITALE PERFEZIONATO

• Main Author: WIEDMANN SIEGFRIED KURT
• Format: Patent
• Language: Italian
• Published: 10.12.1986
• Edition: 4
• Subjects: BASIC ELECTRONIC CIRCUITRY; ELECTRICITY; PULSE TECHNIQUE

Bipolar logic circuits such as inverters and NAND circuits are disclosed which are of extremely low DC power dissipation and very high speed. The basic circuit is an inverter circuit which incorporates at least a single switchable transistor (3). The emitter (6) of the NPN transistor (3) is connected to a potential level which may be ground while the collector is connected via a load device, a resistor or a complementary PNP transistor (2), to a positive power supply potential. The base (8) of the NPN transistor (3) is connected to a source (10) of standby current and via a parallel combination of a capacitor (14) and diode (12) to an input terminal (15). When the NPN transistor (3) is switched OFF by the application of a negatively going signal, standby current from the current source (10) is switched to ground via the diode (12) which has a lower switching point than the emitter-base diode of the NPN transistor. The capacitor (14) in parallel with the diode, is charged during this period so that when a positive going transient is applied at the input, the diode is backward-biased and the transient is applied along with the standby current to the base (8) of the NPN transistor, switching it to the conducting or ON state. In addition to the basic logic circuit, a two-input NAND circuit which includes a pair of PNP bipolar transistors and a pair of NPN bipolar transistors disclosed.