Modified widlar source and logic circuit using same

A logic circuit for performing a logical OR function between a plurality of input signals received at respective bases of a plurality of transistors, each of the plurality of transistors having collectors coupled to a first power supply voltage terminal, and having emitters coupled together and to a current source and providing an output signal therefrom, the current source comprising:

• a first transistor having a collector coupled to the emitter of said plurality of transistors and providing a first terminal of the current source, a base, and an emitter;
• a first resistor having a first terminal coupled to said emitter of said first transistor, and a second terminal coupled to a second power supply voltage terminal;
• a second resistor having a first terminal coupled to the first power supply voltage terminal, and a second terminal coupled to said base of said first transistor;
• a second transistor having a collector coupled to said second terminal of said second resistor, a base coupled to said second terminal of said second resistor, and an emitter;
• a third resistor having a first terminal coupled to said emitter of said second transistor, and a second terminal coupled to said second terminal of said first resistor;
• and
• means coupled to said first power supply voltage terminal and to said second terminal of said second resistor, for selectively reducing a resistance between the first power supply voltage terminal and said second terminal of said resistor in response to a control signal.

A logic circuit comprising:

• switching means for selectively coupling an output terminal to a predetermined logic potential in response to a predetermined logic function between a plurality of input signals;
• a first transistor having a collector coupled to said output terminal, a base, and an emitter;
• a first resistor having a first terminal coupled to said emitter of said first transistor, and a second terminal coupled to a first power supply voltage terminal;
• a second resistor having a first terminal coupled to a second power supply voltage terminal, and a second terminal coupled to said base of said first transistor;
• a second transistor having a collector coupled to said second terminal of said second resistor, a base coupled to said second terminal of said second resistor, and an emitter;
• a third resistor having a first terminal coupled to said emitter of said second transistor, and a second terminal coupled to said second terminal of said first resistor;
• and
• means coupled to said second power supply voltage terminal and to said second terminal of said second resistor, for selectively reducing a resistance between the first power supply voltage terminal and said second terminal of said resistor in response to a control signal.