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US 4,063,116 AGranted
Temperature compensated current source
AssigneeRaytheon Company
InventorJames C. Schmoock
Life of this patent
Estimating the term…
Abstract
A temperature compensated, switchable current source wherein a Darlington pair of transistors in the output section of such current source is coupled to a source of switching signals through two electrical paths, each having a switching transistor and a diode network. The diode networks are arranged to produce a voltage variation at the input to the Darlington pair which varies inversely to the temperature variation developed across the base-emitter junctions of the Darlington pair of transistors. Coupling the Darlington pair of transistors to the source of switching signals through two switching transistors enables the current source to be rapidly driven from a conducting state to a nonconducting state in response to the switching signals.
Claims24
A temperature compensated switching circuit, comprising:
- a. an emitter-follower circuit including a pair of transistors arranged in a Darlington configuration, a first one of such pair of transistors having a base electrode adapted for coupling to a source of switching signals through two electrical paths and an emitter electrode connected to the base electrode of a second one of such pair of transistors, and a resistor connected between the emitter electrode of the second one of the pair of transistors and ground;
- b. a pair of input transistors disposed in corresponding ones of such paths, each one of such transistors being arranged in a grounded emitter configuration having base electrodes adapted for coupling to the source of switching signals and collector electrodes coupled to the base electrode of the first one of the pair of transistors in the Darlington configuration;
- and
- c. means, including a pair of diode networks coupled to the collector electrodes of the pair of input transistors, for producing a voltage variation at the base electrode of the first one of the pair of transistors in the Darlington configuration which varies inversely to the temperature variation developed across the base-emitter junctions of the pair of transistors arranged in the Darlington configuration.
1 more element
A temperature compensated, switchable current source, comprising:
- an emitter-follower circuit adapted to provide, at a terminal, a reference voltage for such current source when such current source is in a conducting state, such circuit including a first transistor having a base electrode adapted for coupling to a source of switching signals through two electrical paths and an emitter electrode coupled to such terminal through a second transistor in such emitter-follower circuit and a resistor connected to ground and to the emitter electrode of the second transistor at such terminal, the reference voltage varying with temperature over a range of temperatures as the base-to-emitter voltages of such transistors vary with such temperature and wherein each one of such electrical paths has disposed therein a pair of switching transistors arranged in a grounded emitter configuration having base electrodes adapted for coupling to the source of switching signals and collector electrodes coupled to the base electrode of the first transistor in the emitter-follower circuit;
- and means, including a pair of diode networks coupled to the collector electrodes of the pair of switching transistors, for producing a voltage at the base electrode of the first transistor in the emitter-follower circuit which varies in temperature over the range of temperatures maintaining the voltage at the terminal substantially constant over the temperature range.
A switching circuit, comprising:
- a. an emitter follower circuit having:
- i. a resistor;
- and
- ii. a pair of output transistors, a first one thereof having a base electrode and a second one of such pair of transistors having:
- A. a base electrode connected to an emitter electrode of the first one of the pair of output transistors;
- B. a collector electrode connected to the collector electrode of the first one of the pair of output transistors;
- and
- C. an emitter electrode coupled to ground through said resistor;
- b. a pair of input transistors having base electrodes coupled to a source of switching signals and grounded emitter electrodes, a first one of the pair of input transistors having a collector electrode connected to the base electrode of the first one of the pair of output transistors;
- c. a coupling transistor having a base electrode connected to a collector electrode of a second one of the pair of input transistors and an emitter electrode coupled to the base electrode of the first one of the pair of output transistors;
- and
- d. a pair of diode networks coupled between ground and the collector electrodes of corresponding ones of the pair of input transistors.
9 more elements
A temperature compensated switching circuit, comprising:
- a. an emitter-follower circuit comprising a pair of transistors arranged in a Darlington configuration;
- b. means for switching such pair of transistors to either a conducting state or a nonconducting state selectively in accordance with a control signal producing a reference voltage at an emitter electrode of a first one of the pair transistors in the Darlington configuration when such transistor is in a conducting state, such means including a pair of input transistors arranged in a grounded emitter configuration having base electrodes adapted for coupling to a source of the switching signals and collector electrodes coupled to a base electrode of a second one of the pair of transistors in the Darlington configuration;
- and
- c. means, including a pair of diode networks coupled between ground and corresponding ones of the pair of collector electrodes of the pair of input transistors, for maintaining the reference voltage substantially invariant with temperature variations over a predetermined range of temperatures.
1 more element
A switching circuit, comprising:
- a. an emitter-follower circuit having a pair of output transistors, a first one thereof having a base and a second one of such pair of output transistors having:
- i. a base connected to an emitter of the first one of the pair of output transistors;
- and
- ii. a collector connected to the collector of the first one of the pair of output transistors;
- b. a pair of input transistors having bases coupled to a source of switching signals, a first one of the pair of input transistors having a collector connected to the base of the first one of the pair of output transistors;
- c. a junction semiconductor device having one terminal connected to a collector of a second one of the pair of input transistors and a second terminal coupled to the base of the first one of the pair of output transistors;
- and
- d. a pair of diode networks coupled to the collectors of corresponding ones of the pair of input transistors.
5 more elements
Dependencies are inferred from the claim text.