TEMPERATURE DEPENDENT VOLTAGE REFERENCE CIRCUIT
First Claim
1. In combination:
- a first and a second input terminal between which a temperaturedependent reference voltage is produced;
a first and a second transistor of the same conductivity type, each operated at substantially the same temperature upon which temperature said reference voltage depends, each of said first and said second transistors having a base and an emitter electrode and a base-emitter junction therebetween and each having a collector electrode;
a potential divider having an input circuit connected between said first and said second input terminals and having an output circuit connected between the base electrodes of said first and said second transistors;
means for supplying an operating current flow between said first and said second input terminals;
means for conducting a portion of said operating current from said first input terminal to the joined emitter electrodes of said first and said second transistors;
a first current amplifier having an input terminal connected to said first transistor collector electrode, having a common terminal connected to said second input terminal, having an output terminal connected to said second transistor collector electrode, and having an inverting or negative current gain between its said input and output terminals; and
a second current amplifier having an input terminal connected to said first current amplifier output terminal and having a common and an output terminal connected to separate ones of said first and said second input terminals;
a degenerative feedback loop being formed by the aforesaid connections, which operates to maintain the densities of current flow through the base-emitter junctions of said first and said second transistors in a predetermined ratio other than unity.
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Abstract
A fractional part of a voltage to be regulated is applied between the base electrodes of first and second emitter-coupled transistors having base-emitter junctions with different VBE versus current characteristics. The collector currents of the first and the second transistors are caused to be in a predetermined ratio by a degenerative feedback loop which adjusts the value of the voltage to be regulated. Since the aforesaid fractional part of this voltage must vary linearly with the temperature change of the first and second transistors in order to maintain their collector currents equal, the voltage to be regulated must vary inversely as this fraction with that temperature change. The fractional part can be of fixed value, in which case the voltage to be regulated will vary linearly with the temperature change of the first and second transistors, or it can be changed from one value to another to cause the voltage to be regulated to vary in a more complex manner with temperature.
28 Citations
13 Claims
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1. In combination:
- a first and a second input terminal between which a temperaturedependent reference voltage is produced;
a first and a second transistor of the same conductivity type, each operated at substantially the same temperature upon which temperature said reference voltage depends, each of said first and said second transistors having a base and an emitter electrode and a base-emitter junction therebetween and each having a collector electrode;
a potential divider having an input circuit connected between said first and said second input terminals and having an output circuit connected between the base electrodes of said first and said second transistors;
means for supplying an operating current flow between said first and said second input terminals;
means for conducting a portion of said operating current from said first input terminal to the joined emitter electrodes of said first and said second transistors;
a first current amplifier having an input terminal connected to said first transistor collector electrode, having a common terminal connected to said second input terminal, having an output terminal connected to said second transistor collector electrode, and having an inverting or negative current gain between its said input and output terminals; and
a second current amplifier having an input terminal connected to said first current amplifier output terminal and having a common and an output terminal connected to separate ones of said first and said second input terminals;
a degenerative feedback loop being formed by the aforesaid connections, which operates to maintain the densities of current flow through the base-emitter junctions of said first and said second transistors in a predetermined ratio other than unity.
- a first and a second input terminal between which a temperaturedependent reference voltage is produced;
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2. The combination set forth in claim 1 wherein:
- said first and said second transistors have dissimilar base-emitter junctions causing their respective emitter current versus base-emitter voltage characteristics to differ from each other, and said first current amplifier has a current gain of substantially minus unity.
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3. The combination set forth in claim 1 wherein:
- said first and said second transistors have base-emitter junctions which are alike and have like emItter current versus base-emitter voltage characteristics, and said first current amplifier has a current gain other than minus unity.
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4. A circuit for producing between a first and a second input terminals a voltage of interest comprising:
- a source of operating current connected between said first and said second input terminals;
first and second transistors of the same conductivity type, each operated at substantially the same temperature upon which temperature said voltage of interest depends, each of said first and said second transistors having a base electrode and an emitter electrode with a base-emitter junction therebetween and having a collector electrode;
means for conducting a first portion of said operating current, which means is connected between said first input terminal and the joined emitter electrodes of said first and said second transistors;
means responsive to said voltage of interest to provide a potential difference which is applied between the base electrodes of said first and said second transistors to cause collector current flows in said first and said second transistors in a prescribed proportion corresponding to unequal densities of emitter current flow through their respective base-emitter junctions;
means coupled to each of the collector electrodes of said first and said second transistors to sense their collector currents and responsive to any tendency for these collector currents to depart from their prescribed proportion for altering said voltage of interest to counteract said tendency, whereby said potential difference varies proportionally with said temperature and said voltage of interest varies directly though not necessarily proportionally with said temperature.
- a source of operating current connected between said first and said second input terminals;
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5. A circuit as claimed in claim 4 wherein said means responsive to said voltage of interest to provide a potential difference comprises:
- a first resistive element connected between said base electrodes of said first and said second transistors and at least a first further resistive element connected in serial combination with said first resistive element between said first and said second input terminals.
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6. A circuit as claimed in claim 5 having:
- a device with a conduction threshold; and
an additional resistive element connected serially therewith between one of the base electrodes of said first and said second transistors and the end of said first further resistive element remote from said first resistive element.
- a device with a conduction threshold; and
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7. A circuit as claimed in claim 4 wherein said means responsive to said voltage of interest to provide a potential difference comprises:
- a first resistive element connecting said first input terminal and said first transistor base electrode;
a second resistive element connecting said first transistor base electrode and said second transistor base electrode; and
a third resistive element connecting said second transistor base electrode and said second input terminal.
- a first resistive element connecting said first input terminal and said first transistor base electrode;
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8. A circuit as claimed in claim 4 wherein said means to sense collector currents and for altering said voltage of interest to counteract any tendency for them to depart from their prescribed proportion includes:
- an inverting current amplifier having an input circuit and an output circuit to which the collector electrodes of said first and said second transistors are respectively connected, said current amplifier having a current gain of magnitude equal to said prescribed proportion; and
another amplifier having an input circuit coupled to the output circuit of the aforesaid current amplifier and having an output circuit coupled to said first and said second terminals.
- an inverting current amplifier having an input circuit and an output circuit to which the collector electrodes of said first and said second transistors are respectively connected, said current amplifier having a current gain of magnitude equal to said prescribed proportion; and
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9. A circuit as claimed in claim 8 wherein said inverting current amplifier comprises:
- a third and a fourth transistor of a conductivity type complementary to that of said first and said second transistors, each having a base and an emitter electrode with a base-emitter junction therebetween and each having a collector electrode, the collectoR electrodes of said third and said fourth transistors being connected respectively to the collector electrodes of said first and said second transistors, the base electrodes of said third and said fourth transistors being connected to said third transistor collector electrode, and the emitter electrodes of said third and said fourth transistors being connected to said second input terminal.
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10. A circuit as claimed in claim 9 wherein:
- a fifth transistor of the same conductivity type as said third and said fourth transistors is included as a common-emitter amplifier stage in said another amplifier, said fifth transistor having a base and an emitter electrode with a base-emitter junction therebetween and having a collector electrode, said fifth transistor base electrode being connected to the collector electrodes of said second and said fourth transistors to receive the difference in their collector currents, and said fifth transistor emitter electrode being connected to said second input terminal, and means for conducting a second portion of said operating current which is substantially equal to said first portion is connected between said first input terminal and said fifth transistor collector electrode.
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11. Reference voltage circuit for providing at least a first temperature-dependent reference voltage comprising:
- first and second transistors of the same conductivity type, each operated at substantially the same temperature upon which temperature said reference voltage depends, each having a base electrode and an emitter electrode with a base-emitter junction therebetween and each having a collector electrode, said first transistor base-emitter junction being characterized by a larger emitter current flow for any given base-emitter potential than said second transistor base-emitter junction;
means connected to the emitter electrodes of said first and said second transistors to maintain them at the same potential;
means connected to the collector electrodes of each of said first and said second transistors for receiving their respective collector currents and comparing them to develop a signal proportional to the difference between them and;
means for applying said signal between the base electrodes of said first and said second transistors, to complete a degenerative feedback loop for said signal.
- first and second transistors of the same conductivity type, each operated at substantially the same temperature upon which temperature said reference voltage depends, each having a base electrode and an emitter electrode with a base-emitter junction therebetween and each having a collector electrode, said first transistor base-emitter junction being characterized by a larger emitter current flow for any given base-emitter potential than said second transistor base-emitter junction;
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12. Reference voltage circuit as claimed in claim 11 wherein said means for applying said signal includes:
- a potential divider having an output circuit connected between the base electrodes of said first and said second transistors and having an input circuit connected to receive said signal whereby said signal is a second temperature-dependent reference voltage scaled up from said first temperature-dependent reference voltage by the voltage division ratio of said potential divider.
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13. In combination:
- means for supplying a reference potential;
means for supplying a first and a second current, which currents are substantially equal to each other;
a first and a second transistor of a first conductivity type, each having a principal conduction path between a first and a second electrode and having a control electrode for controlling the conductance of its said principal conduction path, the first electrodes of said first and said second transistors being connected together and connected to said means for supplying a first and a second currents to receive said first current;
a third and a fourth and a fifth transistor of a second conductivity type complementary to said first conductivity type, each having a base and a collector electrode, all having emitter electrodes interconnected and connected to said means for supplying a reference potential;
said third and said fourth transistor collector electrodes being respectively connected to separate ones of the second electrodes of said first and said second transistors, said fifth transistor collector electrode being connected to said means for supplying a first And a second currents to receive said second current, said base electrodes of said third and said fourth transistors each being coupled to said third transistor collector electrode, said fifth transistor base electrode being coupled to said fourth transistor collector electrode;
means for supplying an input signal potential referred to said reference potential, which input signal is applied between the control electrodes of said first and said second transistors; and
means connected to said fifth transistor collector electrode to sense whether or not the collector current flow of said fifth transistor exceeds said second current in magnitude.
- means for supplying a reference potential;
Specification