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US 5,206,581 AGranted
Constant voltage circuit
AssigneeKabushiki Kaisha Toshiba
InventorYoshihiro Yoshida
Life of this patent
Estimating the term…
Abstract
In a constant voltage circuit, when a second resistor element is inserted between the base and collector of a first transistor and between the other terminal of a first resistor element and the base of a second transistor, a basic equation for calculating a bandgap voltage reference can be calculated free from a base-emitter voltage of the third transistor. Therefore, since a change in base-emitter voltage on the basis of a change in current flowing through the third transistor does not appear as an output voltage, the output voltage can be stabilized.
Claims7
A constant voltage circuit comprising:
- a control circuit having input and output terminals in which an output at said output terminal is controlled according to a current at said input terminal;
- a first resistor element having a first terminal connected to said output terminal of said control circuit;
- a second resistor element having a first terminal connected to a second terminal of said first resistor element;
- a first transistor of a first polarity having a base connected to said second terminal of said first resistor element, a collector connected to a second terminal of said second resistor element, and an emitter connected to a first node;
- a third resistor element having a first terminal connected to said output terminal of said control circuit;
- a second transistor of the first polarity having a collector connected to a second terminal of said third resistor element, a base connected to said second terminal of said second resistor element, and an emitter connected to said first node;
- and
- a third transistor of the first polarity having a collector connected to said input terminal of said control circuit, a base connected to said second terminal of said third resistor element, and an emitter connected to said first node;
- said control circuit including:
- a current source having a first terminal connected to a second node having a predetermined potential applied thereto and a second terminal connected to said collector of said third transistor,
- a fifth transistor of a second polarity having an emitter connected to said second node and a collector connected to said first terminal of said first resistor element, to said first terminal of said third resistor element and to a third node at which an output voltage is provided, and
- a sixth transistor of the first polarity having a collector connected to a base of said fifth transistor, a base connected to said collector of said third transistor, and an emitter connected to said first node.
9 more elements
A constant voltage circuit comprising:
- a control circuit having an input terminal and first and second output terminals in which an output at said first and second output terminals is controlled according to a current at said input terminal, said control circuit further having a terminal connected to a second node having a predetermined potential applied thereto;
- a first resistor element having a first terminal connected to said first output terminal of said control circuit;
- a second resistor element having a first terminal connected to a second terminal of said first resistor element;
- a first transistor of a first polarity having a base connected to said second terminal of said first resistor element, a collector connected to a second terminal of said second resistor element, and an emitter connected to a first node;
- a third resistor element having a first terminal connected to said second output terminal of said control circuit;
- a second transistor of the first polarity having a collector connected to a second terminal of said third resistor element, a base connected to said second terminal of said second resistor element, and an emitter connected to said first node;
- and
- a third transistor of the first polarity having a collector connected to said input terminal of said control circuit, a base connected to said second terminal of said third resistor element, and an emitter connected to said first node.
5 more elements
Dependencies are inferred from the claim text.