Transistorized bridge rectifier circuit with overcurrent protection for use in telephones
First Claim
1. A transistorized bridge rectifier circuit with overcurrent protection for joining an electronic circuit of a telephone subscriber set to a telephone line having first and second wires, said rectifier circuit comprising:
- first, second, third, and fourth elements of a bridge, each element having a first and a second terminal, said second terminal of said first element being connected to said second terminal of said second element and said second terminal of said third element being connected to said second terminal of said fourth element, said connections respectively constituting first and second coupling terminals to which is connected said electronic circuit of said telephone subscriber set;
said first terminals of said first and third elements being connected to said first wire of said telephone line, and said first terminal of said second and fourth elements being connected to said second wire of said telephone line;
each element of said bridge comprising at least one first bipolar transistor having its emitter and collector connected between said first and second terminals of its element, said emitter of said first transistor being connected to said first terminal of its element, said transistors of said first and second elements having a first type of conductivity which is the opposite from a second type of conductivity of the transistors of said third and fourth elements;
the base of each of said transistors are connected to a control circuit means which is sensitive to the polarity of the telephone line voltage across said first and second wires and which controls the conduction of said transistors of said first and fourth elements of said bridge so as to be opposite to the conduction of said transistors of said second and third elements of said bridge, wherein a base of said first transistor of each of said third and fourth bridge elements is connected to said second terminal of its element by means of a first semiconductor element having a bipolar junction which is normally reverse-biased.
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Accused Products
Abstract
A transistorized bridge rectifier circuit with overcurrent protection which can be integrated monolithically is used for joining to a two-wire telephone line to the electronic circuits of a telephone subscriber set connected thereto. The circuit includes a transistorized bridge having a circuit arranged in the manner of a Graetz bridge. Rather than using separate elements for overcurrent protection, the circuit uses the bridge circuit elements themselves as protection elements. Diodes or diode connected transistors are respectively connected between the base and collector of transistors in two arms of the Graetz bridge and the resultant circuit thus provides overcurrent protection without the need of additional protection elements.
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Citations
29 Claims
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1. A transistorized bridge rectifier circuit with overcurrent protection for joining an electronic circuit of a telephone subscriber set to a telephone line having first and second wires, said rectifier circuit comprising:
- first, second, third, and fourth elements of a bridge, each element having a first and a second terminal, said second terminal of said first element being connected to said second terminal of said second element and said second terminal of said third element being connected to said second terminal of said fourth element, said connections respectively constituting first and second coupling terminals to which is connected said electronic circuit of said telephone subscriber set;
said first terminals of said first and third elements being connected to said first wire of said telephone line, and said first terminal of said second and fourth elements being connected to said second wire of said telephone line;
each element of said bridge comprising at least one first bipolar transistor having its emitter and collector connected between said first and second terminals of its element, said emitter of said first transistor being connected to said first terminal of its element, said transistors of said first and second elements having a first type of conductivity which is the opposite from a second type of conductivity of the transistors of said third and fourth elements;
the base of each of said transistors are connected to a control circuit means which is sensitive to the polarity of the telephone line voltage across said first and second wires and which controls the conduction of said transistors of said first and fourth elements of said bridge so as to be opposite to the conduction of said transistors of said second and third elements of said bridge, wherein a base of said first transistor of each of said third and fourth bridge elements is connected to said second terminal of its element by means of a first semiconductor element having a bipolar junction which is normally reverse-biased. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
- first, second, third, and fourth elements of a bridge, each element having a first and a second terminal, said second terminal of said first element being connected to said second terminal of said second element and said second terminal of said third element being connected to said second terminal of said fourth element, said connections respectively constituting first and second coupling terminals to which is connected said electronic circuit of said telephone subscriber set;
Specification