Switching regulator overload protection circuit

Claim 2

The circuit comprising: a pair of input terminals adapted for connection to a source of potential; a pair of output terminals adapted for connection to a load; a first transistor having a control electrode and two main electrodes, one main electrode having a connection to one input terminal, the other main electrode having a connection to one output terminal; feedback means connected between said pair of output terminals and the control electrode of said transistor for controlling the conduction of current through said transistor in response to the potential appearing between said output terminals; first means comprising a second and third transistor, each having two main electrodes and a control electrode, for providing a path connected across the main electrodes of the first transistor, said path comprising the main electrodes of the second transistor and one main electrode and the control electrode of the third transistor, said third transistor being maintained in a normally non-conducting condition; second means connecting the control electrodes of the first and second transistors; and third means connecting the other main electrode of the third transistor and said feedback means responsive to the conduction of current through the third transistor for providing a signal to said feedback means for rendering said first transistor nonconductive.

Claim 3

The circuit according to claim 1 wherein said third means comprises a monostable multivibrator.

Claim 4

A voltage regulator comprising: a pair of input terminals adapted for connection to a source of unregulated voltage; a pair of output terminals adapted for connection to a load; a first transistor having a control electrode And two main electrodes, one main electrode having a connection to one input terminal, the other main electrode having a connection to one output terminal; feedback means connected between said pair of output terminals and the control electrode of said first transistor for controlling the conduction of current through said first transistor main electrodes in response to the voltage appearing between said output terminals; a second transistor having a control electrode and two main electrodes, the control electrode of said second transistor having a connection to the other main electrode of said first transistor; means comprising the collector emitter path of at least one additional transistor and at least one bias level setting device connected between one main electrode of said second transistor and said one input terminal for maintaining the potential at said one main electrode of said second transistor at a level with respect to the potential at the control electrode of said second transistor such that said second transistor is normally non-conducting; said second transistor being rendered conductive upon the occurrence of a voltage above a certain value across the main electrodes of said first transistor; and means connected between the other main electrode of said second transistor and said feedback means, responsive to the conduction of current through said second transistor for providing a signal to said feedback means for rendering said first transistor non-conductive.

Claim 5

A voltage regulator comprising: a pair of input terminals adapted for connection to a source of unregulated voltage; a pair of output terminals adapted for connection to a load; a first transistor having a control electrode And two main electrodes, one main electrode having a connection to one input terminal, the other main electrode having a connection to one output terminal; feedback means connected between said pair of output terminals and the control electrode of said first transistor for controlling the conduction of current through said first transistor main electrodes in response to the voltage appearing between said output terminals; a second transistor having a control electrode and two main electrodes, the control electrode of said second transistor having a connection to the other main electrode of said first transistor; means comprising the collector emitter path of at least one additional transistor and at least one bias level setting device connected between one main electrode of said second transistor and said one input terminal for maintaining the potential at said one main electrode of said second transistor at a level with respect to the potential at the control electrode of said second transistor such that said second transistor is normally non-conducting; said second transistor being rendered conductive upon the occurrence of a voltage above a certain value across the main electrodes of said first transistor; and means connected between the other main electrode of said second transistor and said feedback means, responsive to the conduction of current through said second transistor for providing a signal to said feedback means for rendering said first transistor non-conductive.

Claim 6

The voltage regulator according to claim 3 wherein said at least one bias level setting device comprises at least one diode connected in series circuit with said one main electrode of said second transistor and the collector to emitter path of said at least one additional transistor.

Claim 7

The voltage regulator according to claim 4 wherein said at least one bias level setting device comprises at least one zener diode connected in series circuit with said one main electrode of said second transistor and the collector to emitter path of said at least one additional transistor.

Claim 8

The voltage regulator according to claim 4 wherein said means connected between the other main electrode of said second transistor and said feedback means comprises: a parallel RC circuit having one terminal connected in circuit with the other main electrode of said second transistor the other terminal of said RC circuit being connected to the other output terminal; and a monostable multivibrator responsive to the signal appearing at said one terminal of said RC circuit for providing a periodic signal to said feedback means for rendering said first transistor periodically non-conductive.

Claim 9

A series pass switching regulator comprising: a pair of input terminals adapted for connection to a source of unregulated voltage; a pair of output terminals adapted for connection to a load; first, second and third transistors each having a control electrode and two main electrodes, the first main electrodes of said first and second transistor having a connection therebetween, the control electrodes of said first and second transistor having a connection therebetween, the second main electrode of said first transistor having a connection to the control electrode of said third transistor and the first main electrode of said third transistor having a connection to the second main electrode of said second transistor; means for connecting one of said input terminals to the first main electrode of said first transistor; means for connecting the second main electrode of said first transistor to one of said output terminals; means for connecting the other input terminal to the other output terminal; a feedback means connected between said pair of output terminals and said control electrode of said first transistor for controlling the conduction of current through said first transistor in response to the voltage appearing across said pair of output terminals; and mEans, connected between the second main electrode of said third transistor and said feedback means, adapted for preventing the conduction of current through the main electrodes of said first transistor upon the occurrence of a voltage across the main electrodes of said first transistor beyond a certain level.

Claim 10

A series pass switching regulator comprising: a pair of input terminals adapted for connection to a source of unregulated voltage; a pair of output terminals adapted for connection to a load; first, second and third transistors each having a control electrode and two main electrodes, the first main electrodes of said first and second transistor having a connection therebetween, the control electrodes of said first and second transistor having a connection therebetween, the second main electrode of said first transistor having a connection to the control electrode of said third transistor and the first main electrode of said third transistor having a connection to the second main electrode of said second transistor; means for connecting one of said input terminals to the first main electrode of said first transistor; means for connecting the second main electrode of said first transistor to one of said output terminals; means for connecting the other input terminal to the other output terminal; a feedback means connected between said pair of output terminals and said control electrode of said first transistor for controlling the conduction of current through said first transistor in response to the voltage appearing across said pair of output terminals; and mEans, connected between the second main electrode of said third transistor and said feedback means, adapted for preventing the conduction of current through the main electrodes of said first transistor upon the occurrence of a voltage across the main electrodes of said first transistor beyond a certain level.

Claim 11

The series pass switching regulator according to claim 7 further comprising: a diode having the anode electrode thereof connected to said other input terminal and the cathode electrode thereof connected to the other main electrode of said first transistor; an inductive energy storage device connected between the cathode electrode of said diode and said one output terminal; and a capacitor connected across said pair of output terminals.

Claim 12

The regulator according to claim 8 wherein said feedback means comprises: a resistive voltage divider connected across said pair of output terminals for sensing the voltage appearing across said output terminals and for providing a control voltage related thereto; a controllable oscillator means responsive to said control voltage for providing a switching signal; and amplifier means connected to the control electrode of said first transistor, said amplifying means being responsive to said switching signal for controlling the conduction of current through said first transistor.

Claim 13

The regulator according to claim 9 wherein said means connected between said third transistor main electrode and said feedback means includes a means coupled to said oscillator means for inhibiting said switching signal upon the occurrence of a voltage across the main electrodes of said first transistor beyond a certain level.

Claim 14

The regulator according to claim 10 wherein said included means comprises a monostable multivibrator.

Claim 15

The regulator according to claim 11 further comprising a parallel RC circuit connected in circuit with the second main electrode of said third transistor and said other output terminal.

Claim 16

The regulator according to claim 12 further comprising at least one additional diode connected between the first main electrode of the third transistor and the second main electrode of the second transistor.

Claim 17

The regulator according to claim 12 further comprising at least one zener diode connected between the first main electrode of the third transistor and the second main electrode of the second transistor.