Voltage protection circuit

Claim 2

In a television receiver having horizontal deflection circuitry including drive circuitry, protection circuitry comprising: a source of energizing voltage connected to said horizontal deflection circuitry for providing an energizing voltage thereto; sensing means connected to said source for providing a control signal in response to voltages from said source exceeding a threshold; a controlled rectifier having an output electrode and a control electrode connected to said sensing means for switching from a first conducting condition to a second conducting condition in response to said control signal; and means connecting said output electrode of said controlled rectifier to said drive circuitry for altering the bias thereof when said sensing means provides said control signal to bias said drive circuitry in an inoperative condition.

Claim 3

Protection circuitry as defined in claim 1 wherein said sensing means includes a zener diode.

Claim 4

Protection circuitry as defined in claim 1 wherein said source of energizing voltage includes a voltage regulator having a regulator transistor and a driver transistor connected to said regulator transistor; and said sensing means includes a sensing transistor connected between an output of said regulator transistor ane an output of said drive transistor, and means connecting an output elEctrode of said sensing transistor to said control electrode of said controlled rectifier.

Claim 5

In a television receiver having deflection circuitry for generating horizontal and vertical deflection signals, protection circuitry for disabling the horizontal deflection circuitry in response to excessive energizing voltage comprising: a source of energizing voltage coupled to said horizontal deflection apparatus for providing an energizing voltage thereto; sensing means connected to said source for providing a control signal in response to an energizing voltage in excess of a predetermined threshold; current control means having an output electrode and a control electrode connected to said sensing means for switching from a first conducting condition to a second conducting condition in response to said control signal; and means connecting said output electrode to said horizontal deflection circuitry for disabling said horizontal deflection circuitry when said current control means switches to said second conducting condition.

Claim 6

In a television receiver having deflection circuitry for generating horizontal and vertical deflection signals, protection circuitry for disabling the horizontal deflection circuitry in response to excessive energizing voltage comprising: a source of energizing voltage coupled to said horizontal deflection apparatus for providing an energizing voltage thereto; sensing means connected to said source for providing a control signal in response to an energizing voltage in excess of a predetermined threshold; current control means having an output electrode and a control electrode connected to said sensing means for switching from a first conducting condition to a second conducting condition in response to said control signal; and means connecting said output electrode to said horizontal deflection circuitry for disabling said horizontal deflection circuitry when said current control means switches to said second conducting condition.

Claim 7

Protection circuitry as defined in claim 4 wherein said current control means is a controlled rectifier.

Claim 8

Protection circuitry as defined in claim 5 wherein said horizontal deflection circuitry includes an oscillator and a drive transistor connected thereto, said output electrode of said controlled rectifier being connected to a bias circuit for said driver transistor for altering the bias thereof when said controlled rectifier switches to said second conducting condition.

Claim 9

Protection circuitry as defined in claim 5 wherein said sensing means includes a zener diode.

Claim 10

Protection circuitry as defined in claim 5 wherein said source of energizing voltage includes a voltage regulator having a driver transistor and a regulator transistor connected thereto for providing a regulated energizing voltage; wherein said sensing means includes a sensing transistor having an input electrode connected to said regulator transistor for receiving said energizing voltage, an output electrode, and a reference electrode connected to a point of reference potential; and further including means connecting said output electrode of said sensing transistor to said control electrode of said controlled rectifier.

Claim 11

Protection circuitry as defined in claim 8 wherein said point of reference potential is an output electrode of said driver transistor.

Claim 12

Protection circuitry for a voltage regulator having a series regulator transistor comprising: sensing means connected to an output electrode of said regulator transistor for providing a control signal when the voltage of said output electrode exceeds a threshold; and current control means connected between an input electrode of said regulator transistor and a reference potential level and having a control electrode connected to said sensing means for shorting said input electrode of said regulator transistor to said reference potential level in response to said control signal.

Claim 13

Protection circuitry for a voltage regulator having a series regulator transistor comprising: sensing means connected to an output electrode of said regulator transistor for providing a control signal when the voltage of said output electrode exceeds a threshold; and current control means connected between an input electrode of said regulator transistor and a reference potential level and having a control electrode connected to said sensing means for shorting said input electrode of said regulator transistor to said reference potential level in response to said control signal.

Claim 14

Protection circuitry as defined in claim 10 wherein said sensing means includes a zener diode and said current control means includes a controlled rectifier.