US 5,491,794 A · Fault protection using microprocessor power up reset

Abstract

In a television receiver, a microprocessor controls a horizontal deflection circuit which is coupled to run mode power supply to define a standby operating mode and a run operating mode. The microprocessor has a power-up reset input terminal which initializes operation upon application of AC mains power. The run mode power supply is coupled to at least one load which is subject to overcurrent or overvoltage faults. A fault detection circuit detects fault conditions in the run mode power supply loads such as overvoltage or overcurrent and anomalous vertical deflection current. Upon fault detection the fault detection circuit triggers a power up reset circuit which applies a momentary reset pulse to the power-up reset input of the microprocessor. Upon receipt of the reset pulse, the microprocessor controls the horizontal deflection circuit to place the run mode power supply in the standby operating mode. Thus power is removed from the run mode load subject to the overvoltage or overcurrent or anomalous condition, and the television receiver assumes a standby condition.

Claims18

Dependent claims

A video display device having fault protection apparatus for controlling said video display device, said fault protection apparatus comprising:

a horizontal deflection circuit;
a horizontal oscillator coupled to said horizontal deflection circuit and controlled to be operative in a run mode and inoperative in a standby mode;
a run mode power supply energized by operation of said deflection circuit for supplying power to a run mode load;
a fault detection circuit having at least one sensing input coupled to said run mode load to detect a fault condition and generating a reset signal responsive to detection of said fault condition;
and
a microprocessor control circuit having a reset input coupled to said reset signal and having an output signal coupled for controlling said operation of said horizontal oscillator, said microprocessor enabling said run mode absent detection of said fault condition and initiating said standby mode responsive to detection of said fault condition in said run mode load, said deflection circuit, said run mode power supply and said run mode load being thereby deactivated.

3 more elements

A video display having fault protection apparatus for controlling operation of said display, said apparatus, comprising:

a horizontal deflection circuit controlled to be operative in a run mode and inoperative in a standby mode;
a run mode power supply energized by operation of said horizontal deflection circuit for supplying power to a run mode load;
a vertical deflection circuit generating a vertical scanning component of said video display;
a fault detection circuit having at least one sensing input coupled to said vertical deflection circuit to detect a fault condition therein and generating a reset signal responsive to said fault condition in said vertical deflection circuit;
a microprocessor having a reset input, coupled to receive said reset signal, and generating an output control signal, said output control signal having a first condition for selecting a run mode and a second condition for selecting a standby mode, said output control signal being coupled to said horizontal deflection circuit to control said operation;
said microprocessor selecting said run mode absent said vertical deflection circuit fault condition and generating said output control signal having said first condition for activating said deflection circuit, said run mode power supply and said run mode load;
and,
said microprocessor initiating said standby mode responsive to a detected fault in said vertical deflection circuit and generating said output control signal having said second condition deactivating said deflection circuit, said run mode power supply and said run mode load.

5 more elements

Dependencies are inferred from the claim text.

Fault protection using microprocessor power up reset

Life of this patent

Fault protection using microprocessor power up reset

Life of this patent

Abstract

Claims18