Digital cut-off control loop for TV using speeding and blanking circuits

An RGB control circuit for use in television and video display control, comprising:

• an up/down counter circuit configured to receive a display driver current and to generate a digital output signal in response thereto;
• a digital-to-analog converter having an input coupled to an output of the counter circuit and configured to receive the digital output signal from the counter circuit and to output an analog control signal;
• a speeding comparator circuit comprising a plurality of comparators, each comparator having an input coupled in parallel with the other comparator circuits to a cathode current output for determining and outputting a measure of a difference between the cathode current output and a predetermined value;
• and
• a speeding logic circuit having an input coupled to an output of the speeding comparator circuit and further having a first output coupled to the counter circuit, the speeding logic circuit configured to control the counting rate of the counter circuit according to a measure of a difference between the cathode current and the predetermined value to provide a variable up counting rate and a variable down counting rate.

A digital cut-off control loop circuit for television and video display control, comprising:

• a display driver current sensor;
• an up/down counter circuit having an input coupled to the display driver current sensor and an output;
• an analog output circuit having an input coupled to the output of the up/down counter and an output coupled to control the display driver current;
• a speeding comparator comprising a plurality of comparator circuits each having an input coupled in parallel with the display driver current sensor and configured to determine and output a measure of the difference between a sensed display driver current and a predetermined value;
• a speeding logic circuit having an input coupled to an output of the speeding comparator and having an output coupled to a further input of the up/down counter circuit for controlling a counting rate of the up/down counter circuit according to a measure of a difference between the display driver current and the predetermined value;
• a current reference circuit comprising a comparator having a first input coupled to the display driver current sensor and a second input coupled to a leak voltage reference source and an output coupled to a capacitor;
• and
• a warm-up circuit comprising a comparator having a first input coupled to the display driver current sensor and a second input coupled to a starting voltage source.

An RGB control circuit for use in television/video display control, comprising:

• a display driver current sensor;
• a 9-bit counter circuit and 9-bit analog output circuit coupled to control the display driver current;
• a speeding comparator having a plurality of comparator circuits coupled in parallel with the display driver current sensor as input, for determining and outputting a measure of the difference between the sensed display driver current and a predetermined value thereof;
• and
• a speeding logic circuit coupled to the speeding comparator and counter circuit, and arranged to control the up/down counting rate of the counter circuit according to said measure of difference in display driver current, wherein the counter circuit and the analog output circuit are both 9-bit circuits.

An RGB control circuit for use in television and video display control, comprising:

• an up/down 9-bit counter circuit configured to receive a display driver current and to generate a digital output signal in response thereto;
• a 9-bit digital-to-analog converter having an input coupled to an output of the counter circuit and configured to receive the digital output signal from the counter circuit and to output an analog control signal;
• a speeding comparator circuit comprising a plurality of comparators, each comparator having an input coupled in parallel with the other comparator circuits to a cathode current output for determining and outputting a measure of a difference between the cathode current output and a predetermined value;
• and
• a speeding logic circuit having an input coupled to an output of the speeding comparator circuit and further having a first output coupled to the counter circuit, the speeding logic circuit configured to control the counting rate of the counter circuit according to a measure of a difference between the cathode current and the predetermined value to provide a variable up counting rate and a variable down counting rate, wherein the counter circuit comprises a 9-bit up/down counter, and further wherein the digital-to-analog converter comprises a 9-bit digital-to-analog converter.