Adaptive control boost current method and apparatus
AssigneeClare Micronix Integrated Systems, Inc.
InventorRobert LeChevalier
Life of this patent
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Abstract
A method and apparatus for adapting and applying current boost levels to precharge current-driven elements in a matrix, and a method to make devices for this purpose. Elements are driven during successive scan cycles, each having a precharge period and an exposure period. One or more conduction voltages are sensed while an element conducts a selected exposure current, with early samples taken nearer the beginning of exposures and late samples taken nearer the end. Charge delivered during the precharge period is adjusted to reduce differences between early and late voltage samples.
Claims82
A method of controlling a quantity of electrical charge provided to a matrix display connection during a precharge period, the method comprising:
- driving a current through a matrix element connected to a first matrix connection during a conduction period;
- deriving a control voltage from at least one voltage from a path of the current;
- adjusting the quantity of electrical charge based at least in part upon the derived control voltage;
- and
- providing the adjusted electrical charge quantity to a second matrix connection during the precharge period.
A method of adapting a precharge current delivered to a matrix, the method comprising:
- selecting the matrix element for sampling;
- applying a predetermined precharge current to the matrix element during a precharge period of a scan cycle;
- driving an exposure current into the selected matrix element during an exposure period of the scan cycle;
- sampling a conduction voltage during the exposure period of the scan cycle;
- and
- determining a subsequent precharge current level for the matrix element based at least in part on the sampled conduction voltage.
A method of manufacturing a circuit for controlling current drive to display elements, comprising:
- configuring a plurality of exposure current sources to provide exposure currents to a plurality of display elements during an exposure period;
- connecting a voltage sampling circuit, configured to obtain a plurality of sample voltages, to at least one conduction path of the exposure currents;
- configuring combiner circuitry to combine the plurality of sample voltages;
- connecting a precharge current source to at least one of the plurality of display elements to supply a precharge current thereto during a precharge period;
- and
- providing a control, responsive to a combination of the plurality of sample voltages, of the precharge current delivery.
A method of controlling conduction of electrical charge to a matrix display during a precharge period, the method comprising:
- supplying a current to a matrix element during a conduction period;
- deriving a control voltage from at least one voltage from a path of the conduction period current;
- adjusting a charge quantity based at least in part upon the derived control voltage;
- and
- providing the adjusted charge quantity to at least one matrix element during a subsequent precharge period.
An apparatus for driving current in devices of a matrix, comprising:
- a first driver circuit connectable to a first terminal of a matrix element to provide a current thereto;
- a sink circuit connectable to a second terminal of the matrix element to accept current conducted by the matrix element;
- a sensing circuit configured to store a voltage developed when the matrix element conducts part of the current;
- and
- a second driver circuit configured to output a quantity of charge which varies in response to the stored voltage.
An apparatus for controlling the supply of a current to a plurality of display elements, comprising:
- an exposure current source configured to provide a current to at least one of the display elements during exposure periods;
- a voltage sampling circuit configured to obtain a plurality of sample voltages from a conduction path of the exposure current;
- a sample voltage combiner configured to combine the plurality of sample voltages;
- and
- a precharge circuit configured to change a precharge current level based at least in part upon the combined sample voltages.
An apparatus for driving current in devices of a matrix, comprising:
- means for driving current to a matrix element during a conduction period;
- means for receiving current from the matrix element;
- means for sensing a voltage developed when the matrix element conducts at least part of the conduction current;
- and
- means for outputting, during a precharge period, a quantity of charge which varies in response to a signal derived from the means for sensing the voltage.
Dependencies are inferred from the claim text.