Self-calibration of power delivery control to firing resistors
AssigneeHewlett-Packard Development Company, L.P.
InventorGeorge H. Corrigan
Life of this patent
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Abstract
A fluid ejection device having an internal power supply path and a power regular providing an offset voltage from the internal power supply path voltage. A self-calibration circuit in the inkjet printhead determines a regulation band of the power regulator defined by a lower set point offset voltage and an upper set point offset voltage. The inkjet printhead includes a group of nozzles, a corresponding group of firing resistors, and a corresponding group of switches controllable to couple a selected firing resistor of the group of firing resistors between the internal power supply path and the offset voltage to thereby permit electrical current to pass through the selected firing resistor to cause a corresponding selected nozzle to fire.
Claims25
A fluid ejection device comprising:
- an internal power supply path;
- a power regulator providing an offset voltage from the internal power supply path voltage, the power regulator including a self-calibration circuit adapted to determine a regulation band of the power regulator defined by a lower set point offset voltage and an upper set point offset voltage;
- a group of nozzles;
- a corresponding group of firing resistors;
- and
- a corresponding group of switches controllable to couple a selected firing resistor of the group of firing resistors between the internal power supply path and the offset voltage to thereby permit electrical current to pass through the selected firing resistor to cause a corresponding selected nozzle to fire.
A fluid ejection assembly comprising:
- at least one fluid ejection device, each fluid ejection device including:
- an internal power supply path;
- a power regulator providing an offset voltage from the internal power supply path voltage, the power regulator including a self-calibration circuit adapted to determine a regulation band of the power regulator defined by a lower set point offset voltage and an upper set point offset voltage;
- a group of nozzles;
- a corresponding group of firing resistors;
- and
- a corresponding group of switches controllable to couple a selected firing resistor of the group of firing resistors between the internal power supply path and the offset voltage to thereby permit electrical current to pass through the selected firing resistor to cause a corresponding selected nozzle to fire.
A method of self-calibrating power delivery control to firing resistors in an fluid ejection device comprising:
- coupling a selected firing resistor of a group of firing resistors between an internal power supply path and an offset voltage from the internal power supply path voltage to cause electrical current to pass through the selected firing resistor to cause a corresponding selected nozzle to fire;
- and
- determining a power regulation band defined by a lower set point offset voltage and an upper set point offset voltage.
A self-calibrating power regulator in an fluid ejection device comprising:
- a power delivery control loop providing an offset voltage from an internal power supply path voltage, wherein a selected firing resistor in the fluid ejection device is coupled between the internal power supply path and the offset voltage to cause electrical current to pass through the selected firing resistor to cause a corresponding selected nozzle to fire;
- and
- a self-calibration circuit adapted to determine a regulation band of the power regulator defined by a lower set point offset voltage and an upper set point offset voltage.
The self-calibrating power regulator of claim 25 wherein the self-calibration circuit includes:
- a set point up/down counter storing a set point offset voltage digital value representing a desired offset voltage, wherein the power delivery control loop is responsive to the offset voltage digital value to provide the offset voltage;
- and
- a set point controller receiving a fire pulse, a start calculation signal, and an in regulation signal which is activated based on the power regulator being in regulation, the set point controller activating a count signal to the set point up/down counter at every received fire pulse in a first set point calculation operation occurring between a first active start calculation signal and a second active start calculation signal unless an active in regulation signal has been received during the first set point calculation operation, wherein an activated count signal causes the set point up/down counter to increment or decrement.
Dependencies are inferred from the claim text.