Adjustable voltage controlled DC to DC switcher current source
AssigneeHewlett-Packard Company
InventorMichael Andrews
Life of this patent
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Abstract
An adjustable voltage controlled current source for supplying a constant current to a load may comprise a DC to DC switcher in a commonly known topology, including boost, buck, or boost/buck. The current from the DC to DC switcher is measured with one or more current sensing resistors or one or more inductively coupled current sensing windings such as a transformer or Hall-effect device. The current measurement is then coupled to the feedback input of the DC to DC switcher. The current measurement may have a DC bias added to meet the feedback voltage requirements of the DC to DC switcher. An external current set point may be combined with the current measurement to externally set the current output.
Claims19
A voltage controlled current source for supplying a selectable constant current to a load, comprising:
- a DC to DC switcher comprising a feedback input and a constant current output for supplying a constant current to the load;
- one or more current sensing resistors coupled to said constant current output;
- and
- an electrical coupling between at least one of said current sensing resistors and said feedback input.
A voltage controlled current source for supplying a selectable constant current to a load, comprising:
- a DC to DC switcher comprising a feedback input and a constant current output for supplying a constant current to the load;
- one or more current sensing windings inductively coupled to said current output;
- and
- an electrical coupling between at least one of said current sensing windings and said feedback input.
A method of supplying a constant current using a voltage controlled DC to DC switcher, comprising:
- a) measuring an output current from the voltage controlled DC to DC switcher as a current indicating voltage;
- and
- b) feeding said current indicating voltage into a feedback input on said voltage controlled DC to DC switcher to maintain the output current at a constant level.
Dependencies are inferred from the claim text.