Overload protection for a voltage conversion circuit
AssigneeSperry Corporation
InventorCharles A. Clark, Jr.
Life of this patent
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Abstract
A voltage converter of the transformer type which incorporates at least one switching transistor coupled to control the application of current to the transformer primary and circuitry for switching the transistor on and off to control the current through the primary winding. When the output of the converter is shorted, the switching rate undesirably increases causing potential damage to the converter. A frequency detecting circuit detects the increase in switching frequency and acts to reduce the input voltage to the converter to prevent damage thereto.
Claims5
In a voltage conversion circuit responsive to an input DC voltage for providing an output voltage to a load, said circuit being of the type including a transformer having a primary winding and a secondary winding, said secondary winding producing said output voltage, said circuit further including a switching means responsive to a control signal for applying said input voltage across said primary winding for producing a current therein which increases as a function of time, the rate of said increase being a function of the impedance of said load, and means responsive to the instantaneous value of said current in said primary winding exceeding a preselected value for providing said control signal to said switching means, wherein the improvement comprises:
- frequency responsive means coupled to said switching means for sensing the switching frequency thereof and responsive to a frequency in excess of a given rate for causing the decrease of said input DC voltage to said primary winding.
Dependencies are inferred from the claim text.