Current foldback circuit for a DC power supply
First Claim
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1. A DC power supply comprising:
- a. input means for receiving input power at an input voltage;
b. output means, connected to said input means, for producing output power at another, output voltage, said output means having a control input and being responsive to a control signal applied to said control input to vary said output voltage; and
c. control means, connected to said output means, for producing said control signal, said control means including;
1. a differential amplifier having first and second inputs and an output connected to said control input of said output means, said differential amplifier producing said control signal at said output thereof;
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Abstract
A DC power supply having an input stage receiving input power at one voltage and an output stage connected to the input stage producing output power at another, output voltage. The output stage receives a control signal reducing the output voltage by a prescribed amount when the output current exceeds a given level. The control unit includes a comparator which compares the output current with a reference level and produces a current foldback signal if the output current exceeds the reference level.
64 Citations
7 Claims
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1. A DC power supply comprising:
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a. input means for receiving input power at an input voltage; b. output means, connected to said input means, for producing output power at another, output voltage, said output means having a control input and being responsive to a control signal applied to said control input to vary said output voltage; and c. control means, connected to said output means, for producing said control signal, said control means including; 1. a differential amplifier having first and second inputs and an output connected to said control input of said output means, said differential amplifier producing said control signal at said output thereof; 2. - View Dependent Claims (3, 7)
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2. a voltage divider circuit having two resistors connected in series with a first terminal at one end of the resistor series, a second terminal at the opposite end of the resistor series and a center terminal between the two resistors, said center terminal being connected to said first input of said differential amplifier;
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3. output voltage sensing means, connected to said second input of said differential amplifier, for producing a signal representative of said output voltage; 4. a first reference voltage source connected to said first terminal of said resistor series; 5. a comparator, capable of assuming two logic states and having first and second inputs and an output connected to said second terminal of said resistor series, said comparator (1) assuming a first logic state and connecting said second terminal to ground if the voltage applied to said second input thereof exceeds the voltage applied to said first input thereof, and (2) assuming a second logic state and providing an open circuit to said second terminal if the voltage applied to said second input thereof is less than the voltage applied to said first input thereof; 6. a second reference voltage source connected to said first input of said comparator; and 7. output current sensing means, connected to said second input of said comparator, for producing a signal representative of the output current supplied by said output means at said output voltage; whereby said output voltage is reduced by a prescribed amount when the voltage applied to the second input of said comparator exceeds the voltage - View Dependent Claims (4, 5, 6)
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Specification