Controller for switch mode power supply
First Claim
1. A power supply controller for use in a power supply which provides a load current at a regulated output voltage, said power supply controller being formed in a single integrated circuit and comprising:
- a current sense input configured to receive a current sense voltage indicative of a magnitude of the load current;
current limit circuitry, including a first band-gap reference circuit powered by the current sense voltage, and configured to provide a first output indicative of a relative magnitudes of the current sense voltage and a first reference voltage, with the first reference voltage being produced by the first band-gap reference circuit;
voltage control circuitry configured to provide a second output indicative of a relative magnitudes of an output sense voltage related to the regulated output voltage and a second reference voltage; and
combining circuitry configured to provide a feedback signal based on the first and second outputs.
5 Assignments
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Accused Products
Abstract
An integrated circuit power supply controller for use in a power supply that provides voltage regulating and current limiting functions. A current limit circuit is provided that includes a band-gap circuit for producing a reference voltage for precisely setting the current limit point, with the band-gap circuit being powered by a current sense voltage indicative of the load current rather than being powered by the regulated output voltage. Thus, the current limit circuit will operate even the power supply output is shorted. Voltage control circuitry is provided also includes a band-gap circuit for precisely controlling the magnitude of the regulated output voltage.
48 Citations
26 Claims
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1. A power supply controller for use in a power supply which provides a load current at a regulated output voltage, said power supply controller being formed in a single integrated circuit and comprising:
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a current sense input configured to receive a current sense voltage indicative of a magnitude of the load current;
current limit circuitry, including a first band-gap reference circuit powered by the current sense voltage, and configured to provide a first output indicative of a relative magnitudes of the current sense voltage and a first reference voltage, with the first reference voltage being produced by the first band-gap reference circuit;
voltage control circuitry configured to provide a second output indicative of a relative magnitudes of an output sense voltage related to the regulated output voltage and a second reference voltage; and
combining circuitry configured to provide a feedback signal based on the first and second outputs. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A power supply controller for use in a power supply which provides a load current at a regulated output voltage, said power supply controller being formed in an integrated circuit having first, second, third and fourth integrated circuit terminals, said controller including:
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current limit circuitry configured to provide a first output indicative of a magnitude of a current sense signal indicative of the load current and a reference, with the current limit circuit including a first band-gap reference circuit which includes a positive temperature coefficient circuit element and a negative temperature coefficient circuit element connected in series between the first and second integrated circuit terminals;
voltage control circuitry configured to provide a second output indicative of a relative magnitude of a voltage sense signal related to the regulated output voltage and a second reference, with the voltage control circuitry including a second band-gap reference circuit which includes a positive temperature coefficient circuit element and a negative temperature coefficient circuit element connected in series between the first and fourth integrated circuit terminals; and
combining circuitry configured to provide a feedback signal to the third integrated circuit output terminal in response to the first and second outputs. - View Dependent Claims (19, 20, 21, 22)
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23. A power supply controller for use in a power supply which provides a load current at a regulated output voltage, said controller including:
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a current sense resistor connected to conduct the load current and disposed intermediate first and second circuit nodes;
a first band-gap circuit which includes a pair of bipolar transistors, a positive temperature coefficient circuit element producing a voltage derived from a difference in base-emitter voltages of the pair of bipolar transistors and a negative temperature coefficient circuit element coefficient, with the positive and negative temperature coefficient elements connected in series between the first and second circuit nodes;
a drive transistor responsive to the first band-gap circuit and connected to provide a first output, with the first output having a state determined by a magnitude of the current sense voltage; and
an optical coupler having an input responsive to the first output and an output to be connected to a regulator circuit. - View Dependent Claims (24, 25, 26)
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Specification