Device for voltage regulation with a low internal dissipation of energy
First Claim
1. A voltage regulator for providing a regulated voltage and comprising:
- a first transistor having a power terminal connected to a power supply;
a second transistor having an output terminal and being connected to said first transistor through a common terminal;
an external resistive circuit connected between said common terminal and said output terminal;
an output current of said voltage regulator being equal to a sum of a first current passing through said external resistive circuit and a second current passing through said second transistor;
a control circuit connected to an input of said second transistor to turn on said second transistor for providing said second current when said first current exceeds a predetermined value; and
a comparison circuit which feeds back said regulated voltage to said input of said second transistor to regulate said regulated voltages;
wherein said control circuit comprises a third transistor configured as a current mirror of said first transistor to bias said second transistor, and wherein a fourth transistor is configured as another current mirror of said first transistor to bias said comparison circuit, said third and fourth transistors having a surface area which is smaller than a surface area of said first and second transistors.
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Accused Products
Abstract
A voltage regulator is disclosed which is connected to an external resistor. The voltage regulator provides a regulated voltage and includes first and second transistors. The first transistor has a power terminal connected to a power supply and the second transistor has an output terminal to output the regulated voltage. The second transistor is connected to the first transistor through a common terminal. The external resistive circuit is connected between the common terminal and the output terminal. An output current of the voltage regulator on the output terminal is equal to a sum of a first current passing through the resistive circuit and a second current passing through the second transistor. A control circuit is also provided which is connected to the input of the second transistor to turn on the second transistor for providing the second current when the first current exceeds a predetermined value. The voltage regulator also includes a comparison circuit which feeds back the regulated voltage to an input of the second transistor to regulate the regulated voltage.
35 Citations
15 Claims
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1. A voltage regulator for providing a regulated voltage and comprising:
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a first transistor having a power terminal connected to a power supply; a second transistor having an output terminal and being connected to said first transistor through a common terminal; an external resistive circuit connected between said common terminal and said output terminal;
an output current of said voltage regulator being equal to a sum of a first current passing through said external resistive circuit and a second current passing through said second transistor;a control circuit connected to an input of said second transistor to turn on said second transistor for providing said second current when said first current exceeds a predetermined value; and a comparison circuit which feeds back said regulated voltage to said input of said second transistor to regulate said regulated voltages; wherein said control circuit comprises a third transistor configured as a current mirror of said first transistor to bias said second transistor, and wherein a fourth transistor is configured as another current mirror of said first transistor to bias said comparison circuit, said third and fourth transistors having a surface area which is smaller than a surface area of said first and second transistors. - View Dependent Claims (2)
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3. A voltage for providing a regulated voltage and comprising:
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a first transistor having a power terminal connected to a power supply; a second transistor having an output terminal and being connected to said first transistor through a common terminal; an external resistive circuit connected between said common terminal and said output terminal;
an output current of said voltage regulator being equal to a sum of a first current passing through said external resistive circuit and a second current passing through said second transistor; anda control circuit connected to an input of said second transistor to turn on said second transistor for providing said second current when said first current exceeds a predetermined value; wherein said control circuit comprises a third transistor configured as a current mirror of said first transistor to bias said second transistor, and wherein a fourth transistor is configured as another current mirror of said first transistor to bias a comparison circuit connected between said output terminal and an input of said second transistor, said third and fourth transistors having a surface area which is smaller than a surface area of said first and second transistors. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10)
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11. A voltage regulator comprising a control circuit, a buffer circuit and a resistive circuit connected to said buffer circuit, an output current of said voltage regulator being equal to a sum of a first current passing through said resistive circuit and a second current provided directly from said buffer circuit,
said control circuit turning on said second transistor to shunt said resistive circuit when said first current exceeds a predetermined value, wherein said control circuit comprises a third transistor configured as a current mirror of said first transistor to bias said second transistor, and wherein a fourth transistor is configured as another current mirror of said first transistor to bias a comparison circuit connected between said output terminal and an input of said second transistor, said third and fourth transistors having a surface area which is smaller than a surface area of said first and second transistors.
Specification