Apparatus and method for a low voltage bandgap voltage reference generator
First Claim
1. A bandgap voltage generator, comprising:
- a non-cascode current mirror that is connected to a power supply input and that produces a plurality of current mirror outputs in response to said power supply input and a control input;
a differential amplifier for sensing first and second current mirror outputs of said non-cascode current mirror, and having an output responsive thereto that controls said non-cascode current mirror using said control input so that said current mirror outputs have substantially the same current and voltage;
a first bipolar device connected to a first current mirror output through a first resistor;
a second bipolar device connected to a second current mirror output; and
a third bipolar device connected to a third current mirror output through a second resistor, said third current mirror output producing a reference output voltage responsive to said power supply input.
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Abstract
A bandgap voltage generator generates an output reference voltage and is configured to operate from a low voltage power supply and consumes low power. The bandgap voltage generator includes a non-cascode current mirror that is directly connected to a power supply input and that produces current mirror outputs in response to the power supply input. A differential amplifier senses two of the current mirror outputs, and generates an output that controls the non-cascode current mirror so that the current mirror outputs produce substantially the same current and voltage at the sensed current mirror outputs. A bandgap core circuit includes first and second bipolar devices that receive the constant current from the two current mirror outputs. The first bipolar device is scaled in size relative to the second bipolar device so as to produce an output voltage at a third current mirror output that is multiple of the characteristic bandgap voltage of the bipolar devices. The non-cascode current mirror includes FET devices having their respective sources connected to the power supply input, and having their respective drains connected to the respective current mirror outputs. The FETs are not implemented with a cascode configuration, so that the bandgap voltage generator can operate with a low voltage power supply and also consumes low power.
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Citations
25 Claims
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1. A bandgap voltage generator, comprising:
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a non-cascode current mirror that is connected to a power supply input and that produces a plurality of current mirror outputs in response to said power supply input and a control input;
a differential amplifier for sensing first and second current mirror outputs of said non-cascode current mirror, and having an output responsive thereto that controls said non-cascode current mirror using said control input so that said current mirror outputs have substantially the same current and voltage;
a first bipolar device connected to a first current mirror output through a first resistor;
a second bipolar device connected to a second current mirror output; and
a third bipolar device connected to a third current mirror output through a second resistor, said third current mirror output producing a reference output voltage responsive to said power supply input. - View Dependent Claims (2, 3, 4, 5, 7, 8, 9, 10, 23, 24, 25)
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6. The bandgap voltage generator of 5, wherein said second resistor is scaled relative to said first resistor.
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11. A method of generating a reference voltage, comprising:
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directly receiving current from a power supply source;
generating a plurality of current outputs responsive to said power supply source, including the step of mirroring a first current output to generate a second current output;
sensing a voltage at said first and second current outputs, and controlling the step of mirroring to maintain a constant current and voltage at said first and second current outputs;
receiving said constant currents at respective first and second bipolar devices, the first and second bipolar devices having a characteristic bandgap voltage; and
generating an output reference voltage that is based on said characteristic bandgap voltage. - View Dependent Claims (12, 13, 14, 15)
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16. A bandgap voltage generator, comprising:
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a non-cascode current mirror that is connected to a power supply and that produces a first, second, and third current mirror outputs in response to said power supply;
means for controlling said non-cascode current mirror so that said first and second current mirror outputs each produce a substantially constant current; and
a bandgap core circuit having first and second bipolar devices that receive said substantially constant currents from said first and second current mirror outputs;
said first and second bipolar devices having a characteristic bandgap voltage, and said first bipolar device scaled relative to said second bipolar device so as to produce an output voltage at said third current mirror output that is multiple of said characteristic bandgap voltage based on a size ratio of said first bipolar device to said second bipolar device. - View Dependent Claims (17, 18, 19, 20, 21, 22)
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Specification