Fast start-up low-voltage bandgap reference voltage generator
AssigneeRichtek Technology Corporation
InventorsKwan-Jen Chu, Nien-Hui Kung, Hsuan-Kai Wang
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Abstract
A fast start-up low-voltage bandgap reference voltage generator uses two current generators to provide a first current having a positive temperature coefficient and a second current having a negative temperature coefficient, respectively, and a resistor to generate a temperature independent output voltage according to the sum of the first and second currents. The current generator for providing the first current has a self-bias circuit which uses a single MOSFET to establish the first current, and thereby avoids error caused by mismatched MOSFETs.
Claims16
A fast start-up low-voltage bandgap reference voltage generator, comprising:
- a first current generator having a self-bias circuit, operative to provide a first current having a positive temperature coefficient, the self-bias circuit including:
- a first MOSFET having an output terminal for providing the first current;
- a first operational amplifier having an output terminal connected to a control terminal of the first MOSFET;
- a first BJT configured as a diode;
- a first resistor connected between a first input terminal of the first operational amplifier and the first BJT;
- a second resistor connected between the output terminal of the first MOSFET and the first input terminal of the first operational amplifier;
- a third resistor connected between the output terminal of the first MOSFET and a second input terminal of the first operational amplifier;
- and
- a second BJT configured as a diode, connected to the second input terminal of the first operational amplifier;
- a second current generator connected to the first current generator, operative to provide a second current having a negative temperature coefficient;
- a current summation circuit connected to the first and second current generators, operative to generate a summed current equal to a sum of the first and second currents;
- and
- an output resistor connected to the current summation circuit, receiving the summed current to generate an output voltage.
Dependencies are inferred from the claim text.