Back to results
US 8,947,067 B1Granted
Automatic bandgap voltage calibration
AssigneeMarvell International Ltd.
InventorHossein Zarei
Life of this patent
Estimating the term…
Abstract
Disclosed is bandgap voltage reference generator having a programmable resistor. The programmable resistor can be programmed to provide a proper ratio between the PTAT current and the CTAT current to reduce the effect of process variations on the bandgap voltage. The bandgap voltage reference generator includes a calibration circuit that programs the programmable resistor.
Claims20
A circuit comprising:
- a first circuit part comprising op-amp, a first resistor, and first and second p-n junctions, and configured to produce a voltage across the first resistor substantially equal to a difference between a voltage of the first p-n junction and a voltage of the second p-n junction;
- a second circuit part comprising a series connection of a current source, a second resistor, and a third p-n junction;
- a control signal from the first circuit part coupled to the current source in the second circuit part to generate a current flow in the second circuit part that is substantially equal to a current flowing through the first resistor;
- an output terminal configured to output a voltage level substantially equal to a voltage across the second resistor and a voltage across the third p-n junction;
- and
- a calibration circuit comprising:
- an internal reference voltage source configured to generate one or more internal reference voltage levels;
- a p-n junction voltage source configured to output a reference p-n junction voltage level;
- an amplifier configured to output a difference signal indicative of a difference between one of the internal reference levels and the reference p-n junction voltage level;
- and
- a switch control circuit connected to the internal reference voltage source and to the amplifier, and configured to output switch control signals based on the internal reference voltage levels and a difference between two input signals to the amplifier,
- the switch control signals being coupled to set a resistance value of the second resistor, wherein the resistance value of the second resistor is set in accordance with the switch control signals.
9 more elements
A circuit comprising:
- means for generating a bandgap voltage level including first and second resistors and a current control signal, wherein the current control signal is based on a voltage across the first resistor, wherein the current control signal is used to generate a current flow through the second resistor and to generate a voltage across a p-n junction, wherein the bandgap voltage level is equal to a sum of a voltage across the second resistor and the voltage across the p-n junction, wherein the second resistor is programmable;
- means, connected to the second resistor, for programming the second resistor comprising:
- first means, connected to the current control signal, for generating a plurality of internal reference voltages based on the current control signal;
- second means for generating a reference p-n junction voltage level;
- and
- third means for producing switch control signals based on the reference p-n junction voltage level and the one or more internal reference voltages, wherein the switch control signals are connected to the second resistor, wherein the resistance value of the second resistor is set in accordance with the switch control signals.
3 more elements
A method in a voltage reference circuit comprising:
- generating a first current flow through a first p-n junction of the voltage reference circuit;
- generating a second current flow through a second p-n junction and a first resistor of the voltage reference circuit;
- generating a third current flow through a third p-n junction and a second resistor of the voltage reference circuit, wherein the first, second, and third current flows are substantially equal, wherein a voltage across the third p-n junction and a voltage across the second resistor constitute an output reference voltage level of the voltage reference circuit;
- and
- calibrating the second resistor, comprising:
- generating a plurality of internal reference voltages;
- detecting a voltage level across a fourth p-n junction;
- generating switch control signals based on a detected voltage across the fourth p-n junction and the internal reference voltages, including a difference between the detected voltage and one of the internal reference voltages;
- and
- setting a value of the second resistor using the switch control signals,
- wherein sensitivity of the output reference voltage level to variations in ambient temperature is based on a ratio of resistance values of the first resistor and the second resistor.
8 more elements
Dependencies are inferred from the claim text.