Ultra low power tracked low voltage reference source
First Claim
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1. A reference voltage source for an integrated circuit comprising:
- a trimmable voltage reference for providing a reference voltage for the integrated circuit;
a bandgap voltage reference;
a differential sensing device for comparing the reference voltage provided by the trimmable voltage reference to a voltage provided by the bandgap voltage reference; and
a controller responsive to an output of the differential sensing device for adjusting the trimmable voltage reference while the output of the differential sensing device has an initial value and for providing a signal to power down the bandgap voltage reference when the output of the differential sensing device transitions to a second value.
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Abstract
A reference voltage source for an integrated circuit includes a first voltage reference that is adjustable, a second voltage reference, a differential sensing device to compare a voltage provided by the first voltage reference to a voltage provided by the second voltage reference, a controller to provide a trim control signal to the first voltage reference in response to an output of the differential sensing device for adjusting the first voltage reference and to provide a signal to power down the second voltage reference after the first voltage reference has been adjusted.
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Citations
26 Claims
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1. A reference voltage source for an integrated circuit comprising:
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a trimmable voltage reference for providing a reference voltage for the integrated circuit;
a bandgap voltage reference;
a differential sensing device for comparing the reference voltage provided by the trimmable voltage reference to a voltage provided by the bandgap voltage reference; and
a controller responsive to an output of the differential sensing device for adjusting the trimmable voltage reference while the output of the differential sensing device has an initial value and for providing a signal to power down the bandgap voltage reference when the output of the differential sensing device transitions to a second value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A reference voltage source for an integrated circuit comprising:
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a trimmable voltage reference for providing a reference voltage for the integrated circuit;
a bandgap voltage reference;
a differential sensing device for comparing the reference voltage provided by the trimmable voltage reference to a voltage provided by the bandgap voltage reference; and
a controller responsive to an output of the differential sensing device for adjusting the trimmable voltage reference while the output of the differential sensing device has an initial value and for providing a signal to power down the bandgap voltage reference and the differential sensing device when the output of the differential sensing device transitions to a second value;
wherein the controller is adapted to periodically provide a signal to reactivate the bandgap voltage reference and the differential sensing device for periodically adjusting the trimmable voltage reference. - View Dependent Claims (10, 11)
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12. A method for adjusting a reference voltage for an integrated circuit comprising:
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enabling a first reference voltage and a second reference voltage;
comparing the first reference voltage to the second reference voltage;
adjusting the first reference voltage in response to the comparison to the second reference voltage until the comparison indicates that a transition has occurred relative to a differential between the first reference voltage and the second reference voltage;
ceasing to adjust the first reference voltage after the comparison indicates that the transition has occurred. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A method for adjusting a reference voltage for an integrated circuit, comprising:
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activating a first reference voltage source to generate a first voltage signal, wherein the first reference voltage source is adjustable in response to a value of a trim signal to modify the first voltage signal;
after activating the first reference voltage source, activating a second reference voltage source to generate a second voltage signal and activating a differential sensing device for comparing the first voltage signal to the second voltage signal;
waiting for the second voltage signal to stabilize;
after the second voltage signal has stabilized, analyzing an output of the differential sensing device, wherein the output of the differential sensing device has an initial value of a first logic level or a second logic level;
adjusting the value of the trim signal by increasing the value of the trim signal if the initial value of the output of the differential sensing device is the first logic level and decreasing the value of the trim signal if the initial value of the output of the differential sensing device is the second logic level; and
discontinuing adjustment of the value of the trim signal in response to the output of the differential sensing device transitioning to the second logic level if the initial value was the first logic level or transitioning to the first logic level if the initial value was the second logic level. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26)
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Specification