Robust trimming scheme for low power RC oscillator compatible with high temperature operation
First Claim
1. A frequency generator, comprising:
- a comparator configured to output an oscillating voltage signal having a first frequency;
a RC network circuit coupled between an input and an output of the comparator, wherein the RC network circuit comprises;
a resistor network;
a capacitor network comprising a plurality of capacitors, wherein each capacitor of the plurality of capacitors comprises a first plate and a second plate, and wherein the second plates of the plurality of capacitors are coupled together; and
a frequency testing circuit configured to determine whether the first frequency is within an expected frequency range, wherein the frequency testing circuit is configured to selectively connect the first plate of some of the capacitors disposed in the capacitor network to a non-varying voltage and other capacitors disposed in the capacitor network to an input of the capacitor network when the first frequency is outside of the expected frequency range;
a first logic gate having a first input coupled to the frequency testing circuit, a second input coupled to an output of the comparator, and an output coupled to a first one of the plurality of capacitors; and
a second logic gate having a first input coupled to the frequency testing circuit, a second input coupled to the output of the comparator, and an output coupled to a second one of the plurality of capacitors and not to the first one of the plurality of capacitors.
1 Assignment
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Accused Products
Abstract
In some embodiments, the present disclosure relates to a frequency generator having a resistor network and a capacitor network. The capacitor network has a plurality of capacitors connected in parallel with one another. A comparator is configured to output an oscillating voltage signal. An input of the comparator is connected to the output of the resistor network and the output of the capacitor network. A frequency testing circuit is configured to calculate a frequency of the oscillating voltage signal and determine whether the frequency is within a range of an expected frequency. The frequency testing circuit may also be configured to selectively connect a first plate of the plurality of capacitors to a non-varying voltage or to the input of the capacitor network to adjust a frequency of the oscillating voltage signal.
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Citations
20 Claims
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1. A frequency generator, comprising:
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a comparator configured to output an oscillating voltage signal having a first frequency; a RC network circuit coupled between an input and an output of the comparator, wherein the RC network circuit comprises; a resistor network; a capacitor network comprising a plurality of capacitors, wherein each capacitor of the plurality of capacitors comprises a first plate and a second plate, and wherein the second plates of the plurality of capacitors are coupled together; and a frequency testing circuit configured to determine whether the first frequency is within an expected frequency range, wherein the frequency testing circuit is configured to selectively connect the first plate of some of the capacitors disposed in the capacitor network to a non-varying voltage and other capacitors disposed in the capacitor network to an input of the capacitor network when the first frequency is outside of the expected frequency range; a first logic gate having a first input coupled to the frequency testing circuit, a second input coupled to an output of the comparator, and an output coupled to a first one of the plurality of capacitors; and a second logic gate having a first input coupled to the frequency testing circuit, a second input coupled to the output of the comparator, and an output coupled to a second one of the plurality of capacitors and not to the first one of the plurality of capacitors. - View Dependent Claims (2, 3, 4, 20)
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5. An electronic oscillator, comprising:
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a comparator connected to a first node and a third node; a resistor network disposed between the first node and the third node; an inverter connected to the first node and a second node; a plurality of capacitors respectively comprising a first plate and a second plate connected to the third node; a plurality of logic gates respectively comprising a first input connected to the second node, a second input, and an output connected to the first plate of one of the plurality of capacitors; and a memory unit connected to the second input of the plurality of logic gates, wherein the memory unit is configured to output a separate signal to the second input of the plurality of logic gates, wherein the separate signal determines whether the first plate of one of the plurality of capacitors is connected to the second node or a non-varying voltage. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for tuning an output frequency of an electronic oscillator, comprising:
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determining whether a first frequency of an electronic oscillator is within a range of an expected output frequency, wherein the electronic oscillator comprises a comparator connected to a RC network circuit comprising a capacitor network and a resistor network; upon determining the first frequency is not within the range of the expected output frequency, adjusting the first frequency of the electronic oscillator by selectively tuning a capacitance ratio of a first number of a plurality of capacitors within the capacitor network and a second number of the plurality of capacitors, wherein the first number of the plurality of capacitors respectively have a first plate connected to an output of an inverter coupled to the comparator, and wherein a second number of the plurality of capacitors respectively have a first plate connected to a non-varying voltage; after selectively tuning the capacitance ratio, determining whether a second frequency is within the range of the expected output frequency; and upon determining the second frequency is within the range of the expected output frequency, fixing the capacitance ratio between the first number of the plurality of capacitors and the second number of the plurality of capacitors. - View Dependent Claims (15, 16, 17, 18, 19)
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Specification