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US 2017/0255220 A1Published application
Crystal-less clock that is invariant with process, supply voltage, and temperature
AssigneeQUALCOMM Incorporated
InventorsShyam SIVAKUMAR, Kevin WANG
Life of this patent
Estimating the term…
Abstract
A method of generating a bandgap voltage in an electronic circuit includes generating a bandgap current. The method further includes operating the electronic circuit using the bandgap voltage and the bandgap current. The operating can be based on a relationship, such as a ratio of the bandgap voltage to the bandgap current.
Claims30
A circuit comprising:
- a first current generator configured to generate a first current that varies with temperature;
- a second current generator configured to generate a second current that varies with temperature in opposite relation to the first current;
- a voltage generating circuit connected to the first current generator and the second current generator and having an output for a bandgap voltage based on the first current and the second current;
- a current generating circuit connected to the first current generator and the second current generator and having an output for a bandgap current based on the first current and the second current;
- a capacitor selectively configurable in a first configuration to receive the bandgap current to charge the capacitor and a second configuration to discharge the capacitor;
- and
- a comparator configured to produce a comparator signal based on the bandgap voltage and a capacitor voltage across the capacitor, the capacitor being configured in the first configuration and the second configuration in response to the comparator signal, the comparator signal varying in time in response to the capacitor being charged and discharged, the comparator signal having a period that is based at least in part on the bandgap voltage across a resistor and the bandgap current.
4 more elements
A circuit comprising:
- an RC oscillator comprising a proportional to absolute temperature (PTAT) core and a complementary to absolute temperature (CTAT) core configured to generate a bandgap voltage and a bandgap current, the RC oscillator configured to generate a temperature invariant reference frequency having a period that is based on the bandgap voltage and the bandgap current;
- a frequency generator;
- and
- a calibration engine having an output for a multiplier and configured to produce the multiplier based on the temperature invariant reference frequency of the RC oscillator and an external reference frequency,
- the frequency generator configured to generate an output signal by regulating a frequency of the output signal to the temperature invariant reference frequency of the RC oscillator times the multiplier to produce a temperature invariant output frequency.
2 more elements
A circuit comprising:
- a first voltage generator configured to generate a first voltage that varies with temperature;
- a second voltage generator configured to generate a second voltage that varies with temperature in opposite relation to the first voltage;
- a current generating circuit connected to the first current generator and the second voltage generator and having an output for a bandgap current based on the first voltage and the second voltage;
- a voltage generating circuit connected to the first voltage generator and the second voltage generator and having an output for a bandgap voltage based on the first voltage and the second voltage;
- a capacitor selectively configurable in a first configuration to receive the bandgap current to charge the capacitor and a second configuration to discharge the capacitor;
- and
- a comparator configured to produce a comparator signal based on the bandgap voltage and a capacitor voltage across the capacitor, the capacitor being configured in the first configuration and the second configuration in response to the comparator signal, the comparator signal varying in time in response to the capacitor being charged and discharged, the comparator signal having a period that is based on the bandgap voltage across a resistor and the bandgap current.
4 more elements
A method in an electronic circuit comprising:
- generating a bandgap voltage;
- generating a bandgap current;
- and
- operating the electronic circuit using the bandgap voltage and the bandgap current.
1 more element
Dependencies are inferred from the claim text.