# US 2019/0173427 A1 · Temperature compensation of a quartz crystal oscillator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0173427 A1 - Document ID: US20190173427A1 - Status: Published application - Kind: A1 - Application number: 16/207,751 - Filed: 2018-12-03 - Published: 2019-06-06 - Earliest claimed: 2017-12-04 - Assignees: STMicroelectronics (Grenoble 2) SAS; STMicroelectronics (Alps) SAS - Applicants: STMicroelectronics (Grenoble 2) SAS; STMicroelectronics (Alps) SAS - Inventors: Benoit MARCHAND; Francois DRUILHE - Web page: https://patentgrep.com/patent/US20190173427A1 ## CPC - H03B 5/366: {and comprising means for varying the frequency by a variable voltage or current} - H03B 5/04: Modifications of generator to compensate for variations in physical values, e.g. power supply, load, temperature - H03L 1/026: {by using a memory for digitally storing correction values (H03L1/025 takes precedence)} - H03L 1/028: {of generators comprising piezoelectric resonators (H03L1/021, H03L1/022 take precedence; oscillation generators with a piezoelectric resonator H03B5/32)} - H03L 7/0991: {the oscillator being a digital oscillator, e.g. composed of a fixed oscillator followed by a variable frequency divider (H03L7/0995 takes precedence; fixed oscillators with means for selecting among various phases H03L7/0814)} - H03L 7/183: a time difference being used for locking the loop, the counter counting between fixed numbers or the frequency divider dividing by a fixed number {(H03L7/1806 takes precedence)} - H03B: GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS (generators adapted for electrophonic musical instruments G10H; masers or lasers H01S; generation of oscillations in plasma H05H) - H03L: AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES (generation of oscillations H03B) ## Abstract A quartz crystal resonator is coupled to an electronic circuit. A capacitive or resistive element is provided for adjusting a frequency of the quartz crystal resonator on activation or deactivation of a function of a circuit. Control is made according to a model of an expected variation of a temperature of the quartz crystal resonator. ## Claims ### Claim 1 A method of controlling a quartz crystal resonator coupled to an electronic circuit, comprising: in response to activation or deactivation of a function of the electronic circuit, controlling at least one capacitive or resistive element for adjusting a quartz crystal resonator frequency according to a model of an expected variation of a temperature of the quartz crystal resonator. ### Claim 2 (depends on 1) The method of claim 1, wherein said model is applied to an initial temperature measured on activation or deactivation of the function. ### Claim 3 (depends on 1) The method of claim 1, wherein said model is represented by a table of control values for said capacitive or resistive element. ### Claim 4 (depends on 1) The method of claim 1, wherein said at least one capacitive or resistive element is an array of switchable capacitors. ### Claim 5 (depends on 4) The method of claim 4, further comprising pulse-width modulation controlling of switching of at least one capacitor in said array of switchable capacitors. ### Claim 6 (depends on 1) The method of claim 1, further comprising generating said model by measuring variation of the quartz crystal resonator frequency as a result of the activation or the deactivation of said function. ### Claim 7 (depends on 6) The method of claim 6, wherein said measurement of the variation of the quartz crystal resonator frequency is performed on a test circuit. ### Claim 8 (depends on 1) The method of claim 1, wherein said function is a radio frequency transmission function. ### Claim 9 (depends on 8) The method of claim 8, wherein the transmission function respects the LoRa standard. ### Claim 10 An electronic device, comprising: a circuit; and a quartz crystal resonator; wherein the circuit is configured to control at least one capacitive or resistive element for adjusting a quartz crystal resonator frequency, in response to activation or deactivation of a function of an electronic circuit, according to a model of an expected variation of a temperature of the quartz crystal resonator. ### Claim 11 (depends on 10) The device of claim 10, wherein said circuit is a microcontroller. ### Claim 12 (depends on 10) The device of claim 10, wherein said model is represented by a table of control values for said capacitive or resistive element. ### Claim 13 (depends on 10) The device of claim 10, wherein said at least one capacitive or resistive element is an array of switchable capacitors. ### Claim 14 (depends on 13) The device of claim 13, further comprising a circuit configured to effectuate a pulse-width modulation control over switching of at least one capacitor in said array of switchable capacitors. ### Claim 15 (depends on 10) The device of claim 10, wherein said function is a radio frequency transmission function. ### Claim 16 (depends on 15) The device of claim 15, wherein the transmission function respects the LoRa standard. ### Claim 17 A circuit, comprising: a quartz crystal resonator having a first terminal and a second terminal; a first switchable capacitor circuit coupled between the first terminal and a reference node; a second switchable capacitor circuit coupled between the second terminal and the reference node; a control circuit configured to control operation of the first and second switchable capacitor circuits to adjust a quartz crystal resonator frequency, on activation or deactivation of a function of an electronic circuit, according to a model of an expected variation of a temperature of the quartz crystal resonator. ### Claim 18 (depends on 17) The circuit of claim 17, wherein each of the first and second switchable capacitor circuits is implemented by an array of switchable capacitors. ### Claim 19 (depends on 17) The circuit of claim 17, wherein said model is represented by a table of control values for said first and second switchable capacitor circuits. ### Claim 20 (depends on 17) The circuit of claim 17, wherein said first and second switchable capacitor circuits are an array of switchable capacitors. ### Claim 21 (depends on 20) The circuit of claim 20, further comprising pulse-width modulation controlling of said array. ### Claim 22 (depends on 17) The circuit of claim 17, wherein said model is obtained by measurement of the variation of the frequency supplied by the quartz crystal resonator as a result of the activation or the deactivation of said function.