# US 2019/0379281 A1 · Bandwidth adaptation in a phase-locked loop of a local oscillator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0379281 A1 - Document ID: US20190379281A1 - Status: Published application - Kind: A1 - Application number: 16/408,708 - Filed: 2019-05-10 - Published: 2019-12-12 - Earliest claimed: 2018-06-06 - Assignees: Infineon Technologies AG - Applicants: Infineon Technologies AG - Inventors: Lukas Heschl - Web page: https://patentgrep.com/patent/US20190379281A1 ## CPC - G01S 13/343: {using sawtooth modulation} - H02M 3/07: using capacitors charged and discharged alternately by semiconductor devices with control electrode {, e.g. charge pumps} - G01S 7/032: {Constructional details for solid-state radar subsystems} - G01S 7/35: Details of non-pulse systems - G01S 7/4008: {of transmitters} - G01S 13/32: using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated - G01S 13/931: of land vehicles - H03L 7/093: using special filtering or amplification characteristics in the loop (H03L7/087 - H03L7/091 take precedence) - H03L 7/099: concerning mainly the controlled oscillator of the loop - H03L 7/101: {using an additional control signal to the controlled loop oscillator derived from a signal generated in the loop (H03L7/113, H03L7/187 take precedence)} - H03L 7/107: using a variable transfer function for the loop, e.g. low pass filter having a variable bandwidth - H03L 7/1072: {by changing characteristics of the charge pump, e.g. changing the gain} - H03L 7/193: the frequency divider/counter comprising a commutable pre-divider, e.g. a two modulus divider - H03L 7/1974: {for fractional frequency division} - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES - H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P) - H03L: AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES (generation of oscillations H03B) ## Abstract An RF circuit comprises a charge pump configured to generate current pulses having a first current amplitude and a predetermined duration; and a capacitive element configured to receive the current pulses and to generate a tuning voltage depending thereon. An RF oscillator is configured to generate an RF signal having a frequency that is dependent on the tuning voltage. The RF circuit comprises a measuring circuit configured to generate a measurement signal representing the tuning voltage or the frequency of the RF signal. A controller circuit is configured to drive the charge pump in order to change the first amplitude of a current pulse by a current difference, and ascertain a first change in the measurement signal and a second change in the measurement signal. A measurement value for the first amplitude can be calculated based on the first change and the second change based on the current difference. ## Claims ### Claim 1 A radio-frequency (RF) circuit comprising: a charge pump configured to generate current pulses having a first current amplitude and a predetermined duration; a capacitive element coupled to the charge pump and configured to receive the current pulses and to generate a tuning voltage based on the current pulses; an RF oscillator coupled to the capacitive element and configured to generate an RF signal having a frequency that is dependent on the tuning voltage, a measuring circuit configured to generate a measurement signal representing the tuning voltage or the frequency of the RF signal and; a controller circuit coupled to the charge pump and the measuring circuit and configured: to drive the charge pump so as to change the first current amplitude of a current pulse by a current difference to ascertain a first change in the measurement signal, wherein the first change is a reaction to a first current pulse of the current pulses having the first current amplitude, and a second change in the measurement signal, wherein the second change is a reaction to a second current pulse of the current pulses having a second current amplitude, and to calculate a measurement value for the first current amplitude based on the first change in the measurement signal, the second change in the measurement signal, and the current difference. ### Claim 2 (depends on 1) The RF circuit as claimed in claim 1, wherein the charge pump, the capacitive element, and the RF oscillator are part of a phase-locked loop, wherein the phase-locked loop is at least temporarily inactive, such that the charge pump is driven independently of the frequency of the RF signal. ### Claim 3 (depends on 2) The RF circuit as claimed in claim 2, wherein an operating point of the RF oscillator is settable such that the RF oscillator generates a setpoint frequency, with the phase-locked loop being active, if the tuning voltage corresponds to a reference value. ### Claim 4 (depends on 3) The RF circuit as claimed in claim 3, wherein the controller circuit is further configured: to generate a further tuning voltage that determines the operating point of the RF oscillator, before a current pulse is generated by the charge pump, with the phase-locked loop being active, to set the further tuning voltage such that the tuning voltage corresponds to a reference value. ### Claim 5 (depends on 1) The RF circuit as claimed in claim 1, wherein the capacitive element comprises a loop filter connected downstream of the charge pump. ### Claim 6 (depends on 1) The RF circuit as claimed in claim 1, wherein the controller circuit is further configured: to drive the charge pump such that the first current amplitude is adapted depending on the measurement value calculated for the first current amplitude. ### Claim 7 (depends on 1) The RF circuit as claimed in claim 1, wherein the controller circuit is further configured: to calculate a component parameter of the charge pump and/or of the capacitive element based on changes in the measurement signal and the current difference. ### Claim 8 (depends on 7) The RF circuit as claimed in claim 7, wherein the capacitive element is a loop filter and the component parameter is a total capacitance of the loop filter. ### Claim 9 A method comprising: generating current pulses having a settable current amplitude and a predetermined duration using a charge pump, wherein generating the current pulses comprises generating a first current pulse having a first amplitude and generating a second current pulse having a second amplitude, which differs from the first amplitude by a current difference, converting the current pulses into a tuning voltage for a radio-frequency (RF) oscillator in such a way that the tuning voltage changes as a reaction to each current pulse depending on the amplitude thereof, wherein a frequency of the RF oscillator is dependent on the tuning voltage; generating a measurement signal representing the tuning voltage or the frequency of the RF oscillator; determining a first change in the measurement signal as a reaction to the first current pulse and a second change in the measurement signal as a reaction to the second current pulse: and calculating the first amplitude based on the current difference the first change in the measurement signal, and the second change in the measurement signal. ### Claim 10 (depends on 9) The method as claimed in claim 9, further comprising: setting an operating point of the RF oscillators, such that the RF oscillator generates a setpoint frequency if the tuning voltage corresponds to a reference valued, wherein, while setting the operating point, the charge pump and the RF oscillator are part of an active phase-locked loop. ### Claim 11 (depends on 10) The method as claimed in claim 10, wherein the phase-locked loop is not active while generating the first current pulse and the second current pulse, such that the charge pump is driven independently of the frequency of the RF signal. ### Claim 12 (depends on 9) The method as claimed in claim 9, wherein converting the current pulses into the tuning voltage for the RF oscillator comprises: feeding the current pulses to an input of a loop filter having a total capacitance, and transferring charges transported by the current pulses to the total capacitance. ### Claim 13 (depends on 9) The method as claimed in claim 9, wherein generating the current pulses additionally comprises generating a third current pulse having a third amplitude, and wherein the method further comprises: determining a third change in the measurement signal as a reaction to the third current pulse; and calculating a current error of the current difference between the second amplitude and the first amplitude and/or a current difference between the third amplitude and the first amplitude based on the first change, the second change, and the third change in the measurement signal. ### Claim 14 (depends on 9) The method as claimed in claim 9, further comprising: calculating a component parameter of the charge pump and/or of a capacitive element, which generates the tuning voltage, based on changes in the measurement signal and the current difference. ### Claim 15 (depends on 14) The method as claimed in claim 14, wherein the capacitive element is a loop filter and the component parameter is a total capacitance of the loop filter. ### Claim 16 (depends on 15) The method as claimed in claim 15, further comprising: adapting the total capacitance of the loop filter based on the total capacitance of the loop filter and a setpoint value for the total capacitance. ### Claim 17 A radio-frequency (RF) circuit comprising: a charge pump configured to generate current pulses, wherein the current pulses include a first current pulse having a first amplitude and a second current pulse having a second amplitude, wherein the second amplitude differs from the first amplitude by a current difference; a capacitive element configured to receive the current pulses and generate a tuning voltage based on the current pulses; an RF oscillator configured to generate an RF signal having a frequency that is dependent on the tuning voltage; a measuring circuit configured to generate a measurement signal representing the tuning voltage or the frequency of the RF signal; and a controller circuit configured to: determine a first change in the measurement signal based on the first current pulse, determine a second change in the measurement signal based on the second current pulse, and calculate the first amplitude of the first current pulse based on the first change in the measurement signal, the second change in the measurement signal, and the current difference. ### Claim 18 (depends on 17) The RF circuit as claimed in claim 17, wherein the charge pump, the capacitive element, and the RF oscillator are part of a phase-locked loop, wherein the phase-locked loop is at least temporarily inactive, such that the charge pump is driven independently of the frequency of the RF signal. ### Claim 19 (depends on 18) The RF circuit as claimed in claim 18, wherein an operating point of the RF oscillator is settable such that the RF oscillator generates a setpoint frequency, with the phase-locked loop being active, if the tuning voltage corresponds to a reference value. ### Claim 20 (depends on 17) The RF circuit as claimed in claim 17, wherein the capacitive element comprises a loop filter connected downstream of the charge pump, the RF oscillator is coupled to the capacitive element, and the controller circuit is coupled to the charge pump and the measuring circuit.