# US 2020/0403571 A1 · Circuit device, oscillator, electronic apparatus, and vehicle > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0403571 A1 - Document ID: US20200403571A1 - Status: Published application - Kind: A1 - Application number: 16/906,098 - Filed: 2020-06-19 - Published: 2020-12-24 - Earliest claimed: 2019-06-21 - Assignees: Seiko Epson Corporation - Applicants: Seiko Epson Corporation - Inventors: Takashi NOMIYA; Naoki II - Web page: https://patentgrep.com/patent/US20200403571A1 ## CPC - H03B 5/04: Modifications of generator to compensate for variations in physical values, e.g. power supply, load, temperature - H03B 5/36: active element in amplifier being semiconductor device ({H03B5/323, H03B5/326} , H03B5/38 take precedence) - H03B 5/362: {the amplifier being a single transistor (H03B5/364 - H03B5/368 take precedence)} - H03H 7/06: including resistors (H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence) - H03H 7/54: Modifications of networks to reduce influence of variations of temperature - 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) - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) ## Abstract The circuit device includes a current generation circuit configured to generate a temperature compensation current based on a temperature detection voltage, and a current-voltage conversion circuit configured to perform current-voltage conversion on the temperature compensation current to output a temperature compensation voltage. The current-voltage conversion circuit includes an operational amplifier, and a feedback circuit. The operational amplifier includes a differential section having a current mirror circuit and differential pair transistors, an output section configured to output the temperature compensation voltage, and an RC low-pass filter configured to output a signal obtained by performing a low-pass filter process on an output signal of the differential section to an input node of the output section. ## Claims ### Claim 1 A circuit device comprising: a current generation circuit configured to generate a temperature compensation current based on a temperature detection voltage; and a current-voltage conversion circuit configured to perform current-voltage conversion on the temperature compensation current to output a temperature compensation voltage, wherein the current-voltage conversion circuit includes an operational amplifier having a first input node to which the temperature compensation current is input, and an output node configured to output the temperature compensation voltage, and a feedback circuit disposed between the first input node and the output node of the operational amplifier, and the operational amplifier includes a differential section having a current mirror circuit and differential pair transistors, an output section configured to output the temperature compensation voltage, and an RC low-pass filter configured to output a signal obtained by performing a low-pass filter process on an output signal of the differential section to an input node of the output section. ### Claim 2 (depends on 1) The circuit device according to claim 1, wherein the RC low-pass filter includes a variable resistive circuit which is disposed between an output node of the differential section and the input node of the output section, and a resistance value of which is variable, and a capacitor one end of which is coupled to the output node of the differential section. ### Claim 3 (depends on 2) The circuit device according to claim 2, wherein the variable resistive circuit includes a resistor disposed between the output node of the differential section and the input node of the output section, and a switch disposed in parallel to the resistor between the output node of the differential section and the input node of the output section. ### Claim 4 (depends on 3) The circuit device according to claim 3 further comprising: a regulator having a second RC low-pass filter to supply the current generation circuit with a regulated voltage, wherein the switch changes from an on state to an off state after a predetermined wait period elapses from when an operation of the second RC low-pass filter is enabled. ### Claim 5 (depends on 4) The circuit device according to claim 4, wherein the regulator includes a second operational amplifier, the second operational amplifier includes a second differential section having a second current mirror circuit and second differential pair transistors, a second output section configured to output the regulated voltage, and the second RC low-pass filter, and the second RC low-pass filter outputs a signal obtained by performing a low-pass filter process on an output signal of the second differential section to an input node of the second output section. ### Claim 6 (depends on 1) The circuit device according to claim 1, wherein the output section includes a P-type transistor which is disposed between a high potential side power supply voltage and the output node of the operational amplifier, and in which the input node of the output section is coupled to a gate, and a bipolar transistor which is disposed between the output node of the operational amplifier and a low potential side power supply voltage, and in which a bias voltage is input to a base. ### Claim 7 (depends on 1) The circuit device according to claim 1, wherein the differential section includes, as the differential pair transistors, a first bipolar transistor in which the first input node is coupled to a base, and a second bipolar transistor in which a second input node to which a reference voltage is input is coupled to a base. ### Claim 8 (depends on 7) The circuit device according to claim 7, wherein the differential section includes a third bipolar transistor which is disposed between a set of the first bipolar transistor and the second bipolar transistor and a low potential side power supply voltage, and in which the bias voltage is input to a base. ### Claim 9 (depends on 3) The circuit device according to claim 3 further comprising: an oscillation circuit configured to oscillate a resonator; and an output circuit configured to output a clock signal based on an output signal of the oscillation circuit, wherein the temperature compensation voltage from the current-voltage conversion circuit is input to the oscillation circuit, and the switch changes from an on state to an off state after a predetermined wait period elapses from when the output circuit starts to output the clock signal. ### Claim 10 (depends on 9) An oscillator comprising: the circuit device according to claim 9; and the resonator. ### Claim 11 (depends on 1) An electronic apparatus comprising: the circuit device according to claim 1; and a processing device which operates based on an output signal from the circuit device. ### Claim 12 (depends on 1) A vehicle comprising: the circuit device according to claim 1; and a processing device which operates based on an output signal from the circuit device.