# US 11,444,615 B2 · Termination circuit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,444,615 B2 - Document ID: US11444615B2 - Status: Granted - Kind: B2 - Application number: 17/163,559 - Filed: 2021-02-01 - Published: 2022-08-04 - Granted: 2022-09-13 - Earliest claimed: 2021-02-01 - Assignees: Novatek Microelectronics Corp. - Applicants: Novatek Microelectronics Corp. - Inventors: Liang-Ting Kuo; Chih-Yuan Kung; Kuan-Ting Lin; Chu-Wei Hsia - Web page: https://patentgrep.com/patent/US11444615B2 ## CPC - H03K 17/08122: {in field-effect transistor switches} - H04L 25/0298: {Arrangement for terminating transmission lines} - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A termination circuit, including a termination resistor, a first switch circuit, a second switch circuit, and a control circuit, is provided. A first end of the termination resistor is coupled to a signal pad. A first end of the first switch circuit is coupled to a second end of the termination resistor. A first end of the second switch circuit is coupled to a second end of the first switch circuit. A second end of the second switch circuit is coupled to a reference voltage line. During a period when the second switch circuit is turned on, the control circuit turns on the first switch circuit with a bias voltage. During a period when the second switch circuit is turned off, the control circuit turns off the first switch circuit with a voltage of the first end of the first switch circuit. ## Claims ### Claim 1 A termination circuit, comprising: a termination resistor, having a first end coupled to a signal pad; a first switch circuit, having a first end coupled to a second end of the termination resistor; a second switch circuit, having a first end coupled to a second end of the first switch circuit, wherein a second end of the second switch circuit is coupled to a reference voltage line, and the second switch circuit is controlled by a control signal; and a control circuit, configured to control the first switch circuit, wherein during a period when the control signal turns on the second switch circuit, the control circuit transmits a bias voltage to a control end of the first switch circuit to turn on the first switch circuit; and during a period when the control signal turns off the second switch circuit, the control circuit transmits a voltage of the first end of the first switch circuit to the control end of the first switch circuit to turn off the first switch circuit. ### Claim 2 (depends on 1) The termination circuit according to claim 1, wherein the termination circuit is adapted to be configured in an integrated circuit, and a peak voltage level of a signal of the signal pad is higher than a supply voltage of the integrated circuit. ### Claim 3 (depends on 1) The termination circuit according to claim 1, wherein a voltage swing range of the control signal is from the bias voltage to a supply voltage. ### Claim 4 (depends on 1) The termination circuit according to claim 1, wherein the bias voltage is greater than 0V. ### Claim 5 (depends on 4) The termination circuit according to claim 4, wherein in a case where the first switch circuit and the second switch circuit are turned on, a difference between voltages of two ends of the termination resistor is a voltage drop, a difference between voltage of the signal pad and voltage of the reference voltage line is a voltage difference, and the bias voltage is greater than a difference value between the voltage difference and the voltage drop. ### Claim 6 (depends on 1) The termination circuit according to claim 1, wherein the first switch circuit comprises: a transistor, having a gate coupled to the control circuit, wherein a source of the transistor is coupled to the second end of the termination resistor, a drain of the transistor is coupled to the first end of the second switch circuit, and a bulk of the transistor is coupled to the drain of the transistor. ### Claim 7 (depends on 1) The termination circuit according to claim 1, wherein the first switch circuit comprises: a first transistor, having a gate coupled to the control circuit, wherein a source of the first transistor is coupled to the second end of the termination resistor, and a bulk of the first transistor is coupled to a drain of the first transistor; and a second transistor, having a gate coupled to the control circuit, wherein a source of the second transistor is coupled to the drain of the first transistor, a drain of the second transistor is coupled to the first end of the second switch circuit, and a bulk of the second transistor is coupled to the drain of the second transistor. ### Claim 8 (depends on 1) The termination circuit according to claim 1, wherein the second switch circuit comprises: a transistor, having a gate controlled by the control signal, wherein a source of the transistor is coupled to the second end of the first switch circuit, a drain of the transistor is coupled to the reference voltage line, and a bulk of the transistor is coupled to the drain of the transistor. ### Claim 9 (depends on 1) The termination circuit according to claim 1, wherein the control circuit comprises: a first transistor, having a gate coupled to a supply voltage, wherein a source of the first transistor is coupled to the first end of the first switch circuit, and a drain of the first transistor is coupled to the control end of the first switch circuit; a second transistor, having a gate coupled to the supply voltage, wherein a drain of the second transistor is coupled to the control end of the first switch circuit, and a bulk of the second transistor is coupled to a source of the second transistor; and a third transistor, having a gate adapted to receive an inverted signal of the control signal, wherein a drain of the third transistor is coupled to the source of the second transistor, a source of the third transistor is adapted to receive the bias voltage, and a bulk of the third transistor is coupled to the source of the third transistor.