# US 10,374,595 B1 · Self-adjustable RF switch cell > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,374,595 B1 - Document ID: US10374595B1 - Status: Granted - Kind: B1 - Application number: 15/876,972 - Filed: 2018-01-22 - Published: 2019-07-25 - Granted: 2019-08-06 - Earliest claimed: 2018-01-22 - Assignees: Infineon Technologies AG - Applicants: Infineon Technologies AG - Inventors: Winfried Bakalski - Web page: https://patentgrep.com/patent/US10374595B1 ## CPC - H03K 17/16: Modifications for eliminating interference voltages or currents - H03K 17/08104: {in field-effect transistor switches (H03K17/0812, H03K17/0814 take precedence)} - H03K 17/102: {in field-effect transistor switches} - H03K 17/693: Switching arrangements with several input- or output-terminals, e.g. multiplexers, distributors (logic circuits H03K19/00; code converters H03M5/00, H03M7/00) - H03K 2217/9401: Calibration techniques - 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) ## Abstract An RF switch includes two or more coupled RF switch cells, each RF switch cell including a transistor having a first source/drain node, a second source/drain node, and a gate node, a first varactor is coupled between the first source/drain node and the gate node, and a second varactor is coupled between the second source/drain node and the gate node. ## Claims ### Claim 1 A self-adjustable RF switch cell comprising: a transistor comprising a first current node, a second current node, and a control node; a first circuit having a voltage-adjustable capacitive element coupled between the first current node and the control node; and a second circuit having a voltage-adjustable capacitive element matched to the first circuit coupled between the second current node and the control node, wherein the first and second circuits are configured for maintaining an operating condition of the self-adjustable RF switch cell independently of substrate parasitic elements. ### Claim 2 (depends on 1) The self-adjustable RF switch cell of claim 1, wherein the substrate parasitic elements include at least one of a parasitic current, resistance, or capacitance. ### Claim 3 (depends on 1) The self-adjustable RF switch cell of claim 1, wherein the first circuit and the second circuit each comprise a varactor. ### Claim 4 (depends on 1) The self-adjustable RF switch cell of claim 1, wherein the first circuit and the second circuit each comprise a capacitor-connected transistor. ### Claim 5 (depends on 1) The self-adjustable RF switch cell of claim 1, further comprising a resistor coupled between the first current node and the second current node. ### Claim 6 (depends on 1) The self-adjustable RF switch cell of claim 1, further comprising an additional transistor having a current path coupled between the first current node and the second current node and an additional control node coupled to a constant voltage source. ### Claim 7 An RF switch comprising: a plurality of series-coupled RF switch cells, at least one of the RF switch cells comprising: a transistor comprising a first current node, a second current node, and a control node; a first varactor coupled between the first current node and the control node; and a second varactor coupled between the second current node and the control node. ### Claim 8 (depends on 7) The RF switch of claim 7, wherein the transistor of the at least one of the RF switch cells comprises a first n-channel transistor having a collector coupled to the first current node, a source coupled to the second current node, and a gate coupled to the control node. ### Claim 9 (depends on 7) The RF switch of claim 7, wherein the first varactor of the at least one of the RF switch cells comprises a second n-channel transistor having a collector coupled to the first current node, a source coupled to the first current node, and a gate coupled to the control node. ### Claim 10 (depends on 7) The RF switch of claim 7, wherein the second varactor of the at least one of the RF switch cells comprises a third n-channel transistor having a collector coupled to the second current node, a source coupled to the second current node, and a gate coupled to the control node. ### Claim 11 (depends on 7) The RF switch of claim 7, wherein the at least one of the RF switch cells further comprises a resistor coupled between the first current node and the second current node. ### Claim 12 (depends on 7) The RF switch of claim 7, wherein the at least one of the RF switch cells further comprises a fourth n-channel transistor having a collector coupled to the first current node, a source coupled to the second current node, and a gate coupled to a constant voltage source. ### Claim 13 (depends on 7) The switch of claim 7, wherein a first switch cell is coupled to an RF voltage source and a last switch cell is coupled to ground. ### Claim 14 (depends on 7) The RF switch of claim 7, wherein a first RF switch cell is coupled to a first RF voltage source and a last RF switch cell is coupled to a second RF voltage source. ### Claim 15 (depends on 7) The RF switch of claim 7, wherein the transistor of a first RF switch cell has a first channel length, and the transistor of a second switch cell has a second channel length different from the first channel length. ### Claim 16 (depends on 7) The RF switch of claim 7, wherein the first current node of an Nth RF switch cell is coupled to the second current node of an (N−1)th RF switch cell, and the second current node of the Nth RF switch cell is coupled to the first current node of an (N+1)th RF switch cell. ### Claim 17 (depends on 7) The RF switch of claim 7, further comprising a driver coupled to the control node of each of the series coupled RF switch cells. ### Claim 18 A method of operating an RF switch comprising a plurality of RF switch cells, at least one of the switch cells including a transistor, the method comprising: adjusting a first capacitor coupled between a first current node of the transistor and a control node of the transistor according to a voltage across the at least one of the RF switch cells; and adjusting a second capacitor coupled between a second current node of the transistor and the control node of the transistor according to the voltage across the at least one of the RF switch cells. ### Claim 19 (depends on 18) The method of claim 18, further comprising adjusting a resistor coupled between the first current node and the second current node of the at least one of the RF switch cells. ### Claim 20 (depends on 19) The method of claim 19, wherein adjusting the resistor comprises adjusting the resistor according to the voltage across the at least one of the RF switch cells.