# US 2024/0201722 A1 · Bandgap cell > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2024/0201722 A1 - Document ID: US20240201722A1 - Status: Published application - Kind: A1 - Application number: 18/082,697 - Filed: 2022-12-16 - Published: 2024-06-20 - Earliest claimed: 2022-12-16 - Assignees: Renesas Electronics Corporation - Applicants: Renesas Electronics Corporation - Inventors: Nishant Singh THAKUR - Web page: https://patentgrep.com/patent/US20240201722A1 ## CPC - G05F 3/22: wherein the transistors are of the bipolar type only (G05F3/26, G05F3/30 take precedence) - G05F 3/30: Regulators using the difference between the base-emitter voltages of two bipolar transistors operating at different current densities (G05F3/26 takes precedence) - G05F: SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES ## Abstract A self-starting bandgap cell for generating a reference voltage. ## Claims ### Claim 1 A self-starting bandgap cell for generating a reference voltage. ### Claim 2 (depends on 1) The self-starting bandgap cell of claim 1, comprising a negative threshold transistor configured to provide an operating current when coupled to a supply voltage, the reference voltage being generated when the operating current flows in the self-starting bandgap cell. ### Claim 3 (depends on 2) The self-starting bandgap cell of claim 2, comprising: an amplifier comprising a first input terminal, a second input terminal and an output terminal, the output terminal being coupled to a gate of the negative threshold transistor; and a resistor string comprising a plurality of resistive elements coupled in series with the negative threshold transistor, the resistor string being coupled to the first and second input terminals of the amplifier. ### Claim 4 (depends on 3) The self-starting bandgap cell of claim 3, wherein the plurality of resistive elements comprises a first resistor, a second resistor and a third resistor. ### Claim 5 (depends on 4) The self-starting bandgap cell of claim 4, wherein one or both of the second and third resistors comprises a variable resistor. ### Claim 6 (depends on 4) The self-starting bandgap cell of claim 4, wherein the second resistor is coupled to the first resistor at the first input terminal of the amplifier and the first resistor is coupled to the third resistor at the second input terminal of the amplifier. ### Claim 7 (depends on 6) The self-starting bandgap cell of claim 6, comprising a first circuit component coupled to the resistor string, the first circuit component comprising a diode, an NPN bipolar junction transistor or a PNP bipolar junction transistor. ### Claim 8 (depends on 7) The self-starting bandgap cell of claim 7, wherein the amplifier comprises a BJT input pair comprising: a first input bipolar junction transistor; and a second input bipolar junction transistor; wherein: the first input bipolar junction transistor is coupled to one of the first input terminal and the second input terminal and the second input bipolar junction transistor is coupled to the other of the first input terminal and the second input terminal; and the BJT input pair is configured to receive an amplifier bias current. ### Claim 9 (depends on 8) The self-starting bandgap cell of claim 8, wherein the BJT input pair is configured to provide a first voltage at the first input terminal of the amplifier and a second voltage at the second input terminal of the amplifier. ### Claim 10 (depends on 9) The self-starting bandgap cell of claim 9, wherein the BJT input pair is configured to have a BJT area ratio to provide the first voltage at the first input terminal of the amplifier and the second voltage at the second input terminal of the amplifier. ### Claim 11 (depends on 10) The self-starting bandgap cell of claim 10, wherein the BJT area ratio is 1:8 or 1:4 or2:8 or1:16 or2:16. ### Claim 12 (depends on 8) The self-starting bandgap cell of claim 8, configured to receive the amplifier bias current from external circuitry. ### Claim 13 (depends on 8) The self-starting bandgap cell of claim 8, wherein: the first component comprises the diode or the PNP bipolar junction transistor; and the first and second input bipolar junction transistors are PNP bipolar junction transistors. ### Claim 14 (depends on 13) The self-starting bandgap cell of claim 13, wherein: the first component comprises a first terminal coupled to the third resistor and a second terminal coupled to the negative threshold transistor at an output node, the reference voltage being provided at the output node during operation; a base of the first input bipolar junction transistor is coupled to the first input terminal; and a base of the second input bipolar junction transistor is coupled to the second input terminal. ### Claim 15 (depends on 14) The self-starting bandgap cell of claim 14, wherein the BJT input pair is configured to provide a first voltage at the first input terminal of the amplifier and a second voltage at the second input terminal of the amplifier ### Claim 16 (depends on 15) The self-starting bandgap cell of claim 15, wherein the BJT input pair is configured to have an offset ratio to provide the first voltage at the first input terminal of the amplifier and the second voltage at the second input terminal of the amplifier ### Claim 17 (depends on 16) The self-starting bandgap cell of claim 16, wherein the BJT area ratio is 1:8 or 1:4 or2:8 or1:16 or2:16. ### Claim 18 (depends on 8) The self-starting bandgap cell of claim 8, wherein: the first component comprises the diode or the NPN bipolar junction transistor; and the first and second input bipolar junction transistors are NPN bipolar junction transistors. ### Claim 19 (depends on 18) The self-starting bandgap cell of claim 18, wherein: the first component comprises a first terminal coupled to the second resistor and a second terminal coupled to a voltage terminal; the third resistor is coupled to the negative threshold transistor at an output node, the reference voltage being provided at the output node during operation; a base of the first input bipolar junction transistor is coupled to the second input terminal; and a base of the second input bipolar junction transistor is coupled to the first input terminal. ### Claim 20 A method of generating a reference voltage using a self-starting bandgap cell.