# US 5,708,420 A · Voltage detection circuit compensated in technology and temperature > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,708,420 A - Document ID: US5708420A - Status: Granted - Kind: A - Application number: 08/589,220 - Filed: 1996-01-22 - Granted: 1998-01-13 - Earliest claimed: 1995-01-23 - Assignees: SGS-Thomson Microelectronics S.A. - Inventors: Sylvie Drouot - Web page: https://patentgrep.com/patent/US5708420A ## CPC - G05F 1/567: for temperature compensation - G01R 19/16519: {using FET's} - G05F 3/262: {using field-effect transistors only} - G01R 19/16538: {in AC or DC supplies (G01R19/16519 and G01R19/16528 take precedence)} - G01R 19/16576: {comparing DC or AC voltage with one threshold (G01R19/16514, G01R19/16519, G01R19/16528, G01R19/16533 and G01R19/1659 take precedence)} - G05F: SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) ## Abstract A voltage detection circuit includes a first resistive arm receiving an internal voltage to produce a basic current, current amplification circuitry to produce a reference current proportional to the basic current, a second resistive arm to produce a reference voltage representing the reference current, a voltage source to produce a control voltage from the reference voltage and a logic circuit to produce a binary signal from the control voltage, the state of the binary signal representing the value of the internal voltage. ## Claims ### Claim 1 A voltage detection circuit which provides a binary signal having a state that represents a value of an internal voltage, the voltage detection circuit comprising: a first resistive arm which receives the internal voltage and produces a basic current, current amplification means which produces a reference current proportional to the basic current, a second resistive arm which produces a reference voltage representing the reference current, a voltage source which produces a control voltage from the reference voltage, and a logic circuit which produces the binary signal from the control voltage. ### Claim 2 (depends on 1) The circuit according to claim 1, wherein a temperature coefficient of the first resistive arm is more positive than a temperature coefficient of the second resistive arm. ### Claim 3 (depends on 1) The circuit according to claim 1, wherein one or both of the first resistive arm the second resistive arm comprise series-connected resistors of different types. ### Claim 4 (depends on 1) The circuit according to claim 1, wherein the voltage source comprises at least one resistor comprising a positive temperature coefficient. ### Claim 5 (depends on 4) The circuit according to claim 4, wherein the voltage source comprises a field-effect transistor having a channel series-connected with the resistor and receiving the reference voltage at a control gate. ### Claim 6 (depends on 4) The circuit according to claim 4, wherein the resistor of the voltage source is formed by series-connected resistors of different types. ### Claim 7 (depends on 5) The circuit according to claim 5, wherein a value of the product of the temperature coefficient of the resistor of the voltage source and of a factor of transconductance of the transistor of this voltage source is relatively independent of the temperature. ### Claim 8 (depends on 5) The circuit according to claim 5, wherein the current amplification means comprise a current mirror formed by amplification transistors of a same type as the transistor of the voltage source. ### Claim 9 (depends on 5) The circuit according to claim 5, wherein the first resistive arm comprises at least one shift diode formed by means of a transistor of a same type as that of the transistor of the voltage source. ### Claim 10 A voltage detection circuit comprising: a first resistive arm having an input which receives a first voltage and which outputs a first current; a current amplifier which amplifies said first current to produce a reference current; a second resistive arm which receives said reference current as an input, and outputs a corresponding reference voltage; a voltage source which produces a control voltage from said reference voltage; and a logic circuit which converts said control voltage to a binary signal which represents a value of said first voltage. ### Claim 11 (depends on 10) The voltage detection circuit of claim 10, wherein said first resistive arm comprises at least one shift diode. ### Claim 12 (depends on 10) The voltage detection circuit of claim 10, wherein a temperature coefficient of the first resistive arm is more positive than a temperature coefficient of the second resistive arm. ### Claim 13 (depends on 10) The voltage detection circuit of claim 10, wherein said current amplifier comprises a current mirror having an input for receiving said first current and an output for outputting said reference current. ### Claim 14 (depends on 13) The voltage detection circuit of claim 13, wherein said current mirror comprises a first transistor having a first terminal coupled to said input of said current mirror, a second terminal coupled to said input of said current mirror and a third terminal coupled to ground, and a second transistor having a first terminal coupled to said output of said current mirror, a second terminal coupled to said input of said current mirror and a third terminal coupled to ground. ### Claim 15 (depends on 10) The voltage detection circuit of claim 10, wherein said voltage source comprises at least one resistor having a positive temperature coefficient. ### Claim 16 (depends on 15) The voltage detection circuit of claim 15, wherein said voltage source comprises a transistor having a first terminal coupled to a terminal of said resistor and a second terminal coupled to receive the reference voltage. ### Claim 17 (depends on 16) The voltage detection circuit of claim 16, wherein a value of the product of the temperature coefficient of said resistor and a factor of transconductance of said transistor is relatively independent of temperature. ### Claim 18 A voltage detecting method comprising the steps of: (a) converting an internal voltage to a first current; (b) amplifying said first current to product a reference current; (c) producing a reference voltage from said reference current; (d) converting said reference voltage to a control voltage; and (e) outputting a signal which represents a voltage level of said internal voltage. ### Claim 19 (depends on 18) The method of claim 18, wherein step (b) comprises using a current mirror to amplify said first current. ### Claim 20 (depends on 18) The method of claim 18, wherein step (d) comprises using a voltage source to convert said reference voltage to said control voltage.