# US 5,703,476 A · Reference voltage generator, having a double slope temperature characteristic, for a voltage regulator of an automotive alternator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,703,476 A - Document ID: US5703476A - Status: Granted - Kind: A - Application number: 08/674,321 - Filed: 1996-07-01 - Granted: 1997-12-30 - Earliest claimed: 1995-06-30 - Assignees: SGS-Thomson Microelectronics S.A. - Inventors: Mauro Merlo; Franco Cocetta; Fabio Marchio; Massimo Grasso; Bruno Murari - Web page: https://patentgrep.com/patent/US5703476A ## CPC - G05F 1/463: {Sources providing an output which depends on temperature} - G05F 3/225: {producing a current or voltage as a predetermined function of the temperature} - H02J 7/975: {in response to temperature} - Y10S 323/907: Temperature compensation of semiconductor - G05F: SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract A reference voltage generator having a dual slope temperature characteristic, for use in an automotive alternator voltage regulator, comprises a bandgap circuit (R1,R2,R3,R4) which generates a voltage (A) having a thermal drift coefficient of zero and a voltage (B) having a non-zero thermal drift coefficient. These voltages are applied to a voltage divider (R5,R6) and a voltage-follower type of circuit (OPA1). A unidirectional conduction amplifier circuit (OPA2) has an input terminal connected to an intermediate point (C) on the voltage divider. A second voltage divider (R7,R8) is connected between the output terminals of the voltage-follower circuit (D) and the amplifier circuit (E) . An intermediate node (F) of the second voltage divider is coupled to an output terminal (VREF) of the generator. ## Claims ### Claim 1 A reference voltage generator having a dual slope temperature characteristic and being integratable monolithically, for use in a voltage regulator, characterized in that it comprises a circuit means effective to generate a first voltage having a thermal drift coefficient of zero and a second voltage having a predetermined non-zero thermal drift coefficient, a first voltage divider and first voltage-follower circuit which are respectively applied said first and second voltages, a unidirectional conduction amplifier circuit having an input terminal connected to an intermediate node of the first voltage divider, and a second voltage divider connected between an output terminal of the amplifier circuit and an output terminal of the voltage-follower circuit, an intermediate node of said second voltage divider being coupled to an output terminal of the generator. ### Claim 2 (depends on 1) A voltage generator according to claim 1, wherein, connected between the intermediate node of the second voltage divider and the output terminal of the generator, is a second circuit of the voltage-follower type. ### Claim 3 (depends on 2) A voltage generator according to claim 2, wherein the circuit means effective to generate said first and second voltages comprises a bandgap type of circuit. ### Claim 4 (depends on 2) A voltage generator according to claim 2, wherein the value of said second voltage decreases as temperature rises. ### Claim 5 (depends on 2) A voltage generator according to claim 2, wherein the unidirectional conduction amplifier circuit comprises a feedback operational amplifier having a circuit element of junction type at its output end. ### Claim 6 (depends on 1) A voltage generator according to claim 1, wherein the circuit means effective to generate said first and second voltages comprises a bandgap type of circuit. ### Claim 7 (depends on 6) A voltage generator according to claim 6, wherein said second voltage is generated between a ground and an intermediate node of a voltage divider, between one terminal of which and said ground said first voltage is generated. ### Claim 8 (depends on 6) A voltage generator according to claim 6, wherein the value of said second voltage decreases as temperature rises. ### Claim 9 (depends on 6) A voltage generator according to claim 6, wherein the first voltage-follower circuit comprises a feedback operational amplifier having a gain of unity. ### Claim 10 (depends on 6) A voltage generator according to claim 6, wherein the unidirectional conduction amplifier circuit comprises a feedback operational amplifier having a circuit element of junction type at its output end. ### Claim 11 (depends on 6) A voltage generator according to claim 6, wherein the second voltage follower circuit is a feedback operational amplifier having a gain of unity. ### Claim 12 (depends on 1) A voltage generator according to claim 1, wherein the value of said second voltage decreases as temperature rises. ### Claim 13 (depends on 1) A voltage generator according to claim 1, wherein the first voltage-follower circuit comprises a feedback operational amplifier having a gain of unity. ### Claim 14 (depends on 1) A voltage generator according to claim 1, wherein the unidirectional conduction amplifier circuit comprises a feedback operational amplifier having a circuit element of junction type at its output end. ### Claim 15 A reference voltage generator having a multi-slope temperature characteristic and being integratable monolithically, for use in a voltage regulator, characterized in that it comprises a circuit means effective to generate a first voltage having a thermal drift coefficient of zero and at least second and third voltages having predetermined respective non-zero thermal drift coefficients, a first voltage divider and at least first and second voltage-follower circuits which are respectively applied said first, second and third voltages, a unidirectional conduction amplifier circuit having an input terminal connected to an intermediate node of the first voltage divider and an output terminal connected through a first resistive element to an output circuit node which is coupled to an output terminal of the reference voltage generator, also connected to said output circuit node through a second and a third resistive element, respectively, being respective output terminals of said at least first and second voltage follower circuits. ### Claim 16 (depends on 15) A voltage generator according to claim 15, wherein, connected between the output circuit node and the output terminal of the generator is a circuit of the voltage-follower type. ### Claim 17 (depends on 16) A voltage generator according to claim 16, wherein the circuit means effective to generate said first and at least second and third voltages comprises a circuit of the bandgap type. ### Claim 18 (depends on 15) A voltage generator according to claim 15, wherein the circuit means effective to generate said first and at least second and third voltages comprises a circuit of the bandgap type. ### Claim 19 (depends on 16) A voltage generator according to claim 16, wherein the circuit means effective to generate said first and at least second and third voltages comprises a circuit of the bandgap type. ### Claim 20 (depends on 15) A voltage generator according to claim 15, wherein the unidirectional conduction amplifier circuits are each comprised of a feedback operational amplifier having an output terminal connected to said connecting node. ### Claim 21 A reference voltage generator having a multi-slope temperature characteristic and being integratable monolithically, for use in a voltage regulator, characterized in that it comprises a circuit means effective to generate a first voltage having a thermal drift coefficient of zero and at least second and third voltages having predetermined respective non-zero thermal drift coefficients, at least one first voltage divider and at least first and second voltage-follower circuits which are respectively applied said first, second and third voltages, at least one unidirectional conduction amplifier circuit having an input terminal connected to an intermediate node of said at least one first voltage divider and an output terminal connected through a first resistive element to an output circuit node which is coupled to an output terminal of the reference voltage generator, also connected to said output circuit node through a second and a third resistive element, respectively, being respective output terminals of said at least first and second voltage follower circuits. ### Claim 22 (depends on 21) A voltage generator according to claim 21, wherein, connected between the output circuit node and the output terminal of the generator is a circuit of the voltage-follower type. ### Claim 23 (depends on 22) A voltage generator according to claim 22, wherein the circuit means effective to generate said at least one first voltage and at least second and third voltages comprises a circuit of the bandgap type. ### Claim 24 (depends on 22) A voltage generator according to claim 22, wherein each unidirectional conduction amplifier circuit comprises a feedback operational amplifier having an output terminal connected to said connecting node. ### Claim 25 (depends on 21) A voltage generator according to claim 21, wherein the circuit means effective to generate said at least one first voltage and at least second and third voltages comprises a circuit of the bandgap type. ### Claim 26 (depends on 21) A voltage generator according to claim 21, wherein each unidirectional conduction amplifier circuit comprises a feedback operational amplifier having an output terminal connected to said connecting node.