IP Library › Granted Patent US 12,669,836
Granted Patent B2
US 12,669,836 · App. 18/325,603 · Granted Jun 30, 2026

Bandgap reference circuit for producing fixed reference signals

Inventors: Eslam Abdelbadie (Oslo, NO); Torunn Roraas (Oslo, NO)
Assignee: TEXAS INSTRUMENTS INCORPORATED
G05F1/468G05F1/567G05F1/575
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Quick Facts
Patent No.
US 12,669,836
App. No.
18/325,603
Granted
Jun 30, 2026
Kind
B2
Abstract

Embodiments disclosed herein relate to reference signals produced by integrated circuits. In an example, a reference circuit is provided. The reference circuit includes a first transistor, a second transistor, and an operational amplifier. The first transistor includes an input configured to couple to a voltage supply, an output coupled to a first resistor and a second resistor, and a control coupled to an output of the operational amplifier. The first resistor is coupled in series with a third resistor, and the second resistor is coupled in series with the second transistor. The second transistor includes an input and a control coupled with the second resistor and an output coupled to ground. The operational amplifier includes a first input coupled between the first and third resistors and a second input coupled between the second resistor and second transistor.

Claims (58)

1 . A reference circuit, comprising:

a first transistor;

a second transistor;

a first resistor;

a second resistor;

a third resistor; and

an operational amplifier including a positive input terminal and a negative input terminal;

wherein the first transistor includes a current path terminal, and a control terminal coupled to an output of the operational amplifier;

wherein the first resistor includes a first terminal coupled to the current path terminal of the first transistor, and a second terminal coupled to the positive input terminal of the operational amplifier;

wherein the second resistor includes a first terminal coupled to the current path terminal of the first transistor, and a second terminal coupled to the negative input terminal of the operational amplifier;

wherein the second transistor includes a current path terminal coupled to the negative input terminal of the operational amplifier, and a control terminal coupled to the current path terminal of the second transistor; and

wherein the third resistor includes a first terminal coupled to the positive input terminal of the operational amplifier, and a second terminal coupled to a ground terminal.

2 . The reference circuit of claim 1 , wherein the reference circuit is configured to provide a reference current that comprises a proportional to absolute temperature (PTAT) component and a complementary to absolute temperature (CTAT) component.

3 . The reference circuit of claim 1 , wherein the third resistor is a variable resistor configurable to control a first current through the first resistor and a second current through the second resistor.

4 . The reference circuit of claim 3 , wherein a resistance of the variable resistor is selected based on a desired value for the first and second currents.

5 . The reference circuit of claim 1 , wherein a voltage of a voltage supply coupled to the first transistor changes based on a temperature of the voltage supply.

6 . The reference circuit of claim 1 , wherein a start-up circuit is coupled to the first terminals of the first and second resistors.

7 . The reference circuit of claim 6 , wherein the start-up circuit is further coupled to the current path terminal of the second transistor.

8 . The reference circuit of claim 7 , wherein the start-up circuit receives a divided reference current at the current path terminal of the second transistor.

9 . The reference circuit of claim 8 , wherein the start-up circuit provides, to the first resistor and the second resistor, a start-up current based on the divided reference current.

10 . The reference circuit of claim 1 , wherein a load circuit is coupled to the control terminal of the first transistor to receive a reference current.

11 . A circuit, comprising:

a start-up circuit;

a load circuit; and

a reference circuit coupled to the start-up circuit and the load circuit and

configurable to provide a reference current to the load circuit;

wherein the reference circuit comprises:

a first transistor;

a second transistor;

a first resistor;

a second resistor;

a third resistor; and

an operational amplifier including a positive input terminal and a negative input terminal;

wherein the first transistor includes a current path terminal, and a control terminal coupled to an output of the operational amplifier;

wherein the first resistor includes a first terminal coupled to the current path terminal of the first transistor, and a second terminal coupled to the positive input terminal of the operational amplifier;

wherein the second resistor includes a first terminal coupled to the current path terminal of the first transistor, and a second terminal coupled to the negative input terminal of the operational amplifier;

wherein the second transistor includes a current path terminal coupled to the negative input terminal of the operational amplifier, and a control terminal coupled to the current path terminal of the second transistor; and

wherein the third resistor includes a first terminal coupled to the positive input terminal of the operational amplifier, and a second terminal coupled to a ground terminal.

12 . The circuit of claim 11 , wherein the reference current comprises a proportional to absolute temperature (PTAT) component and a complementary to absolute temperature (CTAT) component.

13 . The circuit of claim 11 , wherein the third resistor is a variable resistor configurable to control a first current through the first resistor and second current through the second resistor.

14 . The circuit of claim 13 , wherein a resistance of the variable resistor is selected based on a desired value for the first and second currents.

15 . The circuit of claim 11 , wherein a voltage of a voltage supply changes based on a temperature of the voltage supply.

16 . The circuit of claim 11 , wherein the start-up circuit comprises a plurality of transistors.

17 . The circuit of claim 16 , wherein a first transistor of the start-up circuit is coupled to the current path terminal of the second transistor and receives a divided reference current from the reference circuit.

18 . The circuit of claim 17 , wherein a second transistor of the start-up circuit is coupled to the current path terminal of the first transistor and to the first terminals of the first and second resistors of the reference circuit and provides a start-up current to the first and second resistors based on the divided reference current.

19 . The circuit of claim 11 , wherein the load circuit is coupled to the control terminal of the first transistor of the reference circuit.

20 . A reference circuit, comprising:

a first transistor;

a second transistor;

a first resistor;

a second resistor;

a variable resistor; and

an operational amplifier;

wherein the first transistor includes a current path terminal, and a control terminal coupled to an output of the operational amplifier;

wherein the first resistor includes a first terminal coupled to the current path terminal of the first transistor, and a second terminal coupled to the operational amplifier;

wherein the second resistor includes a first terminal coupled to the current path terminal of the first transistor, and a second terminal coupled to the operational amplifier;

wherein the second transistor includes a current path terminal coupled to the operational amplifier, and a control terminal coupled to the current path terminal of the second transistor; and

wherein the variable resistor includes a first terminal coupled to the operational amplifier, and a second terminal coupled to a ground node, and is configurable to control a first current through the first resistor and a second current through the second resistor.