IP Library › Granted Patent US 12704563
Granted Patent B2
US 12704563 · App. 18/789,985 · Granted Aug 11, 2026

Magnetic gain correction of hall effect sensors

Inventors: Charles Parkhurst (Murphy, TX); Keith Ryan Green (McKinney, TX); Gabriel De La Cruz Hernandez (Dallas, TX); Sergio Orjuela (Dallas, TX)
Assignee: TEXAS INSTRUMENTS INCORPORATED
G01R33/0082G01K7/16G01R33/07
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Quick Facts
Patent No.
US 12704563
App. No.
18/789,985
Granted
Aug 11, 2026
Kind
B2
Abstract

A circuit includes a bias current generator, a temperature compensation circuit, and a Hall effect sensor. The bias current generator has a first input, a second input, a first terminal, and a second terminal. The bias current generator includes a resistor circuit having a first terminal and a second terminal coupled to the first terminal and the second terminal of the bias current generator respectively. The temperature compensation circuit has a first input, a second input coupled to the first input of the bias current generator, and an output coupled to the second input of the bias current generator. The Hall effect sensor has a first terminal coupled to the first terminal of the bias current generator, a second terminal, a third terminal, and a fourth terminal.

Claims (61)

1 . A circuit comprising:

a bias current generator having a first input, a second input, a first terminal, and a second terminal, wherein the bias current generator includes a resistor circuit having first and second terminals coupled to the first and second terminals of the bias current generator respectively;

a temperature compensation circuit having a first input, a second input coupled to the first input of the bias current generator, and an output coupled to the second input of the bias current generator; and

a Hall effect sensor having a first terminal coupled to the first terminal of the bias current generator, a second terminal, a third terminal, and a fourth terminal.

2 . The circuit of claim 1 , wherein the temperature compensation circuit includes:

a first current source having an input and an output;

a first transistor having a first terminal coupled to the output of the first current source, a second terminal, and a control terminal coupled to the first terminal;

a second transistor having a first terminal coupled to the second terminal of the first transistor, a second terminal, and a control terminal coupled to the first input of the temperature compensation circuit;

a third transistor having a first terminal coupled to the input of the first current source, a second terminal, and a control terminal coupled to the control terminal of the first transistor; and

a fourth transistor having a first terminal coupled to the second terminal of the third transistor, a second terminal coupled to the output of the temperature compensation circuit, and a control terminal coupled to the first input of the temperature compensation circuit.

3 . The circuit of claim 2 , wherein the temperature compensation circuit further includes:

a first resistor having a first terminal coupled to the second terminal of the first transistor and a second terminal coupled to the first terminal of the second transistor; and

a second resistor having a first terminal coupled to the second terminal of the third transistor and a second terminal coupled to the first terminal of the fourth transistor.

4 . The circuit of claim 1 , wherein the bias current generator includes a reference current generator having an input coupled to the first input of the bias current generator, a first terminal coupled to the first terminal of the resistor circuit, and a second terminal coupled to the second terminal of the resistor circuit.

5 . The circuit of claim 4 , wherein the bias current generator further has a third terminal coupled to the second terminal of the Hall effect sensor, and wherein the bias current generator further includes a current mirror having a first terminal coupled to the third terminal of the bias current generator, a second terminal coupled to the second input of the bias current generator, a third terminal coupled to the first terminal of the bias current generator, and a fourth terminal coupled to the second terminal of the bias current generator.

6 . The circuit of claim 5 , further comprising an amplifier having a first input coupled to the third terminal of the Hall effect sensor, and a second input coupled to the fourth terminal of the Hall effect sensor.

7 . The circuit of claim 6 , further comprising a common mode feedback circuit having a first input, a second input coupled to the first input of the amplifier, a third input coupled to the second input of the amplifier, a first terminal coupled to the first terminal of the current mirror, a second terminal coupled to the first terminal of the Hall effect sensor.

8 . The circuit of claim 1 , wherein the resistor circuit includes an additional Hall effect sensor.

9 . A circuit comprising:

a reference current generator having an input, a first terminal, and a second terminal, the reference current generator including a resistor circuit having a first terminal coupled to the first terminal of the reference current generator and a second terminal coupled to the second terminal of the reference current generator;

a current mirror having a first terminal, a second terminal coupled to the first terminal of the reference current generator, a third terminal, and a fourth terminal coupled to the second terminal of the reference current generator;

a Hall effect sensor having a first terminal coupled to the first terminal of the current mirror and a second terminal coupled to the third terminal of the current mirror;

a temperature sensor having an output; and

a temperature compensation circuit having a first input coupled to the output of the temperature sensor, a second input coupled to the input of the reference current generator, and an output coupled to the second terminal of the current mirror.

10 . The circuit of claim 9 , wherein the temperature sensor includes:

a proportional to absolute temperature (PTAT) current source having an input, and an output coupled to the output of the temperature sensor; and

a zero-temperature coefficient (ZTC) resistor having a first terminal coupled to the output of the PTAT current source, and a second terminal.

11 . The circuit of claim 10 , wherein the resistor circuit further includes first trimming circuitry configured to adjust a resistance of the resistor circuit responsive to a first digital trimming signal.

12 . The circuit of claim 11 , wherein the ZTC resistor further includes second trimming circuitry configured to adjust a resistance of the ZTC resistor responsive to a second digital trimming signal.

13 . The circuit of claim 11 , wherein the resistor circuit includes a polysilicon resistor.

14 . The circuit of claim 9 , wherein the temperature compensation circuit includes:

a first current source having an input and an output;

a first transistor having a first terminal coupled to the output of the first current source, a second terminal, and a control terminal coupled to the first terminal;

a second transistor having a first terminal coupled to the second terminal of the first transistor, a second terminal, and a control terminal coupled to the first input of the temperature compensation circuit;

a third transistor having a first terminal coupled to the input of the first current source, a second terminal, and a control terminal coupled to the control terminal of the first transistor; and

a fourth transistor having a first terminal coupled to the second terminal of the third transistor, a second terminal coupled to the output of the temperature compensation circuit, and a control terminal coupled to the first input of the temperature compensation circuit.

15 . A temperature compensation circuit having a first input, a second input, and an output, the temperature compensation circuit comprising:

a first current source having an input and an output;

a first transistor having a first terminal coupled to the output of the first current source, a second terminal, and a control terminal coupled to the first terminal;

a second transistor having a first terminal coupled to the second terminal of the first transistor, a second terminal, and a control terminal coupled to the first input of the temperature compensation circuit;

a third transistor having a first terminal coupled to the input of the first current source, a second terminal, and a control terminal coupled to the control terminal of the first transistor; and

a fourth transistor having a first terminal coupled to the second terminal of the third transistor, a second terminal coupled to the output of the temperature compensation circuit, and a control terminal coupled to the second input of the temperature compensation circuit.

16 . The temperature compensation circuit of claim 15 , further comprising:

a second current source having an input coupled to the input of the first current source, and an output;

a fifth transistor having a first terminal coupled to the output of the second current source, a second terminal, and a control terminal coupled to the first terminal;

a sixth transistor having a first terminal coupled to the second terminal of the fifth transistor, a second terminal coupled to the second terminal of the second transistor, and a control terminal coupled to the second input of the temperature compensation circuit;

a seventh transistor having a first terminal coupled to the input of the second current source, a second terminal, and a control terminal coupled to the control terminal of the fifth transistor; and

an eighth transistor having a first terminal coupled to the second terminal of the seventh transistor, a second terminal, and a control terminal coupled to the first input of the temperature compensation circuit.

17 . The temperature compensation circuit of claim 16 , further comprising:

a ninth transistor having a first terminal coupled to the second terminal of the second transistor and the second terminal of the sixth transistor, a second terminal, and a control terminal coupled to the first terminal.

18 . The temperature compensation circuit of claim 16 , further comprising:

a first resistor having a first terminal coupled to the second terminal of the first transistor, and a second terminal coupled to the first terminal of the second transistor;

a second resistor having a first terminal coupled to the second terminal of the third transistor, and a second terminal coupled to the first terminal of the fourth transistor;

a third resistor having a first terminal coupled to the second terminal of the fifth transistor, and a second terminal coupled to the first terminal of the sixth transistor; and

a fourth resistor having a first terminal coupled to the second terminal of the seventh transistor, and a second terminal coupled to the first terminal of the eighth transistor.

19 . The temperature compensation circuit of claim 15 , further comprising:

a fifth transistor having a first terminal coupled to the second terminal of the fourth transistor, a second terminal, and a control terminal coupled to the first terminal;

a sixth transistor having a first terminal, a second terminal coupled to the second terminal of the fifth transistor, and a control terminal coupled to the control terminal of the fifth transistor;

a seventh transistor having a first terminal coupled to the input of the first current source, a second terminal coupled to the first terminal of the sixth transistor, and a control terminal coupled to the second terminal; and

an eighth transistor having a first terminal coupled to the first terminal of the seventh transistor, a second terminal coupled to the output of the temperature compensation circuit, and a control terminal coupled to the control terminal of the seventh transistor.

20 . The temperature compensation circuit of claim 15 , wherein the first current source includes a zero-temperature coefficient (ZTC) current source.