Temperature drift compensation

• US 10,976,763 B2
• Filed: 12/17/2019
• Issued: 04/13/2021
• Est. Priority Date: 04/07/2017
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Krishnan, Sandeep Shylaja
• Primary Examiner(s): Nguyen, Hai L
• Application Number:
  US16/716,841
• Publication Number:
  US 20200133325A1
• Time in Patent Office: 483 Days
• CPC Class Codes: G05F 1/468 characterised by reference voltage circuitry, e.g. soft start, remote shutdown
• CPC Class Codes: G05F 1/575 characterised by the feedback circuit
• CPC Class Codes: H03M 1/089 of temperature variations

Abstract

A voltage reference circuit includes a bandgap circuit and a temperature compensation circuit. The temperature compensation circuit includes a first trim circuit, a second trim circuit, and a resistive digital-to-analog converter. The resistive digital-to-analog converter is coupled to the first trim circuit, the second trim circuit, and the bandgap circuit. The resistive digital-to-analog converter is configured to generate a temperature compensation voltage, and to provide the temperature compensation voltage to the bandgap circuit.

Claims

1. A method for trimming a voltage reference circuit, comprising:

adjusting an output voltage of a bandgap circuit to a reference voltage at a first temperature;

generating a temperature compensation voltage to adjust the output voltage as a function of temperature, the generating comprising setting a first resistive digital-to-analog converter to produce a weighted sum of a voltage proportional to absolute temperature and a voltage complementary to absolute temperature; and

providing the temperature compensation voltage to the bandgap circuit to adjust the output voltage.

2. The method of claim 1, further comprising generating the voltage proportional to absolute temperature as the output voltage less three diode drop voltages.

3. The method of claim 1, further comprising generating the voltage complementary to absolute temperature as two diode drop voltages.

4. The method of claim 1, further comprising setting a second resistive digital-to-analog converter to scale the voltage proportional to absolute temperature to the reference voltage at the first temperature.

5. The method of claim 4, further comprising opening a switch disposed between the first resistive digital-to-analog converter and a third resistive digital-to-analog converter while setting the second resistive digital-to-analog converter.

6. The method of claim 4, further comprising setting a third resistive digital-to-analog converter to scale the voltage complementary to absolute temperature to the reference voltage at the first temperature.

7. The method of claim 6, further comprising opening a switch disposed between the first resistive digital-to-analog converter and the second resistive digital-to-analog converter while setting the third resistive digital-to-analog converter.

8. The method of claim 1, further comprising opening a switch to disconnect the first resistive digital-to-analog converter from the bandgap circuit while adjusting the output voltage of the bandgap circuit.