Circuit for generating a temperature dependent output

Patent metadata

Field	Value
Publication number	US-11320319-B2
Application number	US-201916706422-A
Country	US
Kind code	B2
Filing date	Dec 6, 2019
Priority date	Dec 6, 2019
Publication date	May 3, 2022
Grant date	May 3, 2022

Abstract

The present disclosure provides a circuit for generating a complimentary to absolute temperature (CTAT) voltage reference. The primary contributor to the voltage reference is first bipolar junction transistor, which is configured in diode mode, to produce the CTAT voltage. Such references include a non-linear component. A pair of bipolar junction transistors are coupled to the first bipolar junction transistor, and are configured to generate a delta base-emitter voltage. By coupling one of the pair to a proportional to absolute temperature current source, and the other to a current course which is substantially independent of absolute temperature, a further non-linear component is introduced, which is complimentary to the non-linear component introduced by the first bipolar junction transistor. The pair of bipolar transistors share a common emitter area size. As such, the non-linear component of the first bipolar junction transistor is compensated by the delta base-emitter arrangement, resulting in a more linear output.

First claim

The invention claimed is:

1. A circuit for producing a reference output, comprising:
a base-emitter voltage generator of a reference generation module, configured to generate a first reference output having a first temperature dependent non-linear component; and
a non-linearity compensation module including a delta base-emitter voltage generator configured to generate a delta base-emitter voltage as a second reference output having a second temperature dependent non-linear component, wherein the delta base-emitter voltage generator is configured to receive a proportional to absolute temperature, PTAT, current and a zero change to absolute temperature, ZTAT, current;
wherein the base-emitter voltage generator of the reference generation module and the delta base-emitter voltage of the non-linearity compensation module are coupled together such that the first and second reference outputs generate the circuit reference output, and such that the delta base-emitter voltage provides the PTAT current to the base-emitter voltage generator and the second temperature dependent non-linear component at least partially compensates for the first non-linear component.

2. A circuit according to claim 1 , wherein the circuit is configured such that the second reference output is subtracted from the first reference output.

3. A circuit according to claim 1 , wherein the reference output and the first reference output are complimentary to absolute temperature.

4. A circuit according to claim 1 , wherein the reference generation module comprises a first current source, configured to supply the delta base-emitter voltage generator with the PTAT current.

5. A circuit according to claim 4 , wherein the base-emitter voltage generator is a first bipolar junction transistor, BJT.

6. A circuit according to claim 5 , wherein the delta base-emitter generator comprises a second BJT and a third BJT, wherein the second BJT is coupled to the first current source, such that the second BJT is supplied with the PTAT current and the first BJT receives the PTAT current from the second BJT, and the second module further comprises a second current source, configured to supply the third BJT with the ZTAT current.

7. A circuit according to claim 6 , wherein the emitter areas of the second and third BJTs are the same.

8. A circuit according to claim 7 , wherein the first BJT is arranged in a diode configuration, and is coupled between the second BJT and ground; the base terminals of the second and third BJTs are coupled together and to a fourth BJT, which is configured to supply a base current to the second and third BJTs.

9. A circuit according to claim 6 , wherein the circuit further comprises a MOSFET and a fifth BJT, coupled to the third BJT, and arranged in a nested amplifier configuration to provide the reference output at the output.

10. The circuit of claim 1 , in combination with:
one or more additional non-linearity compensation modules, configured to generate one or more further reference outputs having one or more additional temperature dependent non-linear components;
wherein the one or more additional non-linearity compensation modules are coupled such that the first, second and one or more further reference outputs generate the circuit reference output, and such that the second temperature dependent non-linear component and the one or more additional temperature dependent non-linear components at least partially compensates for the first non-linear component.

11. A circuit for producing an output which is complimentary to absolute temperature, the circuit comprising:
a base-emitter voltage generator, configured to generate a voltage which is complimentary to absolute temperature, V CTAT , and which includes a first non-linear component; and
one or more delta base-emitter voltage generator cells, coupled to the base-emitter voltage generator, and arranged to compensate for the first non-linear component, each cell configured to generate a delta base-emitter voltage having a further non-linear component, wherein the one or more delta base-emitter voltage generator cells each receive a proportional to absolute temperature, PTAT, current and a zero change to absolute temperature, ZTAT, current, and at least one of the one or more delta base-emitter voltage generator cells provide the PTAT current to the base-emitter voltage generator.

12. A circuit according to claim 11 , wherein the one or more delta base-emitter voltage generator cells is four cells.

13. The circuit of claim 1 , included within a temperature sensor.

14. A method of compensating for non-linearity in a temperature dependent voltage reference, the method comprising:
generating a first temperature dependent voltage reference having a first non-linear component;
generating one or more further voltage references, each having a further non-linear component and configured to receive a proportional to absolute temperature, PTAT, current and a zero change to absolute temperature, ZTAT, current;
combining the first temperature dependent voltage reference with the one or more further voltage references in order provide the PTAT current to the first temperature dependent voltage reference and to produce a temperature dependent output voltage reference in which the first non-linear component is at least partially compensated by the one or more further voltage references.

15. A method according to claim 14 , wherein the step of generating a first temperature dependent voltage includes generating a complimentary to absolute temperature reference voltage using the base-emitter junction of a first bipolar transistor.

16. A method according to claim 15 , further comprising supplying the collector of the first bipolar transistor with a proportional to absolute temperature current source.

17. A method according to claim 14 , wherein the step of generating one or more further reference voltages includes generating one or more delta base-emitter voltages using one or more pairs of bipolar junction transistors.

18. A method according to claim 17 , further comprising supplying the collector of one of the pair of BJTs with a proportional to absolute temperature current, and supplying the collector of the other of the pair of BJTs with a current which is substantially independent of absolute temperature.

Assignees

• Analog Devices International Unlimited Co

Inventors

• Bucur Viorel

Classifications

• G01K7/01 Primary

  using semiconducting elements having PN junctions (G01K7/02, G01K7/16, G01K7/30 take precedence) · CPC title

• G05F3/225

  producing a current or voltage as a predetermined function of the temperature · CPC title

• H03K17/14

  Modifications for compensating variations of physical values, e.g. of temperature · CPC title

• G05F3/02

  Regulating voltage or current · CPC title

• G05F3/22

  wherein the transistors are of the bipolar type only (G05F3/26, G05F3/30 take precedence) · CPC title