SYSTEMS AND METHODS FOR TRIMMING BANDGAP OFFSET WITH BIPOLAR DIODE ELEMENTS

• US 20100123514A1
• Filed: 11/05/2009
• Published: 05/20/2010
• Est. Priority Date: 11/18/2008
• Status: Active Grant

• Current Assignee: Microchip Technology Incorporated
• Original Assignee: Microchip Technology Incorporated
• Inventors: Le, Minh, Martin, Woowai
• Granted Patent: US 8,022,751 B2
• Time in Patent Office: Days
• US Class Current: 327/539
• CPC Class Codes: G05F 3/30 Regulators using the difference between the base-emitter voltages of two bipolar transistors operating at different current densities G05F3/26 takes precedence

Abstract

An integrated circuit has an untrimmed bandgap generation circuit; and a bandgap generation circuit coupled to the untrimmed bandgap generation circuit. The bandgap generation circuit has a current source controlled by the untrimmed bandgap generation circuit and coupled in series with a resistor and a first bipolar diode device, one or more of bipolar diode devices, each bipolar diode device coupled in parallel with the first bipolar diode device, wherein a trimmed bandgap reference voltage output of the integrated circuit is a function of the number of bipolar diode devices.

Claims

1. An integrated circuit, comprising:

an untrimmed bandgap generation circuit; and

a bandgap generation circuit coupled to the untrimmed bandgap generation circuit, the bandgap generation circuit comprising;

a current source controlled by said untrimmed bandgap generation circuit and coupled in series with a resistor and a first bipolar diode device,

one or more of bipolar diode devices, each bipolar diode device coupled in parallel with said first bipolar diode device, wherein a trimmed bandgap reference voltage output of the integrated circuit is a function of the number of bipolar diode devices.

2. The integrated circuit according to claim 1, wherein the one or more bipolar diode devices comprise a bipolar junction transistor.

3. The integrated circuit according to claim 1, wherein the current source is a metal oxide semiconductor field effect transistor (MOSFET).

4. The integrated circuit according to claim 1, wherein the one or more bipolar diode devices are coupled in parallel with said first bipolar diode through respective metal oxide semiconductor field effect transistors (MOSFET) coupled in series with each bipolar diode device.

5. The integrated circuit according to claim 4, wherein the one or more bipolar diode devices are at least two bipolar diode device which are dimensioned differently.

6. The integrated circuit according to claim 1, wherein at least one bipolar diode devices is coupled in parallel with said first bipolar diode through a fuse coupled in series with said at least one bipolar diode device.

7. The integrated circuit according to claim 4, further comprising a control unit for controlling said metal oxide semiconductor field effect transistors (MOSFET) coupled in series with each bipolar diode device.

8. The integrated circuit according to claim 7, wherein the control unit comprises non-volatile memory.

9. The integrated circuit according to claim 4, wherein the resistor is formed by at least two resistors coupled in series.

10. The integrated circuit according to claim 1, wherein the untrimmed bandgap generation circuit comprises a first and second branch each having a current source, a resistor and a bipolar diode device coupled in series, and a differential amplifier coupled with said first and second branch and having an output controlling said current sources.

11. The integrated circuit according to claim 10, wherein the first branch comprises a series of two resistors and the node between the two resistors is coupled with said differential amplifier, and wherein the second branch is connected to said differential amplifier at a node between said resistor and said bipolar diode device.

12. The integrated circuit according to claim 10, wherein each bipolar diode device of the untrimmed bandgap generation circuit comprise a bipolar junction transistor.

13. The integrated circuit according to claim 10, wherein each current source of the untrimmed bandgap generation circuit is a metal oxide semiconductor field effect transistor (MOSFET).

14. A system for trimming bandgap output, the system comprising:

an untrimmed bandgap generation circuit;

a bandgap generation circuit coupled to the untrimmed bandgap generation circuit, the bandgap generation circuit comprising;

a current source controlled by said untrimmed bandgap generation circuit and coupled in series with a resistor and a first bipolar diode device,

one or more of bipolar diode devices, each bipolar diode coupled in series with a switch wherein said series of bipolar diode device and switch is coupled in parallel with said first bipolar diode; and

a processor providing control signals for said switches, wherein a trimmed bandgap output of the integrated circuit is a function of the number of bipolar diode devices coupled in parallel through said switches.

15. The system according to claim 14, wherein the one or more bipolar diode devices comprise a bipolar junction transistor.

16. The system according to claim 14, wherein the current source is a metal oxide semiconductor field effect transistor (MOSFET).

17. The system according to claim 14, wherein the switches are metal oxide semiconductor field effect transistors (MOSFET).

18. The system according to claim 14, further comprising a control unit for controlling said switches.

19. The system according to claim 18, wherein the control unit comprises non-volatile memory.

20. The system according to claim 14, wherein the resistor is formed by at least two resistors coupled in series.

21. A method for trimming a bandgap reference voltage, the method comprising the steps of:

Generating an untrimmed bandgap voltage by a bandgap circuit having an internal feedback signal;

Providing at least one trimmable bandgap branch comprising;

a current source coupled in series with a resistor and a first bipolar diode device, and

one or more of bipolar diode devices, each bipolar diode coupled in series with a switch wherein said series of bipolar diode device and switch is coupled in parallel with said first bipolar diode;

Controlling said current source by said internal feedback signal; and

Controlling said switches wherein a trimmed bandgap output of the trimmable bandgap branch is a function of the number of bipolar diode devices coupled in parallel through said switches.

22. The method according to claim 21, wherein said switches are controlled directly by a processor.

23. The method according to claim 21, wherein said switches are controlled through a selection circuit.

24. The method according to claim 21, wherein at least one switch is a fuse and further comprising the step of setting said fuse.