Low voltage bandgap reference circuit

• US 6,531,857 B2
• Filed: 11/08/2001
• Issued: 03/11/2003
• Est. Priority Date: 11/09/2000
• Status: Expired due to Term

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Agere Systems Incorporated (Broadcom, Inc.)
• Inventors: Ju, Peicheng
• Primary Examiner(s): Riley, Shawn
• Application Number:
  US10/007,913
• Publication Number:
  US 20020093325A1
• Time in Patent Office: 488 Days
• Field of Search: 323/315, 323/312, 323/313, 323/314, 323/316, 323/278, 327/538
• US Class Current: 323/316
• 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

A bandgap reference circuit that uses reduced substrate area while requiring relatively low voltage. The circuit may include a bipolar transistor with a resistor electrically connected across the emitter-base of the bipolar transistor. The resistor sums a first current with a second current and also generates a fractional V_EB. The bandgap reference circuit may have a first current proportional to V_EB, and a second current proportional to a PTAT current. An impedance booster may be incorporated into the circuit. Also disclosed is a method of regulating a voltage level using embodiments of the bandgap reference circuit.

Claims

1. A bandgap reference circuit comprising:

a bipolar transistor;

a resistor electrically connected across an emitter-base of the bipolar transistor;

wherein the resistor sums a first current with a second current and generates a fractional V_EB.

2. The bandgap reference of claim 1 wherein the first and second currents have opposite temperature coefficients.

3. The bandgap reference circuit of claim 1 wherein the first current is proportional to V_EB, and the second current is proportional to a PTAT current.

4. The bandgap reference circuit of claim 1 further comprising an impedance booster.

5. The bandgap reference circuit of claim 4 wherein the impedance booster includes a gain stage.

6. The bandgap reference circuit of claim 1 comprising digital CMOS technology.

7. The bandgap reference circuit of claim 1 wherein the bandgap reference circuit comprises about 0.16 μ

m digital CMOS technology.

8. The bandgap reference circuit of claim 1 wherein the bandgap reference circuit operates with a supply voltage of less than about 0.80 V.

9. The bandgap reference circuit of claim 1 wherein the bandgap reference circuit operates with a supply voltage of less than about 0.75 V.

10. The bandgap reference circuit of claim 1 wherein the bandgap reference circuit operates with a supply voltage of less than about 0.70 V.

20. A semiconductor device comprising a bandgap reference circuit according to claim 1.

11. A method of regulating a voltage level comprising:

providing a bipolar transistor;

electrically connecting a resistor across an emitter-base of the bipolar transistor;

summing a first current with a second currents by the resistor; and

generating a fractional V_EB by the resistor.

12. The method claim 11 wherein the first and second currents have opposite temperature coefficients.

13. The method of claim 11 wherein the first current is proportional to V_EB, and the second current is proportional to a PTAT current.

14. The method of claim 11 further comprising:

boosting the impedance.

15. The method of claim 14 wherein the impedance is boosted with the use of a gain stage.

16. The method of claim 11 wherein the bandgap reference circuit comprises about 0.16 μ

m digital CMOS technology.

17. The method of claim 11 wherein the bandgap reference circuit operates with a supply voltage of less than about 0.80 V.

18. The method of claim 11 wherein the bandgap reference circuit operates with a supply voltage of less than about 0.75 V.

19. The method of claim 11 wherein the bandgap reference circuit operates with a supply voltage of less than about 0.70 V.