NUMERICAL BAND GAP

• US 20080258804A1
• Filed: 04/17/2008
• Published: 10/23/2008
• Est. Priority Date: 04/17/2007
• Status: Active Grant

• Current Assignee: Monterey Research, LLC (Vector Capital Corporation)
• Original Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Inventors: Kutz, Harold
• Granted Patent: US 8,130,025 B2
• Time in Patent Office: Days
• US Class Current: 327/539
• CPC Class Codes: H03K 19/177 arranged in matrix form

Abstract

A system includes a bandgap temperature sensor to generate multiple base-emitter voltages. The system also include a controller to detect the base-emitter voltages generated by the bandgap temperature sensor and to generate a bandgap reference voltage according to the multiple base-emitter voltage signals, the bandgap reference voltage having a voltage level that remains substantially constant relative to environmental temperature variations.

Claims

1. A device comprising:

a bandgap temperature sensor to generate multiple base-emitter voltages; and

a system controller to detect the base-emitter voltages generated by the bandgap temperature sensor and to generate a bandgap reference voltage according to the multiple base-emitter voltages, the bandgap reference voltage having a voltage level that remains substantially constant relative to a temperature associated with the bandgap temperature sensor.

2. The device of claim 1, where the system controller is operable to determine a difference in the base-emitter voltages, and to generate the bandgap reference voltage from the difference in the base-emitter voltages and at least one of the base-emitter voltages.

3. The device of claim 2, where the system controller is operable to add the difference in the base-emitter voltages to one of the base-emitter voltages to generate the bandgap reference voltage.

4. The device of claim 3, where the system controller is operable to multiply the difference in the base-emitter voltages to a constant value and then to add the multiplied difference in the base-emitter voltages to one of the base-emitter voltages to generate the bandgap reference voltage.

5. The device of claim 4, where the constant value is based at least in part on characteristics of the bandgap temperature sensor.

6. The device of claim 1 where the bandgap temperature sensor includes a variable current source to provide a first current to a transistor to generate a first base-emitter voltage signal, and to provide a second current to the transistor to generate a second base-emitter voltage signal.

7. The device of claim 1 including an analog-to-digital converter to convert base-emitter voltages into digital base-emitter voltage signals, the system controller to generate the bandgap voltage according to the digital base-emitter voltage signals.

8. A method comprising:

detecting multiple base-emitter voltages generated by a bandgap temperature sensor; and

generating a bandgap reference voltage according to the multiple base-emitter voltage signals, the bandgap reference voltage to remain substantially constant relative to environmental temperature variations.

9. The method of claim 8, includes:

determining a difference in the base-emitter voltages; and

generating the bandgap reference voltage from the difference in the base-emitter voltages and at least one of the base-emitter voltages.

10. The method of claim 9, where generating the bandgap reference voltage includes adding the difference in the base-emitter voltages to one of the base-emitter voltages.

11. The method of claim 10, re generating the bandgap reference voltage includes:

multiplying the difference in the base-emitter voltages to a constant value; and

adding the multiplied difference in the base-emitter voltages to one of the base-emitter voltages.

12. The method of claim 11, where the constant value is based at least in part on the characteristics of the bandgap temperature sensor.

13. The method of claim 8, includes:

generating a first base-emitter voltage signal when a first current signal is provided to a transistor;

generating a second base-emitter voltage signal when a second current signal is provided to the transistor;

determining a difference between the first base-emitter voltage signal and the second base-emitter voltage signal; and

generating the bandgap reference voltage based, at least in part, on the determined difference between the first base-emitter voltage signal and the second base-emitter voltage signal.

14. A system comprising:

a memory to store computer-readable instructions; and

a microprocessor to receive the instructions stored in memory, the instructions, when executed, cause the microprocessor to;

identify multiple base-emitter voltages generated by a bandgap temperature sensor; and

generate a bandgap reference voltage according to the multiple base-emitter voltage signals, where the bandgap reference voltage having a voltage level that remains substantially constant relative to environmental temperature variations.

15. The system of claim 14, where the microprocessor is operable to determine a difference in the base-emitter voltages, and generate the bandgap reference voltage from the difference in the base-emitter voltages and at least one of the base-emitter voltages.

16. The system of claim 15 where the base-emitter voltages decrease as the environmental temperature increases, and the difference in the base-emitter voltages increases as the environment temperature increases.

17. The system of claim 15, where the microprocessor is operable to add the difference in the base-emitter voltages to one of the base-emitter voltages to generate the bandgap reference voltage.

18. The system of claim 17, where the microprocessor is operable to multiply the difference in the base-emitter voltages to a constant value, and add the multiplied difference in the base-emitter voltages to one of the base-emitter voltages to generate the bandgap reference voltage.

19. The system of claim 18, where the constant value is based at least in part on the characteristics of the bandgap temperature sensor.

20. The system of claim 14,

where the bandgap temperature sensor is operable to generate a first base-emitter voltage signal when a first current signal is provided to a transistor and to generate a second base-emitter voltage signal when a second current signal is provided to the transistor;

and

where the microprocessor is operable to determine a difference between the first base-emitter voltage signal and the second base-emitter voltage signal, and generate the bandgap reference voltage based, at least in part, on the determined difference between the first base-emitter voltage signal and the second base-emitter voltage signal.