Temperature sensor with digital bandgap

• US 8,092,083 B2
• Filed: 10/01/2007
• Issued: 01/10/2012
• Est. Priority Date: 04/17/2007
• Status: Active Grant

• Current Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Original Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Inventors: Venkataraman, Garthik, Kutz, Harold, Mar, Monte
• Primary Examiner(s): VERBITSKY, GAIL KAPLAN
• Application Number:
  US11/865,672
• Publication Number:
  US 20080259998A1
• Time in Patent Office: 1,562 Days
• Field of Search: 374/100, 374/170, 374/171, 374/172, 374/163, 374/178, 374/183, 374/1, 327512-513, 327 64- 65, 702/99, 702130-136, 257/47, 257/48, 257/213, 257/467, 257/470, 324/762.08
• US Class Current: 374/178
• CPC Class Codes: G01K 7/01 using semiconducting elements having PN junctions G01K7/02, G01K7/16, G01K7/30 take precedence
• CPC Class Codes: H03K 5/2481 with at least one differential stage
• CPC Class Codes: H03K 5/249 using clock signals
• CPC Class Codes: H03M 3/43 the quantiser being a single bit one
• CPC Class Codes: H03M 3/456 the modulator having a first order loop filter in the feedforward path

Abstract

A system comprises a temperature sensor generate multiple base-emitter voltage signals by sequentially providing various currents to a transistor, and a system controller to determine a differential voltage signal according to the multiple base-emitter voltage signals, the differential voltage signal proportional to an environmental temperature associated with the transistor.

Claims

1. A method comprising:

generating multiple base-emitter voltage signals by sequentially providing various currents to a transistor;

determining a differential voltage signal according to the multiple base-emitter voltage signals, the differential voltage signal proportional to an environmental temperature associated with the transistor;

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

determining the differential voltage signal, at least in part, according to the determined difference between the first base-emitter voltage signal and the second base-emitter voltage signal;

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

determining difference between at least one of the first base-emitter voltage signal and the third base-emitter voltage signal or the second base-emitter voltage signal and the third base-emitter voltage signal; and

determining the differential voltage signal, at least in part, according to the determined difference between at least one of the first base-emitter voltage signal and the third base-emitter voltage signal or the second base-emitter voltage signal and the third base-emitter voltage signal;

wherein determining the differential voltage signal includes averaging multiple differences determined between various base-emitter voltage signals.

2. The method of claim 1 wherein the multiple base-emitter voltage signals are analog base-emitter voltage signals;

and

converting the analog base-emitter voltage signals to digital base-emitter voltage signals for use in determining the differential voltage signal.

3. The method of claim 1 wherein converting the analog base-emitter voltage signals to digital base-emitter voltage signals is performed by a passive analog-to-digital converter.

4. A system comprising:

means for generating multiple base-emitter voltage signals by sequentially providing various currents to a transistor;

means for determining a differential voltage signal according to the multiple base-emitter voltage signals, the differential voltage signal proportional to an environmental temperature associated with the transistor

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

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

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

means for determining the differential voltage signal, at least in part, according to the determined difference between the first base-emitter voltage signal and the second base-emitter voltage signal;

means for generating a third base-emitter voltage signal when a third current signal is provided to the transistor;

means for determining difference between at least one of the first base-emitter voltage signal and the third base-emitter voltage signal or the second base-emitter voltage signal and the third base-emitter voltage signal;

means for determining the differential voltage signal, at least in part;

according to the determined difference between at least one of the first base-emitter voltage signal and the third base-emitter voltage signal or the second base-emitter voltage signal and the third base-emitter voltage signal;

means for averaging multiple differences determined between various base-emitter voltage signals to determine the differential voltage signal.

5. The system of claim 4 wherein the multiple base-emitter voltage signals are analog base-emitter voltage signals and further comprising a means for converting the analog base-emitter voltage signals to digital base-emitter voltage signals for use in determining the differential voltage signal.