Temperature detection circuit

• US 7,821,320 B2
• Filed: 01/31/2008
• Issued: 10/26/2010
• Est. Priority Date: 02/07/2007
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Ueda, Susumu
• Primary Examiner(s): Donovan; Lincoln
• Assistant Examiner(s): Jager; Ryan C
• Application Number:
  US12/010,902
• Publication Number:
  US 20080187026A1
• Time in Patent Office: 999 Days
• Field of Search: 327/83, 327/262, 327/512, 327/513
• US Class Current: 327/512
• CPC Class Codes: G01K 7/015 using microstructures, e.g. made of silicon
• CPC Class Codes: G01K 7/20 in a specially-adapted circuit, e.g. bridge circuit

Abstract

A temperature detection circuit includes a bandgap reference voltage generation circuit, a detection output circuit, and an output conversion circuit. The bandgap reference voltage generation circuit generates a first reference voltage and causes a bias current to flow through a current path to produce a thermal voltage. The current path has a first resistor. The detection output circuit has a second resistor and causes a mirror current of the bias current to flow through the second resistor. The output conversion circuit uses a second reference voltage to convert a voltage drop across the second resistor to a predetermined output form to detect a temperature. The first and second resistors are substantially identical in temperature dependence. The second reference voltage is generated from the first reference voltage.

Claims

1. A temperature detection circuit comprising:

a bandgap reference voltage generation circuit for generating a first reference voltage, the bandgap reference voltage generation circuit including a current path to produce a thermal voltage and being configured to cause a bias current to flow through the current path, the current path having a first resistor;

a detection output circuit having a second resistor, the detection output circuit being configured to cause a mirror current of the bias current to flow through the second resistor; and

an output conversion circuit that uses a second reference voltage to convert a voltage drop across the second resistor to a predetermined output form representing a detected temperature,

wherein the first and second resistors are substantially identical in temperature dependence,

wherein the second reference voltage is generated from the first reference voltage,

wherein the bandgap reference voltage generation circuit and the detection output circuit include a plurality of bipolar transistors and a plurality of resistors, and

wherein each of the plurality of bipolar transistors has an emitter coupled to a power supply line through a corresponding one of the plurality of resistors.

2. The temperature detection circuit according to claim 1,

wherein the each of the plurality of bipolar transistors has transistor members cascaded together.

3. The temperature detection circuit according to claim 1,

wherein the bandgap reference voltage generation circuit and the detection output circuit are implemented on a silicon-on-insulator substrate, and

wherein each circuit element of the bandgap reference voltage generation circuit and the detection output circuit are disposed in a trench-isolated region of the silicon-on-insulator substrate.

4. The temperature detection circuit according to claim 1,

wherein the bandgap reference voltage generation circuit and the detection output circuit include a plurality of transistors coupled to a power supply line, and

wherein each transistor has transistor members cascaded together.

5. The temperature detection circuit according to claim 1,

wherein the output conversion circuit is an analog-to-digital converter.

6. The temperature detection circuit according to claim 1,

wherein the output conversion circuit is a comparator.

7. A temperature detection circuit comprising:

a bandgap reference voltage generation circuit for generating a first reference voltage, the bandgap reference voltage generation circuit including a current path to produce a thermal voltage and being configured to cause a bias current to flow through the current path, the current path having a first resistor;

a detection output circuit having a second resistor, the detection output circuit being configured to cause a mirror current of the bias current to flow through the second resistor; and

an output conversion circuit that uses a second reference voltage to convert a voltage drop across the second resistor to a predetermined output form to detect a temperature,

wherein the first and second resistors are substantially identical in temperature dependence,

wherein the second reference voltage is generated from the first reference voltage,

wherein the bandgap reference voltage generation circuit and the detection output circuit include a plurality of bipolar transistors and a plurality of resistors, and

wherein each of the plurality of bipolar transistors has an emitter coupled to a power supply line through a corresponding one of the plurality of resistors.

8. The temperature detection circuit according to claim 7,

wherein the each of the plurality of bipolar transistors has transistor members cascaded together.

9. The temperature detection circuit according to claim 7,

wherein the bandgap reference voltage generation circuit and the detection output circuit are implemented on a silicon-on-insulator substrate, and

wherein each circuit element of the bandgap reference voltage generation circuit and the detection output circuit are disposed in a trench-isolated region of the silicon-on-insulator substrate.