BANDGAP CIRCUIT AND TEMPERATURE SENSING CIRCUIT INCLUDING THE SAME

• US 20100164608A1
• Filed: 04/24/2009
• Published: 07/01/2010
• Est. Priority Date: 12/26/2008
• Status: Abandoned Application

• Current Assignee: Hynix Semiconductor Incorporated (SK Hynix Inc.)
• Original Assignee: Hynix Semiconductor Incorporated (SK Hynix Inc.)
• Inventors: SHIN, Yoon-Jae
• Application Number:
  US12/429,317
• Publication Number:
  US 20100164608A1
• 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

A temperature sensing circuit includes a bandgap unit configured to output a temperature voltage varying according to a temperature and a reference voltage sustaining a predetermined level. A comparator is configured to compare the temperature voltage and the reference voltage and output temperature information.

Claims

1. A temperature sensing circuit, comprising:

a bandgap unit configured to output a temperature voltage varying according to a temperature and a reference voltage sustaining a predetermined level; and

a comparator configured to compare the temperature voltage outputted from the bandgap unit with the reference voltage and to output temperature information.

2. The temperature sensing circuit of claim 1, wherein the bandgap unit generates a bias voltage that constantly sustains a predetermined level.

3. The temperature sensing circuit of claim 2, wherein the comparator includes:

a differential amplifier configured to compare the temperature voltage with the reference voltage; and

a current amount controller configured to control an amount of current flowing into the differential amplifier in response to the bias voltage.

4. The temperature sensing circuit of claim 1, wherein the bandgap unit includes:

a current generator configured to generate a temperature current varying in an amount of current according to the temperature;

a temperature voltage generator configured to mirror the temperature current and generating the temperature voltage based on voltage drop caused by the mirrored current; and

a reference voltage generator configured to mirror the temperature current and to generate the reference voltage based on sum of an emitter-base voltage of a first transistor and a voltage drop caused by the mirrored current.

5. The temperature sensing circuit of claim 4, wherein the current generator includes a second transistor and a third transistor, and

wherein the temperature current flows in response to a voltage difference between an emitter-base voltage of the second transistor and an emitter-base voltage of the third transistor.

6. A bandgap circuit, comprising:

a current generator configured to generate temperature current varying in an amount of current according to a temperature;

a temperature voltage generator configured to mirror the temperature current outputted from the current generator and to generate a temperature voltage based on a voltage drop caused by the mirrored current; and

a reference voltage generator configured to mirror the temperature current and to generate a reference voltage based on sum of an emitter-based voltage of a first transistor and a voltage drop caused by the mirror current.

7. The bandgap circuit of claim 6, wherein the current generator includes a second transistor and a third transistor, and

wherein the temperature current flows in response to a voltage difference between an emitter-base voltage of the second transistor and an emitter-base voltage of the third transistor.

8. The bandgap circuit of claim 6, wherein the current generator includes:

a second transistor having a base and a collector connected to a ground;

a resistor connected between an emitter of the second transistor and a first node;

a third transistor having a base and a collector connected to ground and an emitter connected to a second node;

a calculation amplifier configured to receive the first node and the second node as connected inputs;

a fourth transistor configured to supply current to the first node in response to output of the calculation amplifier; and

a fifth transistor configured to supply current to the second node in response to the output of the calculation amplifier.

9. The bandgap circuit of claim 8, wherein the temperature voltage generator includes:

a sixth transistor configured to supply current to the temperature voltage generator in response to the output of the calculation amplifier; and

a resistor connected between the sixth transistor and a ground end and supplying the temperature voltage.

10. The bandgap circuit of claim 9, wherein the reference voltage generator includes:

a seventh transistor configured to supply current to the reference voltage generator in response to the output of the calculation amplifier;

a resistor connected between the seventh transistor and a reference voltage output terminal; and

a third transistor having a base and a collector, and an emitter connected to the reference voltage output terminal.

11. The bandgap circuit of claim 8, wherein the bandgap circuit further includes a current limiting unit configured to cause current to flow into the bandgap circuit at an initial stage and limiting current flowing into the bandgap circuit at a peak stage.

12. The bandgap circuit of claim 7, wherein the second transistor and the third transistor are different in size.