Temperature sensor

• US 9,909,931 B2
• Filed: 04/24/2015
• Issued: 03/06/2018
• Est. Priority Date: 11/25/2014
• Status: Active Grant

• Current Assignee: SK Hynix Inc.
• Original Assignee: SK Hynix Inc.
• Inventors: Park, Kyu Tae, Passerini, Marco
• Primary Examiner(s): Shah, Manish S
• Application Number:
  US14/695,829
• Publication Number:
  US 20160146677A1
• Time in Patent Office: 1,047 Days
• CPC Class Codes: G01K 7/16 using resistive elements resistive elements per se H01C, H01L

Abstract

A temperature sensor includes a first current generating circuit configured to generate a first current being constant regardless of temperature changes, a cascode circuit configured to generate a cascode voltage, a second current generating circuit configured to generate a second current being in inverse proportion to temperature, and a compensated voltage output circuit configured to output a compensated voltage having various temperature coefficients in response to the first current and the second current.

Claims

1. A temperature sensor, comprising:

a first current generating circuit configured to generate a first current, the first current having a substantially constant magnitude regardless of temperature changes, wherein the first current generating circuit includes a first amplifier which generates the first current according to a bandgap reference voltage and a feedback voltage, wherein the bandgap voltage is not affected by the first current;

a cascode circuit configured to generate a cascode voltage;

a second current generating circuit configured to generate a second current, the second current having a magnitude that varies in inverse proportion to a temperature; and

a compensated voltage output circuit configured to output, using the first current and the second current, a compensated voltage having one or more predetermined temperature coefficients, wherein the compensated voltage has a value according to a temperature.

2. The temperature sensor of claim 1, wherein the first current generating circuit is configured to generate the first current by using a bandgap reference voltage.

3. The temperature sensor of claim 1, wherein the cascode circuit is configured to stably output the cascode voltage in response to the first current.

4. The temperature sensor of claim 1, wherein the second current generating circuit is configured to generate the second current using the cascode voltage.

5. The temperature sensor of claim 1, wherein the compensated voltage output circuit has a cascode current mirror configuration configured to output the compensated voltage having the one or more predetermined temperature coefficients.

6. A temperature sensor, comprising:

a first current generating circuit configured to generate a first current according to a bandgap reference voltage, wherein the first current has a constant magnitude regardless of temperature changes, wherein the bandgap voltage is not affected by the first current;

a cascode circuit configured to generate a cascode voltage according to the first current;

a second current generating circuit configured to generate a second current using the cascode voltage, wherein the second current has a magnitude that varies in inverse proportion to temperature; and

a compensated voltage output circuit suitable for outputting a compensated voltage having one or more predetermined temperature coefficients according to the first current and the second current, wherein the compensated voltage has a value according to a temperature.

7. The temperature sensor of claim 6, wherein the first current generating circuit comprises:

a first switch including a PMOS transistor coupled between a first node to which a power voltage is applied, and a third node, wherein a turn-on level of the first switch is controlled according to the first current;

a second switch including a PMOS transistor coupled between the third node and a fourth node from which a feedback reference voltage is generated, wherein a turn-on level of the second switch is controlled according to a potential of a connecting node between a first resistor and a second resistor;

the first resistor and the second resistor coupled in series between the fourth node and a second node coupled to a ground terminal; and

a first amplifier configured to control the magnitude of the first current using a difference between the bandgap reference voltage and the feedback reference voltage.

8. The temperature sensor of claim 6, wherein the cascode circuit comprises:

a third switch including a PMOS transistor coupled between

a first node to which a power voltage is applied, and a sixth node, wherein a turn-on level of the third switch is controlled according to the first current;

a fourth switch including a PMOS transistor coupled between the sixth node and a seventh node, wherein a turn-on level of the fourth switch is controlled according to a potential of the seventh node; and

a third resistor coupled between the seventh node and a second node coupled to a ground terminal.

9. The temperature sensor of claim 6, wherein the second current generating circuit comprises:

a fifth switch including a PMOS transistor coupled between a first node to which a power voltage is applied, and a fourteenth node, wherein a turn-on level of the fifth switch is controlled according to the second current;

a seventh switch including a PMOS transistor coupled between the fourteenth node and a fifteenth node, wherein a turn-on level of the seventh switch is controlled according to the cascode voltage;

a fourth resistor coupled between the fifteenth node and a second node coupled to a ground terminal;

a sixth switch including a PMOS transistor coupled between the first node and a sixteenth node, wherein a turn-on level of the sixth switch is controlled according to the second current;

an eighth switch including a PMOS transistor coupled between the sixteenth node and a seventeenth node, wherein a turn-on level of the eighth switch is controlled according to the cascode voltage;

a diode coupled between the seventeenth node and the second node, and outputting a second voltage to the seventeenth node; and

a second amplifier configured to control the magnitude of the second current using a difference between a first voltage of the fifteenth node with the second voltage.

10. The temperature sensor of claim 6, wherein the compensated voltage output circuit includes a single cascode current mirror circuit or a multi-cascode current mirror circuit, or both.

11. The temperature sensor of claim 10, wherein the single cascode current mirror circuit comprises:

a ninth switch including a PMOS transistor coupled between a first node to which a power voltage is applied, and an eighth node, wherein a turn-on level of the ninth switch is controlled according to the first current;

a tenth switch including a PMOS transistor coupled between the eighth node and a ninth node, wherein a turn-on level of the tenth switch is controlled according to the cascode voltage;

an eleventh switch including an NMOS transistor coupled between the ninth node and a second node coupled to a ground terminal, wherein the eleventh switch is turned on or off according to a potential of the ninth node;

a twelfth switch including a PMOS transistor coupled between the first node and a tenth node, wherein a turn-on level of the twelfth switch is controlled according to the first current;

a thirteenth switch including a PMOS transistor coupled between the tenth node and an eleventh node, wherein a turn-on level of the thirteenth switch is controlled according to the cascode voltage;

a fourteenth switch including a PMOS transistor coupled between the first node and a twelfth node, wherein a turn-on level of the fourteenth switch is controlled according to the second current;

a fifteenth switch including a PMOS transistor coupled between the twelfth node and the eleventh node, wherein a turn-on level of the fifteenth switch is controlled according to the cascode voltage;

a sixteenth switch including an NMOS transistor coupled between the twelfth node and the second node, wherein the sixteen switch is turned on or off according to a potential of the ninth node; and

a fifth resistor coupled between the eleventh node and the second node.

12. The temperature sensor of claim 10, wherein the multi-cascode current mirror circuit comprises:

a first trim unit configured to perform a trimming operation according to the first current, the cascode voltage and offset bits;

a second trim unit configured to perform a trimming operation according to the first current, the cascode voltage and multi-level bits;

a third trim unit configured to perform a trimming operation according to the second current, the cascode voltage and multi-derivative bits;

a fourth trim unit configured to perform a trimming operation according to the multi-derivative bits; and

a discharge unit configured to activate or deactivate the first and fourth trim units.

13. The temperature sensor of claim 12, wherein the first trim unit includes a plurality of switch groups each including first enable switches, zero dependency on absolute temperature (ZTAT) switches, and cascode switches coupled in series between a first node to which a power voltage is applied and a ninth node coupled to the discharge unit, wherein the plurality of switch groups are coupled in parallel between the first node and the ninth node.

14. The temperature sensor of claim 13, wherein the first enable switches included in the plurality of switch groups include PMOS transistors each having a turn-on level controlled according to the offset bits,

the ZTAT switches included in the switch groups include PMOS transistors each having a turn-on level controlled according to the first current, and

the cascode switches included in the switch groups include PMOS transistors each having a turn-on level controlled according to the cascode voltage.

15. The temperature sensor of claim 12, wherein the second trim unit includes a plurality of switch groups each including first enable switches, ZTAT switches and cascode switches coupled in series between a first node to which a power voltage is applied and an eleventh node through which the compensated voltage is output, wherein the plurality of switch groups are coupled in parallel between the first node and the eleventh node.

16. The temperature sensor of claim 15, wherein the first enable switches included in the switch groups include PMOS transistors each having a turn-on level controlled according to the multi-level bits,

the ZTAT switches included in the switch groups include PMOS transistors each having a turn-on level controlled according to the first current, and

the cascode switches included in the switch groups include PMOS transistors each having a turn-on level controlled according to the cascode voltage.

17. The temperature sensor of claim 12, wherein the third trim unit includes a plurality of switch groups including first enable switches, complementary-to-temperature (CTAT) switches and cascode switches coupled in series between a first node to which a power voltage is applied, and an eleventh node through which the compensated voltage is output, wherein the plurality of switch groups are coupled in parallel between the first node and the eleventh node.

18. The temperature sensor of claim 17, wherein the first enable switches included in the switch groups include PMOS transistors each having a turn-on level controlled according to the multi-derivative bits,

the CTAT switches included in the switch groups include PMOS transistors each having a turn-on level controlled according to the second current, and

the cascode switches included in the switch groups include PMOS transistors each having a turn-on level controlled according to the cascode voltage.

19. The temperature sensor of claim 12, wherein the fourth trim unit comprises:

NMOS transistors coupled to the third trim unit and configured to operate according to an output voltage of the first trim unit; and

NMOS transistors coupled between the NMOS transistors and a second node coupled to a ground terminal and configured to operate according to the multi-derivative bits.

20. The temperature sensor of claim 12, wherein the discharge unit comprises:

a first NMOS transistor coupled to the first trim unit and configured to operate according to an output voltage of the first trim unit; and

a second NMOS transistor coupled between the first NMOS transistor and a second node coupled to a ground terminal and configured to operate according to an enable signal.