THERMAL CAPACITY CONTROL FOR RELATIVE TEMPERATURE-BASED THERMAL SHUTDOWN

• US 20200136369A1
• Filed: 03/29/2019
• Published: 04/30/2020
• Est. Priority Date: 10/24/2018
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: CHAUHAN, ANKUR, CHAUDHARI, PARAGKUMAR, GUPTA, VISHAL
• Granted Patent: US 11,545,418 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 1/206 comprising thermal management
• CPC Class Codes: G06F 1/26 Power supply means, e.g. regulation thereof for memories G11C
• CPC Class Codes: G06F 1/28 Supervision thereof, e.g. detecting power-supply failure by out of limits supervision
• CPC Class Codes: H01L 2021/60015 using plate connectors, e.g. layer, film
• CPC Class Codes: H01L 21/50 Assembly of semiconductor devices using processes or apparatus not provided for in a single one of the subgroups H01L21/06 - H01L21/326, e.g. sealing of a cap to a base of a container
• CPC Class Codes: H01L 23/34 Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements thermal treatment apparatus H01L21/00
• CPC Class Codes: H01L 23/49513 having bonding material between chip and die pad
• CPC Class Codes: H01L 23/49534 Multi-layer
• CPC Class Codes: H01L 23/49541 Geometry of the lead-frame
• CPC Class Codes: H01L 23/49548 Cross section geometry H01L23/49562 takes precedence
• CPC Class Codes: H01L 23/49555 the bent parts being the outer leads
• CPC Class Codes: H01L 23/49558 Insulating layers on lead frames, e.g. bridging members
• CPC Class Codes: H01L 23/49582 Metallic layers on lead frames
• CPC Class Codes: H02H 3/42 responsive to product of voltage and current
• CPC Class Codes: H02H 5/042 using temperature dependent resistors
• CPC Class Codes: H02H 5/047 using a temperature responsive switch
• CPC Class Codes: H02H 6/00 Emergency protective circuit arrangements responsive to undesired changes from normal non-electric working conditions using simulators of the apparatus being protected, e.g. using thermal images
• CPC Class Codes: H02H 7/222 for switches
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A device includes a relative temperature detector configured to determine a temperature difference between a device temperature sensed near a switch device and an ambient temperature sensed outside the switch device. The relative temperature detector is configured to generate a relative temperature output signal based on comparing the temperature difference to a relative temperature threshold. A power detector is configured to generate a power level signal based on comparing an indication of switch power of the switch device to a power threshold. The power level signal specifies whether the indication of switch power is above or below the power threshold. A thermal capacity control is configured to disable the switch device based on the power level signal specifying that the indication of switch power is above the power threshold and based on the relative temperature output signal indicating the temperature difference is above the relative temperature threshold.

Claims

1. A device, comprising:

a relative temperature detector configured to determine a temperature difference between a device temperature sensed near a switch device and an ambient temperature sensed outside the switch device, the relative temperature detector configured to generate a relative temperature output signal based on comparing the temperature difference to a relative temperature threshold;

a power detector configured to generate a power level signal based on comparing an indication of switch power of the switch device to a power threshold, wherein the power level signal specifies whether the indication of switch power is above or below the power threshold; and

a thermal capacity control configured to disable the switch device based on the power level signal specifying that the indication of switch power is above the power threshold and based on the relative temperature output signal indicating the temperature difference is above the relative temperature threshold.

2. The device of claim 1, wherein the thermal capacity control is configured to increase the relative temperature threshold in the relative temperature detector based on the power level signal specifying that the indication of switch power is below the power threshold.

3. The device of claim 1, wherein the thermal capacity control comprises a logic gate configured to disable the relative temperature output based on by the power capability detector detecting that the indication of switch power of the switch device is below the power threshold.

4. The device of claim 1, wherein the relative temperature threshold comprises at least two relative temperature thresholds, wherein the thermal capacity control is configured to select a first of the at least two relative temperature thresholds based on the based on the power level signal specifying that indication of switch power is below the power threshold, and the thermal capacity control being configured to select a second of the at least two relative temperature thresholds based on the power level signal specifying that indication of switch power is above the power threshold.

5. The device of claim 1, further comprising a device control circuit configured to enable or disable the switch device in response to a control signal from the thermal capacity control.

6. The device of claim 5, wherein the control signal is a first control signal, the device further comprising a peak temperature detector configured to generate a second control signal based on comparing the device temperature to an absolute temperature threshold, the device control circuit configured to enable or disable the switch device based on the first control signal and the second control signal.

7. The device of claim 1, further comprising a device temperature sensor configured to provide an indication of the sensed temperature of the switch device, the device temperature sensor comprising one of a forward diode circuit, a scaled current circuit, or a temperature-dependent resistor circuit;

and

an ambient temperature sensor configured to provide an indication of the sensed temperature of the ambient temperature outside the switch device, the ambient temperature sensor comprising one of a forward diode circuit, a scaled current circuit, or a temperature-dependent resistor circuit.

8. The device of claim 1, wherein the power detector further comprises a comparator circuit configured to compare a voltage potential across the switch device with respect to a power threshold voltage to generate the power level signal based on the comparison.

9. The device of claim 1, wherein the power detector further comprises a trans-linear circuit configured to perform a multiplication of a voltage potential across the switch device with respect to output current of the switch device to generate the power level signal.

10. The device of claim 1, wherein the relative temperature detector includes a subtraction circuit configured to determine the temperature difference between the device temperature and the ambient temperature.

11. The device of claim 1, wherein the thermal capacity control is configured to enable the switch device to provide power based on the power level signal specifying the indication of power of the switch device is below the power threshold.

12. A circuit, comprising:

a subtractor configured to generate a difference output signal based on subtracting an ambient temperature measurement outside a switch device from a device temperature measurement near the switch device;

a first comparator configured to generate a relative temperature output signal based on comparing the difference output signal to a relative temperature threshold;

a voltage sensor configured to generate a sensor output signal based on a voltage sensed across the switch device;

a second comparator configured to generate a power level signal based on comparing the sensor output signal to a power threshold; and

a thermal capacity control configured to generate a thermal capacity output signal based on the relative temperature output signal and the power level signal, the thermal capacity control configured to disable the relative temperature output signal based on the sensor output signal being detected below the power threshold.

13. The circuit of claim 12, wherein the thermal capacity control is configured to increase the relative temperature threshold based on the sensor output signal being detected below the power threshold.

14. The circuit of claim 12, wherein the thermal capacity control comprises a logic gate configured to disable the relative temperature output based on the sensor output signal being detected below the power threshold.

15. The circuit of claim 12, wherein the relative temperature threshold comprises at least two relative temperature thresholds, wherein the thermal capacity control is configured to select a first of the at least two relative temperature thresholds based on an indication of power of the switch device being below the power threshold, and the thermal capacity control being configured to select a second of the at least two relative temperature thresholds based on the indication of switch power of the switch device being detected above the power threshold.

16. The circuit of claim 12, further comprising a device control circuit configured to enable or disable the switch device in response to a control signal from the thermal capacity control, wherein the control signal is based on the relative temperature output and the power level signal.

17. The circuit of claim 16, wherein the control signal is a first control signal, the circuit further comprising a peak temperature detector configured to generate a second control signal based on comparing the device temperature to an absolute temperature threshold, the device control circuit configured to enable or disable the switch device based on the first control signal and the second control signal.

18. The circuit of claim 12, further comprising a device temperature sensor configured to provide an indication of the sensed temperature of the switch device, the device temperature sensor comprising one of a forward diode circuit, a scaled current circuit, or a temperature-dependent resistor circuit;

and

an ambient temperature sensor configured to provide an indication of the sensed temperature of the ambient temperature outside the switch device, the ambient temperature sensor comprising one of a forward diode circuit, a scaled current circuit, or a temperature-dependent resistor circuit.

19. A method, comprising:

receiving an indication of relative temperature based on a temperature of a switch device and an ambient temperature;

receiving an indication of switch power for the switch device;

comparing the relative temperature indication with a relative temperature threshold to provide a thermal shutdown control signal based on the relative temperature indication being above the threshold;

comparing the switch power indication with a power threshold to provide an indication of switch power; and

overriding the thermal shutdown signal to enable the switch device based on the switch power indication being below the power threshold.

20. The method of claim 19, further comprising disabling the switch device based on the relative temperature indication being above the relative temperature threshold and the switch power indication being above the power threshold.