METHOD AND SYSTEM FOR POWER SWITCH TEMPERATURE REGULATION

• US 20130063098A1
• Filed: 09/14/2011
• Published: 03/14/2013
• Est. Priority Date: 09/14/2011
• Status: Active Grant

• Current Assignee: Microchip Technology Incorporated
• Original Assignee: Standard Microsystems Corporation (Microchip Technology Incorporated)
• Inventors: Knowlton, Timothy J., Fischbach, Christopher
• Granted Patent: US 8,884,589 B2
• Time in Patent Office: Days
• US Class Current: 320/137
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries

Abstract

The invention is related to a method and system for temperature regulation of a power switch during charging of a portable device. The method includes the steps of establishing a connection between the portable device and a charging circuit, monitoring a charging current supplied from the charging circuit to the portable device, monitoring a temperature of the power switch, while the portable device is being charged, comparing the monitored temperature with a predefined threshold temperature, and restricting the charging current, based on the comparison.

Claims

1. A method for regulating temperature of a charger having a port power switch, the method comprising:

monitoring the port power switch temperature;

comparing the monitored temperature with a predefined threshold temperature; and

restricting the charger current output, based on the comparison.

2. The method of claim 1 further comprising attaching a portable device with the charger.

3. The method of claim 2, wherein the power switch operates at a constant voltage mode.

4. The method of claim 3, wherein the current increases in constant voltage mode based on a determination that the monitored temperature is below the threshold temperature.

5. The method of claim 1, wherein the step of restricting the current includes:

maintaining the current to a fixed constant current value;

or

reducing a maximum current limit associated with the port power switch.

6. The method of claim 5, wherein the fixed constant current value is assigned by switching the power switch to a constant current mode upon a determination that the current exceeds the maximum current limit.

7. The method of claim 6, wherein the current is maintained at the fixed constant current value based on a determination than the monitored temperature is below the threshold temperature.

8. The method of claim 5, wherein the restricting step reduces the maximum current limit value when the monitored temperature exceeds the predefined threshold temperature.

9. The method of claim 1 further including repeating the monitoring, comparing and restricting step upon a determination that the monitored temperature is above the threshold temperature.

10. A system for regulating temperature of a charger having a power switch, the system comprising:

a sensing module configured to measure the power switch temperature;

a comparator configured to compare the monitored temperature with a predefined threshold temperature; and

a controller configured to restrict the charger current based on the comparison.

11. The system of claim 10 further comprising a connector adapted to attach a portable device to the charger.

12. The system of claim 10, wherein the charging current increases upon a determination that the measured temperature is below the threshold temperature.

13. The system of claim 10, wherein the controller is configured to:

maintain the charger current to a fixed constant current value;

or

reduce a maximum current limit value associated the power switch.

14. The system of claim 13, wherein the charging current attains the fixed constant current value when the charging current exceeds the maximum current limit value.

15. The system of claim 13, wherein the controller maintains the charging current to the fixed constant current value upon on a determination that the monitored temperature is below the threshold temperature.

16. The system of claim 13, wherein in the controller reduces the maximum current limit value upon a determination that the monitored temperature is above the threshold temperature.

17. The system of claim 16, wherein the controller is configured to reduce the maximum current limit value until the monitored temperature is above the threshold temperature.