METHOD AND CIRCUIT OF DETECTING ATTACHMENT AND DETACHMENT BETWEEN A PORTABLE DEVICE AND A POWER CONVERTER

• US 20150311806A1
• Filed: 04/22/2015
• Published: 10/29/2015
• Est. Priority Date: 04/24/2014
• Status: Active Grant

• Current Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Original Assignee: Fairchild Taiwan Corp (ON Semiconductor Corporation)
• Inventors: KIM, EUI-SOO, CHUNG, BONG-GEUN, KOO, GWAN-BON, KIM, JU-HYUN, PARK, YOUNG-BAE
• Granted Patent: US 9,917,518 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/00036 Charger exchanging data with battery
• CPC Class Codes: H02J 7/00047 with provisions for charging different types of batteries
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/0049 Detection of fully charged condition
• CPC Class Codes: H02M 1/0032 Control circuits allowing low power mode operation, e.g. in standby mode
• CPC Class Codes: H02M 3/33507 with automatic control of the output voltage or current, e.g. flyback converters H02M3/33561, H02M3/33569 take precedence
• CPC Class Codes: H02M 3/33523 with galvanic isolation between input and output of both the power stage and the feedback loop
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A method and a circuit of detecting attachment and detachment between a portable device and a power converter are provided. The method and the circuit confirm attachment of the portable device to the power converter and generate an attachment signal. The method and the circuit further detect a bus voltage of the power converter for confirming detachment of the portable device from the power converter.

Claims

1. A circuit for detecting attachment and detachment between a portable device (PD) and a power converter, comprising:

a PD attachment detection circuit coupled to at least one connecting terminal of said power converter for confirming attachment of said portable device to said power converter and generating an attachment signal; and

a PD detachment detection circuit detecting a bus voltage of said power converter according to an enabling signal, said enabling signal being generated when said power converter enters a light-load condition, wherein said PD detachment detection circuit confirms detachment of said portable device from said power converter by detecting a voltage drop of said bus voltage of said power converter.

2. The circuit as claimed in claim 1, wherein said at least one connecting terminal of said power converter is a data terminal.

3. The circuit as claimed in claim 1, wherein said at least one connecting terminal of said power converter is a current-sense terminal.

4. The circuit as claimed in claim 1, the circuit further comprises a load detection circuit to detect said light-load condition of said power converter in response to said attachment signal, and generate said enabling signal.

5. The circuit as claimed in claim 2, wherein said attachment of said portable device to said power converter is confirmed by said PD attachment detection circuit when an increase of said voltage at said data terminal is detected by said PD attachment detection circuit.

6. The circuit as claimed in claim 3, wherein said attachment of said portable device to said power converter is confirmed by recognizing a pattern current generated by said portable device.

7. The circuit as claimed in claim 4, wherein said load detection circuit detects a voltage of a transformer of said power converter for detecting said light-load condition of said power converter and generating said enabling signal.

8. The circuit as claimed in claim 1, further comprising:

a gate driver controlling a BUS switch which is coupled between an output capacitor and a bus capacitor of said power converter for generating said bus voltage across said bus capacitor.

9. The circuit as claimed in claim 8, wherein said PD detachment detection circuit controls said gate driver to turn off said BUS switch in response to said enabling signal, said PD detachment detection circuit memorizes said bus voltage before turning off said BUS switch, and monitors said voltage drop of said bus voltage after turning off said BUS switch for confirming said detachment of said portable device from said power converter.

10. The circuit as claimed in claim 9, wherein said PD detachment detection circuit controls said gate driver to turn off said BUS switch when said enabling signal indicates said light-load condition of said power converter.

11. A method of detecting attachment and detachment between a portable device (PD) and a power converter, comprising:

confirming attachment of said portable device to said power converter and generating an attachment signal;

detecting a bus voltage of said power converter in response to an enabling signal, said enabling signal being generated when said power converter enters a light-load condition, wherein detachment of said portable device from said power converter is confirmed by detecting a voltage drop of said bus voltage of said power converter.

12. The method as claimed in claim 11, wherein said attachment signal is generated by detecting a voltage at a data terminal of said power converter.

13. The method as claimed in claim 11, wherein said attachment signal is generated by recognizing a pattern current at a current-sense terminal of said power converter, said pattern current is generated by said portable device.

14. The method as claimed in claim 12, wherein said attachment of said portable device to said power converter is confirmed when an increase of said voltage at said data terminal is detected.

15. The method as claimed in claim 11, further comprising:

detecting a voltage of a transformer of said power converter in response to said attachment signal for detecting said light-load condition of said power converter and generating said enabling signal.

16. The method as claimed in claim 11, further comprising:

controlling a BUS switch which is coupled between an output capacitor and a bus capacitor of said power converter for generating said bus voltage across said bus capacitor.

17. The method as claimed in claim 16, further comprising:

memorizing said bus voltage before turning off said BUS switch; and

monitoring said voltage drop of said bus voltage after turning off said BUS switch for confirming said detachment of said portable device from said power converter.

18. The method as claimed in claim 17, wherein said BUS switch is turned off when said enabling signal indicates said light-load condition of said power converter.