Control circuit for identifying power adaptor and method for use thereof

• US 7,804,257 B2
• Filed: 12/01/2006
• Issued: 09/28/2010
• Est. Priority Date: 12/01/2006
• Status: Expired due to Fees

• Current Assignee: Hong Fu Jin Precision Industry (Shenzhen) Co., Ltd. (Hon Hai Precision Industry Co., Ltd.), Hon Hai Precision Industry Co., Ltd.
• Original Assignee: Hong Fu Jin Precision Industry (Shenzhen) Co., Ltd. (Hon Hai Precision Industry Co., Ltd.), Hon Hai Precision Industry Co., Ltd.
• Inventors: Jia, Yu-Sen
• Primary Examiner(s): Owens; Douglas W
• Assistant Examiner(s): Vu; Jimmy T
• Application Number:
  US11/565,893
• Publication Number:
  US 20080129123A1
• Time in Patent Office: 1,397 Days
• Field of Search: 315/209.R, 315/224, 315/225, 315/245, 315/246, 315/291, 315/307, 315/362, 363/106, 363/123, 363/127
• US Class Current: 315/307
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters

Abstract

A control circuit (100) being adapted for identifying an adaptor of an electronic device includes an adaptor-side circuit (110) that is incorporated in the adaptor and a system-side circuit (120) that is incorporated in the electronic device. The adaptor-side circuit converts a high alternating voltage coming from a power source to a low direct voltage and has a positive output terminal and a negative output terminal. A voltage dividing circuit (30) is connected with the positive output terminal, and has a control terminal outputting a voltage. The system-side circuit includes a switching circuit (40) connected to the positive output terminal and the control terminal. The voltage outputted by the control terminal is used to switch on the switching circuit in order to energize the electronic device via the direct current voltage outputted by the positive and negative output terminals.

Claims

1. A control circuit being configured to identify an adaptor used with an electronic device, the control circuit comprising:

a system-side circuit that is configured to be incorporated in the electronic device, wherein the system-side circuit includes a switching circuit; and

an adaptor-side circuit that is configured to be incorporated in the adaptor, wherein the adaptor-side circuit is used to convert an alternating current voltage to a direct current voltage and output the direct current voltage by positive and negative output terminals thereof, one of the positive and negative output terminals is coupled to said switching circuit, the other one of the positive and negative output terminals is configured to be coupled to the electronic device, the adaptor-side circuit includes a dividing circuit connected to the one of the positive and negative output terminals that is coupled to said switching circuit, and the dividing circuit has a voltage output control terminal that is connected to said switching circuit and used to switch on said switching circuit so that the electronic device is powered;

said switching circuit comprising two metal-oxide-semiconductor field effect transistors (MOSFETs) and a resistor, the two MOSFETs comprising a P-channel enhancement mode MOSFET whose source is connected to the positive output terminal and an N-channel enhancement mode MOSFET whose gate is connected to the control terminal, a source of the N-channel enhancement mode MOSFET being connected to ground (GND), and a drain of the N-channel enhancement mode MOSFET being connected to a gate of the P-channel enhancement mode MOSFET, the resistor being connected between the positive output terminal and the gate of the P-channel enhancement mode MOSFET, and a drain of the P-channel enhancement mode MOSFET being configured to be coupled to the electronic device.

2. The control circuit as described in claim 1, wherein the dividing circuit comprises two resistors connected in series between the positive output terminal and ground (GND), and the control terminal is connected to a junction between the two resistors.

3. A method of identifying an adaptor used with an electronic device, comprising the following steps:

converting an alternating current voltage inputted to the adaptor into a direct current voltage and outputting the direct current voltage, via one of a pair of positive and negative output terminals of the adaptor, to a switching circuit that is incorporated in the electronic device, the switching circuit comprising a metal-oxide-semiconductor field effect transistor (MOSFET) which has a source and a drain respectively connected to the one of the pair of positive and negative output terminals of the adaptor and the electronic device, wherein the other one of the positive and negative output terminals is connected to the electronic device;

dividing the direct current voltage to form a controlling voltage having a value lower than the direct current voltage; and

inputting the controlling voltage to the switching circuit via a control terminal to switch on the MOSFET of the switching circuit in order to electrically connect the adaptor with the electronic device and power the electronic device using the direct current voltage.

4. The method as described in claim 3, wherein the dividing step is accomplished by a dividing circuit comprising two resistors connected in series, and the controlling voltage comes from a voltage that is distributed on one of the two resistors.

5. The method as described in claim 3, wherein the switching circuit further comprises another MOSFET and one resistor.

6. The method as described in claim 5, wherein the MOSFET is a P-channel enhancement mode MOSFET whose source is connected to the positive output terminal and the another MOSFET is an N-channel enhancement mode MOSFET whose gate is connected to the control terminal, a source of the N-channel enhancement mode MOSFET being connected to ground (GND), and a drain of the N-channel enhancement mode MOSFET being connected to a gate of the P-channel enhancement mode MOSFET, the resistor being connected between the positive output terminal and the gate of the P-channel enhancement mode MOSFET, and the drain of the P-channel enhancement mode MOSFET being coupled to the electronic device.

7. The method as described in claim 3, wherein the switching circuit comprises another MOSFET and two resistors.

8. The method as described in claim 7, wherein the MOSFET is a P-channel enhancement mode MOSFET whose source is connected to the positive output terminal and the another MOSFET is an N-channel enhancement mode MOSFET whose gate is connected to the control terminal, a source of the N-channel enhancement mode MOSFET being connected to ground (GND), a drain of the N-channel enhancement mode MOSFET being connected to a gate of the P-channel enhancement mode MOSFET via one of the two resistors, the other one of the two resistors being connected between the positive output terminal and the gate of the P-channel enhancement mode MOSFET, the drain of the P-channel enhancement mode MOSFET being coupled to the electronic device.

9. The method as described in claim 3, wherein the MOSFET is a P-channel enhancement mode MOSFET, a source of the P-channel enhancement mode MOSFET being connected to the positive output terminal, a gate of the P-channel enhancement mode MOSFET being connected to the control terminal, and a drain of the P-channel enhancement mode MOSFET being coupled to the electronic device.

10. A control circuit for identifying an adaptor for an electronic device, wherein the adaptor is used for converting AC power to DC power to be used by the electronic device, the control circuit comprising:

a dividing circuit incorporated in the adaptor, comprising two resistors connected in series, wherein one of the resistors is connected with a positive output terminal of the adaptor and the other one of the resistors is connected to ground, a control terminal extending from a junction between the two resistors; and

a switching circuit comprising first and second input terminals connecting with the positive output terminal of the adaptor and the control terminal, respectively, and an output terminal connecting with the electronic device, the switching circuit comprising a metal-oxide-semiconductor field effect transistor (MOSFET) which has a drain and a source respectively functioning as the first input terminal and the output terminal, wherein when a the MOSFET in the switching circuit is turned on by the control terminal, the DC power flows from the positive output terminal through the first input terminal and the output terminal of the switch circuit to the electronic device.

11. The control circuit as described in claim 10, wherein the switching circuit further comprises another MOSFET, the MOSFET is a P-channel enhancement mode MOSFET whose source is connected to the positive output terminal, and the another MOSFET is an N-channel enhancement mode MOSFET whose gate is connected to the control terminal, a source of the N-channel enhancement mode MOSFET being connected to ground (GND), and a drain of the N-channel enhancement mode MOSFET being connected to a gate of the P-channel enhancement mode MOSFET, and the drain of the P-channel enhancement mode MOSFET being coupled to the electronic device.

12. The control circuit as described in claim 11, wherein the source and gate of the P-channel enhancement mode MOSFET are interconnected by a third resistor.

13. The control circuit as described in claim 12, further comprising a fourth resistor interconnecting a junction between the third resistor and the gate of the P-channel enhancement mode MOSFET and the drain of the N-channel enhancement mode MOSFET.

14. The control circuit as described in claim 10, wherein the MOSFET is a P-channel enhancement mode MOSFET, the source of the P-channel enhancement mode MOSFET being connected to the positive output terminal, a gate of the P-channel enhancement mode MOSFET being connected to the control terminal, and the drain of the P-channel enhancement mode MOSFET being coupled to the electronic device.

15. A control circuit being configured to identify an adaptor used with an electronic device, the control circuit comprising:

a system-side circuit that is configured to be incorporated in the electronic device, wherein the system-side circuit includes a switching circuit; and

an adaptor-side circuit that is configured to be incorporated in the adaptor, wherein the adaptor-side circuit is used to convert an alternating current voltage to a direct current voltage and output the direct current voltage by positive and negative output terminals thereof, one of the positive and negative output terminals is coupled to the switching circuit, the other one of the positive and negative output terminals is configured to be coupled to the electronic device, the adaptor-side circuit includes a dividing circuit connected to the one of the positive and negative output terminals that is coupled to the switching circuit, and the dividing circuit has a voltage output control terminal that is connected to the switching circuit and used to switch on the switching circuit so that the electronic device is powered;

the switching circuit comprising two metal-oxide-semiconductor field effect transistors (MOSFETs) and two resistors, the two MOSFETs comprising a P-channel enhancement mode MOSFET whose source is connected to the positive output terminal and an N-channel enhancement mode MOSFET whose gate is connected to the control terminal, a source of the N-channel enhancement mode MOSFET being connected to ground (GND), a drain of the N-channel enhancement mode MOSFET being connected to a gate of the P-channel enhancement mode MOSFET via one of the two resistors, the other one of the two resistors being connected between the positive output terminal and the gate of the P-channel enhancement mode MOSFET, and a drain of the P-channel enhancement mode MOSFET being configured to be coupled to the electronic device.

16. A control circuit being configured to identify an adaptor used with an electronic device, the control circuit comprising:

a system-side circuit that is configured to be incorporated in the electronic device, wherein the system-side circuit includes a switching circuit; and

an adaptor-side circuit that is configured to be incorporated in the adaptor, wherein the adaptor-side circuit is used to convert an alternating current voltage to a direct current voltage and output the direct current voltage by positive and negative output terminals thereof, one of the positive and negative output terminals is coupled to the switching circuit, the other one of the positive and negative output terminals is configured to be coupled to the electronic device, the adaptor-side circuit includes a dividing circuit connected to the one of the positive and negative output terminals that is coupled to the switching circuit, and the dividing circuit has a voltage output control terminal that is connected to the switching circuit and used to switch on the switching circuit so that the electronic device is powered;

the switching circuit comprising a P-channel enhancement mode metal-oxide-semiconductor field effect transistor (MOSFET), a source of the P-channel enhancement mode MOSFET being connected to the positive output terminal, a gate of the P-channel enhancement mode MOSFET being connected to the control terminal, and a drain of the P-channel enhancement mode MOSFET being configured to be coupled to the electronic device.