Portable electronic device having universal earphone jack

1. Technical Field

The disclosure generally relates to portable electronic devices, and particularly to a portable electronic device having an earphone jack, which can receive different types of earphone plugs.

2. Description of Related Art

A three pin earphone plug usually includes a first contact portion, a second contact portion, and a third contact portion orderly formed thereon. Referring to the three pin earphone plug shown in FIG. 3 , the first contact portion is a left channel point REC_L. The second contact portion is a right channel point REC_R. The third contact portion is a ground point GND. A four pin earphone plug usually includes a first contact portion, a second contact portion, and a third contact portion orderly formed thereon. Referring to a first type of four pin earphone plug shown in FIG. 4 , the first contact portion is a left channel point REC_L. The second contact portion is a right channel point REC_R. The third contact portion is a microphone channel point MIC. The fourth contact portion is a ground point GND. Referring to a second type of four pin earphone plug shown in FIG. 5 , the first contact portion is a left channel point REC_L. The second contact portion is a right channel point REC_R. The third contact portion is a ground point GND. The fourth contact portion is a microphone channel point MIC. A related portable electronic device usually can use only one of the three pin earphone plug, the first type of four pin earphone plug, or the second type of four pin earphone plug, and lacks flexibility.

Therefore, there is room for improvement within the art.

FIG. 1 is a circuit diagram of the portable electronic device, according to an exemplary embodiment, receiving a three pin earphone plug and a first type of four pin earphone plug.

FIG. 2 is similar to FIG. 1 , but received a second type of four pin earphone plug.

FIG. 3 is a schematic view of the three pin earphone plug of FIG. 1 .

FIG. 4 is a schematic view of the first type of four pin earphone plug of FIG. 1 .

FIG. 5 is a schematic view of the second type of four pin earphone plug of FIG. 2 .

FIG. 1 shows a circuit diagram of a portable electronic device 100 , according to an exemplary embodiment. The portable electronic device 100 includes an earphone jack 11 , a switch 12 , a detecting terminal 13 , a controlling terminal 14 , and an audio processing terminal 15 .

The earphone jack 11 includes a first contact 111 , a second contact 112 , a third contact 113 , a fourth contact 114 , a fifth contact 115 and a sixth contact 116 . The earphone jack 11 can receive different types of earphone plugs. When a three pin earphone plug shown in FIG. 3 is received in the earphone jack 11 , the first contact 111 , and the second contact 112 are respectively connected to the left channel point REC_L, and the right channel point REC_R, and the third contact 113 and the fourth contact 114 are both connected to the ground point GND.

When a first type of four pin earphone plug shown in FIG. 4 is received in the earphone jack 11 , the first contact 111 , the second contact 112 , the third contact 113 , and the fourth contact 114 are respectively connected to the left channel point REC_L, the right channel point REC_R, the microphone point MIC, and the ground point GND.

When a second type of four pin earphone plug shown in FIG. 5 is received in the earphone jack 11 , the first contact 111 , the second contact 112 , the third contact 113 , and the fourth contact 114 are respectively connected to the left channel point REC_L, the right channel point REC_R, the ground point GND, and the microphone point MIC. Furthermore, the fifth contact 115 is grounded.

Also referring to FIG. 2 , the switch 12 includes a first switch D 1 and a second switch D 2 . The first switch D 1 and the second switch D 2 are both single pole double throw switches. The first switch D 1 includes a first movable contact D 11 , a first fixed contact D 12 , and a second fixed contact D 13 . The second switch D 2 includes a second movable contact D 21 , a third fixed contact D 22 , and a fourth fixed contact D 23 . The switch 12 can switch between a first state and a second state. In the first state, the first movable contact D 11 and the second movable contact D 21 are respectively connected to the first fixed contact D 12 and the third fixed contact D 22 . In the second state, the first movable contact D 11 and the second movable contact D 21 are respectively connected to the second fixed contact D 13 and the fourth fixed contact D 23 .

The first movable contact D 11 and the second movable contact D 21 are respectively connected to the fourth contact 114 and the third contact 113 . The first fixed contact D 12 and the fourth fixed contact D 23 are both grounded. The second fixed contact D 13 and the third fixed contact D 21 are both connected to a first power VCC by a first resistor R 1 , and form a first node J 1 .

The detecting terminal 13 is connected to the first node J 1 and configured for detecting the type of the earphone plug received in the earphone jack 11 according to a voltage of the third contact 113 or the fourth contact 114 through the switch 12 . Particularly, when the three pin earphone plug shown in FIG. 3 is received in the earphone jack 11 , the third contact 113 and the fourth contact 114 are both connected to the ground point GND, and a voltage difference between the third contact 113 and the fourth contact 114 is less than a predetermined voltage, such as 0.3 V. Therefore, if the voltage of the first node J 1 is less than the predetermined voltage, the detecting terminal 13 detects that the type of the earphone plug received in the earphone jack 11 is the three pin earphone plug.

When the first type of four pin earphone plug is received in the earphone jack 11 , the third contact 113 and the fourth contact 114 are respectively connected to the microphone point MIC and the ground point GND. The microphone point MIC equals to a field effect transistor and the fourth contact 114 is grounded, and the voltage of the microphone point MIC satisfies a bias voltage range, such as 0.3V<a detected voltage<0.8V. Therefore, if the voltage of the first node J 1 satisfies the bias voltage range, the detecting terminal 13 detects that the type of the earphone plug received in the earphone jack 11 is the first type of the four pin earphone plug.

If the voltage of the node J 1 does not satisfy the bias voltage range and also not less than the predetermined voltage, the detecting terminal 12 detects that the type of the earphone plug received in the earphone jack 11 is the second type of the four pin earphone plug.

The controlling terminal 14 is connected to the switch 12 . The controlling terminal 14 switches the switch 12 to a corresponding state (i.e. the first state or the second state) according to the type of the earphone plug received in the earphone jack 11 .

An end of the audio processing terminal 15 is connected to the first node J 1 . Another end of the audio processing terminal 15 is connected to an audio processing circuit (not shown) of the portable electronic device 100 . The audio processing terminal 15 is used to receive audio by the microphone point MIC of the first type of the four pin earphone plug or the second type of the four pin earphone plug, and transfer the received audio to the audio processing circuit. The audio processing circuit is used to receive and process audio from the audio processing terminal 15 .

The portable electronic device 100 further includes a determination circuit 16 and a receiving terminal 17 . The determination circuit 16 includes a chipset T. A negative electrode of the chipset T is connected to a second power VDD by a second resistor R 2 , and forms a second node J 2 . The second node J 2 is grounded by a third resistor R 3 . A positive electrode of the chipset T is connected to the first power VCC by a fourth resistor R 4 and a fifth resistor R 5 in series, and forms a third node J 3 . The third node J 3 is connected to the sixth contact 116 . The positive electrode of the chipset T is grounded by a capacitor C. The output terminal of the chipset T is connected to the receiving terminal 17 . The voltage of the second node J 2 is set as a reference voltage V ref (V ref =VDD*R2/(R2+R3)).

When an earphone plug is received in the earphone jack 11 , the sixth contact 116 is connected to the fifth contact 115 . So the sixth contact 116 is grounded and the voltage of the third node J 3 is zero. Therefore, the voltage of the third node J 3 is less than the reference voltage V ref , and then the chipset T outputs a low level (e.g., logic 0) to the receiving terminal 17 . If there is on earphone plug received in the earphone jack 11 , the sixth contact 116 is disconnected from the fifth contact 115 , and the reference voltage V ref is less than the voltage of the third node J 3 , and then the chipset T outputs a high level (e.g., logic 1) to the receiving terminal 17 . Accordingly, the receiving terminal 17 can determine whether an earphone plug is received in the earphone jack 11 by the output voltage of the chipset T.

When the receiving terminal 17 determines that there is an earphone plug received in the earphone jack 11 , the detecting terminal 13 determines the type of the earphone plug received in the earphone jack 11 according to the voltage of the first node J 1 . When the detecting contact 13 detects that the three pin earphone plug or the first type of four pin earphone plug is received in the earphone jack 11 , the controlling contact 14 controls the switch 12 to switch to the first state. That is, the first movable contact D 11 and the second movable contact D 21 are respectively connected to the first fixed contact D 12 and the third fixed contact D 22 . The three pin earphone plug and the first type of four pin earphone plug can be used by the portable electronic device 100 .

When the detecting contact 13 detects that the second type of earphone plug is received in the earphone jack 11 , the controlling contact 14 controls the switch 12 to switches to the second state. That is, the first movable contact D 11 and the second movable contact D 21 are respectively connected to the second fixed contact D 13 and the fourth fixed contact D 23 . So the third contact portion of the second type of four pin earphone plug is grounded by the third contact 113 and the switch 12 . The fourth contact portion of the second type of four pin earphone plug is connected to the audio receiving contact 15 by the fourth contact 114 and the switch 12 . The second type of four pin earphone plug can be used by the portable electronic device 100 .

Although certain embodiments of the present disclosure have been specifically described, the present disclosure is not to be construed as being limited thereto. Various changes or modifications may be made to the present disclosure without departing from the scope and spirit of the present disclosure.