Patent Application
20130003985
The disclosure generally relates to audio playing technologies, and particularly, to an audio output controller and an output control method.
Many audio players only include one earphone jack. If more than one user wants to listen to the audio player at the same time, an adapter having more than one earphone jacks to distribute one signal flow output by the player into more than one signal sub-flows is needed. However, the power of each signal sub-flow is usually lower than the signal flow output by the media player. The user needs to manually adjust the output power of media player to ensure each earphone jack of the adapter can output normal volume, which is not convenient and results in low efficiency.
Therefore, it is desirable to provide an audio output controller and method which can overcome the above-mentioned problems.
Many aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
The disclosure is illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean at least one.
The output control unit 150 includes a detector 155 and a determining module 153. The detector 155 includes more than one detecting circuits 157. Each detecting circuit 157 respectively connects with one of the earphone jacks 1700 of the interface unit 170. Each detecting circuit 157 detects whether the corresponding earphone jack 1700 is connected to the earphone. In this embodiment, the interface unit 170 includes two earphone jacks 1700: a first earphone jack 1711 and a second earphone jack 1713. The detector 157 respectively includes a first detecting circuit 157a and a second detecting circuit 157b.
In detail, the detecting unit 230 includes a first operational amplifier 2311, a first resistor 2301, a second resistor 2303, a third resistor 2305, a fourth resistor 2307, a fifth resistor 2309, and a seventh resistor 2310. The first operational amplifier 2311 includes a first input terminal 2313, a second input terminal 2315, and an output terminal 2317. The first terminal pad 1701a connects with a power source VCC via the first resistor 2301. The power source VCC ground via the second resistor 2303 and the third resistor 2305 connected in series. The first input terminal 2313 is connected to a node between the second resistor 2303 and the third resistor 2305. The output terminal 2317 connects with the second terminal pad 1701b via the fifth resistor 2309 and the fourth resistor 2307 which are connected in series. The second terminal 1701b is grounded via the seventh resistor 2310. The second input terminal 2315 is connected to a second node between the fourth resistor 2307 and the fifth resistor 2309. In this embodiment, the first input terminal 2313 is a non-inverting input terminal of the first operational amplifier 2311, the second input terminal 2315 is an inverting input terminal of the first operational amplifier 2311.
The determining unit 232 includes a first transistor 2323, a second transistor 2325, and a sixth resistor 2321. The first transistor 2323 includes a first control terminal 2329, a first conducting terminal 2327, and a second conducting terminal 2331. The second transistor 2325 includes a second control terminal 2337, a third conducting terminal 2333, and a fourth conducting terminal 2335. The first control terminal 2329 and the second control terminal 2337 are connected to the output terminal 2317. The first conducting terminal 2327 is connected to the power source VCC via the sixth resistor 2321. The second conducting terminal 2331 is connected to the third conducting terminal 2333. The fourth conducting terminal 2335 is grounded. A node between the second conducting terminal 2331 and the third conducting terminal 2333 is defined as a detecting output terminal 234 of the detecting circuit 157. In this embodiment, the first transistor 2323 is a P-type transistor. The first control terminal 2329 is a source electrode of the P-type transistor. The first conducting terminal 2327 is a gate electrode of the P-type transistor. The second conducting terminal 2331 is a drain electrode of the P-type transistor. The second transistor 2325 is a N-type transistor. The second control terminal 2337 is a source electrode of the N-type transistor. The third conducting terminal 2333 is a gate electrode of the N-type transistor. The fourth conducting terminal 2335 is a drain electrode of the N-type transistor.
The determining module 153 includes a multiplexer 159 and a second operational amplifier 161. The multiplexer 159 includes a signal input terminal 151, more than one detecting input terminals 236, more than one normal output terminals 163, and an amplifying output terminal 164. The signal input terminal 151 connects with a player for receiving an signal flow. Each detecting input terminal 236 respectively connects with the detecting output terminal 234 of each detecting circuit 157 for receiving a detecting signal output by the detecting circuit 157. Each normal output terminal 163 respectively connects with one of earphone jacks 1700 of the interface unit 170 for transmitting the signal flow not being amplified to the corresponding earphone jack 1700. The amplifying output terminal 164 connects with an input terminal 1635 of the second operational amplifier 161. The other input terminal 1615 of the second operational amplifier 161 is grounded. The output terminal 1617 of the second operational amplifier 161 connects with each earphone jack 1700 for transmitting the signal flow being amplified to each earphone jack 1700. In this embodiment, the multiplexer 159 includes two detecting input terminals 263 corresponding to the first detecting circuit 157a and the second detecting circuit 157b and two normal output terminals 163 corresponding to the first earphone jack 1711 and the second earphone jack 1713. The amplifying output terminal 1617 connects with both the first earphone jack 1711 and the second earphone jack 1713.
For explanation, the resistance of the first resistor 2301 is named as R1, the resistance of the second resistor 2303 is named as R2, the resistance of the third resistor 2305 is named as R3, the resistance of the seventh resistor 2310 is named as R. The voltage of the first input terminal 2313 of the first operational amplifier 2311 is named as U1. The voltage of the second input terminal 2315 of the first operational amplifier 2311 is named as U2. The voltage of the output terminal 2317 of the first operational amplifier 2311 is named as U0. The voltage of the power source VCC is named as VCC. Therefore, the output voltage of the first operational amplifier 2311 can be represented as a formula: Uo=R3/R2(U1−U2).
In operation, when the earphone jack 1700 is connected to the earphone, the first terminal pad 1701a is electrically connected to the second terminal pad 1701b via the connecting terminal of the earphone. The first operational amplifier 2311 operates a subtraction. Therefore, U1=VCC, U2=[R/(R+R1)]*VCC, U0 is a low voltage. The first transistor 2323 is turned on. The detecting circuit 157 outputs a high level detecting signal to the determining module 153 via the detecting output terminal 236. The high level detecting signal is represented as “H”.
When the earphone jack 1700 is not connected to the earphone, the electrical connection between the first terminal pad 1701a and the second terminal 1701b is cut off. Therefore, U1=VCC, U2=0, U0 is a high voltage. The second transistor 2325 is turned on. The detecting circuit 157 outputs a low level detecting signal to the determining module 153 via the detecting output terminal 236. The low level detecting signal is represented as “L”.
The multiplexer 159 run a logic operation according to the input detecting signals to determine which detecting output terminal 163 to output the signal flow to. In this embodiment, the result of the logic operation as shown below:
From the list above, when the first earphone jack 1711 connects with the earphone and the second earphone jack 1713 does not connect with the earphone, the signal flow is transmitted to the first earphone jack 1711 via the first normal output terminal 163. When the second earphone jack 1713 connects with the earphone and the first earphone jack 1711 does not connect with the earphone, the signal flow is transmitted to the second earphone jack 1713 via the second normal output terminal 163. When the first earphone jack 1711 and the second earphone jack 1713 connect with the earphones at a same time, the signal flow is distributed into the first earphone jack 1711 and the second earphone jack 1713 after being amplified by the second operational amplifier 161. Therefore, each signal sub-flow sent to the first earphone jack 1711 or the second earphone jack 1713 can remain at normal power of the original signal flow.
In step S10, each detecting circuit 157 of the detector 155 detects whether each earphone jack 1700 connects with an earphone and outputs a detecting signal representing the connection status of each earphone jack 1700 to the determining module 153.
In step S20, if only one of the earphone jacks 1700 is connected with the earphone, the determining module 153 outputs the signal flow directly to the connected earphone jack 1700 according to the detecting signal from the detecting circuit 157.
In step S30, if more than one of the earphone jack 1700 is connected with the earphones at the same time, the determining module 153 amplifies the signal flow via the second operational amplifier 161.
In step S40, the determining module 153 distributes the signal flow being amplified into more than one signal sub-flows, and correspondingly transmits the signal sub-flows to each connected earphone jack 1700.
It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the disclosure or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201110178984.9 | Jun 2011 | CN | national |
