WO2012174986A1 - 一种音频线头插拔检测直驱电路及方法 - Google Patents

一种音频线头插拔检测直驱电路及方法 Download PDF

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Publication number
WO2012174986A1
WO2012174986A1 PCT/CN2012/076477 CN2012076477W WO2012174986A1 WO 2012174986 A1 WO2012174986 A1 WO 2012174986A1 CN 2012076477 W CN2012076477 W CN 2012076477W WO 2012174986 A1 WO2012174986 A1 WO 2012174986A1
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pull
operational amplifier
audio line
circuit
line head
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PCT/CN2012/076477
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English (en)
French (fr)
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李谋涛
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炬力集成电路设计有限公司
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Publication of WO2012174986A1 publication Critical patent/WO2012174986A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R3/00—Circuits for transducers, loudspeakers or microphones

Definitions

  • Audio line head plugging and detecting direct drive circuit and method The present application claims to be submitted to the Chinese Patent Office on June 23, 2011, the application number is 201110170831.X, and the invention name is "an audio line plug insertion and detection direct drive current and method" The priority of the Chinese Patent Application, the entire contents of which is incorporated herein by reference.
  • TECHNICAL FIELD The present invention relates to detection technologies, and in particular, to an audio line plug insertion and detection direct drive circuit and method. BACKGROUND OF THE INVENTION In the field of electronic equipment applications, it is often necessary to perform plugging and unplugging of an audio line head, and report the detection result to a control circuit of the terminal product for the next step.
  • FIG. 1 is a schematic diagram of a commonly used audio line plug insertion and detection direct drive circuit.
  • the direct drive circuit is widely used because it eliminates the audio line head blocking capacitance.
  • the function of the direct drive circuit is to use the node VRO to provide and the audio line head jack output end OL.
  • the connection end of the audio line head includes a left channel L end, a right channel R end and a ground end GD
  • the audio line head jack connection end includes a left channel output end OL adapted to the audio line head plug. End, the right channel output end OR end and two ground end G, wherein one ground end of the audio line head jack is connected to the operational amplifier, and the other ground end is connected to the control end of the transistor through a resistor.
  • the OL end of the audio head jack When the audio head is inserted, the OL end of the audio head jack is connected to the left end L end of the audio line head, the OR end of the audio head jack is connected to the right end R end of the audio line head, and the ground end of the audio head jack is G
  • the voltage is the voltage of the node VRO (VROS) and is connected to the control terminal of the transistor through a resistor R1.
  • the voltage of the node VRO turns on the transistor, which lowers the voltage of the GPIO (General Purpose Input Output) port. Since the voltage of the GPIO port is pulled up when the audio line is not inserted, the system is high according to the voltage of the GPIO port.
  • the above detection circuit requires an additional GPIO port to provide the detection signal, which occupies the pin pin resource, and the operation amplifier needs to be continuously turned on to ensure that the voltage of the node VRO is equal to the reference voltage, thereby increasing the power consumption.
  • the invention provides an audio line plug insertion and detection direct drive circuit and a method for solving the problem that the prior art needs to occupy an extra GPIO port to detect the insertion and removal of the audio line head, and the operation amplifier needs to be continuously turned on.
  • the invention provides an audio line plug insertion and detection direct drive circuit, comprising: an audio line head jack, a pull-up circuit, a pull-down circuit, an operational amplifier, wherein two ground ends of the audio line head jack are respectively connected with a pull-up circuit and a pull-down circuit Connected, the positive input of the operational amplifier inputs a reference voltage, and the negative input and output of the operational amplifier are respectively connected to the two ground ends of the audio head jack.
  • the negative input terminal of the operational amplifier is connected to the ground terminal connected to the pull-up resistor
  • the output end of the operational amplifier is connected to the ground terminal connected to the pull-down circuit
  • the pull-down capability of the pull-down circuit is greater than that of the pull-up circuit. Pull-up ability.
  • the negative input terminal of the operational amplifier is connected to the ground terminal connected to the pull-down circuit
  • the output end of the operational amplifier is connected to the ground terminal connected to the pull-up resistor
  • the pull-up capability of the pull-up circuit is greater than the pull-down circuit. Pulldown capability.
  • the negative input terminal of the operational amplifier is connected to the ground terminal connected to the pull-up resistor, the output end of the operational amplifier is connected to the ground terminal connected to the pull-down circuit, and the pull-down capability of the pull-down circuit is greater than the pull-up capability of the pull-up circuit;
  • the voltage of the negative input terminal of the operational amplifier is a high voltage signal, it is judged that the audio line head is inserted, and the voltage of the negative input terminal of the operational amplifier is detected as a low voltage signal, and the audio line head is judged to be pulled out.
  • the negative input end of the operational amplifier is connected to the ground connected to the pull-down circuit
  • the output end of the operational amplifier is connected to the ground connected to the pull-up resistor
  • the pull-up capability of the pull-up circuit is greater than the pull-down capability of the pull-down circuit
  • the pull-up circuit includes a power source and a resistor, and the first end of the resistor is connected to the power source, and the second end of the resistor is connected to a ground end of the audio jack.
  • the pull-up circuit comprises a power supply and a MOS transistor, and the source end of the MOS tube is connected to the power supply, and the drain end is connected to a ground end of the audio line head jack.
  • the pull-down circuit includes a resistor, and the first end of the resistor is grounded, and the second end of the resistor is connected to a ground end of the audio jack.
  • the pull-down circuit comprises a MOS transistor, and the source end of the MOS tube is grounded, and the drain end is connected to a ground end of the audio line head jack.
  • the invention relates to an audio line head plugging and detecting method, which is applied to an audio line head plugging and detecting direct drive circuit, wherein the audio line head plugging and detecting direct drive circuit comprises: an audio line head jack, a pull-up circuit, a pull-down circuit, an operational amplifier, wherein The two ground ends of the audio head jack are respectively connected to the pull-up circuit and the pull-down circuit, the positive input terminal of the operational amplifier inputs a reference voltage, and the negative input end and the output end of the operational amplifier are respectively connected with the two ground ends of the audio line head jack. ; Includes:
  • the insertion and removal state of the audio line head is determined.
  • the negative input terminal of the operational amplifier is connected to the ground terminal connected to the pull-up resistor, the output end of the operational amplifier is connected to the ground terminal connected to the pull-down circuit, and the pull-down capability of the pull-down circuit is greater than the pull-up capability of the pull-up circuit;
  • the negative input end of the operational amplifier is connected to the ground connected to the pull-down circuit, the output end of the operational amplifier is connected to the ground connected to the pull-up circuit, and the pull-up capability of the pull-up circuit is greater than the pull-down capability of the pull-down circuit;
  • the voltage at the negative input terminal of the operational amplifier is a low voltage signal, and the audio line head is judged to be inserted, and the voltage at the negative input terminal of the operational amplifier is detected as a high voltage signal, and the audio line head is judged to be pulled out.
  • the operational amplifier can be turned on or off, without affecting the detection result.
  • the audio line head plugging and detecting direct drive circuit and method provided by the invention are simple and reliable, can be detected without occupying an extra GPIO port, and save Pin resources; and whether the operational amplifier is turned on does not affect the correctness of the detection result, thereby reducing Power consumption, in addition, the number of components used in the detection direct drive circuit provided by the present invention is reduced, saving PCB area and reducing cost.
  • FIG. 1 is a schematic diagram of a direct drive circuit for plugging and detecting an audio line head in the prior art
  • FIG. 2 is a flowchart of a method for detecting and inserting an audio line head according to an embodiment of the present invention
  • FIG. 3 is a schematic diagram of an audio line plug insertion and extraction direct drive circuit according to an embodiment of the present invention
  • FIG. 4 is a diagram showing the relationship of the audio line head insertion and removal detection corresponding to the circuit diagram shown in FIG. 3;
  • FIG. 5 is a schematic diagram of another audio line plug insertion and extraction direct drive circuit according to an embodiment of the present invention.
  • FIG. 6 is a diagram showing the relationship of the audio line head insertion and removal detection corresponding to the circuit diagram shown in FIG. 5. detailed description
  • the present invention provides an audio line plug insertion and detection direct drive circuit, including: an audio line head jack, Pulling circuit, pull-down circuit, and operational amplifier, wherein two ground ends of the audio wire jack are respectively connected with a pull-up circuit and a pull-down circuit, and a positive input terminal of the operational amplifier inputs a reference voltage, and a negative input terminal and an output terminal of the operational amplifier respectively Connected to the two ground terminals of the audio jack, since the two ground terminals are respectively connected to the pull-up circuit and the pull-down circuit, the negative input terminal and the output terminal of the operational amplifier are connected to the pull-up circuit and the pull-down circuit.
  • the negative input terminal of the operational amplifier is connected to the ground terminal connected to the pull-up resistor, and the output terminal is connected to the ground terminal connected to the pull-down circuit; or, the negative input terminal of the operational amplifier is connected to the ground terminal connected to the pull-down circuit, and the output terminal and the connection pull-up are connected.
  • the ground ends of the resistors are connected.
  • the negative input terminal of the operational amplifier is connected to the ground terminal connected to the pull-up resistor, that is, the pull-up circuit is connected to the negative input terminal of the operational amplifier, and the output terminal of the operational amplifier is connected to the ground terminal connected to the pull-down circuit.
  • the pull-down circuit is connected to the output of the operational amplifier, and the pull-down capability of the pull-down circuit is greater than the pull-up capability of the pull-up circuit.
  • the negative input terminal of the operational amplifier is connected to the ground terminal connected to the pull-down circuit, that is, the pull-down circuit is connected to the negative input terminal of the operational amplifier, and the output terminal of the operational amplifier and the ground terminal connected to the pull-up resistor are connected.
  • the pull-up circuit is connected to the output of the operational amplifier, and the pull-up capability of the pull-up circuit is greater than the pull-down capability of the pull-down circuit.
  • the pull-up circuit may include a power source and a resistor, and the first end of the resistor is connected to the power source, and the second end of the resistor is connected to a ground end of the audio line jack, because the ground terminal is connected to the output end of the operational amplifier or negative The input, so the second end of the resistor is connected to the output or negative input of the op amp.
  • the pull-up circuit may further include a power source and a MOS tube, and the source end of the MOS tube is connected to the power source, and the drain end is connected to a ground end of the audio line head jack, because the ground end is connected to the output terminal or the negative input of the operational amplifier. So, the drain will be connected to the output or negative input of the op amp.
  • the pull-down circuit may include a resistor, and the first end of the resistor is grounded, and the second end of the resistor is connected to a ground end of the audio jack, because the ground is connected to the negative input or the output of the operational amplifier. Therefore, the second end of the resistor is connected to the negative input or output of the op amp.
  • the pull-down circuit includes a MOS transistor, and the source end of the MOS tube is grounded, and the drain end is connected to a ground end of the audio line head jack. Since the ground end is connected to the negative input end or the output end of the operational amplifier, the drain end Connected to the output or negative input of the op amp.
  • ground end of the second end of the resistor or the drain end of the MOS transistor in the pull-up resistor is different from the ground end connected to the second end of the resistor or the drain end of the MOS transistor.
  • the present invention also provides a method for performing audio line head insertion and removal detection by using the above-mentioned detection direct drive circuit. As shown in FIG. 2, the method includes:
  • Step 201 detecting a voltage of a negative input terminal of the operational amplifier
  • Step 202 Determine the insertion and removal state of the audio line head according to the detected voltage.
  • the pull-up circuit is connected to the negative input terminal of the operational amplifier, the pull-down circuit is connected to the output terminal of the operational amplifier, and the pull-down capability of the pull-down circuit is greater than the pull-up capability of the pull-up circuit;
  • the voltage at the negative input terminal of the amplifier is a high voltage signal, and the audio line head is judged to be inserted, and the voltage at the negative input terminal of the operational amplifier is detected as a low voltage signal, and the audio line head is judged to be pulled out.
  • the pull-down circuit is connected to the negative input terminal of the operational amplifier, and the pull-up circuit and the operational amplification
  • the output of the pull-up circuit is connected, and the pull-up capability of the pull-up circuit is greater than the pull-down capability of the pull-down circuit; when the voltage of the negative input terminal of the operational amplifier is detected as a low-voltage signal, the audio line head is inserted, and the negative input of the operational amplifier is detected.
  • the voltage at the terminal is a high voltage signal, and the audio cable is judged to be pulled out.
  • the high voltage signal in the embodiment is specifically a voltage signal whose voltage value is greater than a first threshold.
  • the low voltage signal in this embodiment is specifically a voltage signal whose voltage value is smaller than a second threshold.
  • setting the first threshold is not less than setting the second threshold.
  • setting the first threshold is greater than setting the second threshold. Also, it can be set according to the connection of the pull-up resistor and the pull-down resistor.
  • the audio line head described in the audio line plug insertion and detection direct drive circuit and method provided by the present invention may be a headphone plug or other audio line head, such as line in. Specific embodiments of the present invention will be described below with reference to the accompanying drawings.
  • a schematic diagram of an audio line plug insertion and detection direct drive circuit includes: an audio line head jack, a pull-up circuit, a pull-down circuit, an operational amplifier, wherein, an audio line head
  • the two ground ends of the jack are respectively connected to the pull-up circuit and the pull-down circuit, wherein one ground end may be referred to as a first ground end, and the other ground end is referred to as a second ground end, and VROS is an audio line head jack and upper
  • the voltage at the ground of the pull circuit is connected, the voltage input to the positive input terminal of the operational amplifier is the reference voltage, and the output terminal is connected to the ground terminal connected to the pull-down resistor, that is, the output terminal of the operational amplifier is connected to the pull-down circuit, and the pull-down circuit is pulled down.
  • the ability is greater than the pull-up capability of the pull-up circuit.
  • the pull-up component used in the pull-up circuit may be a resistor or a MOS transistor.
  • the resistor R3 is used, one end of the R3 is connected to the power source VCC, and the other end of the R3 is connected to the audio line head. The first ground of the hole and the negative input of the operational amplifier.
  • the pull-down component used in the pull-down circuit may be a resistor or a MOS tube.
  • a resistor R4 is used, one end of the R4 is grounded, and the other end of the R4 is connected to the second end of the audio jack jack.
  • the output of the operational amplifier is connected, and R4>R3.
  • the L channel of the left channel of the audio cable is connected to the OL terminal of the audio cable jack, and the R terminal of the right channel of the audio cable is connected to the OR terminal of the audio cable jack, and the GND terminal and the audio cable of the audio cable head.
  • the ground ends of the jacks are connected. Therefore, after the audio head is inserted, the VROS changes from high to low. When the audio head is pulled out, the VROS changes from low to high, so that the audio line head can be inserted and removed according to the voltage change of the VROS.
  • FIG. 4 is a diagram showing the relationship of the audio line head insertion and removal detection corresponding to the circuit shown in FIG. 3.
  • Step 401 detecting VROS, if VROS is detected to be high level, the audio jack is not inserted in the audio jack; if VROS is detected to be low, the audio jack is inserted into the audio jack; and step 403 is performed;
  • Step 402 Continue to detect the VROS. When it is detected that the VROS changes from a high level to a low level, the audio line is determined. Head insertion
  • Step 403 Continue to detect VROS. When it is detected that VROS changes from low level to high level, it is determined that the audio line head is pulled out and ends.
  • VROS is at a high level, and when it is determined that no audio line head is inserted in the audio line head jack, it is determined that the audio line head is inserted into the audio line head jack when:
  • the voltage of the node VRO is the reference voltage.
  • the VROS is also the reference voltage. Since the reference voltage is much smaller than the VROS when the audio line is not inserted, it can be changed from high to low according to VROS. Change, it is determined that the audio line head is inserted.
  • the audio line head can be pulled out according to the voltage of VROS from low to high.
  • a schematic diagram of an audio line plug insertion and detection direct drive circuit includes: an audio line head jack, a pull-up circuit, a pull-down circuit, an operational amplifier, wherein, an audio line head The two ground ends of the jack are respectively connected to the pull-up circuit and the pull-down circuit, the negative input end of the operational amplifier is connected to the pull-down circuit, the positive input terminal inputs the reference voltage VR, and the output end thereof is connected with the ground terminal connected to the pull-up. That is, the output of the operational amplifier is connected to the pull-up circuit, and the pull-up capability of the pull-up circuit is greater than the pull-down capability of the pull-down circuit.
  • the pull-down circuit may be a grounding component of the pull-down component, and the pull-down component may be a resistor or a MOS transistor.
  • the resistor R5 is used, one end of the R5 is grounded, and the other end of the R5 is connected with the operational amplifier.
  • the negative input terminal and the first ground end of the audio cable head jack are connected.
  • the pull-up circuit may be a pull-up component connected to the power supply VCC, and the pull-up component may be a resistor or a MOS transistor.
  • the resistor R6, R6 and the power supply VCC are used. Connected, the other end of R6 is connected to the second ground of the audio jack and the output of the op amp, and R6>R5.
  • the left channel L of the audio line head is connected to the OL end of the audio line head jack, and the right channel R of the audio line head plug is connected to the OR end of the audio line head jack, and the ground line GND of the audio line head and the audio line head The G end of the jack is connected.
  • FIG. 6 is a diagram showing the relationship of the audio line head insertion and removal detection corresponding to the circuit shown in FIG. 5.
  • Step 601 Detect VROS. If VROS is high, determine that the audio jack is inserted into the audio jack, and perform step 602. If VROS is low, the audio jack is not inserted in the audio jack; and step 603 is performed;
  • Step 602 Continue to detect the VROS. When it is detected that the VROS changes from a high level to a low level, the audio line is determined. Pull out the head, end
  • Step 603 Continue to detect VROS. When it is detected that VROS changes from low level to high level, it is determined that the audio line head is inserted and ends.
  • the system can determine that the audio line head is inserted according to the change of VROS from low level to high.
  • the voltage of the node VRO is equal to the reference voltage, so when the audio line head is inserted, the VROS is the reference voltage, which is much larger than the voltage when the audio line is not inserted, so it can be determined according to the change of the VROS.
  • the audio line head is inserted.
  • the audio line head insertion and extraction detection direct drive circuit and the detection method provided by the invention are simple and reliable, can be detected without occupying an extra GPIO port, and save Pin resources; and whether the operational amplifier generating the voltage of the node VRO is turned on does not affect the detection result.
  • the correctness can reduce power consumption, and the number of components used in the detection of the direct drive circuit is reduced by the present invention, which saves PCB area and reduces cost.

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Abstract

一种音频线头插拔检测直驱电路及方法。所述电路包括音频线头插孔、上拉电路、下拉电路、运算放大器，其中，音频线头插孔的两端分别与上拉电路和下拉电路相连，运算放大器的正输入端输入参考电压，运算放大器的负输入端和输出端分别与音频线头插孔的两个地端连接；通过检测运算放大器负输入端的电压，根据检测出的电压确定音频线头的插拔状态。所述音频线头插拔检测直驱电路简单可靠，不需要占用额外的GPIO口即可进行检测，节约了Pin资源；并且运算放大器是否开启不影响检测结果的正确性，可以减少功耗，同时所述检测直驱电路采用的元器件数量减少，节约了印刷电路板（PCB）面积并且降低了成本。

Description

一种音频线头插拔检测直驱电路及方法 本申请要求在 2011年 6月 23日提交中国专利局、 申请号为 201110170831.X、 发明名称为"一种 音频线头插拔检测直驱电流及方法 "的中国专利申请的优先权， 其全部内容通过引用结合在本 申请中。 技术领域 本发明涉及检测技术， 尤其涉及一种音频线头插拔检测直驱电路及方法。 背景技术 在电子设备应用领域， 常需要对音频线头进行插拔检测， 并将检测结果上报给终端产 品的控制电路以便进行下一步工作。
图 1为常用的音频线头插拔检测直驱电路示意图， 直驱电路因为省掉了音频线头隔直 电容而被广泛应用， 直驱电路的作用是利用节点 VRO提供和音频线头插孔输出端 OL和 OR 相同的直流电压。 如图 1所示， 音频线头的连接端包括左声道 L端， 右声道 R端以及接地端 G D , 音频线头插孔的连接端包括与音频线头插头相适配的左声道输出端 OL端， 右声道 输出端 OR端以及两个地端 G, 其中音频线头插孔的一个地端连接运算放大器， 另一个地端 通过电阻连接到晶体管的控制端。
当音频线头插入后， 音频线头插孔的 OL端与音频线头的左声道 L端连接， 音频线头插 孔的 OR端与音频线头的右声道 R端连接， 音频线头插孔的地端 G的电压为节点 VRO的电压 ( VROS ), 并且通过电阻 R1连接到晶体管的控制端。 节点 VRO的电压让晶体管开启， 拉低 了 GPIO ( General Purpose Input Output , 通用输入 /输出） 口的电压， 由于未插入音频线头 时 GPIO口的电压被上拉， 因此系统根据 GPIO口的电压由高变低， 可判定插入了音频线头； 反之， 音频线头拔出后， 晶体管关闭， GPIO口的电压由低变高， 可判定拔出了音频线头。 根据 GPIO口的检测信号， 判断插入音频线头时， 关闭外部扬声器， 打开音频线头连接的扬 声器； 根据检测信号判断拔出音频线头时， 打开外部扬声器， 关闭音频线头连接的扬声器。
采用上述检测电路需要额外的 GPIO口来提供检测信号， 占用了管脚 Pin资源， 并且运 算放大器需要持续开启以保证 节点 VRO的电压等于参考电压， 增大了功耗。 发明内容
本发明提供一种音频线头插拔检测直驱电路及方法， 用以解决现有技术中需要占用额 外的 GPIO口来检测音频线头插拔， 并且需要持续开启运算放大器的问题。 本发明提供一种音频线头插拔检测直驱电路， 包括： 音频线头插孔、 上拉电路、 下拉 电路、 运算放大器， 其中， 音频线头插孔的两个地端分别与上拉电路和下拉电路相连， 运 算放大器的正输入端输入参考电压， 运算放大器的负输入端和输出端分别与音频线头插孔 的两个地端连接。
优选的， 所述运算放大器的负输入端与连接上拉电阻的地端相连， 所述运算放大器的 输出端与连接下拉电路的地端相连， 并且所述下拉电路的下拉能力大于上拉电路的上拉能 力。
优选的， 所述运算放大器的负输入端与连接下拉电路的地端相连， 所述运算放大器的 输出端与连接上拉电阻的地端相连， 并且所述上拉电路的上拉能力大于下拉电路的下拉能 力。
优选的， 运算放大器的负输入端与连接上拉电阻的地端相连， 运算放大器的输出端与 连接下拉电路的地端相连， 并且所述下拉电路的下拉能力大于上拉电路的上拉能力； 当检 测到运算放大器负输入端的电压为高电压信号， 判断音频线头插入， 检测到运算放大器负 输入端的电压为低电压信号， 判断音频线头拔出。
优选的， 运算放大器的负输入端与连接下拉电路的地端相连， 运算放大器的输出端与 连接上拉电阻的地端相连， 并且所述上拉电路的上拉能力大于下拉电路的下拉能力； 当检 测到运算放大器的负输入端的电压为低电压信号， 判断音频线头插入， 检测到运算放大器 的负输入端的电压为高电压信号， 判断音频线头拔出。
所述上拉电路包括电源和电阻， 且电阻的第一端连接电源， 电阻的第二端连接音频线 头插孔的一个地端。
所述上拉电路包括电源和 MOS管， 且 MOS管的源端接电源， 漏端接音频线头插孔的 一个地端。
所述下拉电路包含电阻， 且电阻的第一端接地， 电阻的第二端连接音频线头插孔的一 个地端。
所述下拉电路包含 MOS管，且 MOS管的源端接地，漏端接音频线头插孔的一个地端。 一种音频线头插拔检测方法， 应用于音频线头插拔检测直驱电路中， 所述音频线头插 拔检测直驱电路包括： 音频线头插孔、 上拉电路、 下拉电路、 运算放大器， 其中， 音频线 头插孔的两个地端分别与上拉电路和下拉电路相连， 运算放大器的正输入端输入参考电 压， 运算放大器的负输入端和输出端分别与音频线头插孔的两个地端连接； 包括：
检测运算放大器负输入端的电压；
根据检测出的电压， 确定音频线头的插拔状态。 优选的， 运算放大器的负输入端与连接上拉电阻的地端相连， 运算放大器的输出端与 连接下拉电路的地端相连， 并且所述下拉电路的下拉能力大于上拉电路的上拉能力； 当检 测到运算放大器负输入端的电压为高电压信号， 判断音频线头插入， 检测到运算放大器负 输入端的电压为低电压信号， 判断音频线头拔出。
运算放大器的负输入端与连接下拉电路的地端相连， 运算放大器的输出端与连接上拉 电路的地端相连， 并且所述上拉电路的上拉能力大于下拉电路的下拉能力； 当检测到运算 放大器的负输入端的电压为低电压信号， 判断音频线头插入， 检测到运算放大器的负输入 端的电压为高电压信号， 判断音频线头拔出。
本发明中， 运算放大器可以是开启的， 也可以是关闭的， 不影响检测结果。
本发明提供的音频线头插拔检测直驱电路与方法简单可靠， 不需要占用额外的 GPIO 口即可进行检测， 节约了 Pin资源； 并且运算放大器是否开启不影响检测结果的正确性， 因此可以减少功耗， 另外由于本发明提供的检测直驱电路采用的元器件数量减少， 节约了 PCB面积并且降低了成本。 附图说明
图 1为现有技术中音频线头插拔检测直驱电路原理图；
图 2为本发明实施例所述的音频线头插拔检测方法流程图；
图 3为本发明实施例所述的一种音频线头插拔检测直驱电路原理图；
图 4为图 3所示的电路图对应的音频线头插拔检测关系图；
图 5为本发明实施例所述的另一种音频线头插拔检测直驱电路原理图；
图 6为图 5所示的电路图对应的音频线头插拔检测关系图。 具体实施方式
针对现有技术中需要占用额外的 GPIO 口来检测音频线头的插拔， 并且需要持续开启 运算放大器的问题， 本发明提供一种音频线头插拔检测直驱电路， 包括： 音频线头插孔、 上拉电路、 下拉电路、 运算放大器， 其中， 音频线头插孔的两个地端分别与上拉电路和下 拉电路相连， 运算放大器的正输入端输入参考电压， 运算放大器的负输入端和输出端分别 与音频线头插孔的两个地端连接， 由于两个地端分别与上拉电路和下拉电路相连， 运算放 大器的负输入端和输出端连接上拉电路和下拉电路。 即运算放大器负输入端与连接上拉电 阻的地端相连， 输出端与连接下拉电路的地端相连； 或者， 运算放大器的负输入端与连接 下拉电路的地端相连， 输出端与连接上拉电阻的地端相连。 作为一种具体连接方式， 运算放大器的负输入端与连接上拉电阻的地端相连， 即所述 上拉电路与运算放大器的负输入端相连， 运算放大器的输出端与连接下拉电路的地端相 连， 即所述下拉电路与运算放大器的输出端相连， 并且所述下拉电路的下拉能力大于上拉 电路的上拉能力。
作为另一种具体连接方式， 运算放大器的负输入端与连接下拉电路的地端相连， 即所 述下拉电路与运算放大器的负输入端相连， 运算放大器的输出端与连接上拉电阻的地端相 连， 即所述上拉电路与运算放大器的输出端相连， 并且所述上拉电路的上拉能力大于下拉 电路的下拉能力。
具体的， 所述上拉电路可以包括电源和电阻， 且电阻的第一端连接电源， 电阻的第二 端连接音频线头插孔的一个地端， 由于该地端连接运算放大器的输出端或负输入端， 因此 电阻的第二端会连接运算放大器的输出端或负输入端。
具体的， 所述上拉电路还可以包括电源和 MOS管， 且 MOS管的源端接电源， 漏端接 音频线头插孔的一个地端， 由于该地端连接运算放大器的输出端或负输入端， 因此漏端会 接运算放大器的输出端或负输入端。
具体的， 所述下拉电路中可以包含电阻， 且电阻的第一端接地， 电阻的第二端连接音 频线头插孔的的一个地端， 由于该地端连接运算放大器的负输入端或输出端， 因此电阻的 第二端会连接运算放大器的负输入端或输出端。
具体的， 所述下拉电路中包含 MOS管， 且 MOS管的源端接地， 漏端接音频线头插孔 的一个地端， 由于该地端连接运算放大器的负输入端或输出端， 因此漏端会接运算放大器 的输出端或负输入端。
需要说明的是， 上拉电阻中电阻的第二端或 MOS管的漏端连接的地端， 与下拉电阻 中电阻的第二端或 MOS管的漏端连接的地端为不同的地端。
本发明还提供一种利用上述检测直驱电路进行音频线头插拔检测的方法，如图 2所示， 该方法包括：
步骤 201 : 检测运算放大器负输入端的电压；
步骤 202: 根据检测出的电压， 确定音频线头的插拔状态。
作为第一种检测方法， 上拉电路与运算放大器的负输入端相连， 下拉电路与运算放大 器的输出端相连， 并且所述下拉电路的下拉能力大于上拉电路的上拉能力； 当检测到运算 放大器负输入端的电压为高电压信号， 判断音频线头插入， 检测到运算放大器负输入端的 电压为低电压信号， 判断音频线头拔出。
作为第二种检测方法， 下拉电路与运算放大器的负输入端相连， 上拉电路与运算放大 器的输出端相连， 并且所述上拉电路的上拉能力大于下拉电路的下拉能力； 当检测到运算 放大器的负输入端的电压为低电压信号， 判断音频线头插入， 检测到运算放大器的负输入 端的电压为高电压信号， 判断音频线头拔出。
本实施例所述的高电压信号， 具体为电压值大于设定第一阈值的电压信号， 本实施例 所述的低电压信号， 具体为电压值小于设定第二阈值的电压信号。 优选地， 设定第一阈值 不小于设定第二阈值。 进一步优选地， 设定第一阈值大于设定第二阈值。 并且， 可以根据 上拉电阻和下拉电阻的连接情况进行具体设定。
本发明提供的音频线头插拔检测直驱电路及方法中所述的音频线头可以为耳机插头， 或者其他的音频线头， 比如线路输入（ Line in )。 下面结合附图对本发明的具体实施例进行 说明。
作为本发明提供的第一实施例，如图 3所示为一种音频线头插拔检测直驱电路原理图， 包括： 音频线头插孔、 上拉电路、 下拉电路、 运算放大器， 其中， 音频线头插孔的两个地 端分别与上拉电路和下拉电路相连， 其中可以将一个地端称为第一地端， 将另一个地端称 为第二地端， VROS为音频线头插孔与上拉电路连接的地端的电压， 运算放大器的正输入 端输入的电压为参考电压， 其输出端与连接下拉电阻的地端连接， 即运算放大器的输出端 会连接下拉电路， 所述下拉电路的下拉能力大于上拉电路的上拉能力。
具体的， 所述上拉电路中采用的上拉元器件可以是电阻， 也可以是 MOS管等， 本实 施例中采用电阻 R3， R3的一端与电源 VCC相连， R3的另一端连接音频线头插孔的第一 地端以及运算放大器的负输入端。
具体的， 所述下拉电路采用的下拉元器件可以是电阻， 也可以是 MOS管等， 本实施 例中采用电阻 R4, R4的一端接地， R4的另一端与音频线头插孔的第二地端以及运算放大 器的输出端相连， 并且 R4>R3。
当音频线头插入后， 音频线头的左声道 L端与音频线头插孔的 OL端相连， 音频线头 的右声道 R端与音频线头插孔的 OR端相连， 音频线头的 GND端与音频线头插孔的地端 相连， 因此， 音频线头插入后， VROS从高变低， 当音频线头拔出时， VROS由低变高， 由此可以根据 VROS的电压变化来检测音频线头插入拔出。
图 4为图 3所示电路对应的音频线头插拔检测关系图。
参见图 4所示， 本实施例检测到音频线头插拔的具体过程如下：
步骤 401 : 检测 VROS, 如果检测到 VROS为高电平， 音频插孔内未插有音频线头； 如果检测到 VROS为低电平， 音频插孔内插有音频线头； 执行步骤 403;
步骤 402: 继续检测 VROS , 当检测到 VROS由高电平变为低电平时， 则判定音频线 头插入， 结束；
步骤 403 : 继续检测 VROS , 当检测到 VROS 由低电平变为高电平时， 则判定音频线 头拔出， 结束。
图 4所示实施例中， VROS为高电平， 确定音频线头插孔中没有插入音频线头时， 当 出现以下情况时确定音频线头插入音频线头插孔：
( 1 ) 当运算放大器关闭，由于上下拉电阻的作用， VROS被拉低，系统可根据 VROS 由高电平变成低电平， 判定插入了音频线头。
( 2 ) 当运算放大器开启， 使得节点 VRO 的电压为参考电压， 当音频线头插入后 VROS也为参考电压， 由于参考电压远小于未插入音频线头时的 VROS , 故可 根据 VROS由高变低的变化， 判定插入了音频线头。
无论产生 节点 VRO电压的运算放大器是否开启， VROS被上拉，都可以根据 VROS 的电压由低变高判定拔出了音频线头。
作为本发明提供的第二实施例，如图 5所示为一种音频线头插拔检测直驱电路原理图， 包括： 音频线头插孔、 上拉电路、 下拉电路、 运算放大器， 其中， 音频线头插孔的两个地 端分别与上拉电路和下拉电路相连， 所述运算放大器的负输入端与下拉电路相连， 其正输 入端输入参考电压 VR, 其输出端与连接上拉的地端连接， 即运算放大器的输出端会与上 拉电路相连， 所述上拉电路的上拉能力大于下拉电路的下拉能力。
具体的， 所述下拉电路可以是下拉元器件接地， 所述下拉元器件可以是电阻， 也可以 是 MOS管等， 本实施例中采用电阻 R5 , R5的一端接地， R5的另一端与运算放大器的负 输入端及音频线头插孔的第一地端相连。
具体的， 所述上拉电路可以是上拉元器件与电源 VCC相连， 所述上拉元器件可以是 电阻， 也可以是 MOS管等， 本实施例中采用电阻 R6 , R6的一端与电源 VCC相连， R6 的另一端与音频线头插孔的第二地端及运算放大器的输出端相连， 并且 R6>R5。
当音频线头插入后， 音频线头的左声道 L与音频线头插孔的 OL端相连， 音频线头插 头的右声道 R与音频线头插孔的 OR端相连， 音频线头的接地端 GND与音频线头插孔的 G端相连。
图 6为图 5所示电路对应的音频线头插拔检测关系图。
参见图 6所示， 本实施例检测到音频线头插入的具体过程如下：
步骤 601 : 检测 VROS , 如果 VROS为高电平， 则确定音频插孔内插有音频线头， 执 行步骤 602 , 如果 VROS为低电平， 音频插孔内未插有音频线头； 执行步骤 603 ;
步骤 602: 继续检测 VROS , 当检测到 VROS由高电平变为低电平时， 则判定音频线 头拔出， 结束；
步骤 603 : 继续检测 VROS, 当检测到 VROS 由低电平变为高电平时， 则判定音频线 头插入， 结束。
图 6所示实施例中， VROS为低电平， 音频线头插孔中没有插入音频线头时， 当出现 以下情况时确定音频线头插入音频线头插孔：
( 1 ) 当运算放大器关闭， VROS被拉高， 系统可根据 VROS由低电平变成高的变 化， 判定插入了音频线头。
( 2 ) 当运算放大器开启， 使得节点 VRO的电压等于参考电压， 故当音频线头插入 后 VROS 为参考电压， 远大于未插入音频线头时的电压， 因此可根据 VROS 由氏变高的变化， 判定插入了音频线头。
同理， 无论其中的运算放大器是否开启， 由于运算放大器的负输入端和运算放大器的 输出端之间的连接被断开， 因此， VROS的电压被下拉， 根据 VROS的电压由高变低判定 拔出了音频线头。
本发明提供的音频线头插拔检测直驱电路与检测方法简单可靠， 不需要占用额外的 GPIO口即可进行检测， 节约了 Pin资源； 并且产生节点 VRO的电压的运算放大器是否开 启不影响检测结果的正确性， 因此可以减少功耗， 另外由于本发明提供的检测直驱电路采 用的元器件数量减少， 节约了 PCB面积并且降低了成本。
显然， 本领域的技术人员可以对本发明进行各种改动和变型而不脱离本发明的精神和 范围。这样，倘若本发明的这些修改和变型属于本发明权利要求及其等同技术的范围之内， 则本发明也意图包含这些改动和变型在内。

Claims

权 利 要 求
1、 一种音频线头插拔检测直驱电路， 其特征在于， 包括： 音频线头插孔、 上拉电路、 下拉电路、运算放大器， 其中， 音频线头插孔的两个地端分别与上拉电路和下拉电路相连， 运算放大器的正输入端输入参考电压， 运算放大器的负输入端和输出端分别与音频线头插 孔的两个地端连接。
2、 如权利要求 1 所述的检测直驱电路， 其特征在于， 所述运算放大器的负输入端与 连接上拉电阻的地端相连， 所述运算放大器的输出端与连接下拉电路的地端相连， 并且所 述下拉电路的下拉能力大于上拉电路的上拉能力。
3、 如权利要求 1 所述的检测直驱电路， 其特征在于， 所述运算放大器的负输入端与 连接下拉电路的地端相连， 所述运算放大器的输出端与连接上拉电阻的地端相连， 并且所 述上拉电路的上拉能力大于下拉电路的下拉能力。
4、 如权利要求 1~3 任意一项所述的检测直驱电路， 其特征在于， 所述上拉电路包括 电源和电阻， 且电阻的第一端连接电源， 电阻的第二端连接音频线头插孔的一个地端。
5、 如权利要求 1~3 任意一项所述的检测直驱电路， 其特征在于， 所述上拉电路包括 电源和 MOS管， 且 MOS管的源端接电源， 漏端接音频线头插孔的一个地端。
6、 如权利要求 1~3 任意一项所述的检测直驱电路， 其特征在于， 所述下拉电路包含 电阻， 且电阻的第一端接地， 电阻的第二端连接音频线头插孔的一个地端。
7、 如权利要求 1~3 任意一项所述的检测直驱电路， 其特征在于， 所述下拉电路包含 MOS管， 且 MOS管的源端接地， 漏端接音频线头插孔的一个地端。
8、 一种音频线头插拔检测方法， 应用于音频线头插拔检测直驱电路中， 所述音频线 头插拔检测直驱电路包括： 音频线头插孔、 上拉电路、 下拉电路、 运算放大器， 其中， 音 频线头插孔的两个地端分别与上拉电路和下拉电路相连， 运算放大器的正输入端输入参考 电压，运算放大器的负输入端和输出端分别与音频线头插孔的两个地端连接； 其特征在于， 该方法包括：
检测运算放大器负输入端的电压；
根据检测出的电压， 确定音频线头的插拔状态。
9、 如权利要求 8 所述的方法， 其特征在于， 运算放大器的负输入端与连接上拉电阻 的地端相连， 运算放大器的输出端与连接下拉电路的地端相连， 并且所述下拉电路的下拉 能力大于上拉电路的上拉能力； 当检测到运算放大器负输入端的电压为高电压信号， 判断 音频线头插入， 检测到运算放大器负输入端的电压为低电压信号， 判断音频线头拔出。
10、 如权利要求 8所述的方法， 其特征在于， 运算放大器的负输入端与连接下拉电路 的地端相连， 运算放大器的输出端与连接上拉电阻的地端相连， 并且所述上拉电路的上拉 能力大于下拉电路的下拉能力； 当检测到运算放大器的负输入端的电压为低电压信号， 判 断音频线头插入，检测到运算放大器的负输入端的电压为高电压信号，判断音频线头拔出。
PCT/CN2012/076477 2011-06-23 2012-06-05 一种音频线头插拔检测直驱电路及方法 WO2012174986A1 (zh)

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