Shutdown POP sound preventing circuit on computer mainboard

Abstract

The utility model relates to a shutdown POP sound preventing circuit on a computer mainboard. The circuit is used for being electrically connected with a horn connector (JMONO1) on a computer mainboard and comprises a first NMOS transistor (Q1), a grid electrode of the first NMOS transistor (Q1) is electrically connected with a PCIE reset signal (PCIERST) on the computer mainboard, a drain electrode of the first NMOS transistor (Q1) is electrically connected with a standby power supply on the mainboard, and a source electrode of the first NMOS transistor (Q1) is grounded; the grid electrode of the second NMOS transistor (Q2) and the grid electrode of the third NMOS transistor (Q3) are electrically connected with the drain electrode of the first NMOS transistor (Q1), the source electrode of the second NMOS transistor (Q2) is electrically connected with the source electrode of the third NMOS transistor (Q3), the drain electrode of the second NMOS transistor (Q2) is electrically connected to the signal output pin, and the drain electrode of the third NMOS transistor (Q3) is grounded. According to the shutdown POP sound preventing circuit on the computer mainboard, residual current on a loudspeaker circuit is firstly discharged to the ground through the additional circuit in the shutdown process of the mainboard, the current is prevented from flowing to a loudspeaker, and POP sound is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic computers, and particularly relates to a circuit for preventing POP sound during shutdown on a computer motherboard. Background Art

[0002] POP sound refers to the popping sound generated by a speaker due to the transient impact brought about by various operations such as power-on and power-off of audio devices.

[0003] Whether on a desktop computer or a laptop motherboard, for the audio chip used in the audio drive circuit that drives the speaker to emit sound, whether it has a power amplifier or not, due to the presence of capacitors inside the audio chip and in the circuit, when power is lost, it will inevitably cause the speaker connected to the computer motherboard to produce POP sound.

[0004] Therefore, it is urgent to develop a circuit that can solve the problem of the speaker producing POP sound when the computer motherboard shuts down. Summary of the Invention

[0005] Therefore, the purpose of the utility model is to provide a circuit for preventing POP sound during shutdown on a computer motherboard to solve the problem of the speaker producing POP sound when the computer motherboard shuts down.

[0006] To achieve the above purpose, the utility model provides a circuit for preventing POP sound during shutdown on a computer motherboard, which is used for electrically connecting a speaker connector on the computer motherboard. The signal output pin of the speaker connector is electrically connected to the speaker signal output by the audio drive circuit on the computer motherboard. It is characterized in that it includes: a first NMOS transistor, a second NMOS transistor, and a third NMOS transistor; the gate of the first NMOS transistor is electrically connected to the PCIE reset signal on the computer motherboard, the drain is electrically connected to the standby power supply on the motherboard, and the source is grounded; the gates of the second NMOS transistor and the third NMOS transistor are electrically connected to the drain of the first NMOS transistor, the sources of the second NMOS transistor and the third NMOS transistor are electrically connected, the drain of the second NMOS transistor is electrically connected to the signal output pin, and the drain of the third NMOS transistor is grounded.

[0007] Among them, the models of the first NMOS transistor, the second NMOS transistor, and the third NMOS transistor are LBSS139WT1G.

[0008] Among them, the standby power supply is a 5V standby power supply.

[0009] Among them, the drain of the first NMOS transistor is electrically connected to the standby power supply on the motherboard via a first resistor.

[0010] Among them, the resistance value of the first resistor is 10K ohms.

[0011] Among them, the model of the speaker connector is SWF-25402P.

[0012] In summary, for the anti-shutdown POP sound circuit on the computer motherboard of the present utility model, through an external circuit, during the motherboard shutdown process, the residual current on the speaker circuit is first discharged to the ground, preventing the current from flowing to the speaker and avoiding the occurrence of POP sound. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The following will, with reference to the drawings, make the technical solutions and other beneficial effects of the present utility model obvious through a detailed description of the specific embodiments of the present utility model. In the drawings,

[0014] Figure 1 is a circuit diagram of a preferred embodiment of the anti-shutdown POP sound circuit on the computer motherboard of the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] See Figure 1 , which is a circuit diagram of a preferred embodiment of the anti-shutdown POP sound circuit on the computer motherboard of the present utility model. Figure 1 The upper part in is the newly added circuit based on the original audio drive circuit on the computer motherboard for the technical solution of the present utility model. By adding the circuit of the present utility model, during the motherboard shutdown process, the residual current on the speaker circuit can be first discharged to the ground, preventing the current from flowing to the speaker and avoiding the occurrence of POP sound. Figure 1 The lower part in shows a part of the audio drive circuit on the existing computer motherboard. The audio drive circuit / audio chip emits a speaker signal MONO_OUT, which is electrically connected to the signal output pin of the speaker connector JMONO1 to drive the speaker connected to the speaker connector JMONO1 to emit sound. After the speaker signal MONO_OUT is output, it is filtered by the capacitor C18, and the signal specifically loaded on the signal output pin of the speaker connector JMONO1 is MONO_OUT_CC.

[0016] The anti-shutdown POP sound circuit on the computer motherboard of the present utility model is used for electrically connecting the speaker connector JMONO1 on the computer motherboard. The signal output pin of the speaker connector JMONO1 is electrically connected to the speaker signal output by the audio drive circuit on the computer motherboard, and includes: a first NMOS transistor Q1, a second NMOS transistor Q2, and a third NMOS transistor Q3; the gate of the first NMOS transistor Q1 is electrically connected to the PCIE reset signal PCIE_RST on the computer motherboard, the drain is electrically connected to the standby power supply P5VSB on the motherboard, and the source is grounded; the gates of the second NMOS transistor Q2 and the third NMOS transistor Q3 are electrically connected to the drain of the first NMOS transistor Q1, the sources of the second NMOS transistor Q2 and the third NMOS transistor Q3 are electrically connected, the drain of the second NMOS transistor Q2 is electrically connected to the signal output pin, and the drain of the third NMOS transistor Q3 is grounded.

[0017] In this preferred embodiment, the models of the first NMOS transistor Q1, the second NMOS transistor Q2, and the third NMOS transistor Q3 are LBSS139WT1G; the standby power supply is a 5V standby power supply; the drain of the first NMOS transistor Q1 is electrically connected to the standby power supply on the motherboard via a first resistor R102, and the resistance value of the first resistor R102 is 10K ohms; the model of the speaker connector JMONO1 is SWF-25402P.

[0018] The technical solution of the present utility model adds three NMOS transistors Q1, Q2, and Q3 on the basis of the existing audio drive circuit on the computer motherboard. The conduction / turn-off of Q1 is controlled by the PCIE_RST signal on the computer motherboard. In the prior art, the PCIE_RST signal can be issued by the CPU, and because when the computer motherboard is shut down or enters the S3 state, the timing of the PCIE_RST signal being pulled low is earlier, so that the current can be effectively discharged in advance. When the computer is not in the shutdown or S3 state, the PCIE_RST signal is pulled high. When the PCIE_RST signal is pulled high, Q1 is turned on, and the drain MONO_MOS signal of Q1 is pulled low, and Q2 and Q3 are turned off. At this time, the speaker works normally. When the computer is in the shutdown or S3 state, the PCIE_RST signal is pulled low. When the PCIE_RST signal is pulled low, Q1 is turned off, the MONO_MOS signal is pulled high, and Q2 and Q3 are turned on. At this time, all the current on the speaker circuit will be conducted to the ground, preventing the current from entering the speaker and causing POP sound.

[0019] Moreover, the sources of Q2 and Q3 in this solution are connected. When the computer is normally turned on, the positive and negative of the speaker signal will not be clamped due to the parasitic diode of the MOS transistor itself, so that there is a problem with the speaker sound.

[0020] In summary, for the anti-shutdown POP sound circuit on the computer motherboard of the present utility model, through an additional circuit, during the motherboard shutdown process, the residual current on the speaker circuit is first discharged to the ground, preventing the current from flowing to the speaker and avoiding the occurrence of POP sound.

[0021] As described above, for those of ordinary skill in the art, various corresponding changes and deformations can be made according to the technical solution and technical concept of the present utility model, and all such changes and deformations shall fall within the protection scope of the appended claims of the present utility model.

Claims

1. A circuit for preventing shutdown POP sound on a computer motherboard, which is used to electrically connect to a speaker connector (JMONO1) on the computer motherboard. The signal output pin of the speaker connector (JMONO1) is electrically connected to the speaker signal output by the audio drive circuit on the computer motherboard, and is characterized in that, Including: A first NMOS transistor (Q1), a second NMOS transistor (Q2), and a third NMOS transistor (Q3); the gate of the first NMOS transistor (Q1) is electrically connected to the PCIE reset signal (PCIE_RST) on the computer motherboard, the drain is electrically connected to the standby power supply (P5VSB) on the motherboard, and the source is grounded; the gates of the second NMOS transistor (Q2) and the third NMOS transistor (Q3) are electrically connected to the drain of the first NMOS transistor (Q1), the sources of the second NMOS transistor (Q2) and the third NMOS transistor (Q3) are electrically connected, the drain of the second NMOS transistor (Q2) is electrically connected to the signal output pin, and the drain of the third NMOS transistor (Q3) is grounded.

2. The anti-shutdown POP sound circuit on the computer motherboard according to claim 1, characterized in that, The models of the first NMOS transistor (Q1), the second NMOS transistor (Q2), and the third NMOS transistor (Q3) are LBSS139WT1G.

3. The anti-shutdown POP sound circuit on the computer motherboard according to claim 1, characterized in that, The standby power supply (P5VSB) is a 5V standby power supply.

4. The anti-shutdown POP sound circuit on the computer motherboard according to claim 2, characterized in that The drain of the first NMOS transistor (Q1) is electrically connected to the standby power supply (P5VSB) on the motherboard via a first resistor (R102).

5. The anti-shutdown POP sound circuit on the computer motherboard as described in claim 4, characterized in that, The resistance value of the first resistor (R102) is 10K ohms.

6. The anti-shutdown POP sound circuit on the computer motherboard according to claim 1, characterized in that The model of the speaker connector (JMONO1) is SWF-25402P.

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