CN103037287B - Mute circuit and there is the electronic equipment of this mute circuit - Google Patents
Mute circuit and there is the electronic equipment of this mute circuit Download PDFInfo
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Abstract
The invention discloses a kind of mute circuit and there is the electronic equipment of this mute circuit, the quiet control electronic circuit that this mute circuit is made up of resistance R1 ~ R4, PNP pipe Q1, NPN pipe Q2 and NPN pipe Q3, and the audio frequency power supply power-on and power-off be made up of resistance R5 ~ R8, NPN pipe Q4 and PNP pipe Q5 control electronic circuit.At the PNP pipe Q5 utilizing audio frequency power supply electrifying to control in electronic circuit, audio frequency DAC is powered on, now control the PNP pipe Q1 conducting in quiet control electronic circuit, and make NPN pipe Q2 and NPN pipe Q3 by the left and right audio signal ground connection of this audio frequency DAC, make this audio frequency DAC be in mute state.The present invention is by less components and parts, and adopt two universal inputs to export to control mouths to control audio frequency DAC respectively to power on and quiet control electronic circuit, reaching the sonic boom eliminated and produce when amplifier in power up occurs to change to quiescent point from zero, reduce the cost of system simultaneously.
Description
Technical field
The present invention relates to technical field of circuit design, in particular, relate to a kind of mute circuit and there is the electronic equipment of this mute circuit.
Background technology
Current, TV is in the transition stage from simulated television to Digital Television, and in order to ensure the compatibility between simulated television and Digital Television, the Set Top Box that adopts converts digital television signal to analog signal more.In Set Top Box, first, digital audio after audio decoder decode, then by audio frequency DAC(digital-to-analogconverter, digital analog converter) transferred to analog signal, finally, after amplifier filter and amplification, send linear convergent rate.
Under normal circumstances, Set Top Box works in single supply, unbalanced mode, and its internal circuit need be biased in the quiescent point of a non-zero.Concrete, the audio frequency DAC in Set Top Box is biased in the position a little less than 1/2VA, and VA is the analog power voltage of audio frequency DAC, is generally 3.3V; Be biased in the quiescent point of 1/2Vcc by the output amplifier in Set Top Box, Vcc is amplifier supply voltage, is generally 12V.In order to isolate audio frequency DAC and amplifier, and quiescent points different between amplifier and upstream device input stage, also need to be coupled with electric capacity between which.
But adopt aforesaid way that circuit is set, when Set Top Box power on or lower electricity time, audio frequency DAC and amplifier output can occur from zero to quiescent point, or the transient changing from quiescent point to zero.This transient process becomes the shock pulse of the full amplitude of oscillation after capacitance, can produce very large sonic boom in power amplifier and loudspeaker.In addition, not only can there is above-mentioned transient changing powering on, in the process of lower electricity in audio frequency DAC, even if after power good, when audio frequency DAC starts work, also can due to the opening of decoder clocks, close or frequency shift generation transient changing, thus produce sonic boom.
The typical circuit for the quiet control of Set Top Box is made up of three partial circuits usually at present, as shown in Figure 1: Part I is by resistance R1, R2, R3 and NPN pipe Q1 forms, by software GPIO(general input/output port) control audio frequency DAC start time sonic boom; Part II for powering on, lower electric delay control circuit, by resistance R4, R5, electric capacity C1, C2, diode D1, D2 and PNP pipe Q2 form; Part III is the control section be connected with audio frequency LINE_OUT, is made up of resistance R6, R7 and NPN pipe Q3, Q4.
Circuit as shown in Figure 1, its process eliminating sonic boom is:
When set-top-box opening powers on, resistance R4 charges to electric capacity C1, and diode D2 charges to electric capacity C2, because electric capacity C2 rushes full fast, and electric capacity C1 charges very slow, causes PNP pipe Q2 conducting, and then making NPN pipe Q3, Q4 is conducting also, thus plays muting function;
When Set Top Box closes lower electricity, utilize diode D2 can not the principle of reverse-conducting, the electrostatic leakage on electric capacity C2 be very slow, and electric capacity C1 is discharged by resistance R4 and NPN pipe Q1, thus make PNP pipe Q2 conducting, make NPN pipe Q3, Q4 is also in conducting state, thus reaches muting function;
When Set Top Box start, before opening audio frequency DAC, MUTE_CTL is as MCU(microprocessor) general equipped at outlet port in high level, by NPN pipe Q1, resistance R3, R5 make PNP pipe Q2 conducting, thus make NPN pipe Q3, Q4 conducting, thus reach the sonic boom eliminated when audio frequency DAC starts; After audio frequency DAC opens, then MUTE_CTL is set low, return to normal mode of operation.
Although adopt circuit of the prior art can solve switching on and shutting down and audio frequency DAC opens the sonic boom brought, it is more to there are components and parts in this circuit when reaching muting function, the shortcoming that cost is high.Wherein, this circuit has shared 15 components and parts, wherein also comprises two higher 10UF electric capacity of cost and diode, and due to components and parts more, the PCB(printed circuit board that space required is larger) device is set, further increase cost.
Summary of the invention
In view of this, the object of the embodiment of the present invention is the electronic equipment providing a kind of mute circuit and have this mute circuit, more to overcome components and parts in prior art, the problem that cost is high.
For achieving the above object, the embodiment of the present invention provides following technical scheme:
A kind of mute circuit, comprising: quiet control electronic circuit and audio frequency power-on and power-off control electronic circuit;
Described quiet control electronic circuit comprises: the common port of resistance R1 and resistance R2 parallel connection controls mouth MUTE_CTL and holds with first of SOC (system on a chip) the general output and be connected; The other end ground connection of described resistance R1, the described other end of resistance R2 is connected with the base stage of PNP pipe Q1;
The emitter of described PNP pipe Q1 connects power supply, and the collector electrode of described PNP pipe Q1 is connected with the common port of resistance R3 in parallel and resistance R4;
The other end of described resistance R3 is connected with the base stage of described NPN pipe Q2; The other end of described resistance R4 is connected with the base stage of described NPN pipe Q3; The grounded emitter of described NPN pipe Q2 and NPN pipe Q3;
Collector electrode and the audio frequency of digital audio analog converter DAC of described NPN pipe Q2 export R channel AUDIO_R and hold and be connected, and collector electrode and the audio frequency of described audio frequency DAC of described NPN pipe Q3 export L channel AUDIO_L and hold and be connected;
Described audio frequency power-on and power-off control electronic circuit and comprise: the common port of resistance R5 and resistance R6 parallel connection controls mouth PWR_CTL and holds with second of SOC (system on a chip) the general output and be connected; The other end of described resistance R6 is connected with the base stage of NPN pipe Q4, and the other end of described resistance R5 is connected rear ground connection with the emitter of described NPN pipe Q4;
The collector electrode of described NPN pipe Q4 is connected with resistance R7, the other end of described resistance R7 respectively with one end of resistance R8, and the base stage of PNP pipe Q5 connects;
The other end of described resistance R8 is connected with the emitter of described PNP pipe Q5, and the collector electrode of described PNP pipe Q5 connects the power end of described audio frequency DAC.
Further, also comprise: with described quiet control electronic circuit, described audio frequency power-on and power-off control electronic circuit, and the control circuit that described SOC (system on a chip) connects respectively;
Described control circuit is on said sheets after system electrification, and the PWR_CTL end controlling described SOC (system on a chip) exports high level, powers on to described audio frequency DAC; The MUTE_CTL controlling described SOC (system on a chip) holds output low level, causes described PNP pipe Q1 conducting, to make described NPN pipe Q2 and NPN pipe Q3 by the left and right audio signal ground connection of described audio frequency DAC, makes described audio frequency DAC be in mute state.
A kind of electronic equipment, comprising: mute circuit described above, and the audio frequency DAC be connected with described mute circuit and SOC (system on a chip).
Known via above-mentioned technical scheme, compared with prior art, the embodiment of the invention discloses a kind of mute circuit and there is the electronic equipment of this mute circuit.By utilizing the quiet control electronic circuit be made up of resistance R1 ~ R4, PNP pipe Q1, NPN pipe Q2 and NPN pipe Q3 disclosed in the invention described above embodiment, and the audio frequency power supply electrifying be made up of resistance R5 ~ R8, NPN pipe Q4 and PNP pipe Q5 controls electronic circuit.The present invention is lower by above-mentioned cost, negligible amounts, take PCB surface and amass little components and parts, and adopt two GPIO to control audio frequency DAC respectively to power on and quiet control electronic circuit, while eliminating the sonic boom produced when amplifier can occur to change from zero to quiescent point in power up, realize the object reducing system cost.
Accompanying drawing explanation
In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, be briefly described to the accompanying drawing used required in embodiment or description of the prior art below, apparently, accompanying drawing in the following describes is only embodiments of the invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to the accompanying drawing provided.
Fig. 1 is the structural representation of mute circuit of the prior art;
The structural representation of Fig. 2 a kind of mute circuit disclosed in the embodiment of the present invention;
The structural representation of the quiet control electronic circuit A in Fig. 3 mute circuit disclosed in the embodiment of the present invention;
Audio frequency power-on and power-off in Fig. 4 mute circuit disclosed in the embodiment of the present invention control the structural representation of electronic circuit B;
The structural representation of Fig. 5 another kind of mute circuit disclosed in the embodiment of the present invention two;
The structural representation of Fig. 6 a kind of electronic equipment disclosed in the embodiment of the present invention.
Embodiment
For the purpose of quoting and know, the explanation of the technical term hereinafter used, write a Chinese character in simplified form or abridge and be summarized as follows:
SoC:SystemonChip, system level chip, or SOC (system on a chip);
DAC:digital-to-analogconverter, digital analog converter;
PCB:PrintedCircuitBoard, printed circuit board;
GPIO:GeneralPurposeInputOutput, universal input/output;
PNP: be common cathode, namely the N knot of two PN junctions is connected as base stage, and another two P knot makees the triode of collector and emitter respectively;
NPN: be common anode pole, namely the P knot of two NP knots is connected as base stage, and another two N knot makees the triode of collector and emitter respectively;
DVB:DigitalVideoBroadcasting, digital television broadcasting;
IPTV: IPTV;
DVD: digital versatile disc.
Below in conjunction with the accompanying drawing in the embodiment of the present invention, be clearly and completely described the technical scheme in the embodiment of the present invention, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to the scope of protection of the invention.
From background technology, mute circuit of the prior art needs when reaching muting function to utilize more components and parts, is wherein no lack of the electric capacity of the higher diode of cost and high farad, and the cost of mute circuit is increased.In addition, in the process forming this mute circuit, need the pcb board utilizing area larger to arrange above-mentioned components and parts, in the process that reality uses, this large-area pcb board will limit application scenarios or the environment of the mute circuit of the prior art of its carrying.For the problems referred to above, the following embodiment of the present invention disclose a kind of components and parts few, take PCB surface and amass little mute circuit, adopt two universal inputs/output to control mouth to this mute circuit to control the power-on and power-off of audio frequency power supply and mute circuit respectively, thus realize eliminating the sonic boom that amplifier in power up occurs produces when change from zero to quiescent point, the object of reduction mute circuit cost simultaneously.Be described in detail especially by following examples.
Embodiment one
As shown in Figure 2, disclose a kind of basic structure schematic diagram of mute circuit in this embodiment of the invention one, the mute circuit be arranged on pcb board mainly comprises: quiet control electronic circuit A and audio frequency power-on and power-off control electronic circuit B.
As shown in Figure 3, the structural representation of quiet control electronic circuit A disclosed in the embodiment of the present invention, mainly comprises: show for PNP-BEC in resistance R1, resistance R2, resistance R3, resistance R4, PNP(figure) show for NPN-BEC in pipe Q1, NPN(figure) pipe Q2 and NPN pipe Q3.
Wherein, the annexation between each parts is:
Resistance R1 is in parallel with resistance R2, and the common port of its parallel connection controls mouth MUTE_CTL and holds with first of SOC (system on a chip) SoC the general output and be connected.
The other end ground connection of described resistance R1, the described other end of resistance R2 is connected with the base stage B1 of PNP pipe Q1.The emitter E 1 of described PNP pipe Q1 connects power supply VCC1, and the collector electrode C1 of described PNP pipe Q1 is connected with the common port of resistance R3 in parallel and resistance R4.
The other end of described resistance R3 is connected with the base stage B2 of described NPN pipe Q2; The other end of described resistance R4 is connected with the base stage B3 of described NPN pipe Q3.
The emitter ground connection separately of described NPN pipe Q2 and NPN pipe Q3, i.e. emitter E 2 ground connection of described NPN pipe Q2, emitter E 3 ground connection of described NPN pipe Q3.
The described collector electrode C2 of NPN pipe Q2 and the audio frequency of audio frequency DAC export R channel AUDIO_R and hold and be connected, and collector electrode C3 and the audio frequency of described audio frequency DAC of described NPN pipe Q3 export L channel AUDIO_L and hold and be connected.
As shown in Figure 4, disclosed in the embodiment of the present invention, audio frequency power-on and power-off control the structural representation of electronic circuit B, mainly comprise: resistance R5, resistance R6, resistance R7, resistance R8, NPN pipe Q4 and PNP pipe Q5.
Wherein, the annexation between each parts is:
The common port of resistance R5 and resistance R6 parallel connection controls mouth PWR_CTL and holds with second of SOC (system on a chip) SoC the general output and be connected; The other end of described resistance R6 is connected with the base stage B4 of NPN pipe Q4, and the other end of described resistance R5 is connected rear ground connection with the emitter E 4 of described NPN pipe Q4.
The collector electrode C4 of described NPN pipe Q4 connects with resistance R7, the other end of described resistance R7 respectively with one end of resistance R8, and the base stage B5 of PNP pipe Q5 is connected.
The other end of described resistance R8 is connected with the emitter E 5 of described PNP pipe Q5, and the collector electrode C5 of described PNP pipe Q5 connects the power end VCC2 of described audio frequency DAC.
In the mute circuit disclosed in the invention described above embodiment, PWR_CTL end and MUTE_CTL end are the GPIO pin of Set Top Box SOC (system on a chip) SoC.
Mute circuit disclosed in the embodiment of the present invention only utilizes resistance, PNP pipe and NPN pipe to form, carrying out being controlled mute circuit by the GPIO port of two on SOC (system on a chip) SoC in quiet process, by above-mentioned control in mute circuit disclosed in the embodiment of the present invention, simplify the mode only doing power-on and power-off delay by software circuit.Simultaneously, disclosed in this embodiment of the present invention, mute circuit components and parts are few, the area taking pcb board is little, and adopt two GPIO to control audio frequency DAC respectively to power on and quiet control electronic circuit, while eliminating the sonic boom produced when amplifier can occur to change to quiescent point from zero in power up, also achieve and simplify the structure of mute circuit and the object of cost.
Embodiment two
As shown in Figure 5, based on above-mentioned mute circuit disclosed in the invention described above embodiment, carrying out, in the initialized process of SOC (system on a chip) SoC, also comprising a control circuit 101.This control circuit 101 and quiet control electronic circuit A, described audio frequency power-on and power-off control electronic circuit B, and described SOC (system on a chip) SoC13 connects respectively.
Based on above-mentioned mute circuit disclosed in the invention described above embodiment, carrying out in the initialized process of SOC (system on a chip) SoC, when described SOC (system on a chip) SoC powers on, this control circuit 101 controls described PWR_CTL and holds output high level, namely powers on to described audio frequency DAC.
Meanwhile, this control circuit 101 controls described MUTE_CTL and holds output low level, causes the PNP pipe Q1 conducting in described quiet control electronic circuit A.Now, the conducting due to PNP pipe Q1 causes described NPN pipe Q2 and NPN pipe Q3 by the left and right audio signal ground connection of described audio frequency DAC, thus makes described audio frequency DAC be in mute state.
It should be noted that, this control circuit 101 independent of outside SOC (system on a chip) SoC, also can be arranged at described SOC (system on a chip) SoC inner.
Based on above-mentioned control procedure, utilize PWR_CTL to hold the power-on and power-off controlling audio frequency power supply, utilize MUTE_CTL to hold and control quiet control electronic circuit.By the PNP pipe Q5 utilizing audio frequency power supply electrifying to control in electronic circuit, audio frequency DAC is powered on, control the PNP pipe Q1 conducting in quiet control electronic circuit, and make NPN pipe Q2 and NPN pipe Q3 by the left and right audio signal ground connection of this audio frequency DAC, make this audio frequency DAC be in mute state.
By above-mentioned control in mute circuit disclosed in the embodiment of the present invention, simplify the mode only doing power-on and power-off delay by software circuit.Simultaneously, disclosed in this embodiment of the present invention, mute circuit components and parts are few, the area taking pcb board is little, in the control procedure based on above-mentioned SOC (system on a chip) SoC, quiet object can not only be realized under utilizing the effect of lower-cost resistance, PNP pipe and NPN pipe, also achieve and simplify the structure of mute circuit and the object of cost.
Comprise disclosed in the invention described above embodiment: the mute circuit in the accompanying drawing 2 be made up of the quiet control electronic circuit in accompanying drawing 3 and the control of the audio frequency power-on and power-off in accompanying drawing 4 electronic circuit, it is in the process being applied to Set Top Box, its quiet process 2 to accompanying drawing 4 by reference to the accompanying drawings, is described by following example.
Example one:
System SoC is before Set Top Box powers in other words on said sheets, makes the described resistance R5 ground connection that audio frequency power-on and power-off control in electronic circuit B, makes described NPN pipe Q4 and described PNP pipe Q5 be in non-conducting state, make described audio frequency DAC be in mute state.
On the set-top box during electricity, because audio frequency power-on and power-off control the resistance R5 ground connection in electronic circuit B, cause NPN pipe Q4 and PNP pipe Q5 all can not conducting.Therefore, audio frequency power supply VCC2 is made to be in the state do not powered on.Now, amplifier can not produce from zero to the change of quiescent point, makes audio frequency DAC be in mute state thus.
Example two:
System SoC is before Set Top Box powers in other words on said sheets, make the described resistance R1 ground connection in quiet control electronic circuit A, cause described PNP pipe Q1 and be in conducting state, make described NPN pipe Q2 and NPN pipe Q3 by the left and right audio signal ground connection of described audio frequency DAC, make described audio frequency DAC quiet.
On the set-top box during electricity, due to the described resistance R1 ground connection in quiet control electronic circuit A, PNP pipe Q1 is made to be in conducting state.Now, NPN pipe Q2 and NPN pipe Q3 then respectively by the left and right audio frequency ground connection of audio frequency DAC, namely can switch to ground, thus makes the effect that audio frequency DAC reaches quiet.
In above-mentioned example one and example two, based on the structure of disclosed circuit diagram corresponding in accompanying drawing 3 and accompanying drawing 4, on the set-top box before electricity, the mode of each grounding through resistance is utilized to make triode be in the state of non-conducting or conducting, thus ensure on the set-top box electricity time, make the effect that audio frequency DAC reaches quiet.
When Set Top Box completes after the powering on of SOC (system on a chip) SoC in initialization procedure, now, by described SOC (system on a chip) SoC, first, control MUTE_CTL output low level, the control of the non-essential resistance R1 ground connection of adapter reset condition, causes described PNP pipe Q1 conducting, make described NPN pipe Q2 and NPN pipe Q3 by the left and right audio signal ground connection of described audio frequency DAC, make described audio frequency DAC be in mute state.Secondly, control PWR_CTL holds and exports high level, powers on to described audio frequency DAC.
Now, in the process that described audio frequency DAC powers on, this audio frequency DAC can produce from zero to the change of quiescent point, produces sonic boom.But, audio frequency power-on and power-off in mute circuit disclosed in the embodiment of the present invention control electronic circuit B, it is by SOC (system on a chip) SoC control MUTE_CTL output low level, the control of the non-essential resistance R1 ground connection of adapter reset condition, cause described PNP pipe Q1 conducting, make described NPN pipe Q2 and NPN pipe Q3 by the left and right audio signal ground connection of described audio frequency DAC, due to its continuous action, the sonic boom that audio frequency DAC produces can be eliminated, thus realize making described audio frequency DAC be in the object of mute state.
It should be noted that, and then Set Top Box is carried out in initialized process to audio frequency DAC, and audio frequency DAC also can produce from zero to the change of quiescent point, produces sonic boom.Same, because audio frequency power-on and power-off control the continuous action of electronic circuit B, this sonic boom also can be eliminated.
Finally, after SOC (system on a chip) SoC completes initialization to whole Set Top Box in other words, the described MUTE_CTL end that the power-on and power-off of control connection audio frequency control electronic circuit B exports high level, cause described PNP pipe Q1 and be in non-conducting state, described NPN pipe Q2 and NPN pipe Q3 is in conducting state, the left and right audio signal of described audio frequency DAC is normally exported, that is, makes described audio frequency DAC be in audio frequency NORMAL output mode.
In addition, it should be noted that, in execution any one process above-mentioned, when described SOC (system on a chip) SoC power down or power down suddenly, can cause whole Set Top Box in other words SOC (system on a chip) SoC be in reset mode, now, the low level that audio frequency power-on and power-off control the MUTE_CTL end that electronic circuit B connects can disappear, and namely SOC (system on a chip) SoC loses the control to MUTE_CTL end.Now, the resistance R1 of the ground connection in quiet control electronic circuit A can make PNP pipe Q1 conducting, make described NPN pipe Q2 and NPN pipe Q3 by the left and right audio signal ground connection of described audio frequency DAC, thus continue to realize audio frequency DAC from quiet working point to the sonic boom produced during zero change, reach the object making audio frequency DAC be in mute state.
Based in accompanying drawing 3 disclosed in the invention described above embodiment one and embodiment two and accompanying drawing 4, preferably in situation, the value that the quiet control electronic circuit illustrated and audio frequency power-on and power-off control each resistance in electronic circuit and power supply is: VCC1 is that 3V(lies prostrate), VCC2 is 12V, resistance R1 is 1.7K Ω (kilohm), resistance R2, resistance R3, resistance R4, resistance R6 are 1K Ω, and resistance R5 is 4.7K Ω, and resistance R7 and resistance R8 is 10K Ω.It should be noted that, the value of each components and parts above-mentioned is preferably situation, and the embodiment of the present invention is not limited in this, can replace according to specific circumstances.
In mute circuit disclosed in the invention described above embodiment, by the mode that soft or hard combines, and in the process of the mutual replacement of software control and hardware controls, realize effectively powering on to Set Top Box, the sonic boom produced in the links such as audio frequency DAC initialization and Set Top Box power down carries out the object eliminated, simultaneously, the structure of mute circuit disclosed in the invention described above embodiment, its components and parts are few, therefore the area taking PCB also reduces relatively, its components and parts used are all simple resistance and triode simultaneously, thus the holistic cost of mute circuit disclosed in the embodiment of the present invention is also reduced.
In addition, from the angle of practical application, current most Set Top Box requirements are standby is less than 1W, for such Set Top Box, audio frequency power-on and power-off disclosed in the embodiment of the present invention control electronic circuit except can as a part for mute circuit, also can simultaneously as a part for the stand-by circuit of this Set Top Box.
Embodiment three
Based on a kind of mute circuit disclosed in the invention described above embodiment, the embodiment of the invention also discloses a kind of electronic equipment, as shown in Figure 6, this electronic equipment comprises the above-mentioned mute circuit 11 be made up of accompanying drawing 3 and accompanying drawing 4, and the audio frequency DAC12 be connected with described mute circuit 11 and SOC (system on a chip) SoC13.
By the invention described above embodiment one and embodiment two to the structure of this mute circuit 11, and carry out the description of process of quiet control, this electronic equipment can be specially Set Top Box, its application carrying out quiet control in Set Top Box by reference to the accompanying drawings 3 and accompanying drawing 4, the specific works principle of this mute circuit is:
First, on the set-top box during electricity, the audio frequency power-on and power-off in Fig. 4 control the resistance R5 ground connection in electronic circuit, and NPN pipe Q4 and described PNP pipe Q5 all not conductings, audio frequency power supply VCC2 is in non-power-up state.Now, audio frequency DAC can not occur from zero to the change of quiescent point.And the quiet control sub-circuit portion in Fig. 3, because of resistance R1 ground connection, PNP pipe Q1 is in conducting state, makes described NPN pipe Q2 and NPN pipe Q3 the left and right audio signal of described audio frequency DAC be switched to ground, thus reaches the muting function of audio frequency DAC.
Secondly, after Set Top Box completes and powers on, in quiet control electronic circuit, SOC (system on a chip) SoC controls MUTE_CTL holds output low level, the control of the non-essential resistance R1 ground connection of adapter script.Then same high by SOC (system on a chip) SoC control PWR_CTL output, control electronic circuit by audio frequency power-on and power-off to power on to audio frequency DAC, and the sonic boom that this audio frequency DAC produces from zero to the change of quiescent point in power up, because the MUTE_CTL in quiet control electronic circuit holds output low level continuous action, eliminate the sonic boom that amplifier produces.
Secondly, Set Top Box performs initialization audio frequency DAC, and this audio frequency DAC is in initialization procedure, and output can occur, from zero to quiescent point change, to produce sonic boom.Same, due to the continuous action of quiet control electronic circuit, this sonic boom also can be eliminated.
Finally, wait whole Set Top Box, audio frequency DAC and SOC (system on a chip) SoC, after namely whole system completes initialization, now controlled by SOC (system on a chip) SoC, MUTE_CTL end is set high, removes quiet control, make audio frequency DAC be in audio frequency NORMAL output mode.
In addition, in execution any one process above-mentioned, during Set Top Box power down, because system power failure causes whole system to be in reset mode, the control connecting the MUTE_CTL end of quiet control electronic circuit disappears.Now, be returned to the quiet control of earth resistance R1, and earth resistance R1 can make PNP pipe Q1 conducting, the sonic boom owing to producing when audio frequency DAC and amplifier change to zero from quiescent point can be eliminated based on this quiet control electronic circuit.
Electronic equipment disclosed in the embodiment of the present invention is except can be except Set Top Box, can also be specially: digital television broadcasting DVB Set Top Box or interactive internet protocol television (IPTV) set top box (STB) or digital versatile disc DVD player, or network player, in the process performing quiet control, its operation principle is same or similar.But the electronic equipment that the embodiment of the present invention is applied for the mute circuit of the disclosure is not limited in this.
In sum, embodiment of the present invention mute circuit only utilizes resistance, PNP pipe and NPN pipe to form, components and parts are few, the area taking pcb board is little, and adopt two GPIO to control audio frequency DAC respectively to power on and quiet control electronic circuit, while eliminating the sonic boom produced when amplifier can occur to change to quiescent point from zero in power up, also achieve and simplify the structure of mute circuit and the object of cost.Open components and parts are few, take PCB surface amasss little mute circuit, this mute circuit adopts two GPIO to control mouths and controls the power-on and power-off of audio frequency power supply and mute circuit respectively, thus realize eliminating the sonic boom that power up sound intermediate frequency DAC and amplifier produce produces when change from zero to quiescent point, the object of reduction mute circuit cost simultaneously.
In this specification, each embodiment adopts the mode of going forward one by one to describe, and what each embodiment stressed is the difference with other embodiments, between each embodiment identical similar portion mutually see.For device disclosed in embodiment or system, because it corresponds to the method disclosed in Example, so description is fairly simple, relevant part illustrates see method part.
The software module that the method described in conjunction with embodiment disclosed herein or the step of algorithm can directly use hardware, processor to perform, or the combination of the two is implemented.Software module can be placed in the storage medium of other form any known in random asccess memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable ROM, register, hard disk, moveable magnetic disc, CD-ROM or technical field.
To the above-mentioned explanation of the disclosed embodiments, professional and technical personnel in the field are realized or uses the present invention.To be apparent for those skilled in the art to the multiple amendment of these embodiments, General Principle as defined herein can without departing from the spirit or scope of the present invention, realize in other embodiments.Therefore, the present invention can not be restricted to these embodiments shown in this article, but will meet the widest scope consistent with principle disclosed herein and features of novelty.
Claims (10)
1. a mute circuit, is characterized in that, comprising: quiet control electronic circuit and audio frequency power-on and power-off control electronic circuit;
Described quiet control electronic circuit comprises: the common port of resistance R1 and resistance R2 parallel connection controls mouth MUTE_CTL and holds with first of SOC (system on a chip) the general output and be connected; The other end ground connection of described resistance R1, the described other end of resistance R2 is connected with the base stage of PNP pipe Q1;
The emitter of described PNP pipe Q1 connects power supply, and the collector electrode of described PNP pipe Q1 is connected with the common port of resistance R3 in parallel and resistance R4;
The other end of described resistance R3 is connected with the base stage of NPN pipe Q2; The other end of described resistance R4 is connected with the base stage of NPN pipe Q3; The grounded emitter of described NPN pipe Q2 and NPN pipe Q3;
Collector electrode and the audio frequency of digital audio analog converter DAC of described NPN pipe Q2 export R channel AUDIO_R and hold and be connected, and collector electrode and the audio frequency of described audio frequency DAC of described NPN pipe Q3 export L channel AUDIO_L and hold and be connected;
Described audio frequency power-on and power-off control electronic circuit and comprise: the common port of resistance R5 and resistance R6 parallel connection controls mouth PWR_CTL and holds with second of SOC (system on a chip) the general output and be connected; The other end of described resistance R6 is connected with the base stage of NPN pipe Q4, and the other end of described resistance R5 is connected rear ground connection with the emitter of described NPN pipe Q4;
The collector electrode of described NPN pipe Q4 is connected with resistance R7, the other end of described resistance R7 respectively with one end of resistance R8, and the base stage of PNP pipe Q5 connects;
The other end of described resistance R8 is connected with the emitter of described PNP pipe Q5, and the collector electrode of described PNP pipe Q5 connects the power end of described audio frequency DAC, and the emitter of described PNP pipe Q5 connects power supply.
2. circuit according to claim 1, is characterized in that, also comprises: with described quiet control electronic circuit, and described audio frequency power-on and power-off control electronic circuit, and the control circuit that described SOC (system on a chip) connects respectively;
Described control circuit is on said sheets after system electrification, and the PWR_CTL end controlling described SOC (system on a chip) exports high level, powers on to described audio frequency DAC; The MUTE_CTL controlling described SOC (system on a chip) holds output low level, causes described PNP pipe Q1 conducting, to make described NPN pipe Q2 and NPN pipe Q3 by the left and right audio signal ground connection of described audio frequency DAC, makes described audio frequency DAC be in mute state.
3. circuit according to claim 2, is characterized in that, on said sheets before system electrification, comprising:
Described audio frequency power-on and power-off control the described resistance R5 ground connection in electronic circuit, make described NPN pipe Q4 and described PNP pipe Q5 be in non-conducting state, make described audio frequency DAC be in mute state.
4. circuit according to claim 2, is characterized in that, on said sheets before system electrification, comprising:
Described resistance R1 ground connection in described quiet control electronic circuit, causes described PNP pipe Q1 and is in conducting state, makes described NPN pipe Q2 and NPN pipe Q3 by the left and right audio signal ground connection of described audio frequency DAC, makes described audio frequency DAC quiet.
5. circuit according to claim 2, is characterized in that, also comprises:
After system completes power up on said sheets, described control circuit controls described MUTE_CTL and holds output high level, cause described PNP pipe Q1 and be in non-conducting state, described NPN pipe Q2 and NPN pipe Q3 is in non-conducting state, and the left and right audio signal of described audio frequency DAC is normally exported.
6. according to the circuit in Claims 1 to 5 described in any one, it is characterized in that, also comprise:
When described SOC (system on a chip) power down, the described resistance R1 ground connection in described quiet control electronic circuit, causes described PNP pipe Q1 and is in conducting state, makes described NPN pipe Q2 and NPN pipe Q3 by the left and right audio signal ground connection of described audio frequency DAC;
Described audio frequency power-on and power-off control the described resistance R5 ground connection in electronic circuit, make described NPN pipe Q4 and described PNP pipe Q5 be in non-conducting state, make described audio frequency DAC be in mute state.
7. an electronic equipment, is characterized in that, comprising: mute circuit described in any one in claim 1 ~ 6, and the audio frequency DAC be connected with described mute circuit and SOC (system on a chip).
8. electronic equipment according to claim 7, is characterized in that, described electronic equipment comprises: digital television broadcasting DVB Set Top Box; Or, interactive internet protocol television (IPTV) set top box (STB).
9. electronic equipment according to claim 7, is characterized in that, described electronic equipment comprises: digital versatile disc DVD player.
10. electronic equipment according to claim 7, is characterized in that, described electronic equipment comprises: network player.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210486770.2A CN103037287B (en) | 2012-11-26 | 2012-11-26 | Mute circuit and there is the electronic equipment of this mute circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210486770.2A CN103037287B (en) | 2012-11-26 | 2012-11-26 | Mute circuit and there is the electronic equipment of this mute circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103037287A CN103037287A (en) | 2013-04-10 |
| CN103037287B true CN103037287B (en) | 2015-12-02 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201210486770.2A Expired - Fee Related CN103037287B (en) | 2012-11-26 | 2012-11-26 | Mute circuit and there is the electronic equipment of this mute circuit |
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Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105357610A (en) * | 2015-11-16 | 2016-02-24 | 宁波音王电声股份有限公司 | Microphone |
| CN107426648A (en) * | 2016-05-24 | 2017-12-01 | 华为技术有限公司 | A kind of mute circuit and electronic equipment |
| CN110730399A (en) * | 2018-07-17 | 2020-01-24 | 青岛海信电器股份有限公司 | Display device earphone control circuit and display device |
| CN110677778B (en) * | 2019-10-10 | 2020-12-18 | 深圳市九洲电器有限公司 | Audio mute control circuit and electronic equipment |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102082983B (en) * | 2009-11-26 | 2013-11-06 | 鸿富锦精密工业（深圳）有限公司 | Crackle suppression circuit |
| CN101945316B (en) * | 2010-08-11 | 2013-09-25 | 福建星网视易信息***有限公司 | Startup and shutdown automatic mute circuit of embedded type audio-video equipment |
| CN102098011B (en) * | 2010-12-28 | 2013-11-06 | 东莞常禾电子有限公司 | Circuit for rapidly controlling mute of audio power amplifier |
| CN102572562A (en) * | 2011-12-30 | 2012-07-11 | 福建星网视易信息***有限公司 | Muting circuit of network-version STB (set top box) |
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| CN103037287A (en) | 2013-04-10 |
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