CN200953602Y - Audio frequency power amplifying silent circuit and television with the said silent circuit - Google Patents
Audio frequency power amplifying silent circuit and television with the said silent circuit Download PDFInfo
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- CN200953602Y CN200953602Y CN 200620011167 CN200620011167U CN200953602Y CN 200953602 Y CN200953602 Y CN 200953602Y CN 200620011167 CN200620011167 CN 200620011167 CN 200620011167 U CN200620011167 U CN 200620011167U CN 200953602 Y CN200953602 Y CN 200953602Y
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Abstract
The utility model discloses an audio frequency silencing circuit and a TV set with the silencing circuit, which is characterized in that: a benchmark voltage source tube foot of an audio power amplification chip can be grounded via an energy storage capacitor on the one side and grounded via an optional connection of a switching component; the control end of the switching component is connected to the output end of the control signal of the processor. The utility model, by connecting an energy storage capacitor and a switching control circuit on the benchmark voltage source tube foot of the audio power amplification chip, is able to ensure that when the equipment is turned on or switch from the standby status to the operational status, the DC bias voltage can be prevented, so as to stop the audio output of the power amplification chip and realize the silencing during logging on. When the electric equipment is shut down, the energy storage capacitor discharges and the bias voltage gradually reduces to zero, thus reducing the high frequency component resulted from the instant change of the bias voltage in the power amplification chip, inhibiting the ''bursting sound'' during the turning on and off of the equipment and realizing perfect silencing of the equipment during the logging on and shutdown.
Description
Technical field
The utility model belongs to the mute circuit technical field, specifically, relates to a kind of inhibition electric equipment produces " sudden and violent sound " when switching on and shutting down muting control circuit.
Background technology
General audio frequency power amplifier device powers on and cuts off the power supply moment at electric equipment, and power on stable after, the transient impact that various operations bring can produce " sudden and violent sound " phenomenon, i.e. noise.And general audio frequency power amplifier device all has quiet and idle function, solve " sudden and violent sound " phenomenon method commonly used and be the quiet pin of when the electric equipment switching on and shutting down, directly giving power discharging device or standby pin and add and put one and enable level, make power amplifier be in quiet or holding state; Perhaps make the audio frequency input pin receive ground, reach the quiet purpose of switching on and shutting down by switch.But, rely on the effect of said method elimination power amplifier " sudden and violent sound " often very undesirable merely, be difficult to fundamentally thoroughly solve " sudden and violent sound " problem.
Summary of the invention
The utility model connects the unfavorable problem of quiet effect that muting control circuit produced in order to solve available technology adopting on the quiet pin of power amplifier chip or standby pin or audio frequency input pin, a kind of audio frequency power amplifier mute circuit of new structure is provided, pass through simple circuit configuration, the high-frequency harmonic component that has effectively suppressed generation " sudden and violent sound ", thereby weakened the influence of " sudden and violent sound " greatly, improved quiet effect.
For solving the problems of the technologies described above, the utility model is achieved by the following technical solutions:
A kind of audio frequency power amplifier mute circuit and have the television set of described mute circuit, the reference voltage source pin that audio power amplifies chip connects storage capacitor on the one hand, pass through the gating end ground connection of a switch element on the other hand, the control signal output ends of the control end connection processing device of described switch element.
In order to simplify circuit structure, reduce cost, described switch element adopts a NPN type triode to realize that the base stage of described triode connects the control signal output ends of described processor, collector electrode connects the reference voltage source pin that described audio power amplifies chip, grounded emitter.Wherein, the control signal output ends of described processor is one of them I/O mouth of processor.One end of described storage capacitor connects the reference voltage source pin that audio power amplifies chip, other end ground connection.
Compared with prior art, advantage of the present utility model with good effect is: the utility model is by being connected storage capacitor and ON-OFF control circuit on the reference voltage source pin that amplifies chip at audio power, when making electric equipment in start or from standby to normal operating conditions, stop dc offset voltage to be set up, and then the audio frequency output of blocking-up power amplifier chip, the purpose of realization turn-on muting.And when electric equipment shuts down, by the storage capacitor discharge, make bias voltage drop to zero gradually, reduced the high fdrequency component that the power amplifier chip produces because of bias voltage moment saltus step, thereby reached the purpose of inhibition switching on and shutting down " sudden and violent sounds ", realized the perfect quiet of electric equipment switching on and shutting down.Audio frequency power amplifier mute circuit of the present utility model is simple in structure, reliable and stable, can be widely used in the design of various audio frequency power amplifier mute circuits.
Description of drawings
Fig. 1 is the utility model sound intermediate frequency power amplifier mute circuit schematic diagram.
Embodiment
Below in conjunction with the drawings and specific embodiments the utility model is done explanation in further detail.
The utility model is changed tradition connects muting control circuit on quiet pin, standby pin or the audio frequency input pin of audio frequency power amplifier chip design, proposed a kind ofly on the reference voltage source pin of audio frequency power amplifier chip, to connect control circuit, effectively suppressed the high-frequency harmonic component of generation " sudden and violent sound ", realized that the switching on and shutting down of electric equipment are quiet.
Mute circuit for open and close of the present utility model is that example is specifically addressed with the model for the TDA1517A audio power amplifies chip, and is suitable equally to other audio frequency power amplifier chips.3 pin SVRR of TDA1517A audio frequency power amplifier chip are inner DC reference voltage source capsule pin, and the position of this function pin of the audio frequency power amplifier chip of other models and title may be different, but effect all is the same.The audio frequency power amplifier chip is wanted operate as normal, and the bias voltage of this pin must be set up.Evidence: " sudden and violent sound " that produces when audio frequency power amplifier chip power, power down is exactly that the moment saltus step of bias voltage thus causes.After this moment saltus step launched with Fourier analysis, its spectrum component was very abundant, and " sudden and violent sound " weakened greatly.And the method that reduces spectrum component is exactly that the variation of bias voltage is become slowly, promptly allows rising, the fall time of bias voltage become longer.
To achieve these goals, the utility model proposes a kind of mute circuit for open and close as shown in Figure 1.
Embodiment one, as shown in Figure 1, and an external electrochemical capacitor C261 who is connected to ground on the 3 pin SVRR of TDA1517A audio frequency power amplifier chip N21.The processor MCU of electric equipment is by its I/O mouth output control signal Audio_STB, and control is as conducting and the cut-off state of the NPN type triode V29 of switch element, and then realizes the time that 3 pin to audio frequency power amplifier chip N21 begin to power on.The base stage of described NPN type triode V29 connects the I/O mouth of MCU through resistance R 314, grounded emitter, and collector electrode connects 3 pin of described audio frequency power amplifier chip N21 by resistance R 331.
When electric equipment is started shooting or when standby switches to the state of operate as normal from power on, Audio_STB is a high level, triode V29 conducting, make that the 3 pin voltages of audio frequency power amplifier chip N21 are low level, dc offset voltage is not set up, audio frequency power amplifier chip N21 is in abnormal operating state, does not have audio frequency output.Treat audio frequency power amplifier chip N21 power on stable after, Audio_STB switches to low level, triode V29 ends, dc offset voltage begins to set up, voltage raises gradually from zero, and to capacitor C 261 chargings, after after a while, voltage rises to the bias voltage value of audio frequency power amplifier chip N21, and audio frequency power amplifier chip N21 begins operate as normal.
When the electric equipment power down, the I/O mouth output low level of MCU, so Audio_STB is a low level, triode V29 ends, capacitor C 261 begins discharge, and bias voltage drops to zero gradually, has prolonged rising, the fall time of dc offset voltage like this by the charge and discharge of capacitor C 261, thereby reduced the high fdrequency component that produces because of bias voltage moment saltus step, reached the purpose of effective inhibition switching on and shutting down " sudden and violent sound ".
Audio frequency power amplifier mute circuit of the present utility model is simple in structure, reliable and stable, can weaken effectively that electric equipment powers on and the moment of cutting off the power supply caused " sudden and violent sound ", reaches the quiet effect of switching on and shutting down.This circuit structure can be widely used in the audio frequency power amplifier mute circuit design of audio-visual equipment such as television set.
Certainly; above-mentioned explanation is not to be to restriction of the present utility model; the utility model also is not limited in above-mentioned giving an example, and variation, remodeling, interpolation or replacement that those skilled in the art are made in essential scope of the present utility model also should belong to protection range of the present utility model.
Claims (8)
1. audio frequency power amplifier mute circuit, it is characterized in that: the reference voltage source pin that audio power amplifies chip connects storage capacitor on the one hand, pass through the gating end ground connection of a switch element on the other hand, the control signal output ends of the control end connection processing device of described switch element.
2. audio frequency power amplifier mute circuit according to claim 1, it is characterized in that: described switch element is a NPN type triode, the base stage of described triode connects the control signal output ends of described processor, collector electrode connects the reference voltage source pin that described audio power amplifies chip, grounded emitter.
3. audio frequency power amplifier mute circuit according to claim 2 is characterized in that: the control signal output ends of described processor is one of them I/O mouth of processor.
4. audio frequency power amplifier mute circuit according to claim 1 is characterized in that: an end of described storage capacitor connects the reference voltage source pin that audio power amplifies chip, other end ground connection.
5. television set with the described audio frequency power amplifier mute circuit of claim 1, it is characterized in that: the reference voltage source pin that audio power amplifies chip connects storage capacitor on the one hand, pass through the gating end ground connection of a switch element on the other hand, the control signal output ends of the control end connection processing device of described switch element.
6. television set according to claim 5, it is characterized in that: described switch element is a NPN type triode, the base stage of described triode connects the control signal output ends of described processor, and collector electrode connects the reference voltage source pin that described audio power amplifies chip, grounded emitter.
7. television set according to claim 6 is characterized in that: the control signal output ends of described processor is one of them I/O mouth of processor.
8. television set according to claim 5 is characterized in that: an end of described storage capacitor connects the reference voltage source pin that audio power amplifies chip, other end ground connection.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200620011167 CN200953602Y (en) | 2006-10-18 | 2006-10-18 | Audio frequency power amplifying silent circuit and television with the said silent circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200620011167 CN200953602Y (en) | 2006-10-18 | 2006-10-18 | Audio frequency power amplifying silent circuit and television with the said silent circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN200953602Y true CN200953602Y (en) | 2007-09-26 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200620011167 Expired - Fee Related CN200953602Y (en) | 2006-10-18 | 2006-10-18 | Audio frequency power amplifying silent circuit and television with the said silent circuit |
Country Status (1)
| Country | Link |
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| CN (1) | CN200953602Y (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009149582A1 (en) * | 2008-06-12 | 2009-12-17 | Zoran Corporation | Method and apparatus for mute control |
| CN108495240A (en) * | 2018-04-20 | 2018-09-04 | 中山大学花都产业科技研究院 | A kind of system eliminated audio system and close generation POP sound |
-
2006
- 2006-10-18 CN CN 200620011167 patent/CN200953602Y/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009149582A1 (en) * | 2008-06-12 | 2009-12-17 | Zoran Corporation | Method and apparatus for mute control |
| US8254596B2 (en) | 2008-06-12 | 2012-08-28 | Csr Technology Inc. | Method and apparatus for mute control |
| CN108495240A (en) * | 2018-04-20 | 2018-09-04 | 中山大学花都产业科技研究院 | A kind of system eliminated audio system and close generation POP sound |
| CN108495240B (en) * | 2018-04-20 | 2020-07-24 | 中山大学花都产业科技研究院 | System for eliminating POP sound generated by audio system closing |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20070926 Termination date: 20111018 |