CN201349201Y - Temperature gain control circuit applied to audio-frequency amplifier - Google Patents
Temperature gain control circuit applied to audio-frequency amplifier Download PDFInfo
- Publication number
- CN201349201Y CN201349201Y CNU2009200497593U CN200920049759U CN201349201Y CN 201349201 Y CN201349201 Y CN 201349201Y CN U2009200497593 U CNU2009200497593 U CN U2009200497593U CN 200920049759 U CN200920049759 U CN 200920049759U CN 201349201 Y CN201349201 Y CN 201349201Y
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- electrically connected
- temperature
- driving tube
- temperature detection
- variable gain
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Abstract
The utility model discloses a temperature gain control circuit applied to an audio-frequency amplifier, which comprises a variable gain controller, a temperature detection tube and a driving tube, wherein, the variable gain controller is electrically connected between a signal input terminal and a signal output terminal; the temperature detection tube is arranged on a radiator; the driving tube is electrically connected between the power positive electrode and the variable gain controller; the temperature detection tube is used for detecting temperature variation in the radiator; when the temperature reaches a temperature starting control point of the variable gain controller, the varied temperature in the radiator is converted into a current to be output to the driving tube by the temperature detection tube, and the driving tube outputs and controls the current to control the gain amount of the variable gain controller. When a temperature gain control circuit is mounted, the working hours of a power amplifier can be extended to the maximization, thereby ensuring the power amplifier to be never shut down; and in the practical application, the power amplifier does not mutate along with the continuous linear power reduction in the program content (power density) of a source of sound, so that a user can easily adapt acoustically, and a musical program is guaranteed to be uninterrupted finally.
Description
Technical field
The utility model relates to audio frequency amplifier, especially a kind of temperature gain control circuit that is applied to this audio frequency amplifier.
Background technology
As shown in Figure 5, present power amplifier on the market when the dissipation power of output stage transistor during greater than the load capacity of cooling system, will produce the overheated imagination, at this moment may jeopardize the safety of transistor and power amplifier.Prior art generally is to adopt temperature detect switch (TDS) to cut off the power supply of circuit of certain part or the way of power output, comes protective transistor or power amplifier itself.The problem that such way exists is: power amplifier can protection occur because of overtemperature, can cause sound to stop suddenly, makes power amplifier quit work, thereby influences the broadcast of program and the pause of performance, produces unpredictalbe negative consequences.
Summary of the invention
The purpose of this utility model is to overcome the defective of prior art, and a kind of temperature gain control circuit that is applied to this audio frequency amplifier is provided.
For realizing above purpose, the utility model has been taked following technical scheme: a kind of temperature gain control circuit that is applied to audio frequency amplifier, comprise the variable gain controller that is electrically connected between signal input part and the signal output part, be arranged on the temperature detection pipe on the radiator, be electrically connected on the driving tube between positive source and the described variable gain controller; Described temperature detection pipe detects the variations in temperature in the radiator, when the temperature that reaches described variable gain controller when temperature opens the control point, the temperature detection pipe is that electric current outputs to driving tube with the temperature transition that changes in the radiator, the amount of gain of this driving tube output Control current control variable gain controller.
This temperature gain control circuit is controlled the gain of power amplifier by the temperature rise of detection power module, remove to control the gain loop of power amplifier by a control of the directly proportional relation output of the temperature rise of power model voltage by the temperature detection end, aforesaid temperature gain control circuit is set when opening control point (65 ℃-80 ℃) when the temperature of power model rises to, thereby the temperature gain control circuit will reduce power output by the amount of gain that reduces power amplifier by linear relationship and improve the persistently overheating of mould, realize can never not stopping by power amplifier because of overtemperature prote appears in lasting temperature rise; Utilize the temperature detection pipe of triode to do temperature detection, the linearity is better, and is similar with the temperature characterisitic of heater members/power tube.
Described variable gain controller comprises precision photoelectric coupler, the amplifier chip, first divider resistance, second divider resistance, first current-limiting resistance, the output of this precision photoelectric coupler respectively with the tie point of signal input part and amplifier chip backward end, the forward end of amplifier chip is electrically connected, the input one end ground connection of precision photoelectric coupler, the other end is electrically connected to the negative electrode of rectifier diode, described first divider resistance is electrically connected between the output of the forward end of described amplifier chip and precision photoelectric coupler, described second divider resistance is electrically connected between the forward end and ground of amplifier chip, and described first current-limiting resistance is electrically connected between the backward end of signal input part and amplifier chip; The output of described amplifier chip is electrically connected with signal output part.Precision photoelectric coupler and amplifier chip are formed one group of variable gain controller, its controlled range wide (can reach-70dB) applicability is stronger.
Between the backward end of described amplifier chip and output, be electrically connected with feedback circuit.
Described feedback circuit comprises the negative input end that is electrically connected on described amplifier chip and the feedback resistance between the output, feedback capacity.
The anode of described rectifier diode is electrically connected with the collector electrode of described driving tube by second current-limiting resistance, the emitter of this driving tube is electrically connected to power positive end, the base stage of driving tube is electrically connected with the collector electrode of described temperature detection pipe, between the emitter of driving tube and base stage, be electrically connected with the 3rd divider resistance, also include the 4th divider resistance, it is electrically connected between the collector electrode and base stage of temperature detection pipe, is parallel with electric capacity at the two ends of the 4th divider resistance; Between the base stage of temperature detection pipe and emitter, be electrically connected with adjustable resistance), an end ground connection of this adjustable resistance; Also include filter capacitor, the one end is electrically connected between the anode of second current-limiting resistance and rectifier diode, and the other end is electrically connected with the emitter of described temperature detection pipe.
The utility model compared with prior art has following advantage: behind the temperature gain control circuit of packing into, can maximize the operating time that prolongs power amplifier, thereby guarantee that power amplifier never shuts down; In actual applications, power amplifier has the power of continuous linearity to descend with the programme content (power density) of source of sound and does not have the phenomenon of sudden change, can guarantee again finally that from acoustically acceptant music program never interrupts; Since when the heat build-up of radiator self and structure heat dissipation characteristics reference work ambient temperature are 32 ℃, the radiator that utilizes that opens control point maximizing when test transfers to about 80 ℃ with the temperature adjusting power under music (disco) is dynamic.
Description of drawings
Fig. 1 is the utility model circuit structure diagram;
Fig. 2 is embodiment schematic diagram (one);
Fig. 3 is embodiment schematic diagram (two);
Fig. 4 is the utility model schematic diagram;
Fig. 5 is the prior art circuits schematic diagram.
Embodiment
Below in conjunction with the drawings and specific embodiments content of the present utility model is described in further details.
Embodiment:
See also Fig. 1 and shown in Figure 4, a kind of temperature gain control circuit that is applied on the audio frequency amplifier, comprise the variable gain controller 101 that is electrically connected between signal input part and the signal output part, be arranged on the temperature detection pipe Q1 on the radiator, be electrically connected on the driving tube Q2 between positive source and the described variable gain controller 101; Temperature detection pipe Q1 detects the variations in temperature in the radiator, when the temperature that reaches variable gain controller 101 when temperature opens the control point, temperature detection pipe Q1 is that electric current outputs to driving tube Q2 with the temperature transition that changes in the radiator, the amount of gain of this driving tube Q2 output Control current control variable gain controller 101.
Be electrically connected with feedback circuit 102 between the backward end of amplifier chip U2 and output, feedback circuit 102 comprises the negative input end that is electrically connected on amplifier chip U2 and feedback resistance R8, the feedback capacity C3 between the output.
Temperature detection pipe Q1, driving tube Q2, precision photoelectric coupler U1, one group of Temperature Feedback network of the common composition of amplifier chip U2; Monitoring temperature pipe Q1 utilizes the temperature characterisitic of triode semiconductor self, become an electric current in the variation to remove to drive precision photoelectric coupler U1 through driving tube Q2 again the temperature transition in radiator (heater) variation, thereby realized radiator temperature being improved by the temperature rise control signal gain; What reached temperature gain controller 101 when radiator temperature constantly rises opens the control point, the ever-increasing electric current of temperature detection pipe Q1 makes driving tube Q2 follow the resistance that Control current of output removes to control the linear resistance of precision photoelectric coupler U1, amplifier chip U2 amount of gain is opened and is made decline thereupon, forms a balance point between the power output of power amplifier and temperature rise.
The anode of rectifier diode D1 is electrically connected with the collector electrode C end of driving tube Q2 by the second current-limiting resistance R4, the emitter E end of this driving tube Q2 is electrically connected to power positive end, the base stage B end of driving tube Q2 is electrically connected with the collector electrode C end of temperature detection pipe Q1, between the emitter E end of driving tube Q2 and base stage B end, be electrically connected with the 3rd divider resistance R1, also include the 4th divider resistance R2, it is electrically connected between the collector electrode C end and base stage B end of temperature detection pipe Q1, be connected in parallel to capacitor C 1 at the two ends of the 4th divider resistance R2, this capacitor C 1 is used for balance the 4th divider resistance R2; Between the base stage B of temperature detection pipe Q1 end and emitter E end, be electrically connected with adjustable resistance R3, the end ground connection of this adjustable resistance R3; Also include filter capacitor C2, the one end is electrically connected between the anode of the second current-limiting resistance R4 and rectifier diode D1, and the other end is electrically connected with the emitter E end of temperature detection pipe Q1.
Constitute the inclined to one side threshold voltage of temperature detection pipe Q1 by the 3rd divider resistance R1, the 4th divider resistance R2, adjustable resistance R3, temperature spot when this voltage has determined driving tube Q2 conducting (temperature opens the control point), by regulating the resistance of adjustable resistance R3, can change temperature and open the control point; The linear resistance of precision photoelectric coupler U1 is like being open circuit under normal conditions, and this moment, the amplification coefficient of amplifier was 1; This precision photoelectric coupler U1 is different from photosensitive semiconductor device (phototriode) now commonly used, and the symbol that its receipts connect end is not a triode light, and the induction receiving terminal is finished by photo resistance (resistance characteristic).
(CN2-A, CON3), (CN2-B is CON3) with temperature detection pipe Q1 and driving tube Q2 and variable gain controller 101 corresponding linking together by two connectivity ports for present embodiment.
See also Fig. 2 and shown in Figure 3, Fig. 2 inserts ohmic load for power amplifier, and the sinusoidal wave test curve figure of input 1KHZ is because of the relation of power density and radiator heat-dissipation, practical application (music source) is completely different with the minimum output power test result of sinusoidal wave test, and Fig. 3 is music test schematic diagram.
The main components and parts operating state of present embodiment is:
Temperature detection pipe Q1: saturation conduction, by disconnecting;
Driving tube Q2: saturation conduction, by disconnecting;
Precision photoelectric coupler U1: conducting disconnects;
Amplifier chip U2: the flat conversion of height;
Its course of work is: signal input part SIG IN input high level----signal output part SIG OUT output low level;---------signal output part SIG OUT exports high level to driving tube Q2 saturation conduction to temperature detection pipe Q1 saturation conduction in precision photoelectric coupler U1 conducting--the flat conversion of amplifier chip U2 height--.
Above-listed detailed description is at the specifying of the utility model possible embodiments, and this embodiment is not in order to limiting claim of the present utility model, does not allly break away from the equivalence that the utility model does and implements or change, all should be contained in the claim of this case.
Claims (5)
1, a kind of temperature gain control circuit that is applied to audio frequency amplifier, it is characterized in that: comprise the variable gain controller (101) that is electrically connected between signal input part and the signal output part, be arranged on the temperature detection pipe (Q1) on the radiator, be electrically connected on the driving tube (Q2) between positive source and the described variable gain controller (101); Described temperature detection pipe (Q1) detects the variations in temperature in the radiator, when the temperature that reaches described variable gain controller (101) when temperature opens the control point, temperature detection pipe (Q1) is that electric current outputs to driving tube (Q2) with the temperature transition that changes in the radiator, the amount of gain of this driving tube (Q2) output Control current control variable gain controller (101).
2, the temperature gain control circuit that is applied to audio frequency amplifier as claimed in claim 1, it is characterized in that: described variable gain controller (101) comprises precision photoelectric coupler (U1), amplifier chip (U2), first divider resistance (R5), second divider resistance (R7), first current-limiting resistance (R6), the output of this precision photoelectric coupler (U1) respectively with the tie point of signal input part and amplifier chip (U2) backward end, the forward end of amplifier chip (U2) is electrically connected, the input one end ground connection of precision photoelectric coupler (U1), the other end is electrically connected to the negative electrode of rectifier diode (D1), described first divider resistance (R5) is electrically connected between the output of the forward end of described amplifier chip (U2) and precision photoelectric coupler (U1), described second divider resistance (R7) is electrically connected between the forward end and ground of amplifier chip (U2), and described first current-limiting resistance (R6) is electrically connected between the backward end of signal input part and amplifier chip (U2); The output of described amplifier chip (U2) is electrically connected with signal output part.
3, the temperature gain control circuit that is applied to audio frequency amplifier as claimed in claim 2 is characterized in that: be electrically connected with feedback circuit (102) between the backward end of described amplifier chip (U2) and output.
4, the temperature gain control circuit that is applied on the audio frequency amplifier as claimed in claim 3 is characterized in that: described feedback circuit (102) comprises the negative input end that is electrically connected on described amplifier chip (U2) and the feedback resistance between the output (R8), feedback capacity (C3).
5, the temperature gain control circuit that is applied to audio frequency amplifier as claimed in claim 4, it is characterized in that: the anode of described rectifier diode (D1) is electrically connected with the collector electrode of described driving tube (Q2) by second current-limiting resistance (R4), the emitter of this driving tube (Q2) is electrically connected to power positive end, the base stage of driving tube (Q2) is electrically connected with the collector electrode of described temperature detection pipe (Q1), between the emitter of driving tube (Q2) and base stage, be electrically connected with the 3rd divider resistance (R1), also include the 4th divider resistance (R2), it is electrically connected between the collector electrode and base stage of temperature detection pipe (Q1), is parallel with electric capacity (C1) at the two ends of the 4th divider resistance (R2); Between the base stage of temperature detection pipe (Q1) and emitter, be electrically connected with adjustable resistance (R3), an end ground connection of this adjustable resistance (R3); Also include filter capacitor (C2), the one end is electrically connected between the anode of second current-limiting resistance (R4) and rectifier diode (D1), and the other end is electrically connected with the emitter of described temperature detection pipe (Q1).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2009200497593U CN201349201Y (en) | 2009-01-08 | 2009-01-08 | Temperature gain control circuit applied to audio-frequency amplifier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2009200497593U CN201349201Y (en) | 2009-01-08 | 2009-01-08 | Temperature gain control circuit applied to audio-frequency amplifier |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201349201Y true CN201349201Y (en) | 2009-11-18 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2009200497593U Expired - Fee Related CN201349201Y (en) | 2009-01-08 | 2009-01-08 | Temperature gain control circuit applied to audio-frequency amplifier |
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| CN (1) | CN201349201Y (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104166533A (en) * | 2014-08-08 | 2014-11-26 | 深圳市九洲电器有限公司 | Audio output method and system |
| CN104682885A (en) * | 2015-03-04 | 2015-06-03 | 深圳市芯电威科技有限公司 | Audio frequency power amplifier temperature adjusting circuit and control method |
| CN105703731A (en) * | 2015-12-31 | 2016-06-22 | 嘉兴禾润电子科技有限公司 | Automatic gain control circuit used for D-class audio power amplifier chip |
-
2009
- 2009-01-08 CN CNU2009200497593U patent/CN201349201Y/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104166533A (en) * | 2014-08-08 | 2014-11-26 | 深圳市九洲电器有限公司 | Audio output method and system |
| CN104166533B (en) * | 2014-08-08 | 2017-05-17 | 深圳市九洲电器有限公司 | Audio output method and system |
| CN104682885A (en) * | 2015-03-04 | 2015-06-03 | 深圳市芯电威科技有限公司 | Audio frequency power amplifier temperature adjusting circuit and control method |
| CN105703731A (en) * | 2015-12-31 | 2016-06-22 | 嘉兴禾润电子科技有限公司 | Automatic gain control circuit used for D-class audio power amplifier chip |
| CN105703731B (en) * | 2015-12-31 | 2017-12-22 | 嘉兴禾润电子科技有限公司 | Automatic gain control circuit for D class audio frequency power amplifier chips |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20091118 Termination date: 20170108 |