CN102468808B - Thermal protection circuit and method of audio power amplification circuit - Google Patents
Thermal protection circuit and method of audio power amplification circuit Download PDFInfo
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- CN102468808B CN102468808B CN201010534377.7A CN201010534377A CN102468808B CN 102468808 B CN102468808 B CN 102468808B CN 201010534377 A CN201010534377 A CN 201010534377A CN 102468808 B CN102468808 B CN 102468808B
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Abstract
The invention discloses a thermal protection circuit and a thermal protection method of an audio power amplification circuit. The audio power amplification circuit comprises a preamplifier, an output amplifier, a temperature detector and a gain adjustment circuit, wherein the preamplifier is used for receiving and amplifying an audio signal to generate an amplified audio signal; the output amplifier is used for receiving the amplified audio signal and outputting the amplified audio signal to a rear load; the temperature detector is used for detecting the temperature of the output amplifier to output a temperature signal; and the gain adjustment circuit is used for adjusting the magnitude of the amplified audio signal output by the preamplifier according to the magnitude of the temperature signal.
Description
Technical field
The present invention is about a kind of temperature protection circuit, and further, the present invention system is about a kind of thermal protection circuit and method of audio power amplifying circuit.
Background technology
The object of audio frequency amplifier is on sonorific output element, rebuilds the audio signal of input.Audiorange is about 20Hz～20kHz, and therefore amplifier must have good frequency response within the scope of this.According to the difference of application, watt level is widely different, from the milliwatt level of earphone to TV or computer audio frequency several watts, arrive again " mini " family's stereophonic and automobile audio tens watts, until the more than hundreds of watts of more powerful family expenses and commercial sound system are large to the sound requirement that can meet whole cinema or auditorium.
Fig. 1 is the circuit block diagram of the audio frequency amplifier of prior art.Please refer to Fig. 1, audio frequency amplifier comprises pre-amplifier 101, output stage amplifier 102 and a feedback circuit 103.Pre-amplifier 101 is responsible for the small-signal Vin of input to be amplified, to export the input signal Va after amplification.Because the input signal Va after voltage amplification is still not enough to directly promote loudspeaker, output stage amplifier 102 is mainly the input signal Va after amplifying to be amplified to obtain enough electric currents as electric current promote loudspeaker 104.103 of feedback circuits are to utilize degenerative principle, improve the stability of integrated circuit, and improve frequency response.
The electric current flowing through due to output stage amplifier 102 is larger, and power consumption is also larger, conventionally can be coupled with fin.But the complete dissipation of heat that fin might not distribute output stage amplifier 102, therefore usually has the overheated situation of burning of output stage amplifier 102.For head it off, someone proposes to arrange a temperature detection mechanism, and the temperature of monitoring audio frequency amplifier, in the time that temperature is greater than certain threshold, just closes audio frequency amplifier to avoid audio frequency amplifier to burn.But, so, can allow user's acoustically have uncomfortable sensation.
Summary of the invention
An object of the present invention is to provide a kind of thermal protection circuit of audio amplifier circuit, in order to avoid audio amplifier circuit to be burnt.
Another object of the present invention is to provide a kind of audio amplifier circuit, in order to avoid the running of sticky feeling acoustically of user and protection audio amplifier circuit normal simultaneously.
In view of this, the invention provides a kind of audio power amplifying circuit, this audio power amplifying circuit comprises pre-amplifier, output stage amplifier, Temperature Detector and gain adjustment circuit.Pre-amplifier is in order to receive an audio signal, and amplifies, to produce the audio signal after an amplification.Output stage amplifier is in order to receive the audio signal after this amplification, and exports to the load of rear class.Temperature Detector is in order to detect the temperature of output stage amplifier, to export a temperature signal.Gain adjustment circuit is in order to according to the size of temperature signal, adjusts the size of the audio signal after the amplification that pre-amplifier exports.
According to the audio power amplifying circuit described in preferred embodiment of the present invention, above-mentioned pre-amplifier comprises that one is differential right.In addition, in one embodiment, above-mentioned gain adjustment circuit comprises adjustable current source, this adjustable current source couple above-mentioned differential to and Temperature Detector, in order to the temperature signal of exporting according to said temperature detector, adjust and be supplied to an above-mentioned differential right direct current bias current.
In another embodiment, above-mentioned gain adjustment circuit comprises an attenuator, this attenuator is coupled between pre-amplifier and output stage amplifier, audio signal after the amplification that reception pre-amplifier is exported, the temperature of exporting according to Temperature Detector, the size of the audio signal after adjustment is amplified.In another embodiment, above-mentioned attenuator comprises a transistor and a resistance.Above-mentioned transistor comprises a grid, one first source-drain electrode and one second source-drain electrode, and its grid receives this temperature signal, and its first source-drain electrode couples this pre-amplifier, and receives the audio signal after this amplification.Above-mentioned resistance comprises a first end and one second end, and its first end couples this transistorized the first source-drain electrode, and its second end couples and connects altogether voltage.
According to the audio power amplifying circuit described in preferred embodiment of the present invention, above-mentioned attenuator comprises N transmission lock and N+1 resistance.Each transmission lock comprises respectively an input, an output, and each output couples this output stage amplifier.Each resistance comprises respectively a first end and one second end, the first end of first resistance couples this pre-amplifier, and receive the audio signal after this amplification, the second end of N+1 resistance couples and connects altogether voltage, the second end of K resistance couples the first end of K+1 resistance, and the second end of K resistance couples the input of K transmission lock.Wherein, according to the size of this temperature signal, determine conducting and the cut-off of those N transmission locks, wherein, K and N are natural number, 0 < K≤N.
In another embodiment, above-mentioned attenuator comprises an amplifier, one first resistance, N+1 the second resistance and N transmission lock.Amplifier comprises a first input end, one second input and an output.The first resistance comprises a first end and one second end, and its first end couples this pre-amplifier, and receives the audio signal after this amplification, and its second end couples the first input end of this amplifier.Each second resistance comprises respectively a first end and one second end, and the first end of each the second resistance couples the first input end of this amplifier, and the second end of first the second resistance couples the output of this amplifier.N transmission lock, each transmission lock comprises respectively an input and an output, and the input of K transmission lock couples the second end of K+1 the second resistance, and the output of each transmission lock couples the output of this amplifier.According to the size of this temperature signal, determine conducting and the cut-off of those N transmission locks, wherein, K and N are natural number, 0 < K≤N.
According to the audio power amplifying circuit described in preferred embodiment of the present invention, said temperature detector comprises a thermocouple and an amplifier.Above-mentioned thermocouple comprises one first metal wire and one second metal wire, and wherein the first end of this first metal wire connects the first end of this second metal wire, wherein the first end of this first metal wire contact output stage amplifier.Above-mentioned amplifier couples the second end of this first metal wire and this second metal wire, to export a temperature signal.
The present invention provides a kind of integrated audio power amplifying circuit in addition, and this integrated audio power amplifying circuit comprises pre-amplifier, output stage amplifier, Temperature Detector and gain adjustment circuit.Pre-amplifier is in order to receive an audio signal, and amplifies, to produce the audio signal after an amplification.Output stage amplifier is in order to receive the audio signal after this amplification, and exports to the load of rear class.Temperature Detector is in order to detect the temperature of output stage amplifier, to export a temperature signal.Gain adjustment circuit is in order to according to the size of temperature signal, the size of the audio signal after the amplification that adjustment pre-amplifier is exported, wherein above-mentioned pre-amplifier, above-mentioned output stage amplifier, said temperature detector and above-mentioned gain adjustment circuit are integrated in same integrated circuit.
According to the integrated audio power amplifying circuit described in preferred embodiment of the present invention, said temperature detector comprises a diode, a reference voltage generator and an amplifier.Above-mentioned diode comprises an anode and a negative electrode, and anode couples a bias voltage, and negative electrode couples and connects altogether voltage, and wherein diode arrangement is near the pyrotoxin of integrated audio power amplifying circuit.Above-mentioned reference voltage generator is in order to produce a reference voltage.Above-mentioned amplifier comprises a first input end, one second input and an output, its first input end couples the anode of this diode, its second input couples this reference voltage generator, and to receive this reference voltage, its output is in order to export a temperature signal.In a further embodiment, above-mentioned reference voltage generator comprises a bandgap reference circuit.
The present invention provides a kind of heat radiation protection method of audio amplifier circuit in addition, and the method comprises the following steps: that (a) detects a temperature level of the pyrotoxin of audio amplifier circuit; (b) judge whether temperature level is greater than a temperature threshold; (c) when temperature level is less than temperature threshold, get back to step (b); And (d) when temperature level is greater than temperature threshold, according to temperature level, adjust the size of the output signal of audio amplifier circuit, and wherein, temperature level is higher, and the size of the output signal of audio amplifier circuit is controlled less.
The present invention's spirit is to be that temperature protection is integrated to gain adjusts mechanism, as long as temperature, higher than default threshold value, just, along with the height of temperature, progressively reduces gain.So, can avoid the sound interruption play, that also reduces user acoustically has uncomfortable sensation.
For the present invention's above and other object, feature and advantage can be become apparent, preferred embodiment cited below particularly, and coordinate appended graphicly, be described in detail below.
Brief description of the drawings
Fig. 1 is the circuit block diagram of the audio frequency amplifier of prior art;
Fig. 2 is the flow chart of steps of the indoor environment parameter adjusting method of first embodiment of the invention;
Fig. 3 is the circuit diagram of the audio frequency amplifier of the built-in thermal protection circuit of second embodiment of the invention;
Fig. 4 is the circuit block diagram of the audio frequency amplifier of the built-in thermal protection circuit of third embodiment of the invention;
Fig. 5 is the circuit diagram of the attenuator 404 of the audio frequency amplifier of the built-in thermal protection circuit of fourth embodiment of the invention;
Fig. 6 is another circuit diagram of the attenuator 404 of the audio frequency amplifier of the built-in thermal protection circuit of fifth embodiment of the invention;
Fig. 7 is another circuit diagram of the attenuator 404 of the audio frequency amplifier of the built-in thermal protection circuit of sixth embodiment of the invention;
Fig. 8 is the circuit diagram of the integrated audio power amplifying circuit of seventh embodiment of the invention;
Fig. 9 is the flow chart of the heat radiation protection method of the audio amplifier circuit of eighth embodiment of the invention.
Main element symbol description:
101,201: pre-amplifier
102,202: output stage amplifier
103: feedback circuit
Vin: input signal, audio signal
Va: the audio signal after input signal, amplification after amplification
104: loudspeaker
203: Temperature Detector
204,404: gain adjustment circuit
301: differential right
302: adjustable current source
I301: electric current
205: loudspeaker
501: transistor
502, R801: resistance
Vc: the voltage after being attenuated
A601: amplifier
T601: the first transistor
T602: transistor seconds
T603: the 3rd transistor
R601: the first resistance
R601: the second resistance
R603: the 3rd resistance
R604: the 4th resistance
R605: the 5th resistance
R606: the 6th resistance
TC: temperature control signals
T701: the first transmission lock
T702: the second transmission lock
T703: the 3rd transmission lock
R701: the first resistance
R702: the second resistance
R703: the 3rd resistance
R704: the 4th resistance
801: diode
802: amplifier
803: reference voltage generator
VTC: temperature signal
VREF: reference voltage
S901～S904: each step of the embodiment of the present invention
Embodiment
The first embodiment
Fig. 2 is the circuit block diagram of the audio frequency amplifier of the built-in thermal protection circuit of first embodiment of the invention.Please refer to Fig. 2, this audio frequency amplifier comprises pre-amplifier 201, output stage amplifier 202, Temperature Detector 203 and gain adjustment circuit 204.Pre-amplifier 201 is in order to receive an audio signal Vin, and amplifies, to produce the audio signal Va after an amplification.Output stage amplifier 202 is in order to receive the audio signal Va after amplifying, and the load 205 (being generally loudspeaker) of exporting to rear class.Temperature Detector 203 is in order to detect the temperature of output stage amplifier 202, to export a temperature signal.Because output stage amplifier 203 is that the power of consumption is relatively large for promoting load, it is therefore the main thermal source of audio frequency amplifier.Gain adjustment circuit 204, in order to according to the size of temperature signal, is adjusted the gain of pre-amplifier 201.
When temperature is higher, the gain of pre-amplifier 201 is controlled less, and the electric current that output stage amplifier 202 is exported to load 205 is less, the sound that user the hears sound that also can diminish.Because the big or small sound of sound is gradually to diminish along with the rising of temperature, instead of moment closes.When temperature reduces, gain can heightened again, and it is large that sound also can become gradually.Therefore sound can not closed moment, avoids user's sticky feeling acoustically.
In general, as above-mentioned gain adjustment circuit 204 and Temperature Detector 203 can be considered to be an automatic gain adjustment (Auto Gain Control) circuit.Automatic gain Circuit tuning can be divided into gain controlled amplifying circuit (being the gain adjustment circuit 204 of this case) and control signal forms circuit (being the Temperature Detector 203 of this case) two parts.Following examples describe of the present invention two large circuit respectively.
The second embodiment
Fig. 3 is the circuit diagram of the audio frequency amplifier of the built-in thermal protection circuit of second embodiment of the invention.Please refer to Fig. 3, this embodiment be the first embodiment compared with detailed circuit, wherein, the part of pre-amplifier 201 only shows the differential part to 301 inputs, gain adjustment circuit is for example with an adjustable current source 302.In this embodiment, adjustable current source 302 is to implement (N-MOSFET) by N-type mos field effect transistor.The circuit diagram of embodiment can be known thus, because the gain of pre-amplifier is determined by differential right mutual conductance (gm), as long as adjusted electric current I 301, just can adjust mutual conductance (gm), further just adjust the gain of integrated circuit.Therefore, in this embodiment, when temperature raises, along with the voltage Vb of variations in temperature will decline, electric current I 301 also can and then decline, and the gain of pre-amplifier 201 also just and then declines.
The 3rd embodiment
Fig. 4 is the circuit block diagram of the audio frequency amplifier of the built-in thermal protection circuit of third embodiment of the invention.Please refer to Fig. 4, comparatively different from Fig. 2, the gain adjustment circuit 404 of this embodiment is to be coupled between pre-amplifier 201 and output stage amplifier 202, is the form design with attenuator 404.This kind of design is mainly the size of the signal Va that exports for the pre-amplifier 201 of decaying.In the time of excess Temperature, Va signal just can be reduced, and output stage amplifier 202 just can be with less current drives loudspeaker 205.Because drive current is less, temperature just can decline thereupon.
The 4th embodiment
Fig. 5 is the circuit diagram of the attenuator 404 of the audio frequency amplifier of the built-in thermal protection circuit of fourth embodiment of the invention.Please refer to Fig. 5, this attenuator 404 is made up of a transistor 501 and a resistance 502.In the time of temperature rise, the signal Vb that Temperature Detector 203 is exported can diminish.Because transistor 501 is quite a voltage-controlled resistance, Vb diminishes, and greatly, therefore Va signal is attenuated into Vc by transistor 501 with the dividing potential drop of resistance 502 in voltage-controlled resistance 501 changes.
The 5th embodiment
Fig. 6 is another circuit diagram of the attenuator 404 of the audio frequency amplifier of the built-in thermal protection circuit of fifth embodiment of the invention.Please refer to Fig. 6, this attenuator 404 is made up of an amplifier A601, the first transistor T601, transistor seconds T602, the 3rd transistor T 603 and the first resistance R 601, the second resistance R 602, the 3rd resistance R 603, the 4th resistance R 604, the 5th resistance R 605 and the 6th resistance R 606.In this embodiment, the function of the first transistor T601, transistor seconds T602 and the 3rd transistor T 603 is as switch.Temperature Detector 203 be in this embodiment control the first transistor T601, transistor seconds T602 and the 3rd transistor T 603 with temperature control signals TC conducting whether.Affiliated technical field has knows that the knowledgeable should know conventionally, in actual circuit design, Temperature Detector 203 can be coupled to respectively the grid of the first transistor T601, transistor seconds T602 and the 3rd transistor T 603, and in this embodiment, the above-mentioned relation that couples is not shown.
It is for example the kenel of numerical digit that the temperature control signals TC that Temperature Detector 203 is exported can be designed as.Higher when temperature rise, Temperature Detector 203 is controlled more multiple transistor T601, T602, T603 and is switched on.Because the gain of the attenuator 404 of the present embodiment can be similar to as follows
Wherein, REQ is the equivalent resistance that the first transistor T601, transistor seconds T602, the 3rd transistor T 603 and the first resistance R 601, the second resistance R 602, the 3rd resistance R 603, the 4th resistance R 604 form.Therefore when equivalent resistance REQ is less, gain less.Therefore, work as temperature rise, it is more that transistor T 601, T602, T603 are switched on, and equivalent resistance REQ is less.The signal Vc being output also can be less.
Although only enumerate three transistor Ts 601, T602, T603 at this embodiment, and three resistance R 601 in parallel, R602, R603 are as an example, but, affiliated technical field has knows that the knowledgeable it should be known that transistorized number and the number of resistance are to change according to different designs conventionally.Therefore the present invention is not limited with this embodiment.In addition, this area has and conventionally knows that the knowledgeable it should be known that N-type transistor T 601, T602, T603 can replace with transmission lock or P transistor npn npn, do not repeat them here.
The 6th embodiment
Fig. 7 is another circuit diagram of the attenuator 404 of the audio frequency amplifier of the built-in thermal protection circuit of sixth embodiment of the invention.Please refer to Fig. 7, in this embodiment, this attenuator 404 is made up of the first transmission lock T701, the second transmission lock T702, the 3rd transmission lock T703, the first resistance R 701, the second resistance R 702, the 3rd resistance R 703 and the 4th resistance R 704.It couples relation and illustrates as Fig. 7.Affiliated technical field has knows that the knowledgeable it should be known that in actual circuit design conventionally, and Temperature Detector 203 can be coupled to respectively the first transmission lock T701, the second transmission lock T702 and the 3rd transmission lock T703.Same, it is for example the kenel of numerical digit that the temperature control signals TC that Temperature Detector 203 is exported can be designed as.Comparatively different, transistor T 601, T602 and the T603 of the 5th embodiment can be switched on simultaneously, and in this 6th embodiment, for the convenience designing, transmission lock T701, T702 and T703 only can select one of them to be switched on.
For the present embodiment is described, first assumed temperature has three threshold T1～T3, and T3 > T2 > T1.
When temperature is during lower than the first preset temperature T1, only only have the first transmission lock T701 to be switched on, now
Vc＝Va×(R702+R703+R704)/(R701+R702+R703+R704)
When temperature rise is between above-mentioned the first preset temperature T1 and the second preset temperature T2 time, the first transmission lock T701 is cut off and second transmits lock T702 and be switched on.Now
Vc＝Va×(R703+R704)/(R701+R702+R703+R704)
In the time that temperature is elevated between the second preset temperature T2 and the 3rd preset temperature again, the second transmission lock T702 is cut off and the 3rd transmission lock T703 is switched on.Now
Vc＝Va×(R704)/(R701+R702+R703+R704)
From above-described embodiment, temperature is higher, and the received signal Vc of output stage amplifier 202 is less.So just can suitably control temperature in certain preset range.Although above-described embodiment is to transmit lock T701, T702 and T703 as an example, but, this area has knows that the knowledgeable it should be known that the function of transmission lock indicator cock conventionally, and any element (for example transistor) with switching function can replace.In addition, although above-described embodiment only uses three transmission locks,, this area has knows that the knowledgeable it should be known that the transmission number of lock and the number of resistance are to change according to different designs conventionally, therefore the present invention is not limited with this embodiment.
The 7th embodiment
For Temperature Detector 203 can be combined with pre-amplifier 201, output stage amplifier 202 and gain adjustment circuit 204, the 7th embodiment has proposed an integrated audio power amplifying circuit.This integrated audio power amplifying circuit has been integrated Temperature Detector 203, pre-amplifier 201, output stage amplifier 202 and gain adjustment circuit 204 in same integrated circuit.Fig. 8 is the circuit diagram of the integrated audio power amplifying circuit of seventh embodiment of the invention.Please refer to Fig. 8, in this embodiment, Temperature Detector 203 is to use resistance R 801, diode 801, amplifier 802 and reference voltage generator 803, and wherein, diode 801 is disposed near of output stage amplifier 202.Because the barrier voltages (Barrier Potential) of diode 801 can be along with temperature change.The every rising of barrier voltages of the diode that for instance, silicon forms was once reducing 2.5mV.
In addition, in order to make the temperature signal VTC can be accurately along with temperature change, the reference voltage VREF of reference voltage generator 803 utilizes energy gap Voltage Reference (Bandgap Voltage Reference) circuit to produce.The reference voltage VREF that this energy gap reference circuits produces can reach not with temperature change.The circuit of this Temperature Detector 203 is to utilize amplifier 802 that the barrier voltages of the diode along with temperature change 801 and the voltage difference with the reference voltage VREF of temperature change are not amplified.
The Temperature Detector 203 of this 7th embodiment can be used for controlling the gain adjustment circuit of the second embodiment or the attenuator of the 4th embodiment.If the Temperature Detector 203 of this 7th embodiment will be controlled the attenuator of the 5th embodiment or the 6th embodiment, must additional designs Analogue-to-digital Converter (ADC), transfer temperature signal VTC to numerical digit signal to control the switch of above-mentioned the 5th embodiment or the 6th embodiment.
The 8th embodiment
By above-described embodiment, can be generalized the heat radiation protection method of an audio amplifier circuit.Fig. 9 is the flow chart of the heat radiation protection method of the audio amplifier circuit of eighth embodiment of the invention.Please refer to Fig. 9, the method comprises the following steps:
Step S901: start.
Step S902 a: temperature level that detects the pyrotoxin of audio amplifier circuit.
Step S903: judge whether said temperature size is greater than a temperature threshold.When temperature level is less than this temperature threshold, get back to step S902, continue detected temperatures.When temperature level is greater than said temperature threshold, execution step S904.
Step S904: according to said temperature size, adjust the size of the output signal of audio amplifier circuit, wherein, when temperature level is higher, it is less that the size of the output signal of audio amplifier circuit is adjusted.
In sum, the present invention's spirit is to be that temperature protection is integrated to gain adjusts mechanism, as long as temperature, higher than default threshold value, just, along with the height of temperature, progressively reduces gain.So, can avoid the sound interruption play, that also reduces user acoustically has uncomfortable sensation.
The specific embodiment being proposed in the detailed description of preferred embodiment is only in order to the convenient technology contents that the present invention is described, but not the present invention is narrowly limited to above-described embodiment, do not exceeding the present invention's spirit and the situation of following claim, the many variations of being done is implemented, and all belongs to the present invention's scope.Therefore the present invention's protection range is when being as the criterion depending on the claim person of defining.
Claims (18)
1. an audio power amplifying circuit, is characterized in that, described circuit comprises:
One pre-amplifier, in order to receive an audio signal, and amplifies, to produce the audio signal after an amplification;
One output stage amplifier, receives the audio signal after described amplification, and the load of exporting to rear class;
One Temperature Detector, in order to detect the temperature of described output stage amplifier, to export a temperature signal; And
One gain adjustment circuit, in order to according to the size of temperature signal, adjusts the size of the audio signal after the amplification that described pre-amplifier exports, and wherein, described pre-amplifier comprises that one is differential right; And described gain adjustment circuit comprises:
One adjustable current source, couple described differential to and described Temperature Detector, in order to the temperature signal of exporting according to described Temperature Detector, adjust and be supplied to a described differential right direct current bias current.
2. audio power amplifying circuit as claimed in claim 1, is characterized in that, described Temperature Detector comprises:
One thermocouple, comprises one first metal wire and one second metal wire, and the first end of the first wherein said metal wire connects the first end of the second described metal wire, the described output stage amplifier of first end contact of the first wherein said metal wire;
One amplifier, the second end of the first metal wire described in coupling and the second described metal wire, to export a temperature signal.
3. an audio power amplifying circuit, is characterized in that, described circuit comprises:
One pre-amplifier, in order to receive an audio signal, and amplifies, to produce the audio signal after an amplification;
One output stage amplifier, receives the audio signal after described amplification, and the load of exporting to rear class;
One Temperature Detector, in order to detect the temperature of described output stage amplifier, to export a temperature signal; And
One gain adjustment circuit, in order to according to the size of temperature signal, adjusts the size of the audio signal after the amplification that described pre-amplifier exports, and wherein, described gain adjustment circuit comprises:
One attenuator, be coupled between described pre-amplifier and output stage amplifier, audio signal after the described amplification that pre-amplifier described in receiving is exported, the temperature of exporting according to described Temperature Detector, the size of adjusting the audio signal after described amplification, wherein said attenuator comprises:
One transistor, comprises a grid, one first source-drain electrode and one second source-drain electrode, and its grid receives described temperature signal, and its first source-drain electrode couples described pre-amplifier, and receives the audio signal after described amplification;
One resistance, comprises a first end and one second end, and its first end couples described transistorized the first source-drain electrode, and its second end couples and connects altogether voltage.
4. audio power amplifying circuit as claimed in claim 3, is characterized in that, described Temperature Detector comprises:
One thermocouple, comprises one first metal wire and one second metal wire, and the first end of the first wherein said metal wire connects the first end of the second described metal wire, the described output stage amplifier of first end contact of the first wherein said metal wire;
One amplifier, the second end of the first metal wire described in coupling and the second described metal wire, to export a temperature signal.
5. an audio power amplifying circuit, is characterized in that, described circuit comprises:
One pre-amplifier, in order to receive an audio signal, and amplifies, to produce the audio signal after an amplification;
One output stage amplifier, receives the audio signal after described amplification, and the load of exporting to rear class;
One Temperature Detector, in order to detect the temperature of described output stage amplifier, to export a temperature signal; And
One gain adjustment circuit, in order to according to the size of temperature signal, adjusts the size of the audio signal after the amplification that described pre-amplifier exports, and wherein, described gain adjustment circuit comprises:
One attenuator, be coupled between described pre-amplifier and output stage amplifier, audio signal after the described amplification that pre-amplifier described in receiving is exported, the temperature of exporting according to described Temperature Detector, adjust the size of the audio signal after described amplification, wherein, described attenuator comprises:
N transmission lock, each transmission lock comprises respectively an input, an output, each output couples described output stage amplifier;
N+1 resistance, each resistance comprises respectively a first end and one second end, the first end of first resistance couples described pre-amplifier, and receive the audio signal after described amplification, the second end of N+1 resistance couples and connects altogether voltage, the second end of K resistance couples the first end of K+1 resistance, and the second end of K resistance couples the input of K transmission lock
Wherein, according to the size of described temperature signal, determine conducting and the cut-off of N described transmission lock,
Wherein, K and N are natural number, 0 < K≤N.
6. audio power amplifying circuit as claimed in claim 5, is characterized in that, described Temperature Detector comprises:
One thermocouple, comprises one first metal wire and one second metal wire, and the first end of the first wherein said metal wire connects the first end of the second described metal wire, the described output stage amplifier of first end contact of the first wherein said metal wire;
One amplifier, the second end of the first metal wire described in coupling and the second described metal wire, to export a temperature signal.
7. an audio power amplifying circuit, is characterized in that, described circuit comprises:
One pre-amplifier, in order to receive an audio signal, and amplifies, to produce the audio signal after an amplification;
One output stage amplifier, receives the audio signal after described amplification, and the load of exporting to rear class;
One Temperature Detector, in order to detect the temperature of described output stage amplifier, to export a temperature signal; And
One gain adjustment circuit, in order to according to the size of temperature signal, adjusts the size of the audio signal after the amplification that described pre-amplifier exports, and wherein, described gain adjustment circuit comprises:
One attenuator, be coupled between described pre-amplifier and output stage amplifier, audio signal after the described amplification that pre-amplifier described in receiving is exported, the temperature of exporting according to described Temperature Detector, the size of adjusting the audio signal after described amplification, wherein said attenuator comprises:
One amplifier, comprises a first input end, one second input and an output;
One first resistance, comprises a first end and one second end, and its first end couples described pre-amplifier, and receives the audio signal after described amplification, and its second end couples the first input end of described amplifier;
N+1 the second resistance, each second resistance comprises respectively a first end and one second end, and the first end of each the second resistance couples the first input end of described amplifier, and the second end of first the second resistance couples the output of described amplifier;
N transmission lock, each transmission lock comprises respectively an input and an output, and the input of K transmission lock couples the second end of K+1 the second resistance, and the output of each transmission lock couples the output of described amplifier,
Wherein, according to the size of described temperature signal, determine conducting and the cut-off of N described transmission lock,
Wherein, K and N are natural number, 0 < K≤N.
8. audio power amplifying circuit as claimed in claim 7, is characterized in that, described Temperature Detector comprises:
One thermocouple, comprises one first metal wire and one second metal wire, and the first end of the first wherein said metal wire connects the first end of the second described metal wire, the described output stage amplifier of first end contact of the first wherein said metal wire;
One amplifier, the second end of the first metal wire described in coupling and the second described metal wire, to export a temperature signal.
9. an integrated audio power amplifying circuit, is characterized in that, described circuit comprises
One pre-amplifier, in order to receive an audio signal, and amplifies, to produce the audio signal after an amplification;
One output stage amplifier, receives the audio signal after described amplification, and the load of exporting to rear class;
One Temperature Detector, in order to detect the temperature of described output stage amplifier, to export a temperature signal; And
One gain adjustment circuit, in order to according to the size of temperature signal, adjusts the size of the audio signal after the amplification that described pre-amplifier exports,
Wherein said pre-amplifier, described output stage amplifier, described Temperature Detector and described gain adjustment circuit are integrated in same integrated circuit, wherein said pre-amplifier comprises that one is differential right, wherein, described gain adjustment circuit comprises:
One adjustable current source, couple described differential to and described Temperature Detector, in order to the temperature signal of exporting according to described Temperature Detector, adjust and be supplied to a described differential right direct current bias current.
10. integrated audio power amplifying circuit as claimed in claim 9, is characterized in that, described Temperature Detector comprises:
One diode, comprises an anode and a negative electrode, and described anode couples a bias voltage, and described negative electrode couples and connects altogether voltage, and wherein said diode arrangement is near the pyrotoxin of described integrated audio power amplifying circuit;
One reference voltage generator, in order to produce a reference voltage;
One amplifier, comprise a first input end, one second input and an output, its first input end couples the anode of described diode, and its second input couples described reference voltage generator, to receive described reference voltage, its output is in order to export a temperature signal.
11. integrated audio power amplifying circuits as claimed in claim 10, is characterized in that, described reference voltage generator comprises a bandgap reference circuit.
12. 1 kinds of integrated audio power amplifying circuits, is characterized in that, described circuit comprises
One pre-amplifier, in order to receive an audio signal, and amplifies, to produce the audio signal after an amplification;
One output stage amplifier, receives the audio signal after described amplification, and the load of exporting to rear class;
One Temperature Detector, in order to detect the temperature of described output stage amplifier, to export a temperature signal; And
One gain adjustment circuit, in order to according to the size of temperature signal, adjusts the size of the audio signal after the amplification that described pre-amplifier exports,
Wherein said pre-amplifier, described output stage amplifier, described Temperature Detector and described gain adjustment circuit are integrated in same integrated circuit, and wherein, described gain adjustment circuit comprises:
One attenuator, be coupled between described pre-amplifier and output stage amplifier, audio signal after the described amplification that pre-amplifier described in receiving is exported, the temperature of exporting according to described Temperature Detector, adjust the size of the audio signal after described amplification, wherein, described attenuator comprises:
One transistor, comprises a grid, one first source-drain electrode and one second source-drain electrode, and its grid receives described temperature signal, and its first source-drain electrode couples described pre-amplifier, and receives the audio signal after described amplification;
One resistance, comprises a first end and one second end, and its first end couples described transistorized the first source-drain electrode, and its second end couples and connects altogether voltage.
13. integrated audio power amplifying circuits as claimed in claim 12, is characterized in that, described Temperature Detector comprises:
One diode, comprises an anode and a negative electrode, and described anode couples a bias voltage, and described negative electrode couples and connects altogether voltage, and wherein said diode arrangement is near the pyrotoxin of described integrated audio power amplifying circuit;
One reference voltage generator, in order to produce a reference voltage;
One amplifier, comprise a first input end, one second input and an output, its first input end couples the anode of described diode, and its second input couples described reference voltage generator, to receive described reference voltage, its output is in order to export a temperature signal.
14. 1 kinds of integrated audio power amplifying circuits, is characterized in that, described circuit comprises
One pre-amplifier, in order to receive an audio signal, and amplifies, to produce the audio signal after an amplification;
One output stage amplifier, receives the audio signal after described amplification, and the load of exporting to rear class;
One Temperature Detector, in order to detect the temperature of described output stage amplifier, to export a temperature signal; And
One gain adjustment circuit, in order to according to the size of temperature signal, adjusts the size of the audio signal after the amplification that described pre-amplifier exports,
Wherein said pre-amplifier, described output stage amplifier, described Temperature Detector and described gain adjustment circuit are integrated in same integrated circuit, and wherein, described gain adjustment circuit comprises:
One attenuator, be coupled between described pre-amplifier and output stage amplifier, audio signal after the described amplification that pre-amplifier described in receiving is exported, the temperature of exporting according to described Temperature Detector, adjust the size of the audio signal after described amplification, wherein, described attenuator comprises:
N transmission lock, each transmission lock comprises respectively an input, an output, each output couples described output stage amplifier;
N+1 resistance, each resistance comprises respectively a first end and one second end, the first end of first resistance couples described pre-amplifier, and receive the audio signal after described amplification, the second end of N+1 resistance couples and connects altogether voltage, the second end of K resistance couples the first end of K+1 resistance, and the second end of K resistance couples the input of K transmission lock
Wherein, according to the size of described temperature signal, determine conducting and the cut-off of N described transmission lock,
Wherein, K and N are natural number, 0 < K≤N.
15. integrated audio power amplifying circuits as claimed in claim 14, is characterized in that, described Temperature Detector comprises:
One diode, comprises an anode and a negative electrode, and described anode couples a bias voltage, and described negative electrode couples and connects altogether voltage, and wherein said diode arrangement is near the pyrotoxin of described integrated audio power amplifying circuit;
One reference voltage generator, in order to produce a reference voltage;
One amplifier, comprise a first input end, one second input and an output, its first input end couples the anode of described diode, and its second input couples described reference voltage generator, to receive described reference voltage, its output is in order to export a temperature signal.
16. 1 kinds of integrated audio power amplifying circuits, is characterized in that, described circuit comprises
One pre-amplifier, in order to receive an audio signal, and amplifies, to produce the audio signal after an amplification;
One output stage amplifier, receives the audio signal after described amplification, and the load of exporting to rear class;
One Temperature Detector, in order to detect the temperature of described output stage amplifier, to export a temperature signal; And
One gain adjustment circuit, in order to according to the size of temperature signal, adjusts the size of the audio signal after the amplification that described pre-amplifier exports,
Wherein said pre-amplifier, described output stage amplifier, described Temperature Detector and described gain adjustment circuit are integrated in same integrated circuit, and wherein, described gain adjustment circuit comprises:
One attenuator, be coupled between described pre-amplifier and output stage amplifier, audio signal after the described amplification that pre-amplifier described in receiving is exported, the temperature of exporting according to described Temperature Detector, adjust the size of the audio signal after described amplification, wherein, described attenuator comprises:
One amplifier, comprises a first input end, one second input and an output;
One first resistance, comprises a first end and one second end, and its first end couples described pre-amplifier, and receives the audio signal after described amplification, and its second end couples the first input end of described amplifier;
N+1 the second resistance, each second resistance comprises respectively a first end and one second end, and the first end of each the second resistance couples the first input end of described amplifier, and the second end of first the second resistance couples the output of described amplifier;
N transmission lock, each transmission lock comprises respectively an input and an output, and the input of K transmission lock couples the second end of K+1 the second resistance, and the output of each transmission lock couples the output of described amplifier,
Wherein, according to the size of described temperature signal, determine conducting and the cut-off of N described transmission lock,
Wherein, K and N are natural number, 0 < K≤N.
17. integrated audio power amplifying circuits as claimed in claim 16, is characterized in that, described Temperature Detector comprises:
One diode, comprises an anode and a negative electrode, and described anode couples a bias voltage, and described negative electrode couples and connects altogether voltage, and wherein said diode arrangement is near the pyrotoxin of described integrated audio power amplifying circuit;
One reference voltage generator, in order to produce a reference voltage;
One amplifier, comprise a first input end, one second input and an output, its first input end couples the anode of described diode, and its second input couples described reference voltage generator, to receive described reference voltage, its output is in order to export a temperature signal.
18. integrated audio power amplifying circuits as claimed in claim 17, is characterized in that, described reference voltage generator comprises a bandgap reference circuit.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201010534377.7A CN102468808B (en) | 2010-11-05 | 2010-11-05 | Thermal protection circuit and method of audio power amplification circuit |
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| CN201010534377.7A CN102468808B (en) | 2010-11-05 | 2010-11-05 | Thermal protection circuit and method of audio power amplification circuit |
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| CN102468808A CN102468808A (en) | 2012-05-23 |
| CN102468808B true CN102468808B (en) | 2014-10-29 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104954935B (en) * | 2014-03-26 | 2018-11-06 | 瑞昱半导体股份有限公司 | Audio device and its control method |
| CN105305975A (en) * | 2014-07-22 | 2016-02-03 | 无锡麟力科技有限公司 | Temperature protection modulation circuit of Class D audio power amplifier |
| US9794687B2 (en) * | 2015-09-28 | 2017-10-17 | Cirrus Logic, Inc. | Loudspeaker protection circuitry and methods |
| CN108769813A (en) * | 2018-04-28 | 2018-11-06 | 郑州易通众联电子科技有限公司 | Processing method and processing device for TV fever |
| CN110212496B (en) * | 2019-05-29 | 2024-05-28 | 上海韦尔半导体股份有限公司 | Temperature control circuit and method |
| CN115079747B (en) * | 2022-06-29 | 2023-08-22 | 重庆长安汽车股份有限公司 | Temperature control method and system for vehicle-mounted controller, electronic equipment and storage medium |
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|---|---|---|---|---|
| US5107389A (en) * | 1989-05-22 | 1992-04-21 | Sgs-Thomson Microelectronics S.R.L. | Circuit for limiting temperature without distortion in audio power amplifiers |
| US7342455B2 (en) * | 2004-05-28 | 2008-03-11 | Broadcom Corporation | Temperature sensor insensitive to device offsets with independent adjustment of slope and reference temperature |
| CN100483931C (en) * | 2002-09-23 | 2009-04-29 | 哈曼国际工业有限公司 | Heat protective system of amplifier output stage |
| US7705669B2 (en) * | 2008-05-06 | 2010-04-27 | Himax Media Solutions, Inc. | Preamplifier and method for calibrating offsets therein |
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2010
- 2010-11-05 CN CN201010534377.7A patent/CN102468808B/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5107389A (en) * | 1989-05-22 | 1992-04-21 | Sgs-Thomson Microelectronics S.R.L. | Circuit for limiting temperature without distortion in audio power amplifiers |
| CN100483931C (en) * | 2002-09-23 | 2009-04-29 | 哈曼国际工业有限公司 | Heat protective system of amplifier output stage |
| US7342455B2 (en) * | 2004-05-28 | 2008-03-11 | Broadcom Corporation | Temperature sensor insensitive to device offsets with independent adjustment of slope and reference temperature |
| US7705669B2 (en) * | 2008-05-06 | 2010-04-27 | Himax Media Solutions, Inc. | Preamplifier and method for calibrating offsets therein |
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