CN109586676B - Full-load automatic gain matching power amplifier - Google Patents
Full-load automatic gain matching power amplifier Download PDFInfo
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- CN109586676B CN109586676B CN201910072036.3A CN201910072036A CN109586676B CN 109586676 B CN109586676 B CN 109586676B CN 201910072036 A CN201910072036 A CN 201910072036A CN 109586676 B CN109586676 B CN 109586676B
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/56—Modifications of input or output impedances, not otherwise provided for
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G3/00—Gain control in amplifiers or frequency changers
- H03G3/20—Automatic control
- H03G3/30—Automatic control in amplifiers having semiconductor devices
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Abstract
The invention discloses a full-load automatic gain matching power amplifier, which is suitable for various systems including constant resistance and constant voltage, wherein a singlechip calculates the resistance and output power of an access load according to the test voltage and the test current of a voltage and current detection module; when the output power is larger than the rated power, the reference voltage of the inverting input end of the second operational amplifier is adjusted downwards to enable the output power to be equal to the rated power; when the output power is less than or equal to rated power, taking the test voltage as a reference voltage; when the voltage of the output end of the first operational amplifier is larger than the reference voltage, the second operational amplifier outputs a high potential, the impedance of the linear optocoupler is reduced, and the amplification factor of the first operational amplifier is correspondingly adjusted to enable the voltage of the output end of the first operational amplifier to be smaller than or equal to the reference voltage. When the resistance of the connected load is any value, the gain amplification factor of the front stage is adaptively matched, so that the purpose of stabilizing output power is achieved, and the power amplifier stably works in the designed power.
Description
Technical Field
The invention relates to the technical field of power amplifiers, in particular to a full-load automatic gain matching power amplifier.
Background
In research and practice of the prior art, the inventors of the present invention found that the power output of the same conventional power amplifier is not constant for acoustic industry standard impedances of 32 ohms, 16 ohms, 8 ohms, 4 ohms, 2 ohms, etc. If the same 500W power amplifier is required to output 2 ohms 500W, 4 ohms 500W and 8 ohms 500W, l V broadcasting system, the impedance of the access load needs to be matched. That is, in the prior art, the same 500W power amplifier can output 2 ohms 500W, 4 ohms can only output about 300W, 8 ohms can only output about 130W, the 100V broadcasting system cannot be used at all, and the current broadcasting power amplifier needs to output a transformer.
Therefore, the traditional power amplifier can only be used for a sound box of a fixed-impedance system, and has the problem of power mismatch; the method cannot be used for a sound box of a constant voltage system, and has the problem of impedance matching, such as wasting part of the power supply material under the condition of 8 ohms, and only 130W can be used for 500W.
Disclosure of Invention
The embodiment of the invention provides a full-load automatic gain matching power amplifier which is suitable for various systems including constant resistance and constant voltage, and can adaptively match the gain amplification factor of a front stage when the resistance of an access load is any value, so that the purpose of stabilizing output power is achieved, and the power amplifier can stably work in design power.
In order to solve the technical problems, the embodiment of the invention provides a full-load automatic gain matching power amplifier, which comprises a singlechip, an operational amplification module, a driving amplification module and a voltage and current detection module, wherein the singlechip, the operational amplification module, the driving amplification module and the voltage and current detection module are electrically connected in sequence; the singlechip is also connected with the voltage and current detection module; the operational amplification module comprises a linear optocoupler, and a first operational amplifier and a second operational amplifier which are respectively connected with two ends of the linear optocoupler;
the input signal of the operational amplification module is amplified by a plurality of times of the first operational amplifier and the driving amplification module to obtain output voltage;
the voltage and current detection module attenuates the output voltage by the same multiple to obtain a test voltage and a test current;
the singlechip calculates the resistance of the access load and the output power according to the test voltage and the test current;
when the output power is larger than the rated power, the reference voltage of the inverting input end of the second operational amplifier is adjusted downwards to enable the output power to be equal to the rated power;
when the output power is smaller than or equal to the rated power, taking the test voltage as a reference voltage;
when the voltage of the output end of the first operational amplifier is larger than the reference voltage, the second operational amplifier outputs high potential, the impedance of the linear optocoupler becomes smaller, and meanwhile, the amplification factor of the first operational amplifier is correspondingly adjusted, so that the voltage of the output end of the first operational amplifier is smaller than or equal to the reference voltage.
Further, the full-load automatic gain matching power amplifier further comprises:
And when the resistance of the connected load is reduced, the reference voltage of the inverting input end of the second operational amplifier is regulated down, so that the output power is smaller than or equal to the rated power.
Further, the multiple is preset and adjustable, or is adaptively adjusted according to the impedance of the linear optocoupler.
Further, when the output power is less than or equal to the rated power and the resistance of the access load is unchanged, the reference voltage is constant.
Further, the impedance of the linear optocoupler varies from 100 ohms to 10 megaohms.
Further, the full-load automatic gain matching power amplifier also comprises a switching power supply module for supplying power to the whole machine;
after the switch power supply module is electrified, the singlechip performs system detection in advance, so that the normal operation of the system is ensured.
Further, the full-load automatic gain matching power amplifier further comprises:
After the switch power supply module is electrified, the MUTE of the singlechip outputs high potential, and the voltage of the inverting input end of the second operational amplifier is defaulted to be the reference voltage at the moment.
Further, the inverting input end and the output end of the first operational amplifier are connected with the linear optocoupler;
the output end of the first operational amplifier is respectively connected with the non-inverting input end of the second operational amplifier and the IN pin of the driving amplification module;
two pins of the singlechip are respectively connected with two input ends of the second operational amplifier;
the output end of the second operational amplifier is connected with the linear optocoupler;
And a VS pin and a FSACX pin of the driving amplification module are connected with the same pin of the voltage and current detection module.
Further, the full-load automatic gain matching power amplifier further comprises a display screen and a control keyboard, wherein the display screen and the control keyboard are electrically connected with the single-chip microcomputer, and the display screen is used for displaying the calculation result of the single-chip microcomputer and the operation response result of the control keyboard.
Further, the full-load automatic gain matching power amplifier is suitable for a constant-resistance system and a constant-voltage system, and when the resistance of the connected load is any value, the output power is adaptively adjusted to be smaller than or equal to the rated power.
Compared with the prior art, the full-load automatic gain matching power amplifier provided by the invention is suitable for various systems including constant resistance and constant voltage, and the singlechip calculates the resistance and output power of an access load according to the test voltage and the test current of the voltage and current detection module; when the output power is larger than the rated power, the reference voltage of the inverting input end of the second operational amplifier is adjusted downwards to enable the output power to be equal to the rated power; when the output power is less than or equal to rated power, taking the test voltage as a reference voltage; when the voltage of the output end of the first operational amplifier is larger than the reference voltage, the second operational amplifier outputs a high potential, the impedance of the linear optocoupler is reduced, and the amplification factor of the first operational amplifier is correspondingly adjusted to enable the voltage of the output end of the first operational amplifier to be smaller than or equal to the reference voltage. When the resistance of the connected load is any value, the gain amplification factor of the front stage is adaptively matched, so that the purpose of stabilizing output power is achieved, and the power amplifier stably works in the designed power.
Drawings
FIG. 1 is a schematic diagram of a full load AGC-matched power amplifier according to an embodiment of the present invention;
wherein, the reference numerals in the specification and the drawings are as follows:
m1, a singlechip; m2, PWM drives the amplifying chip; m3, a voltage and current detection module; m4, a switching power supply module; m5, an operational amplification module; m6, a display screen;
U1-A, a first operational amplifier; U1-B, a second operational amplifier;
OP1, linear optocoupler; INPUT, signal INPUT;
d1, a first unidirectional diode; d2, a second unidirectional diode; d3, a third unidirectional diode; d4, a fourth unidirectional diode;
R1, a first resistor; r2, a second resistor; r3, a third resistor; r4, a fourth resistor; r5, a fifth resistor; r6, a sixth resistor;
C1, a first electrolytic capacitor; c2, a second electrolytic capacitor; c3, a third electrolytic capacitor; c4, a fourth electrolytic capacitor; c5, a fifth electrolytic capacitor; c6, a first capacitor; c7, a second capacitor;
q6, a first field effect transistor; q7, a second field effect transistor;
l1, a seventh resistance coil; l2, an eighth resistance coil; r7, a seventh resistor; r8, eighth resistor; r9, ninth resistance.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In order to meet the requirement that when the resistance of the connected load is any value, the gain amplification factor of the front stage is adaptively matched, so that the purpose of stabilizing output power is achieved, and the power amplifier stably works in the designed power. One embodiment of the invention provides a full-load automatic gain matching power amplifier which is suitable for various systems including constant resistance and constant voltage and comprises a singlechip M1, an operational amplification module M5, a driving amplification module M2 and a voltage and current detection module M3 which are electrically connected in sequence. Wherein, the singlechip M1 is also connected with a voltage and current detection module M3; the operational amplifier module M5 comprises a linear optical coupler OP1, and a first operational amplifier U1-A and a second operational amplifier U1-B which are respectively connected with two ends of the linear optical coupler OP 1.
The inverting input end and the output end of the first operational amplifier U1-A are connected with the linear optocoupler OP 1; the output end of the first operational amplifier U1-A is respectively connected with the non-inverting input end of the second operational amplifier U1-B and the IN pin of the driving amplification module M2; two pins of the singlechip M1 are respectively connected with two input ends of the second operational amplifier U1-B; the output end of the second operational amplifier U1-B is connected with the linear optocoupler OP 1; and a VS pin and a FSACX pin of the driving amplification module M2 are connected with the same pin of the voltage and current detection module M3.
For a further detailed description of the circuitry of the full load automatic gain matching power amplifier, please refer to fig. 1.
The operational amplifier module M5 further comprises a first unidirectional diode D1, a second unidirectional diode D2, a first resistor R1 and a second resistor R2; the reference voltage regulation control end of the singlechip M1 is connected with the input end of the first unidirectional diode D1, and the output end of the first unidirectional diode D1 is connected with the inverting input end of the second operational amplifier U1-B; the output end of the second operational amplifier U1-B is connected with the input end of the second unidirectional diode D2, and the output end of the second unidirectional diode D2 is connected with the first end of the linear optocoupler OP1 through the first resistor R1; the second end of the linear optical coupler OP1 is grounded, and the third end and the fourth end of the linear optical coupler OP1 and the second resistor R2 are connected to the inverting input end and the output end of the first operational amplifier U1-A in parallel.
The operational amplifier module M5 further includes a first electrolytic capacitor C1, a second electrolytic capacitor C2, a third electrolytic capacitor C3, a fourth electrolytic capacitor C4, a fifth electrolytic capacitor C5, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, and a first capacitor C6; the positive electrode of the first electrolytic capacitor C1 is connected with the output end of the first unidirectional diode D1, the positive electrode of the second electrolytic capacitor C2 is connected with the output end of the second unidirectional diode D2, and the negative electrode of the first electrolytic capacitor C1 and the negative electrode of the second electrolytic capacitor C2 are grounded;
The non-inverting input end of the second operational amplifier U1-B is connected with the negative electrode of the third electrolytic capacitor C3 through the third resistor R3, and the positive electrode of the third electrolytic capacitor C3 is connected to the singlechip M1 through the fourth resistor R4 and the first capacitor C6 in sequence; the output end of the first operational amplifier U1-A is connected with the positive electrode of the third electrolytic capacitor C3, the output end of the first operational amplifier U1-A is connected with the positive electrode of the fifth electrolytic capacitor C5 through the sixth resistor R6, and the negative electrode of the fifth electrolytic capacitor C5 is connected with the input end of the driving amplification module M2.
The inverting INPUT end of the first operational amplifier U1-A is connected with the negative electrode of the fourth electrolytic capacitor C4 through the fifth resistor R5, the positive electrode of the fourth electrolytic capacitor C4 is connected with one end of the signal INPUT end INPUT, and the non-inverting INPUT end of the first operational amplifier U1-A is connected with the other end of the signal INPUT end INPUT and grounded.
The driving amplifying module M2 includes a driving amplifying chip, a first field effect transistor Q6, a second field effect transistor Q7, a first inductance coil L1, a second inductance coil L2, a third unidirectional diode D3, a fourth unidirectional diode D4, a seventh resistor R7, an eighth resistor R8, and a ninth resistor R9. The first end of the driving amplification chip is connected with the potential control end of the singlechip M1, the second end of the driving amplification chip is connected to the grid electrode of the first field effect transistor Q6 through the seventh resistor R7, the input end of the third unidirectional diode D3 is connected with the grid electrode of the first field effect transistor Q6, and the output end of the third unidirectional diode D3 is connected with the second end of the driving amplification chip; the third end of the driving amplification chip is connected to the grid electrode of the second field effect transistor Q7 through the eighth resistor R8, the input end of the fourth unidirectional diode D4 is connected with the grid electrode of the second field effect transistor Q7, and the output end of the fourth unidirectional diode D4 is connected with the third end of the driving amplification chip; the source electrode of the first field effect tube Q6 is connected with the drain electrode of the second field effect tube Q7; the fourth end of the driving amplification chip is connected to the voltage and current detection module M3 through the first inductance coil L1 and the eighth resistance R8 which are connected in series; the fifth end of the driving amplifying chip is connected to the voltage and current detecting module M3 through the ninth resistor R9.
The driving amplification module M2 further includes a second capacitor C7, one end of the second capacitor C7 is connected to the second inductor L2, and the other end of the second capacitor C7 is grounded.
The input signal of the operational amplifier module M5 is amplified by a plurality of multiples of the first operational amplifier U1-a and the driving amplifier module M2 to obtain an output voltage.
And the voltage and current detection module M3 attenuates the output voltage by the same multiple to obtain a test voltage and a test current.
And the singlechip M1 calculates the resistance of the access load and the output power according to the test voltage and the test current.
When the output power is larger than the rated power, the reference voltage of the inverting input end of the second operational amplifier U1-B is regulated down to enable the output power to be equal to the rated power.
And when the output power is smaller than or equal to the rated power, taking the test voltage as a reference voltage.
When the voltage of the output end of the first operational amplifier U1-A is larger than the reference voltage, the second operational amplifier U1-B outputs high potential, the impedance of the linear optical coupler OP1 becomes smaller, and meanwhile the amplification factor of the first operational amplifier U1-A is correspondingly adjusted, so that the voltage of the output end of the first operational amplifier U1-A is smaller than or equal to the reference voltage.
In order to further describe the aspects of the invention in more detail, some preferred embodiments of the invention are described or illustrated in the following.
In a specific embodiment, a 500W full-load automatic-benefit matching power half-amplifier is taken as an example, and the access load is 8 ohms.
After the whole machine is electrified, the singlechip M1 enters the first 2 seconds of system detection, the working state of the voltage and current detection module M3 is detected, the MUTE of the singlechip M1 outputs high potential at the moment, the reference voltage (point A) of the inverting input end of the second operational amplifier U1-B is 5V, the driving amplification module M2 is in a MUTE state, and the power amplifier does not output at the moment.
Under the condition that the system has no problem, the MUTE of the singlechip M1 outputs low potential, and the driving amplification module M2 turns on a MUTE switch, so that the power amplifier starts to work normally.
When the INPUT signal of the signal INPUT terminal INPUT is 2.5V, the output voltage (point B) is 100V after the signal amplification (the multiple is preset and adjustable or adaptively adjusted according to the impedance of the linear optocoupler OP 1) of 40 times by the first operational amplifier U1-a and the driving amplification module M2.
If the resistance (impedance) of the LOAD connected to the LOAD is zero (the LOAD is not connected to any LOAD to be detected), the output voltage is attenuated by 340 times by the voltage and current detection module M, the test voltage is 2V, and the test current value is 0. At this time, the single chip microcomputer M1 calculates according to the test voltage of 2V and the test current value of 0, and the result is no-load, and the display screen M6 displays the calculation result as no-load.
If the LOAD access LOAD is 8 ohms, the voltage and current detection module M3 tests to obtain a test voltage of 2V and a test current of 12.5A. The singlechip M1 calculates according to the test voltage of 2V and the test current value of 12.5A, the result is 8 ohms, and the display screen M6 displays the calculation result as 8 ohms. At this time, the output power of the power amplifier reaches 1250W and seriously exceeds the rated power of 500W, and at this time, the single chip microcomputer M1 immediately adjusts the reference voltage at the point a down to 1.6V (under the condition that the LOAD resistance value is unchanged, the value is not changed any more).
When the voltage at the point C of the output of the first operational amplifier U1-A exceeds 1.6V, the second operational amplifier U1-B immediately outputs high potential, the linear optocoupler OP1-A starts to work, the impedance of the linear optocoupler OP1-B immediately becomes smaller (the linear optocoupler OP1 is changed by a resistance value of 10 megaohms and 100 ohms), and the amplification factor of the first operational amplifier U1-A is adjusted so that the point C is smaller than or equal to 1.6V, so that the point B is at an output smaller than 63V and rated output 500W power.
In a preferred embodiment, if the resistance of the LOAD is reduced, the single-chip microcomputer M1 will continuously reduce the reference voltage at the point a, so that the working power of the whole system is less than or equal to 500W.
In a specific embodiment, a 500W full-load automatic-benefit-matching power half-amplifier is taken as an example, and the access load is 32 ohms.
After the whole machine is electrified, the singlechip M1 enters the first 2 seconds of system detection, the working state of the voltage and current detection module M3 is detected, the MUTE of the singlechip M1 outputs high potential at the moment, the reference voltage (point A) of the inverting input end of the second operational amplifier U1-B is 5V, the driving amplification module M2 is in a MUTE state, and the power amplifier does not output at the moment.
Under the condition that the system has no problem, the MUTE of the singlechip M1 outputs low potential, and the driving amplification module M2 turns on a MUTE switch, so that the power amplifier starts to work normally.
When the INPUT signal of the signal INPUT terminal INPUT is 2.5V, the output voltage (point B) is 100V after the signal amplification (the multiple is preset and adjustable or adaptively adjusted according to the impedance of the linear optocoupler OP 1) of 40 times by the first operational amplifier U1-a and the driving amplification module M2.
If the resistance (impedance) of the LOAD connected to the LOAD is zero (the LOAD is not connected to any LOAD to be detected), the output voltage is attenuated by 340 times by the voltage and current detection module M, the test voltage is 2.5V, and the test current value is 0. At this time, the single chip microcomputer M1 calculates according to the test voltage of 2V and the test current value of 0, and the result is no-load, and the display screen M6 displays the calculation result as no-load.
If the LOAD access LOAD is 32 ohms, the voltage and current detection module M3 tests to obtain a test voltage of 2V and a test current of 3.5A. The singlechip M1 calculates according to the test voltage of 2V and the test current value of 3.5A, the result is 32 ohms, and the display screen M6 displays the calculation result as 8 ohms. At this time, the output power of the power amplifier reaches 330W and is less than 500W of rated power, at this time, the single chip microcomputer M1 does not adjust the reference voltage of the point a, the reference voltage (point a) is still 5V (under the condition that the LOAD resistance value is unchanged, the value will not change any more), at this time, the power amplifier works in a constant voltage mode, and the voltage of the point C is set to be 2.5V reference.
When the voltage at the point C exceeds 2.5V, the second operational amplifier U1-B immediately outputs a high potential, the linear optocoupler OP1-A starts to work, the impedance of the linear optocoupler OP1-B immediately becomes smaller (the linear optocoupler OP1 is changed by a resistance value of 10 megaohms and 100 ohms), and the amplification factor of the first operational amplifier U1-A is adjusted so that the point C is smaller than or equal to 2.5V, so that the point B is at an output smaller than 100V and does not exceed the rated voltage of a broadcast loudspeaker.
In a preferred embodiment, if the resistance of the LOAD is reduced, the single-chip microcomputer M1 will continuously reduce the reference voltage at the point a, so that the working power of the whole system is less than or equal to 500W.
In a preferred embodiment, based on the foregoing embodiment, the full-load automatic gain matching power amplifier further includes:
and when the resistance of the connected load is reduced, the reference voltage of the inverting input end of the second operational amplifier U1-B is reduced, so that the output power is smaller than or equal to the rated power.
For example, the same 500W power amplifier can output 2 ohms 500W, 4 ohms can output 500W, 8 ohms can output 500W, the same 500W as the l00V broadcasting system, the power amplifier can directly output the power amplifier without needing to output a transformer, and the power amplifier can be used for various places such as a sound box of a fixed-resistance system, a sound box of a fixed-voltage system and the like, and the problem of impedance matching does not exist.
The power amplifier has the advantages that no material is wasted in any condition, 500W can be used for 500W under any condition, and the power amplifier can be used for multiple purposes.
According to the description, the embodiment can meet the purpose of adaptively matching the gain amplification factor of the front stage when the resistance of the access load is any value, so that the purpose of stabilizing the output power is achieved, and the power amplifier can stably work in the designed power.
Preferably, the multiple is preset and adjustable, or is adaptively adjusted according to the impedance of the linear optocoupler OP 1.
Preferably, the reference voltage is constant when the output power is less than or equal to the rated power and the resistance of the access load is unchanged.
Preferably, the impedance of the linear optocoupler OP1 varies from 100 ohms to 10 mega ohms.
Preferably, the full-load automatic gain matching power amplifier further comprises a switching power supply module M4 for power supply of the whole machine;
After the switch power supply module M4 is electrified, the singlechip M1 performs system detection in advance, so that the normal operation of the system is ensured.
Preferably, the full-load automatic gain matching power amplifier further comprises:
After the switch power module M4 is powered on, the MUTE of the single chip microcomputer M1 outputs a high potential, and at this time, the voltage at the inverting input end of the second operational amplifier U1-B defaults to a reference voltage.
Preferably, the full-load automatic gain matching power amplifier further comprises a display screen M6 and a control keyboard, wherein the display screen M6 is electrically connected with the single-chip microcomputer M1, and the display screen M6 is used for displaying a calculation result of the single-chip microcomputer M1 and an operation response result of the control keyboard.
The full-load automatic gain matching power amplifier provided by the invention is suitable for various systems including constant resistance and constant voltage, and the singlechip M1 calculates the resistance and output power of an access load according to the test voltage and the test current of the voltage and current detection module M3; when the output power is larger than the rated power, the reference voltage of the inverting input end of the second operational amplifier U1-B is regulated downwards to enable the output power to be equal to the rated power; when the output power is less than or equal to rated power, taking the test voltage as a reference voltage; when the voltage of the output end of the first operational amplifier U1-A is larger than the reference voltage, the second operational amplifier U1-B outputs a high potential, the impedance of the linear optical coupler OP1 becomes smaller, and the amplification factor of the first operational amplifier U1-A is correspondingly adjusted, so that the voltage of the output end of the first operational amplifier U1-A is smaller than or equal to the reference voltage. When the resistance of the connected load is any value, the gain amplification factor of the front stage is adaptively matched, so that the purpose of stabilizing output power is achieved, and the power amplifier stably works in the designed power.
While the foregoing is directed to the preferred embodiments of the present invention, it will be appreciated by those skilled in the art that changes and modifications may be made without departing from the principles of the invention, such changes and modifications are also intended to be within the scope of the invention.
Claims (10)
1. The full-load automatic gain matching power amplifier is characterized by comprising a singlechip, an operational amplification module, a driving amplification module and a voltage and current detection module which are electrically connected in sequence; the singlechip is also connected with the voltage and current detection module; the operational amplification module comprises a linear optocoupler, and a first operational amplifier and a second operational amplifier which are respectively connected with two ends of the linear optocoupler;
the input signal of the operational amplification module is amplified by a plurality of times of the first operational amplifier and the driving amplification module to obtain output voltage;
the voltage and current detection module attenuates the output voltage by the same multiple to obtain a test voltage and a test current;
the singlechip calculates the resistance of the access load and the output power according to the test voltage and the test current;
when the output power is larger than the rated power, the reference voltage of the inverting input end of the second operational amplifier is adjusted downwards to enable the output power to be equal to the rated power;
when the output power is smaller than or equal to the rated power, taking the test voltage as a reference voltage;
when the voltage of the output end of the first operational amplifier is larger than the reference voltage, the second operational amplifier outputs high potential, the impedance of the linear optocoupler becomes smaller, and meanwhile, the amplification factor of the first operational amplifier is correspondingly adjusted, so that the voltage of the output end of the first operational amplifier is smaller than or equal to the reference voltage.
2. The full load automatic gain matching power amplifier of claim 1, further comprising:
And when the resistance of the connected load is reduced, the reference voltage of the inverting input end of the second operational amplifier is regulated down, so that the output power is smaller than or equal to the rated power.
3. The full load automatic gain matching power amplifier of claim 1, wherein the amplification factor of the first operational amplifier and the amplification factor of the driving amplification module are preset and adjustable, or are adaptively adjusted according to the impedance of the linear optocoupler.
4. The full load automatic gain matching power amplifier of claim 1, wherein the reference voltage is constant when the output power is less than or equal to the rated power and the resistance of the connected load is unchanged.
5. The full load automatic gain matching power amplifier of claim 1, wherein the impedance of the linear optocoupler varies from 100 ohms to 10 mega ohms.
6. The full-load automatic gain matching power amplifier of claim 1, further comprising a switching power supply module for power supply of the complete machine;
after the switch power supply module is electrified, the singlechip performs system detection in advance, so that the normal operation of the system is ensured.
7. The full load automatic gain matching power amplifier of claim 6, further comprising:
After the switch power supply module is electrified, the MUTE of the singlechip outputs high potential, and the voltage of the inverting input end of the second operational amplifier is defaulted to be the reference voltage at the moment.
8. The full load automatic gain matching power amplifier of claim 1, wherein,
The inverting input end and the output end of the first operational amplifier are connected with the linear optocoupler;
The driving amplification module is a PWM driving amplification chip; the output end of the first operational amplifier is respectively connected with the non-inverting input end of the second operational amplifier and the IN pin of the driving amplification module;
two pins of the singlechip are respectively connected with two input ends of the second operational amplifier;
the output end of the second operational amplifier is connected with the linear optocoupler;
And a VS pin and a FSACX pin of the driving amplification module are connected with the same pin of the voltage and current detection module.
9. The full-load automatic gain matching power amplifier according to claim 1, further comprising a display screen and a control keyboard electrically connected with the single chip microcomputer, wherein the display screen is used for displaying a calculation result of the single chip microcomputer and is also used for displaying an operation response result of the control keyboard.
10. The full load automatic gain matching power amplifier according to any one of claims 1 to 9, being adapted to a constant resistance system and a constant voltage system, wherein the output power is adaptively adjusted to be less than or equal to the rated power when the resistance of the connected load is any value.
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| CN201910072036.3A CN109586676B (en) | 2019-01-24 | 2019-01-24 | Full-load automatic gain matching power amplifier |
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| CN209375592U (en) * | 2019-01-24 | 2019-09-10 | 江门市川琪科技有限公司 | A kind of power amplifier circuit |
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| CN209375592U (en) * | 2019-01-24 | 2019-09-10 | 江门市川琪科技有限公司 | A kind of power amplifier circuit |
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