CN110165870B - Constant power control circuit - Google Patents
Constant power control circuit Download PDFInfo
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- CN110165870B CN110165870B CN201810151400.0A CN201810151400A CN110165870B CN 110165870 B CN110165870 B CN 110165870B CN 201810151400 A CN201810151400 A CN 201810151400A CN 110165870 B CN110165870 B CN 110165870B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/0003—Details of control, feedback or regulation circuits
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/0003—Details of control, feedback or regulation circuits
- H02M1/0016—Control circuits providing compensation of output voltage deviations using feedforward of disturbance parameters
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Abstract
The invention provides a constant power control circuit, comprising: a first gain unit, a second gain unit and a voltage clamping unit; the first gain unit is used for amplifying the voltage sampling signal based on a first gain and then performing subtraction processing on the voltage sampling signal and a reference voltage; the second gain unit is used for amplifying the output signal of the first gain unit based on a second gain; the voltage clamping unit is used for executing voltage clamping processing on the output signal of the second gain unit and then outputting a power control reference signal to the current error amplifier. Therefore, the controller can adjust (regulate and reduce) the output current of the power converter along with the actual output voltage by controlling the on/off period of the power switch SW, thereby achieving the functions of overcurrent protection and constant power output control.
Description
Technical Field
The present invention relates to the field of electronic circuits, and more particularly, to a constant power control circuit applied to a power converter, a power supply or a charger (charger).
Background
With the development and progress of electronic technology, various electronic devices and products are widely used in daily life, and a linear power supply (linear power supply) is conventionally used to provide stable voltage/current to the electronic devices. However, the conventional linear Power Supply has disadvantages of large volume and low Power conversion efficiency, so that Switch Mode Power Supply (SMPS) is first disclosed in U.S. patent No. US4,253,137 by Neti r.m. rao, netherlands.
Fig. 1 shows a block diagram of a conventional power converter. As shown in fig. 1, a conventional power converter 1' includes: a rectifying unit 11 'coupled to the voltage source VS', a PFC unit 12 '(power factor correction unit), a power switching unit 13', a transformer unit 14 ', an output rectifying unit 15', an output filtering unit OF ', an error calculating unit 16', an optical coupler OC ', and a control unit 17'; the error calculation unit 16 ' generally includes a voltage error amplifier 161 ' and a current error amplifier 162 '.
It should be known to the electronic engineers familiar with the design and development of the power converter that the voltage error amplifier 161 'and the current error amplifier 162' respectively obtain a voltage sampling signal and a current sampling signal from the output terminal (i.e., the secondary side) of the transformer unit 14 'through a voltage sampling unit VSU' and a current sampling unit CSU ', and further output the voltage/current error signal to the control unit 17' through the optical coupling feedback unit OC ', so that the control unit 17' can correspondingly output a pulse width modulation signal to control the on/off period of the power switch unit 13 ', thereby achieving the effect of stabilizing the output signal of the power converter 1'. It should be noted that only the voltage OR current error signal for informing the control unit 17 'to correspondingly output the pwm signal is outputted through the OR logic gate 163'.
The conventional power converter 1 'is provided with the error calculating unit 16' and can stably output a voltage signal or a current signal. Unfortunately, the error calculation unit 16 'and the control unit 17' cannot control the power converter 1 'to maintain a constant power output because the error calculation unit 16' and the control unit 17 'can only regulate the output voltage or current of the power converter 1' singly.
In view of the fact that the error calculating unit 16 'and the control unit 17' used in the prior art can only singly maintain the constant voltage output or the constant current output of the power supply 1 'and cannot regulate and control the power supply 1' to maintain the constant power output, the inventors of the present invention have made intensive studies and finally developed a constant power control circuit according to the present invention.
Disclosure of Invention
Unlike the prior art in which the feedback unit can only singly maintain the constant voltage output or the constant current output of the power supply, the present invention provides a constant power control circuit, which includes: a first gain unit, a second gain unit and a voltage clamping unit; the first gain unit is used for amplifying the voltage sampling signal based on a first gain and then performing subtraction processing on the voltage sampling signal and a reference voltage. The second gain unit is used for amplifying the output signal of the first gain unit based on a second gain. The voltage clamping unit is used for executing voltage clamping processing on the output signal of the second gain unit and then outputting a power control reference signal to the current error amplifier. Thus, the current error amplifier outputs a current error signal to the controller based on a current sampling signal and the power control reference signal, so that the controller can adjust (reduce) the output current of the power converter along with the actual output voltage by controlling the on/off period of the power switch SW, thereby achieving the functions of overcurrent protection and constant power output control.
To achieve the above objective of the present invention, the inventor provides an embodiment of the constant power control circuit, which is applied in a feedback circuit, wherein the feedback circuit at least includes a current error amplifier, a voltage error amplifier, and an optocoupler; and, the constant power control circuit includes:
a first gain unit electrically connected to a voltage sampling signal and a reference voltage for performing a first amplification process on the voltage sampling signal and the reference voltage based on a first gain and then performing a subtraction process on the voltage sampling signal and the reference voltage after the first amplification process is completed;
a second gain unit electrically connected to the first gain unit for receiving a first output signal of the first gain unit and performing a second amplification process on the first output signal based on a second gain; and
and the voltage clamping unit is electrically connected to the second gain unit and used for receiving a second output signal of the second gain unit, executing voltage clamping processing on the second output signal and then outputting a power control reference signal to the current error amplifier.
In order to achieve the above-mentioned objectives, the present inventors provide a further embodiment of the constant power control circuit, which is applied in a feedback circuit, wherein the feedback circuit at least includes a current error amplifier and a voltage error amplifier; and, the constant power control circuit includes:
a gain unit electrically connected to a voltage sampling signal and a reference voltage for performing an amplification process on the voltage sampling signal based on a gain and then performing a subtraction process on the amplified voltage sampling signal and the reference voltage; and
and the voltage clamping unit is electrically connected to the gain unit and used for receiving an output signal of the gain unit, executing voltage clamping processing on the output signal and then outputting a power control reference signal to the current error amplifier.
Drawings
Fig. 1 shows a circuit block diagram of a power converter provided in the prior art;
FIG. 2 is a block diagram of a feedback circuit 2 of a constant power control circuit according to the present invention;
FIG. 3 shows a circuit architecture diagram of a first embodiment of the constant power control circuit of the present invention;
FIG. 4 shows a functional block diagram of a first embodiment of a constant power control circuit of the present invention;
FIG. 5 shows a graph of output current versus output voltage;
FIG. 6 is a circuit architecture diagram showing a second embodiment of the constant power control circuit of the present invention; and
FIG. 7 shows a functional block diagram of a second embodiment of the constant power control circuit of the present invention.
Description of the symbols:
< present invention >
Feedback circuit of 4 constant power control circuit 2
1 power conversion module 3 load
VSU voltage sampling unit CSU current sampling unit
21 current error amplifier 22 voltage error amplifier
OC optical coupler 23 controller
41 first gain unit 42 second gain unit
43 voltage clamping unit Vsen voltage sampling signal
13 first negative input terminal 12 first positive input terminal
14 first output terminal OP1 first operational amplifier
R366 first resistance R368 second resistance
R367 third resistor R369 fourth resistor
GND ground terminal C362 third capacitor
Second positive input terminal of C363 fourth capacitor 10
9 second negative input terminal 8 second output terminal
OP2 second operational amplifier R363 fifth resistor
C361 first capacitor R362 sixth resistor
R365 seventh resistor C364 second capacitor
D1 first diode SR three-terminal controllable voltage stabilizer
D2 second diode A anode terminal
C cathode terminal R reference terminal
R361 output resistance VCC circuit voltage
41' gain cell VX reference voltage
< conventional fact >
1 'power converter Vs' voltage source
11 'rectifying unit 12' PFC unit
13 'power switch unit 14' transformer unit
15 'output rectifying unit OF' output filtering unit
16 'error calculation Unit OC' optocoupler
17 'control unit 161' voltage error amplifier
162 'current error amplifier VSU' voltage sampling unit
CSU 'current sampling unit 163' OR logic gate
Detailed Description
To further explain the technical means and effects of the present invention adopted to achieve the predetermined object, the following detailed description of the embodiments, structures, features and effects according to the present invention will be made with reference to the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "an embodiment" refers to not necessarily the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
In order to more clearly describe the feedback circuit capable of changing response with the dimming signal, the preferred embodiment of the present invention will be described in detail below with reference to the drawings.
First embodiment
Referring to fig. 2, a block diagram of a feedback circuit having a constant power control circuit according to the present invention is shown. As shown in fig. 2, the constant power control circuit 4 of the present invention is applied in a feedback circuit 2, wherein the feedback circuit 2 is connected between an output terminal of a power conversion module 1 and a power switch SW inside the feedback circuit, and the output terminal of the power conversion module 1 is connected to a load 3. The feedback circuit 2 includes: a voltage sampling unit VSU, a current sampling unit CSU, a current error amplifier 21, a voltage error amplifier 22, an optocoupler OC, and a controller 23.
Continuing with FIG. 2, please refer to FIG. 3 and FIG. 4. Fig. 3 shows a circuit architecture diagram of a first embodiment of the constant power control circuit of the present invention, and fig. 4 shows a functional block diagram of the first embodiment of the constant power control circuit of the present invention. As can be seen from fig. 2 and 3, the constant power control circuit 4 of the present invention mainly includes: a first gain unit 41, a second gain unit 42 and a voltage clamping unit 43; the first gain unit 41 is electrically connected to a voltage sampling signal Vsen and a reference voltage VREF. It should be added that, the voltage sampling unit VSU is electrically connected between the voltage error amplifier 22 and the output terminal of the power conversion module 1; and, the voltage sampling unit VSU simultaneously provides the voltage sampling signal Vsen to the first gain unit 41. As shown in the functional block 41a of fig. 4, after receiving the voltage sampling signal Vsen and the reference voltage VREF, the first gain unit 41 performs a first amplification process on the voltage sampling signal Vsen and the reference voltage VREF based on a first gain a, and then performs a calculation process on the voltage sampling signal Vsen and the reference voltage VREF after the first amplification process is completed. The calculation process of the present invention may be a subtraction process, and the subtraction process is to process a difference value between the voltage sampling signal Vsen and the reference voltage VREF.
On the other hand, the second gain unit 42 is electrically connected to the first gain unit 41 for receiving a first output signal of the first gain unit 41. After receiving the first output signal, the second gain unit 42 performs a second amplification process on the first output signal based on a second gain B, as shown in the functional block 42a of fig. 4. Furthermore, the voltage clamping unit 43 is electrically connected to the second gain unit 42 for receiving a second output signal of the second gain unit 42. As shown in the functional block 43a of fig. 4, after receiving the second output signal, the voltage clamp unit 43 performs a voltage clamp process on the second output signal, and then outputs a power control reference signal CREF to the current error amplifier 21.
With continued reference to fig. 2 and 3. The current sampling unit CSU is electrically connected between the current error amplifier 21 and the output terminal of the power conversion module 1, and is configured to provide a current sampling signal Csen to the current error amplifier 21, where the current error amplifier 21 has a positive input terminal, and the power control reference CREF is connected to the positive input terminal. Thus, the current error amplifier 21 generates a current error signal based on the current sampling signal Csen and the power control reference signal CREF, and transmits the current error signal to the controller 23 through the optocoupler OC. Finally, the controller 23 outputs a PWM control signal to the power switch SW inside the power conversion module 1, so as to adjust (adjust) the output current of the power conversion module 1 along with the actual output voltage by adjusting the on/off period of the power switch SW, thereby achieving the function of overcurrent protection. Further, the function of constant power output control is achieved at the same time.
Fig. 5 shows a graph of output current versus output voltage. It can be seen from fig. 5 that when the output voltage of a typical power supply or power converter is increased, the output current is also increased, which results in the output power of the power supply or power converter being increased, for example, from 1140W to 1200W, and then from 1200W to 1400W. Therefore, in order to adjust (adjust) the output current of the power conversion module 1 with the actual output voltage to achieve the overload current protection and the constant power output control, the first gain a of the first gain unit 41 and the second gain B of the second gain unit 42 must be properly designed. Please refer to the following equations (1), (2) and (3).
In the above equations, Io1 and Io2 are output current values, and Vo1 and Vo2 are output voltage values. And, Vclamp represents a clamping voltage point provided by the voltage clamping unit 43. As can be seen from the equations (1), (2) and (3), the first gain a is adjusted such that (VREF-a × Vo1): (VREF-a × Vo2) ═ Io1: Io 2; meanwhile, the second gain B is adjusted such that (VREF-a × Vo2) × B is Vclamp (i.e., the clamping voltage point). Therefore, in order to make the first gain a of the first gain unit 41 and the second gain B of the second gain unit 42 adjustable, the present inventors have made special designs for the internal circuit architectures of the first gain unit 41 and the second gain unit 42.
In the above equations, Io1 and Io2 are output current values, and Vo1 and Vo2 are output voltage values. And, Vclamp represents a clamping voltage point provided by the voltage clamping unit 43. As can be seen from the equations (1), (2) and (3), the first gain a is adjusted such that (VREF-a × Vo1): (VREF-a × Vo2) ═ Io1: Io 2; meanwhile, the second gain B is adjusted such that (VREF-a × Vo2) × B is Vclamp (i.e., the clamping voltage point). Therefore, in order to make the first gain a of the first gain unit 41 and the second gain B of the second gain unit 42 adjustable, the present inventors have made special designs for the internal circuit architectures of the first gain unit 41 and the second gain unit 42.
As shown in fig. 3, the first gain unit 41 includes: a first operational amplifier OP1 having a first negative input terminal 13, a first positive input terminal 12, and a first output terminal 14, a first resistor R366, a second resistor R368, a third resistor R367, and a fourth resistor R369; wherein, when the calculation process is executed, the voltage sampling signal Vsen is electrically connected to the first negative input terminal 13; the reference voltage VREF is electrically connected to the first positive input terminal 12, two ends of the first resistor R366 are respectively electrically connected between the first negative input terminal 13 and the first output terminal 14, and two ends of the second resistor R368 are respectively electrically connected between the voltage sampling signal Vsen and the first negative input terminal 13. On the other hand, two ends of the third resistor R367 are respectively and electrically connected between the reference voltage VREF and the first positive input end 12, and two ends of the fourth resistor R369 are respectively and electrically connected between a ground GND and the first positive input end 12. It should be noted that the first resistor R366 is connected in parallel with a third capacitor C362, and the third resistor R367 is connected in parallel with a fourth capacitor C363. Thus, by the special design of the internal circuit structure of the first gain unit 41, the first gain a of the first gain unit 41 is adjustable, and is represented by the following formula (4).
In brief, a first ratio between the first resistor R366 and the second resistor R368 is the first gain a; therefore, the first gain a can be adjusted by changing the resistance of the first resistor R366 and/or the second resistor R368. Meanwhile, a second ratio between the third resistor R367 and the fourth resistor R369 is also the first gain a; therefore, the first gain a can be controlled by changing the resistance of the third resistor R367 and/or the fourth resistor R369. On the other hand, fig. 3 shows that the second gain unit 42 includes: a second operational amplifier OP2 having a second positive input terminal 10, a second negative input terminal 9 and a second output terminal 8, a fifth resistor R363, a first capacitor C361 and a sixth resistor R362; two ends of the fifth resistor R363 are respectively electrically connected between the second negative input terminal 9 and the ground GND, and two ends of the sixth resistor R362 are respectively electrically connected between the second negative input terminal 9 and the second output terminal 8. It should be noted that the first output signal passes through a seventh resistor R365, one end of the seventh resistor R365 is electrically connected to the second positive input terminal 10 and the first capacitor C361, the other end of the seventh resistor R365 is electrically connected to the first gain unit 41, and two ends of the first capacitor C361 are respectively electrically connected between the second positive input terminal 10 and the ground GND.
Meanwhile, as can be seen from fig. 3, the voltage clamping unit 43 includes: a second capacitor C364, a first diode D1, a three-terminal controllable regulator SR, and a second diode D2; the three-terminal controllable voltage regulator SR has an anode terminal a, a cathode terminal C, and a reference terminal R, and the cathode terminal C and the anode terminal a are electrically connected to the cathode terminal of the first diode D1 and the ground terminal GND, respectively. On the other hand, one end of the second capacitor C364 is electrically connected to the current error amplifier 21 and the reference terminal R of the three-terminal controllable regulator SR, the other end of the second capacitor C364 is electrically connected to the ground GND, and the positive terminal of the first diode D1 is electrically connected to the second output terminal 8. It should be noted that the second output signal passes through an output resistor R361, one end of the output resistor R361 is electrically connected to the current error amplifier 21 and the positive terminal of the first diode D1, the other end of the output resistor R361 is electrically connected to the second gain unit, and an eighth resistor R360 is provided between the positive terminal of the second diode D2 and the circuit voltage VCC. Moreover, the positive terminal of the second diode D2 is electrically connected to a circuit voltage VCC, and the negative terminal thereof is electrically connected to the negative terminal C. Thus, by the special design of the circuit architecture of the second gain unit 42 and the voltage clamping unit 43, the second gain B of the second gain unit 42 is adjustable, and is represented by the following formula (5). Ri in equation (5) is represented as an input impedance of the current error amplifier 21.
Second embodiment
Please refer to fig. 6 and fig. 7. Fig. 6 shows a circuit architecture diagram of a second embodiment of the constant power control circuit of the present invention, and fig. 7 shows a functional block diagram of the second embodiment of the constant power control circuit of the present invention. Comparing fig. 6 and fig. 3, it can be seen that the second embodiment of the constant power control circuit 4 only includes a gain unit 41' and the same voltage clamping unit 43. It should be noted that the circuit architecture of the voltage clamping unit 43 is not changed, and therefore, the description thereof is not repeated. Unlike the first gain unit 41 of the first embodiment, the gain unit 41' of the second embodiment includes only: a first operational amplifier OP1 having a first negative input terminal 13, a first positive input terminal 12, and a first output terminal 14, a first resistor R366, a second resistor R368, and a third capacitor C362. It is noted that the output resistor R361 is disposed between the first output terminal 14 of the first operational amplifier OP1 and the positive terminal of the first diode D1. The first positive input end 12 of the first operational amplifier OP1 is electrically connected to another reference voltage VX; the first negative input terminal 13 of the first operational amplifier OP1 is electrically connected to the voltage sampling signal Vsen.
It should be especially explained that, in the first embodiment, the reference voltage VREF refers to a reference voltage inside the power supply or the power converter, such as 2.5V. However, the reference voltage Vx used in the second embodiment does not refer to the internal reference voltage. According to the design of the second embodiment of the present invention, as shown in the functional block 41b of fig. 7, after receiving the voltage sampling signal Vsen and the reference voltage VX, the gain unit 41' performs an amplification process on the voltage sampling signal Vsen based on the gain C, and then performs a subtraction process on the amplified voltage sampling signal Vsen and the reference voltage VX. Continuing, as shown in the functional block 43b of fig. 7, after receiving the output signal of the gain unit 41', the voltage clamping unit 43 performs a voltage clamping process on the output signal, and then outputs a power control reference signal CREF to the current error amplifier 21, wherein the current error amplifier has a positive input terminal, and the power control reference signal CREF is based on the positive input terminal.
Thus, the current error amplifier 21 generates a current error signal based on the current sampling signal Csen and the power control reference signal CREF, and transmits the current error signal to the controller 23 through the optocoupler OC. Finally, the controller 23 outputs a PWM control signal to the power switch SW inside the power conversion module 1, so as to adjust (adjust) the output current of the power conversion module 1 along with the actual output voltage by adjusting the on/off period of the power switch SW, thereby achieving the function of overcurrent protection. Further, the function of constant power output control is achieved at the same time. In order to adjust (adjust) the output current of the power conversion module 1 with the actual output voltage to achieve the overload current protection and constant power output control functions, the gain C of the gain unit 41' must be properly designed. Please refer to the following equations (6), (7), (8), and (9).
C＝A×B………………………………………(6)
VX＝VREF×B……………………………………(7)
Thus, the circuit architecture of all embodiments of the constant power control circuit 4 of the present invention has been fully and clearly described above, and it can be understood that the present invention has the following advantages:
(1) as shown in fig. 1, the error calculating unit 16 'and the control unit 17' of the prior art can only singly maintain the constant voltage output or the constant current output of the power supply 1 ', and cannot regulate and control the power supply 1' to maintain the constant power output. In view of the above, the present invention provides a constant power control circuit 4 applicable to the existing feedback circuit 2, which comprises: a first gain unit 41, a second gain unit 42 and a voltage clamping unit 43; the first gain unit 41 is mainly configured to perform a first amplification process on a voltage sampling signal Vsen based on a first gain a, and then perform a subtraction process on the voltage sampling signal Vsen after the first amplification process and a reference voltage VREF. On the other hand, the second gain unit 42 is configured to perform a second amplification process on the first output signal of the first gain unit 41 based on the second gain B, and the voltage clamp unit 43 is configured to perform a voltage clamp process on the second output signal of the second gain unit 42, and then output a power control reference signal CREF to the current error amplifier 21. Thus, the current error amplifier 21 generates a current error signal based on a current sampling signal Csen and the power control reference signal CREF, and transmits the current error signal to the controller 23 through the optocoupler OC, so that the controller 23 can adjust (down) the output current of the power conversion module 1 along with the actual output voltage by controlling the on/off period of the power switch SW, thereby achieving the functions of overcurrent protection and constant power output control.
(2) In addition, it should be emphasized that the constant power control circuit 4 of the present invention is not limited to be applied to a feedback circuit inside a power supply or a power converter, and can also be applied to any voltage-varying type charger for increasing and decreasing an output voltage and an output current to facilitate charging.
While the invention has been described with reference to specific embodiments, the invention is not limited thereto, and any person skilled in the art can easily conceive of changes and substitutions within the technical scope of the invention.
Claims (11)
1. A constant power control circuit is applied in a feedback circuit, wherein the feedback circuit at least comprises a current error amplifier and a voltage error amplifier; and, the constant power control circuit includes:
a first gain unit electrically connected to a voltage sampling signal and a reference voltage, for performing a first amplification process on the voltage sampling signal and the reference voltage based on a first gain, and then performing a calculation process on the voltage sampling signal and the reference voltage after the first amplification process is completed;
a second gain unit electrically connected to the first gain unit for receiving a first output signal of the first gain unit and performing a second amplification process on the first output signal based on a second gain; and
a voltage clamping unit electrically connected to the second gain unit for receiving a second output signal of the second gain unit, performing a voltage clamping process on the second output signal, and outputting a power control reference signal to the current error amplifier;
the voltage clamping unit includes:
a three-terminal controllable regulator having an anode terminal, a cathode terminal, and a reference terminal; the cathode terminal is electrically connected to the cathode terminal of a first diode, and the anode terminal is electrically connected to a ground terminal:
the second output signal passes through an output resistor, one end of the output resistor is electrically connected to the current error amplifier and the positive end of the first diode, and the other end of the output resistor is electrically connected to the second gain unit; and
and one end of the first capacitor is electrically connected to the current error amplifier and the reference end of the three-terminal controllable voltage stabilizer, and the other end of the first capacitor is electrically connected to the ground end.
2. The constant power control circuit according to claim 1, wherein the feedback circuit further comprises:
the voltage sampling unit is electrically connected between the voltage error amplifier and the output end of the power supply conversion module; the voltage sampling unit simultaneously provides the voltage sampling signal to the first gain unit;
the current sampling unit is electrically connected between the current error amplifier and the output end of the power supply conversion module and used for providing a current sampling signal to the current error amplifier;
an optical coupler electrically connected to the current error amplifier and the voltage error amplifier; and
a controller electrically connected to the optical coupler;
the current error amplifier has a positive input terminal, the power control reference signal is linked to the positive input terminal, the current error amplifier generates a current error signal based on the current sampling signal and the power control reference signal, and transmits the current error signal to the controller through the optocoupler.
3. The constant power control circuit according to claim 2, wherein the power conversion module is located inside an electronic device, and the electronic device can be any one of the following: a power converter, a power supply, or a transformer type charger.
4. The constant power control circuit of claim 1, wherein the first gain unit comprises:
a first operational amplifier having a first negative input terminal and a first positive input terminal; wherein, when executing the calculation processing, the voltage sampling signal is electrically connected to the first negative input end; and the reference voltage is electrically connected to the first positive input end.
5. The constant power control circuit of claim 1, wherein the first gain unit comprises:
a first operational amplifier having a first negative input terminal, a first positive input terminal, and a first output terminal;
a first resistor, both ends of which are electrically connected between the first negative input end and the first output end respectively;
a second resistor, both ends of which are electrically connected between the voltage sampling signal and the first negative input end respectively;
a third resistor, both ends of which are electrically connected between the reference voltage and the first positive input end respectively; and
a fourth resistor, both ends of which are electrically connected between a ground end and the first positive input end respectively;
wherein a first ratio is provided between the first resistor and the second resistor, and a second ratio is provided between the third resistor and the fourth resistor; and the first ratio is equal to the second ratio.
6. The constant power control circuit of claim 1, wherein the second gain unit comprises:
a second operational amplifier having a second positive input terminal, a second negative input terminal, and a second output terminal;
a second capacitor, two ends of which are electrically connected between the second positive input end and a ground end respectively;
a fifth resistor, both ends of which are electrically connected between the second negative input end and the ground end respectively;
a sixth resistor, both ends of which are electrically connected between the second negative input end and the second output end respectively; and
the first output signal passes through a seventh resistor, one end of the seventh resistor is electrically connected to the second positive input end and the second capacitor, and the other end of the seventh resistor is electrically connected to the first gain unit.
7. A constant power control circuit is applied in a feedback circuit, wherein the feedback circuit at least comprises a current error amplifier and a voltage error amplifier; and, the constant power control circuit includes:
a gain unit electrically connected to a voltage sampling signal and a reference voltage for performing an amplification process on the voltage sampling signal and the reference voltage based on a gain and then performing a calculation process on the amplified voltage sampling signal and the reference voltage;
a voltage clamping unit electrically connected to the gain unit for receiving an output signal of the gain unit, performing a voltage clamping process on the output signal, and outputting a power control reference signal to the current error amplifier;
the voltage clamping unit comprises an output resistor, a capacitor and a three-terminal controllable voltage stabilizer;
the three-terminal controllable voltage stabilizer is provided with an anode terminal, a cathode terminal and a reference terminal; the cathode end is electrically connected to the cathode end of a first diode, and the anode end is electrically connected to a ground end;
one end of the output resistor is electrically connected to the current error amplifier and the positive end of the first diode, and the other end of the output resistor is electrically connected to the gain unit; and
one end of the capacitor is electrically connected to the current error amplifier and the reference end of the three-terminal controllable voltage stabilizer, and the other end of the capacitor is electrically connected to the ground end.
8. The constant power control circuit according to claim 7, wherein the feedback circuit further comprises:
the voltage sampling unit is electrically connected between the voltage error amplifier and the output end of the power supply conversion module; the voltage sampling unit simultaneously provides the voltage sampling signal to the gain unit;
the current sampling unit is electrically connected between the current error amplifier and the output end of the power supply conversion module and used for providing a current sampling signal to the current error amplifier;
an optical coupler electrically connected to the current error amplifier and the voltage error amplifier; and
a controller electrically connected to the optical coupler;
the current error amplifier has a positive input end, the power control reference signal is linked to the positive input end, the current error amplifier generates a current error signal based on the current sampling signal and the power control reference signal, and transmits the current error signal to the controller through the optocoupler.
9. The constant power control circuit according to claim 8, wherein the power conversion module is located in an electronic device, and the electronic device is any one of the following: a power converter, a power supply, or a transformer type charger.
10. The constant power control circuit as claimed in claim 7, wherein the gain unit comprises:
a first operational amplifier having a first negative input terminal and a first positive input terminal; wherein, when executing the calculation processing, the voltage sampling signal is electrically connected to the first negative input end; and the reference voltage is electrically connected to the first positive input end.
11. The constant power control circuit as claimed in claim 7, wherein the gain unit comprises:
an operational amplifier having a first negative input terminal, a first positive input terminal, and a first output terminal;
a first resistor, both ends of which are electrically connected between the first negative input end and the first output end respectively; and
and the two ends of the second resistor are respectively and electrically connected between the voltage sampling signal and the first negative input end.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
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| CN110165870A (en) | 2019-08-23 |
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