CN114153258A - Power supply closed-loop feedback control circuit and control method - Google Patents
Power supply closed-loop feedback control circuit and control method Download PDFInfo
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Abstract
The invention discloses a power supply closed loop feedback control circuit and a control method in the field of space power supplies of aerospace vehicles, and the power supply closed loop feedback control circuit comprises a first amplifying circuit for amplifying output voltage difference in a split mode and a second amplifying circuit for amplifying output current in a sampling mode, and further comprises a constant voltage comparison circuit and a constant current comparison circuit; the non-inverting input end of the constant voltage comparison circuit is connected with an external constant voltage reference voltage, and the inverting input end of the constant voltage comparison circuit is connected with the output of the first amplifying circuit; the non-inverting input end of the constant current comparison circuit is connected with a peripheral constant current reference voltage, and the inverting input end of the constant current comparison circuit is connected with the output of the second amplification circuit; the output ends of the constant voltage comparison circuit and the constant current comparison circuit are respectively connected with the cathodes of the diodes D1 and D2 in series, the anodes of the diodes D1 and D2 are connected with the power supply end through the circuit R13, and the other circuit is connected with the control signal input end of the PWM controller. The invention improves the practicability and the versatility of the power supply, has simple design, simple and flexible structure, low cost and reliable work and has obvious economic effect.
Description
Technical Field
The invention relates to the field of space power supplies of aerospace crafts, in particular to a power supply closed-loop feedback control circuit and a control method.
Background
In the technical development of space power supplies of aerospace aircrafts at home and abroad, a power supply is mainly a constant-voltage source DC/DC converter, is widely applied to various electronic systems, generally only has a constant-voltage function but not a constant-current function, and simultaneously has an unadjustable constant-voltage output value. The existing constant current source generally adopts a method of additionally adding a current closed loop feedback control circuit on the basis of the traditional constant voltage source to realize constant current output, but has the defects of low circuit output efficiency, large volume, high cost and the like.
Chinese patent CN110231846B proposes a power module feedback control circuit with dual functions of constant current and constant voltage, which can be applied to the feedback control of a power module with a high-power constant current source, and is used to perform error amplification on the output current and voltage of the power module and generate a feedback control signal; through the setting of the control end, the power supply module can work in a constant voltage mode or a constant current mode; when the power supply module works in a constant current mode, the control circuit controls the current output by the power supply module to ensure that the output current is constant, and the output current value is given by an external control signal; when the power supply module works in a constant voltage mode, the control circuit controls the output voltage of the power supply module, the output voltage is ensured to be constant, and the DC/DC converter can be used as a DC voltage conversion DC/DC converter. However, this patent has the following disadvantages:
1. the circuit is complex in composition and difficult to realize, and meanwhile, the constant-voltage mode output is realized by combining the switch S1, so that the circuit is large in size and high in cost;
2. because the voltage stabilizer TL431 is used as a constant voltage reference in the circuit and the constant voltage value is set by combining the resistance ratio of R3/R2, the on-line adjustable function of a constant voltage mode cannot be realized, and the circuit is single, inflexible and inconvenient to use;
3. in the circuit, voltages at multiple positions are subjected to voltage division through a plurality of resistors (resistors R9, R14, R15, R16 and the like) and then input to an input end of an operational amplifier U1 to realize comparison and output, so that the precision of the resistors at the multiple positions is greatly influenced within the full temperature range (-55-125 ℃), and the precision of the output current of the circuit is low.
Therefore, the applicant proposes a power supply closed-loop feedback control circuit and a control method to solve the above problems.
Disclosure of Invention
The present invention is directed to a power supply closed-loop feedback control circuit and a control method thereof, so as to solve the problems in the background art.
In order to achieve the purpose, the invention provides the following technical scheme:
a power supply closed loop feedback control circuit comprises a first amplifying circuit for amplifying output voltage difference in a split mode and a second amplifying circuit for sampling and amplifying output current, and further comprises a constant voltage comparison circuit and a constant current comparison circuit; the non-inverting input end of the constant voltage comparison circuit is connected with an external constant voltage reference voltage, and the inverting input end of the constant voltage comparison circuit is connected with the output of the first amplifying circuit; the non-inverting input end of the constant current comparison circuit is connected with a peripheral constant current reference voltage, and the inverting input end of the constant current comparison circuit is connected with the output of the second amplification circuit; the output ends of the constant voltage comparison circuit and the constant current comparison circuit are respectively connected with the cathodes of the diodes D1 and D2 in series, the anodes of the diodes D1 and D2 are connected with the power supply end through the circuit R13, and the other end of the anode of the diodes is connected with the control signal input end of the PWM controller for controlling the output duty ratio of the power supply.
As a modified scheme of the invention, the first amplifying circuit comprises an operational amplifier U1, resistors R1, R2, R3 and R4; the positive end of a power supply output voltage is connected with the first end of a resistor R1, the second end of a resistor R1 is connected with the non-inverting input end of a first operational amplifier U1, the negative end of the power supply output voltage is connected with the first end of a resistor R2, one path of the second end of the resistor R2 is connected with the inverting input end of the first operational amplifier U1 and the first end of a resistor R3, and the second end of the resistor R3 is connected with the output end of the operational amplifier U1; the output end of the operational amplifier U1 is connected with the constant voltage comparison circuit through a resistor R4, the power supply end is connected with the positive electrode of the power supply end, and the grounding end is connected with the negative electrode of the power supply end.
As an improved scheme of the invention, the second amplifying circuit comprises an operational amplifier U2, resistors R7, R8, R9 and a sampling resistor Rs; the positive end of the power supply output current is connected with the first ends of the resistor R7 and the sampling resistor Rs, the second end of the resistor R7 is connected with the non-inverting input end of the operational amplifier U2, the negative end of the power supply output current is connected with the first end of the resistor R8 and the second end of the sampling resistor Rs, the second end of the resistor R8 is connected with the first end of the resistor R9 and the inverting input end of the operational amplifier U2, the second end of the resistor R9 is connected with the output end of the operational amplifier U2, and the output end of the operational amplifier U2 is connected with the constant-current comparison circuit through the resistor R10.
As an improved scheme of the present invention, the constant voltage comparison circuit includes an operational amplifier U3, a resistor R6, and a diode D1, wherein a non-inverting input terminal of the operational amplifier U3 is connected to a constant voltage reference voltage, an inverting input terminal of the operational amplifier U3 is connected to a second terminal of the resistor R4, and an output terminal of the operational amplifier U3 is connected to a cathode of the diode D1 through a series resistor R6.
As an improvement of the present invention, the constant voltage comparison circuit further includes a resistor R5 and a capacitor C1, and the resistor R5 and the capacitor C1 are connected in series between the inverting input terminal of the operational amplifier U3 and the anode of the diode D1.
As an improved scheme of the present invention, the constant current comparison circuit includes an operational amplifier U4, a resistor R12, and a diode D2, wherein a non-inverting input terminal of the operational amplifier U4 is connected to the constant current reference voltage, an inverting input terminal is connected to a second terminal of the resistor R10, and an output terminal is connected to a cathode of the diode D2 through a series resistor R12.
As an improved scheme of the invention, the constant current comparison circuit further comprises a resistor R11 and a capacitor C2, and the resistor R11 and the capacitor C2 are connected in series between the inverting input terminal of the operational amplifier U4 and the anode of the diode D2.
The control method of the power supply closed-loop feedback control circuit comprises the following steps:
according to the internal parameters of the first amplifying circuit, a constant voltage reference voltage V is givenVREFTo obtain a constant voltage reference voltage VVREFCorresponding output voltage UC；
According to the internal parameters of the second amplifying circuit, a constant current reference voltage V is givenCREFTo obtain a constant current reference voltage VCREFCorresponding output current IC；
Comparing the output U of the first amplifying circuit1And a constant voltage reference voltage VVREF：
If U is1＞VVREFThe anode voltage value of the diode D1 is used as the feedback voltage of the PWM controller, and the PWM controller adjusts the duty ratio to make the power supply output voltage UOAnd a constant voltage reference voltage VVREFCorresponding output voltage UCKeeping the consistency, and enabling the power supply to work in a constant voltage mode;
if U is1<VVREFThe anode voltage value of the diode D2 is used as the feedback voltage of the PWM controller, and the PWM controller adjusts the duty ratio to make the power supply output current IOWith a constant reference voltage VCREFCorresponding output current ICKeeping consistent, the power supply works in a constant current mode.
Has the advantages that: the invention is applied to the closed-loop feedback control of the constant current source and is used for sampling the output current and the output voltage of the power supply, the sampled voltage is amplified and processed by an operational amplifier, and then error amplification is carried out on the sampled voltage, the constant current reference voltage and the constant voltage reference voltage to generate a feedback control signal; the power supply can work in a constant current mode or a constant voltage mode by adjusting and setting a constant current reference voltage or a constant voltage reference voltage. When the power supply works in a constant current mode, the power supply closed loop feedback control circuit performs sampling control on the output current of the power supply to ensure that the output current of the power supply is constant, the magnitude of the output current of the power supply is determined by the magnitude of constant current reference voltage, at the moment, the voltage loop does not work, and only the current loop plays a role; when the power supply works in a constant voltage mode, the power supply closed loop feedback control circuit controls the power supply output voltage to ensure the power supply output voltage to be constant, the size of the power supply output voltage is determined by the size of constant voltage reference voltage, the current loop does not work at the moment, only the voltage loop plays a role, and the power supply can be used as a conventional constant voltage source DC/DC converter at the moment.
In the design of the closed-loop feedback control circuit, when the power supply works in a constant-current mode, the output voltage of the power supply changes along with the change of a load, so that the output current is ensured to be constant; when the output voltage of the power supply changes to the output voltage corresponding to the constant voltage reference voltage, the output voltage of the power supply does not change, the output current of the power supply changes along with the change of the load, and the output voltage of the power supply is ensured to be constant, namely the output voltage of the power supply in the constant voltage mode is also the maximum output voltage of the power supply in the constant current mode.
Compared with the conventional method of additionally adding a current closed loop feedback control circuit on the basis of a constant voltage source circuit to realize constant current output, the method effectively reduces the system volume, improves the practicability and the versatility of the power supply, has simple and flexible design, simple and flexible structure, low cost and reliable work, improves the precision of the power supply output current to a greater degree compared with the prior art, and has obvious economic effect.
Drawings
FIG. 1 is a schematic circuit diagram of the present invention;
fig. 2 is a schematic block diagram of the circuit of the present invention implemented in a constant current source.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1, a power supply closed-loop feedback control circuit includes a first amplifying circuit for amplifying an output voltage difference in a divided manner and a second amplifying circuit for sampling and amplifying an output current, and further includes a constant voltage comparing circuit and a constant current comparing circuit.
The first amplifying circuit comprises an operational amplifier U1, resistors R1, R2, R3 and R4; the positive end of a power supply output voltage is connected with the first end of a resistor R1, the second end of a resistor R1 is connected with the non-inverting input end of a first operational amplifier U1, the negative end of the power supply output voltage is connected with the first end of a resistor R2, one path of the second end of the resistor R2 is connected with the inverting input end of the first operational amplifier U1 and the first end of a resistor R3, and the second end of the resistor R3 is connected with the output end of the operational amplifier U1; the output end of the operational amplifier U1 is connected with a constant voltage comparison circuit through a resistor R4, the power supply end is connected with the positive pole VCC of the power supply end, and the grounding end is connected with the negative pole of the power supply end.
The constant voltage comparison circuit comprises an operational amplifier U3, a resistor R6 and a diode D1, wherein the non-inverting input end of the operational amplifier U3 is connected with a constant voltage reference voltage, the inverting input end of the operational amplifier U3 is connected with the second end of the resistor R4, and the output end of the operational amplifier U3 is connected with the cathode of the diode D1 through a series resistor R6. The power supply end of the operational amplifier U3 is also connected with a power supply end anode VCC, and the grounding end is connected with a power supply end cathode. Preferably, the constant voltage comparison circuit further includes a resistor R5 and a capacitor C1, the resistor R5 and the capacitor C1 are connected in series between the inverting input terminal of the operational amplifier U3 and the anode of the diode D1, and are compensation networks of the phase and the frequency of the operational amplifier U3.
The second amplifying circuit comprises an operational amplifier U2, resistors R7, R8, R9 and a sampling resistor Rs; the positive end of the power supply output current is connected with the resistor R7 and the first end of the sampling resistor Rs, the second end of the resistor R7 is connected with the non-inverting input end of the operational amplifier U2, the negative end of the power supply output current is connected with the first end of the resistor R8 and the second end of the sampling resistor Rs, the second end of the resistor R8 is connected with the first end of the resistor R9 and the inverting input end of the operational amplifier U2, the second end of the resistor R9 is connected with the output end of the operational amplifier U2, and the output end of the operational amplifier U2 is connected with the constant-current comparison circuit through the resistor R10.
The constant current comparison circuit comprises an operational amplifier U4, a resistor R12 and a diode D2, wherein the non-inverting input end of the operational amplifier U4 is connected with a constant current reference voltage, the inverting input end of the operational amplifier U4 is connected with the second end of the resistor R10, and the output end of the operational amplifier U4 is connected with the cathode of the diode D2 through a series resistor R12. The power supply end of the operational amplifier U4 is further connected to the positive electrode of the power supply end, the ground end is connected to the negative electrode power supply end of the power supply end, and the power supply end is generally 12V or 15V. Preferably, the constant current comparison circuit further comprises a resistor R11 and a capacitor C2, wherein the resistor R11 and the capacitor C2 are connected in series between the inverting input terminal of the operational amplifier U4 and the anode of the diode D2, and are compensation networks of the phase and the frequency of the operational amplifier U4.
The control method comprises the following steps:
before the circuit works, a constant voltage reference voltage V is arranged at the non-inverting input end of the operational amplifier U3 by an external (upper computer)VREFThe constant voltage reference voltage VVREFCorresponding output voltage UCThe power supply works in a constant current modeThe maximum output voltage. Meanwhile, a constant-current reference voltage V is arranged at the non-inverting input end of the operational amplifier U4 by an external (upper computer)CREFThe constant current reference voltage VCREFCorresponding output current ICTo set the output current of the power supply when operating.
When the circuit is working, the power supply outputs current IOSampling is carried out through a sampling resistor Rs, and the sampling voltage obtained by the sampling resistor Rs is as follows:
US＝IO×RS (1)
the operational amplifier U2 differentially amplifies the voltage across the sampling resistor Rs, and the amplified voltage of the operational amplifier U2 is:
U2＝US×(1+R9/R8) (2)
constant current reference voltage V under constant current modeCREFWith corresponding output current ICThe relationship of (1) is:
VCREF＝IC×RS×(1+R9/R8) (3)
similarly, the operational amplifier U1 outputs a voltage U to the power supplyODifferential amplification is carried out, and the voltage amplified by the operational amplifier U1 is as follows:
U1＝UO×(1+R3/R2) (4)
constant voltage reference voltage V in constant voltage modeVREFWith corresponding output voltage UCThe relationship of (1) is:
VVREF＝UC×(1+R3/R2) (5)
voltage U output by operational amplifier U11And a constant voltage reference voltage VVREFThe error is processed by an operational amplifier U3, and the output voltage of the operational amplifier U3 is U3. Voltage U output by operational amplifier U22With a constant reference voltage VCREFThe voltage U is output after error processing by an operational amplifier U44。
If the output voltage U of the operational amplifier U22Greater than constant current reference voltage VCREFWhen the voltage at the inverting input end of the operational amplifier U4 is greater than the voltage at the non-inverting input end, the output voltage U4 of the operational amplifier U4 is greater than the voltage at the inverting input end4The diode D2 is conducted, and the anode voltage value of the diode D2 is used as a feedback voltage for controlling the PWM controllerAnd (5) outputting a control signal, and adjusting the output duty ratio of the PWM controller. Whether the load changes or the constant current reference voltage VCREFThe change can be performed through sampling processing of the operational amplifier U2 and comparison output of the operational amplifier U4, and then the duty ratio output by the PWM controller is adjusted, and the output current I of the power supply is adjustedOAlways with constant current reference voltage VCREFCorresponding output current ICKeeping consistent, thereby realizing constant current output.
If the power supply works in the constant current mode, the power supply outputs a voltage U at the momentOAfter differential amplification, the reference voltage V is compared with a constant voltage reference voltageVREFComparing, if less than the constant voltage reference voltage VVREFIf the voltage at the inverting input terminal of the operational amplifier U3 is less than the voltage at the non-inverting input terminal, the output voltage U3 of the operational amplifier U3 is obtained3At a positive voltage VCC, the diode D1 is turned off in the reverse direction, and the constant voltage loop is not active and remains in the constant current mode.
If the power supply outputs the voltage U under the constant current modeOAfter differential amplification, the reference voltage V is compared with a constant voltage reference voltageVREFIs compared with a constant voltage reference voltage VVREFAt this time, the operational amplifier U3 has negative inversion, and outputs the voltage U3The diode D1 is conducted for-VCC, the anode voltage value of the diode D1 is used as feedback voltage for the control signal output of the PWM controller, and the output duty ratio of the PWM controller is adjusted to enable the power supply to output the voltage UOAlways with a constant voltage reference voltage VVREFCorresponding output voltage UCKeeping the consistency, realizing constant voltage output, and converting the constant current loop into a constant voltage mode when the constant current loop does not work.
In general, the load corresponding to the constant current mode is small, and the output voltage U of the operational amplifier U2 does not appear under closed-loop control2Less than constant current reference voltage VCREFThe case (1). When the load becomes large to a certain degree, the constant-current closed-loop regulation is out of control, and the output current IOToo small to result in less than constant current reference voltage VCREFCorresponding output current ICAt this time, the power supply outputs a voltage UOWill be greater than the constant voltage reference voltage VVREFCorresponding output voltage UCI.e. the output of the amplifier U1 is greater than the constant voltage reference voltage VVREFSo that the constant current mode is changed to the constant voltage mode.
Such as: when the reference voltage V is constantVREFSetting the voltage to 5V, and setting a constant voltage reference voltage V of 5V through parameter design of internal resistors (R2, R3)VREFThe corresponding output voltage U at this timeCIs 25V; similarly, the constant current reference voltage VCREFSetting the voltage to 5V, and setting the corresponding output current I at the time through parameter design of internal resistors (Rs, R8 and R9)CIs 5A, therefore, the power supply outputs the voltage U with the load change, such as the load between 0 Ω and 5 ΩOIs not more than output voltage UCThe power supply outputs a constant current 5A and an output current ICAnd the consistency is maintained. If the constant current reference voltage V is setCREFSet to 1V, corresponding to the output current IC1A, and the output voltage U of the power supply varies with the load, such as between 0 omega and 25 omegaOIs not more than output voltage UC(25V), constant current output 1A of the circuit, and output current ICAnd the consistency is maintained.
Therefore, the output of the constant current values of different gears can be effectively adjusted by adjusting the given constant current reference voltage value.
For another example: when the reference voltage V is constantVREFSetting the voltage to 5V, and setting the corresponding output voltage U at the time through parameter design of internal resistors (R2, R3)CIs 25V; similarly, the constant current reference voltage VCREFSetting the voltage to 5V, and setting the corresponding output current I at the time through parameter design of internal resistors (Rs, R8 and R9)CIs 5A, so that the power supply output voltage U varies with load, e.g. at a load > 5 omegaOProcessed by an operational amplifier U1 and then mixed with a constant voltage reference voltage VVREFComparing the output voltage U of the power supplyOIs obviously greater than the constant voltage reference voltage VVREFCorresponding output voltage UCAt this time, the operational amplifier U3 is turned over negatively, the power supply outputs 25V at constant voltage, and the output voltage UCAnd the consistency is maintained.
If the reference voltage V is constantVREFSet to 1V, corresponding to the output voltage UCAt 5V, if the constant current reference voltage V is setCREFSet to 5V, corresponding to the output current IC5A, then the power varies with the load, e.g. at a load > 1 ΩSource output voltage UOIs obviously greater than the constant voltage reference voltage VVREFCorresponding output voltage UCConstant voltage output of 5V and output voltage UCAnd the consistency is maintained.
Therefore, the constant voltage reference voltage V can be flexibly adjusted according to different load conditionsVREFAnd a constant current reference voltage VCREFThe constant current output or the constant voltage output can be realized by respectively setting, and the device has powerful functions and flexible use.
If the circuit is used as a constant voltage source, the constant current reference voltage can be set to be higher, and the constant voltage reference voltage can be set to be lower. If used as a constant current source, the constant voltage reference voltage may be set high and the constant current reference voltage may be set low.
Such as: when the circuit is used as a constant voltage source for 10V constant voltage output, the constant voltage reference voltage V is usedVREFSet to 2V while keeping constant current reference voltage VCREFSet to 5V, the power supply will be used as a constant voltage source of 10V when the output impedance (load) is greater than 2 Ω.
When the circuit is used as a constant current source for 2A constant current output, the constant current reference voltage is set to be 2V, and meanwhile, the constant voltage reference voltage is set to be 5V, so that when the output impedance (load) is less than 12.5 omega, the circuit is used as a 2A constant current source;
according to the practical use process, the output impedance of the constant voltage source is generally larger, and the output impedance of the constant current source is generally smaller. Therefore, the constant voltage reference voltage and the constant current reference voltage are flexibly and respectively set, and the circuit can be used as a constant voltage source and also can be used as a constant current source.
Referring to fig. 2, a schematic block diagram of a circuit implemented in a constant current source according to the present invention is an embodiment of the present invention, and is applied to a closed-loop feedback control circuit in the constant current source. The constant current source circuit comprises input filtering, power conversion, a transformer, rectification, filtering, auxiliary power supply, an isolation transformer, a closed loop feedback control circuit, a PWM control unit and the like, and the requirements of constant current output and constant voltage output of the constant current source can be met by adopting the power supply closed loop feedback control circuit.
The invention is applied to constant current power supplies with different input voltage ranges, the output power is 120W at most, the constant voltage output is 35V at most or the constant current output is 8A at most. Through setting the closed-loop parameters of the power supply closed-loop feedback control circuit, different constant voltage and constant current outputs corresponding to different reference control voltages can be realized.
Although the present description is described in terms of embodiments, not every embodiment includes only a single embodiment, and such description is for clarity only, and those skilled in the art should be able to integrate the description as a whole, and the embodiments can be appropriately combined to form other embodiments as will be understood by those skilled in the art.
Therefore, the above description is only a preferred embodiment of the present application, and is not intended to limit the scope of the present application; all changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.
Claims (8)
1. A power supply closed loop feedback control circuit is characterized by comprising a first amplifying circuit for amplifying output voltage difference in a split mode and a second amplifying circuit for sampling and amplifying output current, a constant voltage comparing circuit and a constant current comparing circuit;
the non-inverting input end of the constant voltage comparison circuit is connected with a peripheral constant voltage reference voltage, and the inverting input end of the constant voltage comparison circuit is connected with the output of the first amplifying circuit; the non-inverting input end of the constant current comparison circuit is connected with a peripheral constant current reference voltage, and the inverting input end of the constant current comparison circuit is connected with the output of the second amplification circuit; the output ends of the constant voltage comparison circuit and the constant current comparison circuit are respectively connected with the cathodes of the diodes D1 and D2 in series, the anodes of the diodes D1 and D2 are connected with the power supply end through the circuit R13, and the other circuit is connected with the control signal input end of the PWM controller for controlling the output duty ratio of the power supply.
2. The closed-loop feedback control circuit of claim 1, wherein said first amplifier circuit comprises an op-amp U1, resistors R1, R2, R3, R4; the positive end of a power supply output voltage is connected with the first end of a resistor R1, the second end of a resistor R1 is connected with the non-inverting input end of a first operational amplifier U1, the negative end of the power supply output voltage is connected with the first end of a resistor R2, one path of the second end of the resistor R2 is connected with the inverting input end of the first operational amplifier U1 and the first end of a resistor R3, and the second end of the resistor R3 is connected with the output end of the operational amplifier U1; the output end of the operational amplifier U1 is connected with the constant voltage comparison circuit through a resistor R4, the power supply end is connected with the positive electrode of the power supply end, and the grounding end is connected with the negative electrode of the power supply end.
3. The closed-loop feedback control circuit of claim 1, wherein said second amplifying circuit comprises an op-amp U2, resistors R7, R8, R9, and a sampling resistor Rs; the positive end of the power supply output current is connected with the first ends of the resistor R7 and the sampling resistor Rs, the second end of the resistor R7 is connected with the non-inverting input end of the operational amplifier U2, the negative end of the power supply output current is connected with the first end of the resistor R8 and the second end of the sampling resistor Rs, the second end of the resistor R8 is connected with the first end of the resistor R9 and the inverting input end of the operational amplifier U2, the second end of the resistor R9 is connected with the output end of the operational amplifier U2, and the output end of the operational amplifier U2 is connected with the constant-current comparison circuit through the resistor R10.
4. The power supply closed-loop feedback control circuit as claimed in claim 2, wherein the constant voltage comparison circuit comprises an operational amplifier U3, a resistor R6 and a diode D1, a non-inverting input terminal of the operational amplifier U3 is connected to a constant voltage reference voltage, an inverting input terminal of the operational amplifier U3 is connected to the second terminal of the resistor R4, and an output terminal of the operational amplifier U3 is connected to the cathode of the diode D1 through a series resistor R6.
5. The power supply closed-loop feedback control circuit as claimed in claim 4, wherein the constant voltage comparison circuit further comprises a resistor R5 and a capacitor C1, and the resistor R5 and the capacitor C1 are connected in series between the inverting input terminal of the operational amplifier U3 and the anode of the diode D1.
6. The power supply closed-loop feedback control circuit as claimed in claim 3, wherein the constant current comparison circuit comprises an operational amplifier U4, a resistor R12 and a diode D2, a non-inverting input terminal of the operational amplifier U4 is connected to the constant current reference voltage, an inverting input terminal is connected to the second terminal of the resistor R10, and an output terminal is connected to the cathode of the diode D2 through a series resistor R12.
7. The power supply closed-loop feedback control circuit as claimed in claim 6, wherein the constant current comparison circuit further comprises a resistor R11 and a capacitor C2, and the resistor R11 and the capacitor C2 are connected in series between the inverting input terminal of the operational amplifier U4 and the anode of the diode D2.
8. The method for controlling the closed-loop feedback control circuit of the power supply according to any one of claims 1 to 7, wherein the method comprises:
according to the internal parameters of the first amplifying circuit, a constant voltage reference voltage V is givenVREFTo obtain a constant voltage reference voltage VVREFCorresponding output voltage UC；
According to the internal parameters of the second amplifying circuit, a constant current reference voltage V is givenCREFTo obtain a constant current reference voltage VCREFCorresponding output current IC；
Comparing the output U of the first amplifying circuit1And a constant voltage reference voltage VVREF：
If U is1＞VVREFThe anode voltage value of the diode D1 is used as the feedback voltage of the PWM controller, and the PWM controller adjusts the duty ratio to make the power supply output voltage UOAnd a constant voltage reference voltage VVREFCorresponding output voltage UCKeeping the consistency, and enabling the power supply to work in a constant voltage mode;
if U is1<VVREFThe anode voltage value of the diode D2 is used as the feedback voltage of the PWM controller, and the PWM controller adjusts the duty ratio to make the power supply output current IOWith a constant reference voltage VCREFCorresponding output current ICKeeping consistent, the power supply works in a constant current mode.
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| CN115390608A (en) * | 2022-07-22 | 2022-11-25 | 上海裕达实业有限公司 | Power supply control circuit and control method for residual gas analysis mass spectrum |
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