CN110336468B - Flyback power circuit, current cut-off method and power supply equipment - Google Patents
Flyback power circuit, current cut-off method and power supply equipment Download PDFInfo
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- CN110336468B CN110336468B CN201910595576.XA CN201910595576A CN110336468B CN 110336468 B CN110336468 B CN 110336468B CN 201910595576 A CN201910595576 A CN 201910595576A CN 110336468 B CN110336468 B CN 110336468B
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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
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
- H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
- H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
- H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
Abstract
The invention relates to the technical field of current control, and discloses a flyback power supply circuit, a current cut-off method and power supply equipment, wherein the flyback power supply circuit comprises: the flyback power supply comprises a flyback transformer, a switching circuit, a release circuit, an interception circuit and a control circuit, wherein the flyback transformer comprises a primary circuit and a secondary circuit which are in coupling connection, when an electric signal of a flyback power supply circuit acquired by the control circuit reaches a preset reference electric signal, the release circuit and the primary circuit are controlled to form a release loop so as to release energy of the primary circuit, and the interception circuit intercepts secondary current flowing through the secondary loop. When controlling secondary current, on the one hand, through the energy of releasing the primary side to secondary current chopping to the secondary side, on the other hand, when releasing the energy of primary side, cut off the secondary current that flows through secondary side circuit through the cut-off circuit, make guarantee once more to secondary current reliable chopping, and then improve the control accuracy to secondary current.
Description
Technical Field
The invention relates to the technical field of current control, in particular to a flyback power supply circuit, a current cut-off method and power supply equipment.
Background
In some special application fields, such as neuron control, laser pulse control, etc., an adjustable high-voltage pulse wave is required, but strict requirements are imposed on the voltage, current amplitude, energy and charge quantity of the high-voltage pulse wave, accurate control is required, and the requirement on control precision is particularly high. Due to the existence of some nonlinear devices in the circuit, precise control of the high voltage pulse becomes difficult.
Disclosure of Invention
An object of an embodiment of the present invention is to provide a flyback power supply circuit, a current blocking method, and a power supply device, so as to accurately control a secondary current of a flyback power supply.
In order to solve the above technical problem, one technical solution adopted by the embodiments of the present invention is: provided is a flyback power supply circuit including:
the flyback transformer comprises a primary side circuit and a secondary side circuit which are coupled and connected;
the switching circuit is connected with the primary side circuit, when the switching circuit is switched on, primary side current flows through the primary side circuit, and when the switching circuit is switched off, the primary side current does not flow through the primary side circuit;
the discharge circuit is connected with the primary side circuit;
the cut-off circuit is connected with the secondary side circuit;
and the control circuit is respectively connected with the switch circuit and the discharge circuit and is used for sampling the electric signal of the flyback power supply circuit, and when the electric signal reaches a preset reference electric signal, the discharge circuit is started so that the discharge circuit and the primary side circuit form a discharge circuit to discharge the energy of the primary side circuit, and the cut-off circuit cuts off the secondary current flowing through the secondary side circuit. In some embodiments, the flyback power supply circuit is configured with the preset reference electrical signal.
In some embodiments of the present invention, the,
the cut-off circuit comprises a voltage stabilizing diode, the anode of the voltage stabilizing diode is connected with the synonym end of the secondary side circuit of the flyback transformer, the cathode of the voltage stabilizing diode is connected with a load, and when the voltage stabilizing diode is cut off, the secondary current of the secondary side circuit is cut off.
In some embodiments, the current cut-off circuit comprises a transient suppression diode, the anode of the transient suppression diode is connected with the synonym terminal of the secondary side circuit of the flyback transformer, and the cathode of the transient suppression diode is connected with a load.
In some embodiments, the current cut-off circuit includes a voltage dependent resistor, one end of the voltage dependent resistor is connected to the synonym terminal of the secondary side circuit of the flyback transformer, and the other end of the voltage dependent resistor is connected to a load.
In some embodiments, the control circuit comprises: a sampling circuit for sampling the signal of the input signal,
the flyback power supply circuit is used for sampling an electric signal of the flyback power supply circuit; and the controller is respectively connected with the sampling circuit, the bleeder circuit and the switch circuit and used for starting the bleeder circuit when the electric signal reaches the reference electric signal, so that the bleeder circuit and the primary side circuit form a bleeder circuit to discharge the energy of the primary side circuit, and the cut-off circuit cuts off the secondary current flowing through the secondary side circuit.
In some embodiments, the bleeding circuit comprises: the first leakage circuit comprises a first leakage switch and a first leakage resistor, wherein the first leakage switch comprises a first terminal, a second terminal and a third terminal, the second terminal is a control terminal, the second terminal is connected with the control circuit, the third terminal is connected with a primary synonym terminal of the flyback transformer, the first terminal is connected with one end of the first leakage resistor, the other end of the first leakage resistor is connected with a primary synonym terminal of the flyback transformer, when the electric signal reaches the reference electric signal, the control circuit controls the first leakage switch to be closed, and the first leakage switch, the primary side of the flyback transformer and the first leakage resistor form a leakage loop to discharge energy of the primary side circuit.
In some embodiments, the bleeding circuit comprises: the second leakage switch comprises a fourth terminal, a fifth terminal and a sixth terminal, the fifth terminal is a control terminal, the fourth terminal is used for being connected with a direct current input cathode of the flyback power circuit, the fifth terminal is connected with the control circuit, the sixth terminal is respectively connected with an anode of the leakage diode and the switch circuit, a cathode of the leakage diode is connected with one end of the second leakage resistor, the other end of the second leakage resistor is connected with a primary side synonym end of the flyback transformer, when the electric signal reaches the preset reference electric signal, the control circuit controls the second leakage switch to be closed and controls the switch circuit to be conducted, and the second leakage resistor, the leakage diode, the switch circuit and the primary side of the flyback transformer form a leakage loop to discharge energy of the primary side circuit .
In another aspect of the embodiments of the present invention, a current blocking method is provided, and is applied to the flyback power supply circuit, where the method includes:
sampling an electric signal of the flyback power supply circuit;
and when the electric signal reaches the reference electric signal, starting the leakage circuit, so that the leakage circuit and the primary side circuit form a leakage loop to discharge the energy of the primary side circuit, and the cut-off circuit cuts off the secondary current flowing through the secondary side circuit.
In another aspect of the embodiments of the present invention, a power supply device is provided, which includes the flyback power supply circuit described above.
The embodiment of the invention has the beneficial effects that: different from the situation in the prior art, in the flyback power supply circuit provided in the embodiment of the present invention, the flyback transformer includes the primary side circuit and the secondary side circuit that are coupled, and the switching circuit is connected to the primary side circuit. The control circuit is respectively connected with the switch circuit and the release circuit, samples the electric signal of the flyback power circuit, starts the release circuit when the electric signal reaches a preset reference electric signal, so that the release circuit and the primary circuit form a release loop to release the energy of the primary circuit, and the cut-off circuit cuts off the secondary current flowing through the secondary circuit. When controlling secondary current, on the one hand, through the energy of releasing the primary side to secondary current chopping to the secondary side, on the other hand, when releasing the energy of primary side, cut off the secondary current that flows through secondary side circuit through the cut-off circuit, make guarantee once more to secondary current reliable chopping, and then improve the control accuracy to secondary current.
Drawings
Fig. 1 is a schematic structural diagram of a power supply equipment system according to an embodiment of the present invention;
fig. 2 is a timing diagram of operation of a prior art flyback power supply circuit secondary current control;
fig. 3 is a schematic structural diagram of a flyback power supply circuit according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of a flyback power supply circuit according to another embodiment of the present invention;
FIG. 5 is a timing diagram illustrating the operation of the secondary current control according to another embodiment of the present invention;
fig. 6 is a schematic structural diagram of a flyback power supply circuit according to yet another embodiment of the present invention;
FIG. 7 is a timing diagram illustrating the operation of secondary current control according to yet another embodiment of the present invention;
fig. 8 is a schematic flow chart of a current chopping method according to an embodiment of the present invention.
Detailed Description
In order to facilitate an understanding of the invention, the invention is described in more detail below with reference to the accompanying drawings and detailed description. It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for descriptive purposes only.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a power supply equipment system according to an embodiment of the present invention. As shown in fig. 1, the power supply device system 10 includes a power supply 100, a flyback power supply circuit 200, and a load 300.
The power supply 100 is connected to the flyback power supply circuit 200 to provide power to the flyback power supply circuit 200, the power supply 100 may be a dc power supply or an ac power supply, and the power supply 100 may be a power supply circuit composed of any suitable discrete components, for example, in some embodiments, the power supply 100 is a power supply circuit composed of a filter circuit, a rectifier circuit, and a voltage regulator circuit, and further for example, in some embodiments, the power supply 100 is an integrated power supply chip.
The flyback power supply circuit 200 processes the power supplied by the power supply 100 to obtain a secondary high-voltage signal, wherein the secondary high-voltage signal may be a secondary high-voltage pulse wave or a secondary high-voltage wave with other shapes.
The flyback power supply circuit 200 is connected to the load 300, and supplies the load 300 with the secondary high-voltage pulse wave, and the load 300 implements a corresponding load control logic according to the driving of the secondary high-voltage pulse wave. When the loads are different, the power supply device system provided by the embodiment of the invention can realize different application functions, for example, the power supply device system 10 can be used in the fields of neuron control, laser pulse control and the like, the power supply device system 10 can generate secondary high-voltage pulse waves and can accurately control secondary high-voltage pulses, for example, chopping secondary high-voltage pulse current and accurately cutting off residual current of the secondary high-voltage pulses.
In some embodiments, the power supply 100 is a dc power supply, the dc power supply includes an anode Vin + and a cathode Vin-, the flyback power circuit includes a primary circuit and a secondary circuit, the anode Vin + of the dc power supply returns to the cathode Vin through the primary circuit, and the secondary circuit generates a secondary current when the primary circuit is disconnected, so as to provide energy to the load 300.
When the secondary side circuit lacks the function of cutting off the secondary current, and when the secondary current is chopped, the timing diagram of the secondary current is as shown in fig. 2, and as can be seen from fig. 2, when the secondary current is chopped, a voltage drop is generated on the primary side circuit due to internal resistance and the like in the primary side circuit and the secondary side circuit, and the voltage is fed back to the secondary side circuit and is applied to two ends of the load 300, so that a residual secondary current is formed, and therefore, the secondary current is not immediately cut off at the chopping time, but is attenuated according to an inductance-resistance series model. Therefore, the system cannot accurately control the secondary current, and the control accuracy is not high.
Therefore, the flyback power supply circuit provided by the embodiment of the invention can at least solve the related technical problems existing in the embodiments. Referring to fig. 3, fig. 3 is a schematic structural diagram of a flyback power supply circuit according to an embodiment of the present invention, the flyback power supply circuit 200 includes a flyback transformer 210, a switching circuit 220, a bleeding circuit 230, a current cut-off circuit 240, and a control circuit 250.
The flyback transformer 210 includes a primary circuit and a secondary circuit coupled to each other;
the switch circuit 220 is connected to the primary side circuit, when the switch circuit 220 is turned on, the primary side current flows through the primary side circuit, and when the switch circuit 220 is turned off, the primary side current does not flow through the primary side circuit;
the bleeding circuit 230 is connected to the primary side circuit;
the cut-off circuit 240 is connected with the secondary side circuit;
the control circuit 250 is respectively connected to the switch circuit 220 and the bleeding circuit 230, and is configured to sample an electrical signal of the flyback power supply circuit, and when the electrical signal attenuates to a preset reference electrical signal, start the bleeding circuit 230, so that the bleeding circuit 230 and the primary circuit form a bleeding loop to bleed off energy of the primary circuit, and the cut-off circuit 240 cuts off a secondary current flowing through the secondary circuit.
When the flyback power supply circuit 200 is working, first the control circuit 250 controls the switch circuit 220 to form a closed loop with the primary circuit and the positive and negative poles of the dc power supply in the power supply equipment system, so that the dc input current of the power supply equipment system flows through the primary circuit to form a primary current, and no current passes through the secondary circuit, then, when energy needs to be supplied to the load 300, the control circuit 250 controls the switch circuit 220 to be disconnected, so that the primary circuit is disconnected with the input of the power supply equipment system, and the secondary circuit of the flyback transformer 210 forms a secondary current, so as to supply power to the load 300, the primary and secondary voltage relationship is in direct proportion to the coil turn ratio relationship of the primary circuit and the secondary circuit of the flyback transformer 210, meanwhile, the control circuit 250 collects the electrical signal of the flyback power supply circuit 200, the electrical signal can be an electrical signal such as current, voltage or charge amount, and when the electrical signal, the control circuit 250 controls the bleeding circuit 230 to start, so that the bleeding circuit 230 and the primary circuit form a bleeding loop to bleed energy of the primary circuit, meanwhile, the cut-off circuit 240 cuts off secondary current flowing through the secondary circuit to achieve accurate control of the secondary current, and also performs accurate chopping on the secondary current, the control circuit 250 controls single pulse, and performs accurate chopping on the single secondary pulse, wherein the value of the preset reference electric signal can be changed according to requirements without setting.
In some embodiments, the flyback transformer 210 is also referred to as a single-ended flyback or "Buck-Boost" converter. When the primary circuit of the transformer is excited by the input voltage of the power supply device, the secondary circuit of the transformer does not provide a power output to the load RL, and the power output is provided to the load RL only after the excitation voltage of the primary circuit of the transformer is turned off.
The primary circuit and the secondary circuit of the flyback transformer 210 are coils arranged according to a certain turn ratio relationship, the synonym end of the primary circuit is respectively connected with the bleeder circuit 230 and the positive input Vin + of the power supply equipment, the synonym end of the primary circuit is respectively connected with the bleeder circuit 230 and the switch circuit 220, the secondary circuit and the load RL form a loop, the secondary circuit can output power to the load RL, the control circuit 250 can acquire the voltage of the primary circuit and the current of the secondary circuit, or acquire electric signals such as the charge quantity of the primary circuit and the secondary circuit, so as to monitor the change of the energy of the primary circuit or the secondary circuit.
In some embodiments, the switch circuit 220 includes a first switch K1, the first switch K1 includes an input terminal, a control terminal, and an output terminal, wherein the output terminal of the first switch K1 is connected to the dotted terminal of the primary circuit of the flyback transformer 210, the control terminal is connected to the control circuit 250, the input terminal is connected to the negative Vin-of the power input, the control circuit 250 can control the first switch K1 to be turned on and off, when the control circuit 250 controls the control terminal and the output terminal of the first switch K1 to be connected, and the first switch K1 is in a closed state, the input voltage of the power device is filtered by the capacitor C1 to excite the primary circuit, and the primary circuit has a primary current flowing through. When power needs to be supplied to the load RL, the control circuit 250 controls the control end and the output end to be disconnected, that is, the first switch K1 is disconnected, the primary side loop is disconnected, and the primary side energy is transmitted to the load RL of the secondary side loop through the flyback transformer 210. The switch circuit 220 may have various forms, such as a contactor, a relay, an electronic switch, a time delay switch, a photoelectric switch, a tact switch, a proximity switch, a double-control switch, and the like, or various combinations thereof.
In some embodiments, the bleeding circuit 230 includes a first bleeding switch K2 and a first bleeding resistor R1, wherein the first bleeding switch K2 includes a first terminal, a second terminal and a third terminal, the second terminal is a control terminal, the second terminal is connected to the control circuit 250, the third terminal is connected to a different-name terminal of the primary side of the flyback transformer 210, the first terminal is connected to one terminal of the first bleeding resistor R1, and the other terminal of the first bleeding resistor R1 is connected to a same-name terminal of the primary side of the flyback transformer 210, wherein when the current or the voltage or the charge amount of the primary side circuit or the secondary side circuit loop reaches a certain value, that is, a preset reference electrical signal is reached, or when the secondary current needs to be chopped, the control circuit 250 controls the second terminal of the first bleeding switch K2 to be connected to the second terminal, that is, the first bleeding switch K2 is in a closed state, the first bleeding switch K2 is connected to the primary side transformer 210 circuit, The first bleeder resistor R1 forms a bleeder circuit to bleed off the energy of the primary side circuit, at this time, the primary side current starts from the dotted terminal of the primary side circuit, passes through the first bleeder resistor R1, then passes through the first bleeder switch K2, then passes through the dotted terminal of the primary side circuit, and returns to the dotted terminal of the primary side circuit, thereby releasing the energy of the primary side circuit, and thus realizing the chopping of the secondary side current.
In some embodiments, the cut-off circuit 240 is configured with a predetermined reference electrical signal, which is a predetermined electrical signal that can be set according to the requirement, when the current of the secondary circuit is chopped, the control circuit 250 activates the bleeding circuit 230 to form the primary bleeding circuit, and the electrical signal value of the secondary circuit at this time is the predetermined reference electrical signal value. The predetermined reference electrical signal configured by the cut-off circuit 240 may be a predetermined reference current, a predetermined reference charge amount, or a predetermined reference voltage.
In some embodiments, the current cutoff circuit 240 includes a zener diode Z1, the anode of the zener diode Z1 is connected to the synonym terminal of the secondary side circuit of the flyback transformer 210, and the cathode of the zener diode Z1 is connected to the load RL. When energy needs to be supplied to the load RL, the control circuit 250 controls the switch circuit 220 to act, so that the primary side loop is disconnected, the current of the secondary side loop starts from the homonymous end of the secondary side circuit, is rectified by the diode D1, passes through the load RL, passes through the voltage regulator tube Z1, passes through the heteronymous end of the secondary side circuit and returns to the homonymous end of the secondary side circuit, and the purpose of supplying energy to the load RL is achieved. When the electrical signal of the flyback power circuit reaches the predetermined reference electrical signal, or when the secondary current of the secondary circuit needs to be chopped, the control circuit 250 starts the bleed-off circuit to bleed off the primary energy, at this time, the voltage of the secondary circuit decreases,
because the voltage of the secondary side circuit is less than the reverse breakdown voltage of the voltage-stabilizing tube, the voltage-stabilizing tube is cut off, and then the secondary side loop is quickly cut off, namely, the secondary current is quickly cut off, no residual secondary current flows in the secondary side loop, and the control precision and the pulse width of the secondary current are ensured by the operation.
In some embodiments, the current cut-off circuit 240 may further include a transient suppression diode, also known as tvs (transient Voltage super) diode, which is a commonly used new type of high-efficiency circuit protection device having extremely fast response time (sub-nanosecond level) and relatively high surge absorption capability. When the two ends of the TVS are subjected to transient high-energy impact, the TVS can change the impedance value between the two ends from high impedance to low impedance at a very high speed so as to absorb a transient large current and clamp the voltage between the two ends of the TVS at a preset value, thereby protecting the following circuit elements from the impact of transient high-voltage spike pulse.
The TVS diode is similar to the common voltage stabilizing diode in working principle, is provided with breakdown voltage, and is conducted if the breakdown voltage is higher than the breakdown voltage. In this embodiment, the anode of the TVS diode is connected to the different-name end of the secondary side circuit of the flyback transformer 210, and the cathode of the TVS diode is connected to the load RL, and the operating principle of the circuit is similar to that of the voltage regulator tube Z1, and therefore, the details are not repeated here.
In some embodiments, the cut-off circuit 240 may further include a voltage dependent resistor R, which is a resistor device with nonlinear current-voltage characteristics and is mainly used for voltage clamping when the circuit is subjected to overvoltage, and absorbing excessive current to protect sensitive devices. The varistor R is provided with a voltage threshold, through which the current flowing when the voltage applied to the varistor is lower than its voltage threshold is extremely small, corresponding to a resistance of infinite magnitude. That is, when the voltage across it is below its voltage threshold, it behaves as an open-state switch. When the voltage across the varistor exceeds its voltage threshold, the current flowing through it increases sharply, corresponding to a resistance of infinitesimal magnitude. That is, when the voltage applied to it is above its voltage threshold, it behaves as a closed-state switch. In this embodiment, one end of the voltage dependent resistor R is connected to the different name end of the secondary side circuit of the flyback transformer 210, and the other end of the voltage dependent resistor R is connected to the load RL, and the working principle in the circuit is similar to that of the voltage regulator tube Z1, and is not described herein again.
In some embodiments, the control circuit 250 includes a sampling circuit 251, which is used for sampling an electrical signal of the flyback power supply circuit, the electrical signal may be a secondary current flowing through the secondary side loop, when the load is supplied with energy, the sampling circuit 251 samples a value of the secondary current at any time, and transmits a detection result to the back-end control circuit. The sampling circuit 251 can also detect the voltage value of the primary circuit, when energy is provided to the load, the primary circuit is in a disconnected state, the primary current is zero, but the voltage of the primary circuit is not zero, and the sampling circuit 251 can acquire the voltage value and transmit the voltage value to the rear-end control circuit so as to be used as a basis for chopping the secondary current, namely, a basis for starting the bleeder circuit. The sampling circuit 251 can also collect the charge quantity, the working principle is the same as that of collecting the primary voltage and collecting the secondary current, in addition, the sampling circuit 251 can be a sensor or any other circuit with the sampling detection function.
The control circuit 250 further comprises a controller 252, the controller 252 is respectively connected with the sampling circuit 251, the bleeding circuit 230 and the switch circuit 220, the controller 252 receives the value of the electrical signal transmitted by the sampling circuit 251, processes the value of the electrical signal, and determines whether a reference electrical signal is reached or not, or whether an electrical signal value required to be chopped is reached or not, if yes, the controller 252 controls the second terminal of the first bleeding switch K2 to be connected with the third terminal, that is, the first bleeding switch K2 is closed, so that the bleeding circuit 230 and the primary circuit form a loop, the primary current flows from the same-name end of the primary circuit through the first bleeding resistor R1, then through the first bleeding switch K2, and then returns to the same-name end of the primary circuit through the different-name end of the primary circuit, so as to bleed off the energy of the primary circuit, meanwhile, the regulator tube Z1 in the secondary circuit is rapidly cut off, and the secondary current of the secondary circuit is rapidly cut off, no residual secondary current exists in the secondary side loop, so that the secondary current is accurately controlled. If not, the controller 252 will continue to control the sampling circuit 251 to collect electrical signals such as secondary current or primary circuit voltage, and keep the state of the first bleeder switch K2, so that the secondary circuit continues to provide energy to the load RL. The controller 252 may be implemented by using at least one of: application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), Field Programmable Gate Arrays (FPGAs), processors, micro-controllers, microprocessors, and other electronic units performing these functions.
In this embodiment, the number of the controllers 252 may be 1 or more. To describe the operation timing sequence of this embodiment, please refer to fig. 5, the cutoff circuit 240 takes a voltage regulator Z1 as an example, the sampling circuit 251 takes a secondary current I as an example, the controller 252 controls the first switch K1 to be closed, so that the dc input power of the power supply device is filtered by the filter capacitor C1, and then the dc input power passes through the primary circuit of the flyback transformer 210 and the first switch K1 to form a closed loop, at this time, the secondary loop has no current, when energy needs to be provided to the load RL, the controller 252 controls the first switch K1 to be opened, then the primary circuit is opened, the secondary loop generates the secondary current I, the current is slowly attenuated, meanwhile, the sampling circuit 251 samples the secondary current I and transmits the secondary current I to the controller 252, the controller 252 processes the sampled current, when the secondary current I reaches a preset reference current, or when the current value of the secondary current I needs to be chopped, the controller 251 controls the first bleeder switch K2 to be closed, so that the first bleeder switch K2, the primary side circuit and the first bleeder resistor R1 form a closed loop to discharge energy of the primary side circuit, meanwhile, as the voltage of the secondary side loop is smaller than the reverse breakdown voltage of the voltage regulator tube Z1, the voltage regulator tube Z1 is cut off, the secondary side loop is rapidly cut off, the secondary side loop does not provide energy for the load RL any more, no residual secondary current exists in the secondary side loop, namely, the secondary current is rapidly cut off, and the control accuracy and the pulse width of the secondary current are ensured.
Referring to fig. 6, fig. 6 is a schematic circuit structure diagram of a flyback power supply circuit according to another embodiment of the present invention. As shown in fig. 6, the flyback power supply circuit shown in fig. 6 differs from the circuit shown in fig. 4 in that:
the bleeder circuit 230 includes a second bleeder switch K3, a second bleeder resistor R2, and a first bleeder diode D2, wherein the second bleeder switch K3 includes a fourth terminal, a fifth terminal, and a sixth terminal, the fourth terminal is connected to a negative terminal Vin-of the dc input of the power supply device, the fifth terminal is connected to the controller 252 in the control circuit 250, the sixth terminal is connected to a positive terminal of the first bleeder diode D2 and a first terminal of the first switch K1 in the switch circuit 220, a negative terminal of the first bleeder diode D2 is connected to one end of the second bleeder resistor R2, and the other end of the second bleeder resistor R2 is connected to a primary different-name terminal of the flyback transformer 210. The second bleed-off switch K3 may be a contactor, a relay, an electronic switch, a time delay switch, an electro-optical switch, a tact switch, a proximity switch, a double-control switch, or a combination thereof.
To describe the operation sequence of this embodiment, please refer to fig. 7, as shown in fig. 7, first, the controller 252 controls the second terminal of the first switch K1 to be connected to the third terminal, the first switch K1 is closed, and at the same time, the fourth terminal of the second bleeder switch K3 is connected to the sixth terminal, the second bleeder switch K3 is closed, so that the primary circuit forms a closed loop, so that the primary current flows through the primary circuit, when energy needs to be supplied to the load RL, the controller controls the second terminal of the first switch K1 to be connected to the first terminal, that is, the first switch K1 is opened, so that the primary circuit is opened, a secondary current I is formed in the secondary circuit, so as to supply energy to the load RL, when the secondary current I reaches a preset reference current, or when a current value that needs to chop the secondary current I, the controller 252 in the control circuit 250 controls the fourth terminal of the second bleeder switch K3 to be connected to the fifth terminal, namely, the second bleeder switch K3 is turned off, and the first switch K1 is controlled to be turned on again, so that the second bleeder resistor R2, the first bleeder diode D2, the first switch K1 and the primary side circuit of the flyback transformer 210 form a bleeder circuit to bleed off energy of the primary side circuit, and meanwhile, the zener diode Z1 in the secondary side circuit is rapidly turned off, so that the secondary current of the secondary side circuit is rapidly cut off, and accurate control of the secondary current is achieved.
Referring to fig. 8, an embodiment of the invention provides a current chopping method, applied to the flyback power circuit, where the current chopping method 300 includes:
step 301: sampling an electric signal of a flyback power circuit;
the electric signal refers to an electric signal such as voltage, current or electric charge quantity, a specific electric signal can be set according to needs, the purpose of collecting the electric signal is to detect energy change in a flyback power supply circuit, when energy needs to be supplied to a load, secondary current flows through a secondary side loop, sampling can be conducted by a sampling circuit to sample the secondary current, the secondary current serves as a basis for chopping the secondary current, the sampling circuit transmits the secondary current to a controller, and the controller processes the data.
Step 302: when the electric signal reaches the preset reference electric signal, the bleeder circuit is started, so that the bleeder circuit and the primary side circuit form a bleeder circuit to discharge the energy of the primary side circuit, and the cut-off circuit cuts off the secondary current flowing through the secondary side circuit.
The controller starts the release circuit when the collected electric signal reaches the preset reference electric signal, so that the release circuit and a primary circuit of the flyback transformer form a closed loop, the energy of the primary circuit can be released through the closed loop, and meanwhile, due to the characteristics of the voltage stabilizing tube, the voltage stabilizing tube is quickly cut off, so that a secondary loop of the flyback transformer is quickly cut off, and the secondary current is also quickly cut off, so that the secondary current is accurately chopped.
An embodiment of the present invention provides a power supply device, which includes the above flyback power supply circuit.
Has the advantages that: in the invention, the sampling circuit is used for sampling the electric signal of the flyback power supply circuit, the controller is used for processing the electric signal, the electric signal is compared with the preset reference electric signal, when the electric signal reaches the preset reference electric signal, the relief circuit is started, so that the relief circuit and the primary circuit form a relief loop to relieve the energy of the primary circuit, and the cutoff circuit cuts off the secondary current flowing through the secondary circuit, so that the circuit can chop the secondary current, the precise control of the secondary current is realized, and the control precision is higher.
It should be noted that the description of the present invention and the accompanying drawings illustrate preferred embodiments of the present invention, but the present invention may be embodied in many different forms and is not limited to the embodiments described in the present specification, which are provided as additional limitations to the present invention and to provide a more thorough understanding of the present disclosure. Moreover, the above technical features are combined with each other to form various embodiments which are not listed above, and all the embodiments are regarded as the scope of the present invention described in the specification; further, modifications and variations will occur to those skilled in the art in light of the foregoing description, and it is intended to cover all such modifications and variations as fall within the true spirit and scope of the invention as defined by the appended claims.
Claims (8)
1. A flyback power supply circuit, comprising:
the flyback transformer comprises a primary side circuit and a secondary side circuit which are coupled and connected;
the switching circuit is connected with the primary side circuit, when the switching circuit is switched on, primary side current flows through the primary side circuit, and when the switching circuit is switched off, the primary side current does not flow through the primary side circuit;
the discharge circuit is connected with the primary side circuit;
the cut-off circuit is connected with the secondary side circuit; the cut-off circuit comprises a voltage stabilizing diode, the anode of the voltage stabilizing diode is connected with the synonym terminal of the secondary side circuit of the flyback transformer, the cathode of the voltage stabilizing diode is connected with a load, and when the voltage stabilizing diode is cut off, the secondary current of the secondary side circuit is cut off;
the control circuit is respectively connected with the switch circuit and the discharge circuit and is used for sampling an electric signal of the flyback power circuit, the flyback power circuit is configured with a preset reference electric signal, and when the electric signal reaches the preset reference electric signal, the discharge circuit is started so that the discharge circuit and the primary circuit form a discharge loop to discharge the energy of the primary circuit, and the cut-off circuit cuts off a secondary current flowing through the secondary circuit;
the flyback power supply circuit accurately controls the secondary high-voltage pulse, chops the secondary high-voltage pulse current and enables the residual current of the secondary high-voltage pulse to be accurately cut off.
2. The flyback power supply circuit of claim 1, wherein the current blocking circuit comprises a transient suppression diode, an anode of the transient suppression diode is connected to the synonym terminal of the flyback transformer secondary side circuit, and a cathode of the transient suppression diode is connected to a load.
3. The flyback power supply circuit of claim 1, wherein the current cutoff circuit comprises a voltage dependent resistor, one end of the voltage dependent resistor is connected to the synonym terminal of the flyback transformer secondary circuit, and the other end of the voltage dependent resistor is connected to a load.
4. A flyback power supply circuit as claimed in any one of claims 1 to 3, wherein the control circuit comprises:
the sampling circuit is used for sampling the electric signal of the flyback power supply circuit;
and the controller is respectively connected with the sampling circuit, the bleeder circuit and the switch circuit and used for starting the bleeder circuit when the electric signal reaches the reference electric signal, so that the bleeder circuit and the primary side circuit form a bleeder circuit to discharge the energy of the primary side circuit, and the cut-off circuit cuts off the secondary current flowing through the secondary side circuit.
5. The flyback power supply circuit of claim 4, wherein the bleed circuit comprises: the first leakage circuit comprises a first leakage switch and a first leakage resistor, wherein the first leakage switch comprises a first terminal, a second terminal and a third terminal, the second terminal is a control terminal, the second terminal is connected with the control circuit, the third terminal is connected with a primary synonym terminal of the flyback transformer, the first terminal is connected with one end of the first leakage resistor, the other end of the first leakage resistor is connected with a primary synonym terminal of the flyback transformer, when the electric signal reaches the reference electric signal, the control circuit controls the first leakage switch to be closed, and the first leakage switch, the primary side of the flyback transformer and the first leakage resistor form a leakage loop to discharge energy of the primary side circuit.
6. The flyback power supply circuit of claim 5, wherein the bleed circuit comprises: the second leakage switch comprises a fourth terminal, a fifth terminal and a sixth terminal, the fifth terminal is a control terminal, the fourth terminal is used for being connected with a direct current input cathode of the flyback power circuit, the fifth terminal is connected with the control circuit, the sixth terminal is respectively connected with an anode of the leakage diode and the switch circuit, a cathode of the leakage diode is connected with one end of the second leakage resistor, the other end of the second leakage resistor is connected with a primary side synonym end of the flyback transformer, when the electric signal reaches the preset reference electric signal, the control circuit controls the second leakage switch to be closed and controls the switch circuit to be conducted, and the second leakage resistor, the leakage diode, the switch circuit and the primary side of the flyback transformer form a leakage loop to discharge energy of the primary side circuit .
7. A current chopping method applied to the flyback power supply circuit as claimed in any one of claims 1 to 6, wherein the method comprises:
sampling an electric signal of the flyback power supply circuit;
and when the electric signal reaches the reference electric signal, starting the leakage circuit, so that the leakage circuit and the primary side circuit form a leakage loop to discharge the energy of the primary side circuit, and the cut-off circuit cuts off the secondary current flowing through the secondary side circuit.
8. A power supply device characterized by comprising a flyback power supply circuit as claimed in any one of claims 1 to 6.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910595576.XA CN110336468B (en) | 2019-07-03 | 2019-07-03 | Flyback power circuit, current cut-off method and power supply equipment |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910595576.XA CN110336468B (en) | 2019-07-03 | 2019-07-03 | Flyback power circuit, current cut-off method and power supply equipment |
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| CN110336468A CN110336468A (en) | 2019-10-15 |
| CN110336468B true CN110336468B (en) | 2020-10-09 |
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| CN113071317B (en) * | 2021-03-23 | 2022-08-02 | 浙江吉利控股集团有限公司 | Discharging circuit, method, motor controller and electric automobile |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP3258620B2 (en) * | 1997-12-26 | 2002-02-18 | 東光株式会社 | Switching power supply |
| JP4218862B2 (en) * | 2002-03-29 | 2009-02-04 | パイオニア株式会社 | Synchronous rectifier circuit for flyback converter |
| DE102013015788A1 (en) * | 2013-09-21 | 2015-03-26 | Diehl Ako Stiftung & Co. Kg | Power supply and method for operating a power supply |
| CN104571432A (en) * | 2013-10-17 | 2015-04-29 | 成都新方洲信息技术有限公司 | Double-track power circuit based on computer |
| CN106100337B (en) * | 2016-01-31 | 2019-07-05 | 深圳麦格米特电气股份有限公司 | A kind of control method of flyback high pressure generator pulse width |
| CN206250979U (en) * | 2016-12-14 | 2017-06-13 | 安徽博微智能电气有限公司 | A kind of quasi-resonance active-clamp flyback converter |
| US10491097B2 (en) * | 2017-04-03 | 2019-11-26 | Texas Instruments Incorporated | Switching time optimizer for soft switching of an isolated converter |
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