A transformer isolation drive circuit and power supply device

Abstract

A transformer isolation drive circuit and power supply device, wherein a control circuit generates a drive control signal according to an input control signal; a first drive switch circuit is turned on or off according to the drive control signal; a transformer generates a first drive voltage according to the conduction of the first drive switch circuit and the input power supply voltage; an excitation inductance absorption circuit resets the transformer; a second drive switch circuit is turned on according to the first drive voltage; a reverse voltage control circuit divides the reverse voltage of the second drive switch circuit, and can effectively reset the isolation drive transformer when the drive switch is turned off, so that a stable drive voltage is output, and the second drive switch circuit can be prevented from being opened by mistake during the transformer resetting process, resulting in damage to components, thereby eliminating a push-pull drive circuit or a drive chip, saving costs, and making the transformer isolation drive circuit suitable for different isolation drive circuits, thereby improving the applicability and safety reliability of the transformer isolation drive circuit.

Description

Technical Field

[0001] The present application belongs to the technical field of drive circuits, and in particular, relates to a transformer isolation drive circuit and a power supply device. Background Art

[0002] At present, the traditional transformer isolation drive circuit is basically divided into two categories. One is that only one signal drives the transformer, and the transformer is reset by the DC blocking capacitor on the primary drive line; the other is that two signals drive the transformer, the pulse width of the two signals is equal, and the transformer is excited in the positive and negative directions, so that the transformer is naturally reset. Among them, the value of the DC blocking capacitor is equal to the product of the input drive signal duty cycle and the input voltage when the one signal drives the transformer. The larger the input pulse width, the higher the capacitor voltage, and the lower the voltage transmitted to the secondary side, which easily causes the secondary side drive voltage to fluctuate with the change of the drive signal duty cycle. The method of eliminating voltage fluctuations by connecting a capacitor in series with the secondary winding to make the voltage of the capacitor equal to the voltage of the DC blocking capacitor on the primary side will cause: when the primary winding is disconnected due to a fault, the capacitor in series with the secondary side loses the primary discharge circuit, thereby charging the driven switch tube, causing the driven switch tube to be mistakenly turned on. In addition, for two-way signal driving transformer, two-way equal pulse width signal positive and negative half-cycle driving can only be used in special scenarios. For example, there must be two input signals, and the phases of the two signals are relatively fixed, generally 180° apart. They are mostly used in half-bridge and full-bridge type circuits, but not suitable for driving circuits such as buck main switch driving circuits.

[0003] Therefore, the conventional technical solution has the problem that the driven switch tube is easily turned on by mistake when the transformer is reset, and the scope of use and occasions of use are limited. Summary of the invention

[0004] The purpose of the present application is to provide a transformer isolation drive circuit and a power supply device, aiming to solve the problem in the traditional transformer drive circuit that the driven switch tube is easily turned on by mistake when the transformer is reset, and the scope of use and occasions of use are limited.

[0005] A first aspect of an embodiment of the present application provides a voltage transformer isolation drive circuit, the voltage transformer isolation drive circuit comprising:

[0006] A control circuit configured to generate a drive control signal according to an input control signal;

[0007] A first drive switch circuit, connected to the control circuit, configured to be turned on or off according to the drive control signal;

[0008] a transformer, wherein a primary winding of the transformer is connected to the first drive switch circuit and is configured to generate a first drive voltage according to the conduction of the first drive switch circuit and a power supply voltage;

[0009] an excitation inductance absorption circuit, connected to the secondary winding of the transformer and configured to reset the transformer;

[0010] a second driving switch circuit, connected to the excitation inductance absorption circuit and the control circuit, and configured to be turned on according to the first driving voltage;

[0011] The reverse voltage control circuit is connected to the secondary winding of the transformer and the second drive switch circuit, and is configured to control the reverse voltage of the second drive switch circuit.

[0012] In one embodiment, the transformer isolation drive circuit further includes:

[0013] The shunt voltage limiting circuit is connected to the second drive switch circuit and is configured to shunt the discharge current of the second drive switch circuit.

[0014] In one embodiment, the transformer isolation drive circuit further includes:

[0015] The leakage inductance absorption circuit is connected to the transformer and the first driving switch circuit, and is configured to absorb the primary leakage inductance of the transformer.

[0016] In one embodiment, the transformer isolation drive circuit further includes:

[0017] The primary excitation inductance absorption circuit is connected to the primary winding of the transformer and the first drive switch circuit, and is configured to reset the primary winding of the transformer.

[0018] In one embodiment, the first driving switch circuit includes: a first field effect transistor; wherein the gate of the first field effect transistor is connected to the control circuit, the source of the first field effect transistor is connected to the power ground, and the drain of the first field effect transistor is connected to the primary winding of the transformer.

[0019] In one embodiment, the excitation inductance absorption circuit includes: a first capacitor; wherein a first end of the first capacitor is connected to the secondary winding of the transformer, and a second end of the first capacitor is connected to the second drive switch circuit.

[0020] In one embodiment, the shunt voltage limiting circuit includes: a first transistor and a first voltage-stabilizing diode; wherein the base of the first transistor is connected to the excitation inductance absorption circuit, the emitter of the first transistor and the cathode of the first voltage-stabilizing diode are commonly connected to the second drive switch circuit, and the collector of the first transistor and the anode of the first voltage-stabilizing diode are commonly connected to the second end of the secondary winding of the transformer and the reverse voltage control circuit.

[0021] In one embodiment, the reverse voltage control circuit includes: a second voltage regulator diode, a second resistor and a third capacitor; wherein the anode of the second voltage regulator diode, the first end of the second resistor and the first end of the third capacitor are commonly connected to the second end of the secondary winding of the transformer, and the cathode of the second voltage regulator diode, the second end of the second resistor and the second end of the third capacitor are commonly connected to the second drive switch circuit.

[0022] In one embodiment, the leakage inductance absorption circuit includes: a first diode, a second capacitor and a first resistor; wherein the anode of the first diode is connected to the second end of the primary winding of the transformer, the cathode of the first diode is connected to the first end of the second capacitor and the first end of the first resistor, and the second end of the second capacitor and the second end of the first resistor are commonly connected to the first end of the primary winding of the transformer.

[0023] A second aspect of an embodiment of the present application provides a power supply device, which includes a transformer isolation drive circuit as described in any one of the above items.

[0024] Compared with the prior art, the embodiments of the present invention have the following beneficial effects: the above-mentioned transformer isolation drive circuit generates a drive control signal according to the input control signal through the control circuit; the first drive switch circuit is turned on or off according to the drive control signal; the transformer generates a first drive voltage according to the conduction of the first drive switch circuit and the input power supply voltage; the excitation inductance absorption circuit resets the transformer; the second drive switch circuit is turned on according to the first drive voltage; the reverse voltage control circuit divides the reverse voltage after the first drive switch circuit is turned off, which can effectively reset the isolation drive transformer when the drive switch is turned off, so that a stable drive voltage is output, and the second drive switch circuit can be prevented from being mistakenly turned on during the transformer resetting process, causing damage to components, eliminating the push-pull drive circuit or the drive chip, saving costs, and making the transformer isolation drive circuit suitable for a variety of different isolation drive circuits, thereby improving the applicability and safety reliability of the transformer isolation drive circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of a structure of a transformer isolation drive circuit provided in an embodiment of the present application;

[0026] Figure 2 Another structural schematic diagram of a transformer isolation drive circuit provided in an embodiment of the present application;

[0027] Figure 3 Another structural schematic diagram of a transformer isolation drive circuit provided in an embodiment of the present application;

[0028] Figure 4 Another structural schematic diagram of a transformer isolation drive circuit provided in an embodiment of the present application;

[0029] Figure 5 Another structural schematic diagram of a transformer isolation drive circuit provided in an embodiment of the present application;

[0030] Figure 6 An exemplary circuit schematic diagram of a transformer isolation drive circuit provided in an embodiment of the present application;

[0031] Figure 7 Another exemplary circuit schematic diagram of a transformer isolation drive circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0032] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0033] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0034] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0035] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0036] Figure 1 A schematic diagram of the structure of a transformer isolation drive circuit provided in the first embodiment of the present application is shown. For the sake of convenience, only the parts related to the present embodiment are shown, which are described in detail as follows:

[0037] A transformer isolation drive circuit comprises: a control circuit 11, a first drive switch circuit 12, a transformer 13, an excitation inductance absorption circuit 14, a second drive switch circuit 15 and a reverse voltage control circuit 16.

[0038] The control circuit 11 is configured to generate a drive control signal according to an input control signal; the first drive switch circuit 12 is connected to the control circuit 11 and configured to be turned on or off according to the drive control signal; the transformer 13, the primary winding of the transformer 13 is connected to the first drive switch circuit 12, and is configured to generate a first drive voltage according to the conduction of the first drive switch circuit and the input power supply voltage; the excitation inductance absorption circuit 14 is connected to the secondary winding of the transformer 13, and is configured to reset the transformer 13; the second drive switch circuit 15 is connected to the excitation inductance absorption circuit 14 and the control circuit 11, and is configured to be turned on according to the first drive voltage; the reverse voltage control circuit 16 is connected to the secondary winding of the transformer 13 and the second drive switch circuit 15, and is configured to divide the reverse voltage of the second drive switch circuit 15.

[0039] In a specific implementation, the input control signal is generated by the user operating the control component according to the power demand or by writing a control program. The first drive switch circuit 12 is a switch circuit controlled by a drive control signal, which may include a single switch tube or multiple switch tubes, but is not a switch tube circuit of a push-pull structure. The control circuit 11 generates a drive control signal according to the input control signal to control the on and off of the first drive switch circuit 12, thereby controlling the primary winding of the transformer 13 to be turned on to the power ground or turning off the connection between the primary winding of the transformer 13 and the power ground. The excitation inductance absorption circuit 14 is charged when the primary winding of the transformer 13 is turned on, and is a low-voltage energy storage. When the primary winding of the transformer 13 is turned off, it absorbs the excitation inductance energy induced from the primary winding to the secondary winding, thereby effectively resetting the transformer 13.

[0040] In a specific implementation, the reverse voltage control circuit 16 is connected to the second end of the secondary winding of the transformer 13. When the first drive switch circuit 12 is turned off according to the drive control signal, the voltage on the secondary winding of the transformer 13 is reversed. The reverse voltage control circuit 16 can prevent the reverse voltage loaded on the second drive switch circuit 15 from being too large and damaging the electronic components of the second drive switch circuit 15. At the same time, the reverse voltage control circuit 16 divides the reverse voltage to control the reverse negative voltage loaded on the second drive switch circuit 15, so as to avoid the second drive switch circuit 15 being mistakenly turned on due to the excitation inductance absorption circuit 14 charging the second drive switch circuit 15 when the primary winding of the transformer 13 fails, thereby causing a potential safety hazard in electricity use, and realizing reverse voltage protection.

[0041] Optionally, the second drive switch circuit 15 includes a drive switch tube, which can be a drive switch tube circuit, such as a single-tube forward circuit, or multiple, such as a double-tube forward circuit, as required. Optionally, the switch tube is a MOS tube or an IGBT tube, etc., which can be turned on according to the first drive voltage so that the corresponding drive power circuit generates the required drive voltage to supply power to the electrical load.

[0042] The embodiment of the present application can achieve effective resetting of the isolation drive transformer when the drive switch is turned off, so that a stable drive voltage is output, and can prevent the second drive switch circuit from being mistakenly turned on during the transformer resetting process, causing damage to components, eliminating the push-pull drive circuit or drive chip, saving costs, and making the transformer isolation drive circuit suitable for a variety of different isolation drive circuits, thereby improving the applicability and safety and reliability of the transformer isolation drive circuit.

[0043] See also Figure 2 In one embodiment, the transformer isolation drive circuit further includes: a shunt voltage limiting circuit 17.

[0044] The shunt voltage limiting circuit 17 is connected to the excitation inductance absorption circuit 14 and the second drive switch circuit 15 , and is configured to shunt the discharge current of the second drive switch circuit 15 .

[0045] In a specific implementation, when the first drive switch circuit 12 is turned off, so that a reverse voltage is generated on the secondary winding of the transformer 13, the shunt voltage limiting circuit 17 can divide the reverse negative voltage and quickly discharge the excitation current induced from the primary winding to the secondary winding of the transformer 13, so that the second drive switch circuit 15 is quickly turned off, further preventing the second drive switch circuit 15 from being mistakenly triggered during the shutdown process, thereby improving the reliability of resetting the transformer 13.

[0046] See also Figure 3 In one embodiment, the transformer isolation driving circuit further includes: a leakage inductance absorption circuit 18.

[0047] The leakage inductance absorption circuit 18 is connected to the transformer 13 and the first driving switch circuit 12 , and is configured to absorb the primary leakage inductance of the transformer 13 .

[0048] In a specific implementation, the leakage inductance absorption circuit 18 is connected to the second end of the primary winding of the transformer 13. When the primary winding of the transformer 13 performs electromagnetic induction according to the input power supply voltage, most of the electromagnetic induction energy is induced to the secondary winding of the transformer 13, and part of the inductance energy (that is, the leakage inductance) is absorbed by the leakage inductance absorption circuit 18, thereby reducing the electromagnetic interference of the primary leakage inductance of the transformer 13 to the circuit; at the same time, it can also reduce the peak voltage generated when the first drive switch circuit 12 is turned off, and prevent the leakage inductance from damaging the circuit components, thereby improving the safety and reliability of the isolated drive transformer circuit.

[0049] See also Figure 4 In one embodiment, the transformer isolation drive circuit further includes: a first filter circuit 19.

[0050] The first filter circuit 19 is connected to the transformer 13 and the first drive switch circuit 12 and is configured to perform filtering and noise reduction processing on the power supply voltage.

[0051] In a specific implementation, the first end of the first filter circuit 13 is connected to the first end of the primary winding of the transformer 13, the second end of the first filter circuit 13 is connected to the second end of the first drive switch circuit 12, and the second end of the primary winding of the transformer 13 is connected to the first end of the first drive switch circuit 12, so that the power supply voltage of the input transformer 13 can be filtered and noise reduced, thereby improving the stability and reliability of the transformer isolation drive circuit.

[0052] See also Figure 5 In one embodiment, the transformer isolation drive circuit further includes: a primary excitation inductance absorption circuit 20.

[0053] The primary excitation inductance absorption circuit 20 is connected to the primary winding of the transformer 13 and the first drive switch circuit 12, and is configured to reset the primary winding of the transformer.

[0054] In a specific implementation, when the first drive switch circuit 12 is turned on, the transformer 13 performs isolation transformation according to the input power supply voltage to generate the first drive voltage. At this time, the primary leakage inductance can be absorbed by the primary excitation inductance absorption circuit 20 to reduce the electromagnetic interference in the circuit. When the first drive switch circuit 12 is turned off, the connection between the primary winding of the transformer 13 and the power ground is disconnected. At this time, the reverse excitation inductance generated by the primary winding of the transformer 13 can be absorbed by the primary excitation inductance absorption circuit 20, thereby resetting the primary winding of the transformer and then resetting the transformer 13.

[0055] The embodiment of the present application can simultaneously reset the primary winding and the secondary winding of the transformer when the first drive switch circuit is turned off, so that the transformer isolation drive circuit can output a stable drive voltage, eliminating the push-pull drive circuit or drive chip, saving costs, and further improving the safety and reliability of the transformer isolation drive circuit.

[0056] See also Figure 6 In one embodiment, the first driving switch circuit 12 includes: a first field effect transistor VT2; wherein the gate of the first field effect transistor VT2 is connected to the control circuit 11, the source of the first field effect transistor VT2 is connected to the power ground, and the drain of the first field effect transistor VT2 is connected to the primary winding of the transformer 13.

[0057] In a specific implementation, the gate of the first field effect transistor VT2 is connected to the control circuit 11 through a series resistor R10, the drain of the first field effect transistor VT2 is connected to the second end 2 of the primary winding of the transformer 13, and the gate-source terminals of the first field effect transistor VT2 are connected in parallel with resistor R11. The first field effect transistor VT2 can be protected by current limiting through resistors R10 and R11.

[0058] In one embodiment, the control circuit 11 includes a controller, such as a high-performance fixed-frequency current mode controller of model UC3843, which can generate a drive control signal according to an input control signal input by a user, and detect the drive voltage in real time to perform feedback adjustment on the drive control signal, thereby controlling the drive voltage required for the precise and stable output of the transformer isolation drive circuit.

[0059] In one embodiment, the second driving switch circuit 15 includes a switch tube, such as a triode, a field effect tube or an IGBT switch tube. Figure 6 In one embodiment, the second driving switch circuit 15 uses a field effect transistor VT1.

[0060] See also Figure 6 In one embodiment, the excitation inductance absorption circuit 14 includes: a first capacitor C1; wherein a first end of the first capacitor C1 is connected to the secondary winding of the transformer 13, and a second end of the first capacitor C1 is connected to the second driving switch circuit 15.

[0061] In a specific implementation, the first end of the first capacitor C1 is connected to the first end 3 of the secondary winding of the transformer 13, and the second end of the first capacitor C1 is connected to the gate of the field effect transistor VT1. In this embodiment, on the secondary winding of the transformer 13, a resistor R1 and a diode D1 are connected in parallel with the first capacitor C1, and a resistor R4 and a resistor R5 are connected in parallel.

[0062] See also Figure 6In one embodiment, the shunt voltage limiting circuit 17 includes: a first transistor Q1 and a first voltage stabilizing diode Z1; wherein, the base of the first transistor Q1 is connected to the excitation inductance absorption circuit 14, the emitter of the first transistor Q1 and the cathode of the first voltage stabilizing diode Z1 are commonly connected to the second driving switch circuit 15, and the collector of the first transistor Q1 and the anode of the first voltage stabilizing diode Z1 are commonly connected to the second end 4 of the secondary winding of the transformer 13 and the reverse voltage control circuit 16.

[0063] In a specific implementation, the second end of the resistor R5, the emitter of the first transistor Q1, and the cathode of the first voltage-stabilizing diode Z1 are connected to the second end of the first capacitor C1 and the gate of the field effect transistor VT1. The base of the first transistor Q1 is connected in series with the resistor R7, and then connected to the second end of the resistor R4 and the first end of the resistor R5. The resistor R7 can prevent the PN junction of the first transistor Q1 from being damaged by excessive voltage. The first voltage-stabilizing diode Z1 can conduct the negative voltage generated by the secondary winding of the transformer 13 when the first field effect transistor VT1 is turned off, thereby preventing the first transistor from being broken down by excessive negative voltage.

[0064] Optionally, the first transistor Q1 is a PNP transistor. Through the first transistor Q1, the resistor R4, the resistor R5 and the resistor R7, when the first field effect transistor VT2 is turned off so that a reverse voltage is generated on the secondary winding of the transformer 13, the reverse negative voltage is divided, and the excitation current induced from the primary winding to the secondary winding of the transformer 13 is quickly discharged, so that the field effect transistor VT1 is quickly turned off, and the field effect transistor VT1 is further prevented from being triggered by mistake during the shutdown process.

[0065] In one embodiment, the first transistor Q1 may also be replaced by a PMOS transistor, which can be turned on when the first field effect transistor VT2 is turned off, so that the field effect transistor VT1 is turned off quickly.

[0066] See also Figure 6 In one embodiment, the reverse voltage control circuit 16 includes: a second voltage zener diode Z2, a second resistor R8 and a third capacitor C4; wherein, the anode of the second voltage zener diode Z2, the first end of the second resistor R8 and the first end of the third capacitor C4 are commonly connected to the second end of the secondary winding of the transformer, and the cathode of the second voltage zener diode Z2, the second end of the second resistor R8 and the second end of the third capacitor C4 are commonly connected to the second driving switch circuit 15.

[0067] In a specific implementation, when the first field effect transistor VT2 is turned off and the secondary winding of the transformer 13 generates a negative voltage at the top and a positive voltage at the bottom, the second voltage zener diode Z2 is turned on to divide the negative voltage generated by the secondary winding of the transformer 13, and the reverse voltage of the field effect transistor VT1 is controlled by the second voltage zener diode Z2, the second resistor R8 and the third capacitor C4.

[0068] See also Figure 7 In one embodiment, the primary excitation inductance absorption circuit 20 includes: a resistor R01, a capacitor C2, a diode D01 and a diode D02. When the first field effect transistor VT2 is turned off, the connection between the primary winding of the transformer 13 and the power ground is disconnected. At this time, the reverse excitation inductance generated by the primary winding of the transformer 13 can be absorbed by the resistor R01, the capacitor C2 and the diode D01, so that the transformer 13 is reset.

[0069] In one embodiment, see Figure 6 and Figure 7 The source of the field effect transistor VT1 is connected to the control circuit 11 after passing through the winding of the transformer T2 to supply power to the control circuit 11, and the power supply voltage input to the control circuit 11 is filtered and noise-reduced through the capacitor C6.

[0070] The following will be combined Figure 6 A brief description of the working principle of the transformer isolation drive circuit:

[0071] The first field effect transistor VT2 is controlled by the driving control signal output by the control circuit 11. Its opening and closing controls the opening and closing of the field effect transistor VT1 driven by the secondary side. The turns ratio of the transformer 13 is adjusted according to the power supply voltage input by the primary side and the required driving voltage, and a group of primary windings of the transformer 13 can correspond to one or more secondary windings and related circuits.

[0072] When the first field effect tube VT2 starts to turn off according to the driving control signal, the primary leakage inductance starts to charge the second capacitor C3 through the first diode D2; the current of the primary winding excitation inductance is induced to the secondary winding, and the current starts to flow through the loop composed of the third capacitor C4, the gate-source of the field effect tube VT1, the first capacitor C1 and the secondary winding. Since the first C1 has a small capacitance, the reverse voltage loaded on both ends of the first capacitor C1 rises quickly, and the voltages across the resistors R5 and R4 become negative on the left and positive on the right, so that the first transistor Q1 starts to conduct, and discharges the third capacitor C4 and the gate-source of the field effect tube VT1; at the same time, since the parasitic gate-source capacitance of the field effect tube VT1 is smaller than that of the first There are three capacitors C4, so the gate-source discharge of the field effect tube VT1 is faster. When the gate-source voltage of the field effect tube VT1 is equal to the negative value of the voltage loaded on both ends of the third capacitor C4, the second voltage zener diode Z2 is turned on, and the voltage of the second voltage zener diode Z2 is negative on the left and positive on the right. When the gate-source voltage of the field effect tube VT1 no longer increases, the field effect tube VT1 withstands the negative voltage of the shutdown, and the field effect tube VT1 is completely turned off and will not be triggered to turn on by mistake; and because the emitter voltage of the first triode Q1 is lower than the collector voltage, no current flows, and the voltage of the first capacitor C1 is equal to the voltage of the secondary winding of the transformer 13, so the excitation current is quickly reduced to zero, and the transformer 13 is reset.

[0073] When the transformer 13 starts to change from off to on, the voltage of the first capacitor C1 starts to discharge from negative on the left to positive on the right. When the first capacitor C1 is discharged to zero, the diode D1 is turned on. The driving voltage with positive on the top and negative on the bottom generated by the secondary winding of the transformer 13 is divided by the resistor R1 and the diode D1, so that the voltage of the gate source of the field effect transistor VT1 rises to a voltage greater than the turn-on voltage Vgs(th) of the field effect transistor VT1, and the field effect transistor VT1 is turned on, so that the transformer isolation drive circuit generates a driving voltage to drive the electrical load. Among them, by adjusting the size of the resistor R1, the turn-on speed of the field effect transistor VT1 can be adjusted; by adjusting the size of the resistor R5, the resistor R4 and the resistor R7, the turn-off speed of the field effect transistor VT1 can be adjusted, and the voltage division by the resistor R5 can prevent the PN junction of the first triode Q1 from being subjected to excessive voltage and being broken down and damaged.

[0074] A second aspect of the present application provides a power supply device, the power supply device comprising a transformer isolation drive circuit as described in any one of the above items.

[0075] In a specific implementation, the power supply device includes the above-mentioned transformer isolation drive circuit and other voltage conversion circuits. The transformer isolation drive circuit, as an auxiliary power supply circuit in the power supply, can generate the required drive voltage according to the drive control signal to assist in power supply. Other voltage conversion circuits, such as AC-DC conversion circuits, inverter circuits, etc., can provide the required power supply voltage according to the circuit design to provide the main power supply.

[0076] The power supply of the embodiment of the present application can effectively reset the isolation drive transformer, so that a stable drive voltage is output to assist in power supply, eliminating the push-pull drive circuit or drive chip, saving costs, and improving the applicability and safety and reliability of the power supply.

[0077] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units, modules, and circuits is used as an example. In actual applications, the above-mentioned functions can be assigned to different functional units, modules, and circuits as needed, that is, the internal structure of the device can be divided into different functional units or modules or circuits to complete all or part of the functions described above. The functional units, modules, and circuits in the embodiments can be integrated into a processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units, modules, and circuits are only for the convenience of distinguishing from each other, and are not used to limit the scope of protection of this application.

[0078] In the above embodiments, the description of each embodiment has its own emphasis. For the part not described or recorded in detail in one embodiment, reference can be made to the relevant description of other embodiments. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0079] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A transformer isolation drive circuit, characterized in that: The transformer isolation drive circuit comprises: A control circuit configured to generate a drive control signal according to an input control signal; A first drive switch circuit, connected to the control circuit, configured to be turned on or off according to the drive control signal; a transformer, wherein a primary winding of the transformer is connected to the first drive switch circuit and is configured to generate a first drive voltage according to the conduction of the first drive switch circuit and a power supply voltage; an excitation inductance absorption circuit, connected to the secondary winding of the transformer and configured to reset the transformer; a second driving switch circuit, connected to the excitation inductance absorption circuit and the control circuit, and configured to be turned on according to the first driving voltage; a reverse voltage control circuit connected to the secondary winding of the transformer and the second drive switch circuit, and configured to control the reverse voltage of the second drive switch circuit; The voltage transformer isolation drive circuit also includes: a primary excitation inductance absorption circuit, connected to the primary winding of the transformer and the first drive switch circuit, and configured to reset the primary winding of the transformer; The excitation inductance absorption circuit comprises: a first capacitor; wherein a first end of the first capacitor is connected to the secondary winding of the transformer, and a second end of the first capacitor is connected to the second drive switch circuit; The primary side excitation inductance absorption circuit includes a resistor R01, a capacitor C2, a diode D01 and a diode D02.

2. The voltage transformer isolation drive circuit according to claim 1, characterized in that: The voltage transformer isolation drive circuit also includes: The shunt voltage limiting circuit is connected to the second drive switch circuit and is configured to shunt the discharge current of the second drive switch circuit.

3. The voltage transformer isolation driving circuit according to claim 1, characterized in that: The voltage transformer isolation drive circuit also includes: The leakage inductance absorption circuit is connected to the transformer and the first driving switch circuit, and is configured to absorb the primary leakage inductance of the transformer.

4. The voltage transformer isolation driving circuit according to claim 1, characterized in that: The first driving switch circuit includes: a first field effect transistor; wherein the gate of the first field effect transistor is connected to the control circuit, the source of the first field effect transistor is connected to the power ground, and the drain of the first field effect transistor is connected to the primary winding of the transformer.

5. The voltage transformer isolation driving circuit according to claim 1, characterized in that: The reverse voltage control circuit includes: a second voltage regulator diode, a second resistor and a third capacitor; wherein, the anode of the second voltage regulator diode, the first end of the second resistor and the first end of the third capacitor are commonly connected to the second end of the secondary winding of the transformer, and the cathode of the second voltage regulator diode, the second end of the second resistor and the second end of the third capacitor are commonly connected to the second drive switch circuit.

6. The voltage transformer isolation driving circuit according to claim 2, characterized in that: The shunt voltage limiting circuit includes: a first transistor and a first voltage-stabilizing diode; wherein the base of the first transistor is connected to the excitation inductance absorption circuit, the emitter of the first transistor and the cathode of the first voltage-stabilizing diode are commonly connected to the second drive switch circuit, and the collector of the first transistor and the anode of the first voltage-stabilizing diode are commonly connected to the second end of the secondary winding of the transformer and the reverse voltage control circuit.

7. The voltage transformer isolation driving circuit according to claim 3, characterized in that: The leakage inductance absorption circuit includes: a first diode, a second capacitor and a first resistor; wherein, the anode of the first diode is connected to the second end of the primary winding of the transformer, the cathode of the first diode is connected to the first end of the second capacitor and the first end of the first resistor, and the second end of the second capacitor and the second end of the first resistor are commonly connected to the first end of the primary winding of the transformer.

8. A power supply device, characterized in that: The power supply device comprises the transformer isolation drive circuit according to any one of claims 1 to 7.

Images