Isolation driving circuit, switching power supply and electronic equipment
By combining the totem pole amplification circuit and transformer in the isolation drive circuit, and introducing specific components into the secondary side circuit, the traditional isolation drive circuit has solved the shortcomings in volume and power consumption, and achieved a more efficient and safer electrical isolation effect.
Patent Information
- Application Number
- CN202411971859.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-30
- Publication Date
- 2025-04-08
AI Technical Summary
Traditional isolation drive circuits are difficult to meet the needs of modern electronic devices in terms of volume and power consumption, especially in miniaturization and low power consumption applications.
By combining the totem pole amplification circuit and the transformer, the control signal is electrically isolated from the power circuit, and a first diode, a first resistor and a P-type switch tube are introduced into the secondary side circuit to stably drive the power switch tube and accurately control its conduction and shutdown.
It improves the stability and safety of the circuit, reduces power consumption, improves working efficiency, and avoids misdirection of power switch tubes, simplifies the circuit structure and reduces manufacturing and maintenance costs.
Smart Images
Figure CN119787783A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the technical field of electronic circuits, and relates to but is not limited to an isolation drive circuit, a switching power supply and an electronic device. Background Art
[0002] With the rapid development of power electronics technology, isolated drive circuits are widely used because they can isolate the electrical connection between the control circuit and the driven circuit, improving the safety and stability of the system. However, with the miniaturization of electronic equipment and the increase in low power consumption requirements, traditional isolated drive circuits can no longer meet the requirements of modern electronic equipment in terms of volume and power consumption. Summary of the invention
[0003] In view of this, embodiments of the present disclosure provide an isolation driving circuit, a switching power supply, and an electronic device.
[0004] In a first aspect, the present disclosure provides an isolation driving circuit, comprising: a primary circuit and a secondary circuit;
[0005] The primary circuit includes a totem pole amplifier circuit and a primary winding of a transformer, the output end of the totem pole amplifier circuit is connected to the same-name end of the primary winding, and the ground end of the totem pole amplifier circuit is connected to the opposite-name end of the primary winding;
[0006] The secondary circuit includes a secondary winding of a transformer, a first diode, a first resistor and a P-type switching tube, wherein an anode of the first diode is connected to a first end of the first resistor and a like-name end of the secondary winding, and a cathode of the first diode is connected to a source of the P-type switching tube as a first output end of the isolation drive circuit, which is used to be connected to a gate of a power switching tube; a second end of the first resistor is connected to a gate of the P-type switching tube, and a drain of the P-type switching tube is connected to an unlike-name end of the secondary winding as a second output end of the isolation drive circuit, which is used to be connected to a source of a power switching tube.
[0007] In some embodiments, the primary circuit further includes a first capacitor and a second resistor;
[0008] The totem pole amplifier circuit includes a first switch tube and a second switch tube; the first electrode of the first switch tube serves as a power supply end of the totem pole amplifier circuit, the second electrode of the first switch tube is connected to the second electrode of the second switch tube as an input end of the totem pole amplifier circuit, the third electrode of the first switch tube is connected to the third electrode of the second switch tube as an output end of the totem pole amplifier circuit, and the first electrode of the second switch tube serves as a ground end of the totem pole amplifier circuit;
[0009] A first end of the second resistor is connected to the output end of the totem pole amplifier circuit, a second end of the second resistor is connected to a first end of the first capacitor, and a second end of the first capacitor is connected to a same-name end of the primary winding;
[0010] or,
[0011] The first end of the second resistor is connected to the output end of the totem pole amplifier circuit, the second end of the second resistor is connected to the same-name end of the primary winding, the first end of the first capacitor is connected to the opposite-name end of the primary winding, and the second end of the first capacitor is connected to the first electrode of the second switch tube.
[0012] In some embodiments, the primary circuit further includes a third resistor;
[0013] A first end of the third resistor is connected to a first end of the first capacitor, and a second end of the third resistor is connected to a second end of the first capacitor.
[0014] In some embodiments, the primary circuit further includes a second diode, a cathode of the second diode is connected to the first end of the first capacitor, and an anode of the second diode is connected to the second end of the first capacitor.
[0015] In some embodiments, the capacitance value of the first capacitor ranges from 30nF to 500nF.
[0016] In some embodiments, the first switch tube is an NPN-type transistor, and the second switch tube is a PNP-type transistor; wherein the first electrode is a collector, the second electrode is a base, and the third electrode is an emitter;
[0017] or,
[0018] The first switch tube is an NMOS transistor, and the second switch tube is a PMOS transistor; wherein the first electrode is a drain, the second electrode is a gate, and the third electrode is a source.
[0019] In some embodiments, the P-type switch tube is a PMOS transistor, the power switch tube is an NMOS transistor, and the gate-source capacitance of the P-type switch tube is smaller than the gate-source capacitance of the power switch tube.
[0020] In some embodiments, the material of the magnetic core body of the transformer includes high magnetic permeability powder, wherein the high magnetic permeability powder includes R5k powder and / or R10k powder.
[0021] In a second aspect, the present disclosure provides a switching power supply, comprising: a dual-switch flyback circuit and the isolation drive circuit described in any one of the first aspects.
[0022] In a third aspect, the present disclosure provides an electronic device, comprising the switching power supply as described in the second aspect.
[0023] On the one hand, in the embodiments of the present disclosure, the electrical isolation between the control signal and the power circuit is achieved through the cooperation of the totem pole amplifier circuit and the transformer, thereby improving the stability and safety of the circuit. On the other hand, the first diode, the first resistor and the P-type switch tube of the secondary circuit are further provided, so that the drive signal output by the secondary circuit can stably drive the power switch tube, accurately control the conduction and shutdown of the power switch tube, reduce power consumption, improve the working efficiency of the circuit, and avoid misconduction of the power switch tube. In addition, the isolation drive circuit provided by the embodiments of the present disclosure has a simple structure, is easy to manufacture and maintain, and reduces costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0025] Figure 1 A specific structural diagram of an isolation driving circuit provided in one embodiment of the present disclosure;
[0026] Figure 2 One of the specific structural diagrams of the isolation driving circuit provided by another embodiment of the present disclosure;
[0027] Figure 3 A second specific structural diagram of an isolation driving circuit provided in another embodiment of the present disclosure;
[0028] Figure 4 A third specific structural diagram of an isolation driving circuit provided in another embodiment of the present disclosure;
[0029] Figure 5 for Figure 4 One of the working principle diagrams of the isolated driving circuit shown;
[0030] Figure 6 for Figure 4 The second schematic diagram of the working principle of the isolation driving circuit shown;
[0031] Fig. 7A A waveform diagram of a driving signal output by a secondary winding of an isolation driving circuit provided by an exemplary embodiment of the present disclosure;
[0032] Figure 7B A waveform diagram of a driving signal output by a secondary winding of an isolation driving circuit provided in yet another embodiment of the present disclosure;
[0033] Figure 8 A fourth specific structural diagram of an isolation driving circuit provided in another embodiment of the present disclosure;
[0034] Fig. 9 An optional structural diagram of a switching power supply provided in an embodiment of the present disclosure. DETAILED DESCRIPTION
[0035] To make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the specific technical solution of the application will be further described in detail below in conjunction with the drawings in the embodiments of the present disclosure. The following embodiments are used to illustrate the present disclosure, but are not used to limit the scope of the present disclosure.
[0036] In the following description, reference is made to “some embodiments” which describe a subset of all possible embodiments, but it will be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.
[0037] In the following description, the terms "first\second\third" are used only as examples to distinguish different objects, and do not represent a specific order for the objects, and do not have a limitation on the order of precedence. It is understandable that the specific order or order of "first\second\third" can be interchanged where permitted, so that the embodiments of the present disclosure described herein can be implemented in an order other than that illustrated or described herein.
[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present disclosure belongs. The terms used herein are only for the purpose of describing the embodiments of the present disclosure and are not intended to limit the present disclosure.
[0039] It should be noted that the technical solutions described in the embodiments of the present disclosure can be arbitrarily combined without conflict.
[0040] In the related art, in order to achieve electrical isolation between the control circuit and the driven circuit, the isolation drive circuit adopts the following method: Figure 1 The structure shown in the figure is used to implement this. Figure 1 As shown, the isolation driving circuit includes a control circuit for generating a driving pulse and a transformer T, wherein the transformer T is used to couple the driving pulse signal connected to the primary circuit to the secondary circuit to realize driving of the power switch tube S1 of the driven circuit.
[0041] However, Figure 1 The isolated drive circuit shown may have problems such as large turn-off loss, large drive loss, low efficiency, insufficient stability, and high cost. These problems are particularly prominent in high-voltage and high-frequency application scenarios.
[0042] In this regard, the present disclosure proposes the following implementation modes.
[0043] In a first aspect, an embodiment of the present disclosure provides an isolation driving circuit, such as Figure 2 As shown, the isolation driving circuit includes: a primary circuit and a secondary circuit; the primary circuit includes a totem pole amplifier circuit 200 and a primary winding T1 of a transformer T, the output terminal N1 of the totem pole amplifier circuit 200 is connected to the same-name terminal a of the primary winding T1, and the ground terminal N2 of the totem pole amplifier circuit 200 is connected to the opposite-name terminal b of the primary winding T1; the secondary circuit includes a secondary winding T2 of the transformer T, a first diode D1, a first resistor R1 and a P-type switch tube P1, the anode of the first diode D1 is connected to the ground terminal N2 of the totem pole amplifier circuit 200, and the ground terminal N2 of the totem pole amplifier circuit 200 is connected to the opposite-name terminal b of the primary winding T1; the secondary circuit includes a secondary winding T2 of the transformer T, a first diode D1, a first resistor R1 and a P-type switch tube P1, the anode of the first diode D1 is connected to the ground terminal N2 of the first diode D1 ... ground terminal N2 of the primary winding T1. A first end of a resistor R1 is connected to a like-name end c of the secondary winding T2, and a cathode of the first diode D1 is connected to a source of the P-type switch tube P1 as a first output end out1 of the isolation drive circuit, which is used to be connected to a gate of the power switch tube S1; a second end of the first resistor R1 is connected to a gate of the P-type switch tube P1, and a drain of the P-type switch tube P1 is connected to an opposite-name end d of the secondary winding T2 as a second output end out2 of the isolation drive circuit, which is used to be connected to a source of the power switch tube S1.
[0044] In some embodiments, Figure 2 The control circuit 100 shown is used to generate a pulse width modulation (PWM) signal. The input end of the totem pole amplifier circuit 200 is connected to the output end of the control circuit 100 to receive the PWM signal.
[0045] In some embodiments, the turns ratio of the primary winding T1 to the secondary winding T2 of the transformer T ranges from 1 to 1.5. More specifically, the turns ratio of the primary winding T1 to the secondary winding T2 of the transformer T is 1, 1.25 or 1.5.
[0046] It should be noted that, in actual use, the coil turns ratio between the primary winding T1 and the secondary winding T2 of the transformer T can be reasonably set according to actual needs.
[0047] In some embodiments, Figure 2As shown, the primary circuit also includes a first capacitor C1 and a second resistor R2; the totem pole amplifier circuit 200 includes a first switch tube Q1 and a second switch tube Q2; the first electrode of the first switch tube Q1 serves as a power supply end of the totem pole amplifier circuit 200, the second electrode of the first switch tube Q1 is connected to the second electrode of the second switch tube Q2 as an input end of the totem pole amplifier circuit 200, the third electrode of the first switch tube Q1 is connected to the third electrode of the second switch tube Q2 as an output end N1 of the totem pole amplifier circuit 200, and the first electrode of the second switch tube Q2 serves as a ground end N2 of the totem pole amplifier circuit 200.
[0048] Exemplarily, the first electrode of the first switch tube Q1 is connected to the power supply Vcc as the power supply end of the totem pole amplifier circuit 200 .
[0049] In some embodiments, Figure 2 As shown, the first end of the second resistor R2 is connected to the output end of the totem pole amplifier circuit 200, the second end of the second resistor R2 is connected to the first end of the first capacitor C1, and the second end of the first capacitor C1 is connected to the same-name end a of the primary winding T1.
[0050] In other embodiments, Figure 3 As shown, the first end of the second resistor R2 is connected to the output end of the totem pole amplifier circuit 200, the second end of the second resistor R2 is connected to the same-name end a of the primary winding T1, the first end of the first capacitor C1 is connected to the opposite-name end b of the primary winding T1, and the second end of the first capacitor C1 is connected to the first electrode of the second switch tube Q2.
[0051] It should be noted that, in the loop formed by the second resistor R2, the first capacitor C1 and the primary winding T1, the positions of the second resistor R2 and the first capacitor C1 can be interchanged. In some specific implementations, Figure 2 The second resistor R shown may also be arranged between the second end of the first capacitor C1 and the same-name end a of the primary winding T1. Figure 3 The second resistor R2 shown can be arranged between the first end of the first capacitor C1 and the opposite end b of the primary winding T1.
[0052] Exemplarily, the second resistor R2 is used as a primary current limiting resistor to suppress circuit oscillation to improve stability and to limit current to protect the transformer.
[0053] Exemplarily, the first capacitor C1 is used to filter out the DC component in the PWM signal to prevent the transformer T from being magnetically saturated.
[0054] In some embodiments, Figure 2 and Figure 3As shown, the primary circuit further includes a third resistor R3; the first end of the third resistor R3 is connected to the first end of the first capacitor C1, and the second end of the third resistor R3 is connected to the second end of the first capacitor C1. In some embodiments, the third resistor R3 is used to control the discharge speed of the first capacitor C1. Specifically, when the first capacitor C1 is discharged, the third resistor R3 is used to adjust the discharge speed of the first capacitor C1. The first capacitor C1 is a certain value, the value of the third resistor R3 increases, and the discharge time of the first capacitor C1 increases. The value of the third resistor R3 decreases, and the discharge time of the first capacitor C1 is shortened.
[0055] In some embodiments, the primary circuit further includes a second diode D2, a cathode of the second diode D2 is connected to the first end of the first capacitor C1, and an anode of the second diode D2 is connected to the second end of the first capacitor C1.
[0056] In some embodiments, when the isolation driving circuit changes from a heavy-load state to a light-load state (eg, the duty cycle of the PWM signal drops suddenly), the second diode D2 is used to suppress high-frequency oscillation caused by the resonance between the primary winding of the transformer and the first capacitor C1.
[0057] In some embodiments, the capacitance value of the first capacitor ranges from 30nF to 500nF. More specifically, the capacitance value of the first capacitor may be 30nF, 100nF, 200nF, 300nF, 400nF or 500nF.
[0058] In some embodiments, the first switch tube Q1 is an NPN type transistor, and the second switch tube Q2 is a PNP type transistor; wherein the first electrode is a collector, the second electrode is a base, and the third electrode is an emitter; or, the first switch tube is an NMOS transistor, and the second switch tube is a PMOS transistor; wherein the first electrode is a drain, the second electrode is a gate, and the third electrode is a source.
[0059] In some embodiments, the P-type switch tube P1 is a PMOS transistor, the power switch tube S1 is an NMOS transistor, and the gate-source capacitance of the P-type switch tube is smaller than the gate-source capacitance of the power switch tube S1.
[0060] In some embodiments, the P-type switch tube is a low-voltage PMOS transistor, and specifically, the withstand voltage range of the low-voltage PMOS transistor is 25 V-35 V. The low-voltage PMOS transistor has a smaller area, which is beneficial to reducing the occupied area of the isolation drive circuit, so as to further reduce the size of the product.
[0061] Furthermore, the gate oxide layer of the low-voltage PMOS transistor is thin, so it has a faster switching speed, which is beneficial to improving the performance of the circuit and reducing the power consumption of the circuit.
[0062] Exemplarily, the gate-source capacitance of the P-type switch tube has a capacitance ranging from 10 pF to 50 pF. More specifically, the gate-source capacitance of the P-type switch tube has a capacitance ranging from 10 pF, 15 pF, 20 pF, 30 pF or 50 pF.
[0063] It should be noted that the capacitance of the gate-source capacitor of the above-mentioned P-type switching tube is only an example. In actual use, on the premise that the capacitance of the gate-source capacitor of the P-type switching tube is smaller than the capacitance of the gate-source capacitor of the power switching tube, the capacitance of the gate-source capacitor of the P-type switching tube can be reasonably selected in combination with specific circuits and application scenarios.
[0064] In some embodiments, the material of the magnetic core body of the transformer includes high magnetic permeability powder, wherein the high magnetic permeability powder includes R5k powder and / or R10k powder.
[0065] In some embodiments, the material of the magnetic core body of the transformer includes R5k powder.
[0066] In some embodiments, the material of the magnetic core body of the transformer includes R10k powder.
[0067] In some embodiments, the material of the magnetic core body of the transformer includes R5k powder and R10k powder.
[0068] On the one hand, due to the high magnetic permeability of R5k powder and R10k powder, a large inductance can be achieved under low turns conditions, while significantly reducing the volume of the transformer core, which is conducive to the miniaturization of the isolation drive circuit. On the other hand, since the core is fixed on the epoxy board by dispensing, the pin spacing is very convenient to design. The spacing between the pins of the primary winding and the secondary winding is designed to be larger to meet the safety requirements in high-voltage applications and improve the reliability of the device. In addition, due to the small size of the transformer core, high excitation inductance, small excitation current, and low loss, the power consumption of the isolation drive circuit is further reduced.
[0069] In some embodiments, the spacing between the pins of the primary winding and the secondary winding of the transformer ranges from 20 mm to 30 mm. More specifically, the spacing between the pins of the primary winding and the secondary winding of the transformer is 20 mm, 25 mm or 30 mm.
[0070] In some embodiments, Figure 4As shown, the isolation driving circuit also includes a fourth resistor R4 and a fifth resistor R5, wherein the fourth resistor R4 is a charging and discharging resistor of the power switch tube S1, the fifth resistor R5 is a voltage dividing resistor, the first ends of the fourth resistor R4 and the fifth resistor R5 are both connected to the gate of the power switch tube S1, the second end of the fourth resistor R4 is connected to the source of the P-type switch tube P1, and the second end of the fifth resistor R5 is connected to the drain of the P-type switch tube P1 and the source of the power switch tube S1.
[0071] Next, refer to Figure 5 and Figure 6 right Figure 4 The working principle of the isolated drive circuit shown is introduced in detail.
[0072] like Figure 5 As shown, when the PWM signal provided by the control circuit 100 is at a high level, the first switch tube Q1 is turned on, the voltage at the same-name terminal a of the primary winding of the transformer T is positive, and the voltage at the opposite-name terminal b of the primary winding is negative, and the excitation current and the primary winding current charge the first capacitor C1 at the same time. The secondary winding induces a positive voltage at the top and a negative voltage at the bottom, which charges the gate-source capacitor of the power switch tube S1 through the turned-on first diode D1, thereby turning on the power switch tube S1. It should be noted that at this time, the P-type switch tube is in the off state.
[0073] In the embodiment of the present disclosure, since the material of the magnetic core body of the transformer T includes high magnetic permeability powder (R5k powder or R10k powder), when the transformer T is working, the primary winding leakage inductance Lpr and the secondary winding leakage inductance Lsr are small, and the excitation inductance Lm is large, so that the excitation current is small, thereby reducing the power consumption of the isolation drive circuit.
[0074] In some embodiments, since the capacitance value of the first capacitor C1 is too large, its charging time constant (related to the equivalent impedance of the transformer winding) becomes larger. When the PWM signal is at a high level, the voltage of the first capacitor C1 is slow to build up, resulting in a very large initial charging current of the first capacitor C1. This initial charging current will flow through the primary winding of the transformer, causing the magnetic core of the transformer to enter a saturated state. After the magnetic core of the transformer enters a saturated state, the inductive reactance drops sharply, and the current of the primary winding will further increase, which may cause overload of circuit components.
[0075] In some embodiments, if the capacitance value of the first capacitor C1 is too small, the voltage of the first capacitor C1 will fluctuate greatly, further causing the drive signal output by the secondary winding to fluctuate or be discontinuous, thus affecting the performance of the isolation drive circuit.
[0076] Therefore, in the embodiment of the present disclosure, the capacitance value of the first capacitor C1 ranges from 30nF to 500nF. By controlling the capacitance value of the first capacitor C1 within the above range, the core saturation of the transformer caused by the large instantaneous charging current during the voltage establishment process of the first capacitor C1 can be avoided, while ensuring the stability of the drive signal output by the secondary winding.
[0077] In some embodiments, Fig. 7A As shown, in the isolation driving circuit without the second resistor R2, the driving signal (voltage signal) output by the secondary winding has a peak (such as Fig. 7A The dotted circle shown in the figure may burn out the power switch tube S1. Figure 7B Shows Figure 4 The waveform of the drive signal output by the secondary winding is shown in Figure 7B It can be seen that the second resistor R2 has a significant suppressive effect on the peak of the driving signal (voltage signal), which can effectively improve the waveform of the driving signal output by the secondary winding and improve the working performance of the power switch tube.
[0078] like Figure 6 As shown, when the PWM signal provided by the control circuit 100 is at a low level, the first switch tube Q1 is turned off and the second switch tube Q2 is turned on. At this time, the first capacitor C1 is discharged. In other words, the voltage of the first capacitor is reversely added to the primary winding, so that the voltage of the same-name terminal a of the primary winding of the transformer T is negative, and the voltage of the opposite-name terminal b of the primary winding is positive. The secondary winding induces a negative voltage at the top and a positive voltage at the bottom, and the first diode is turned off. The gate-source voltage Vgs of the P-type switch tube P1 changes from positive to negative, so the P-type switch tube P1 is turned on, and the gate-source capacitance of the P-type switch tube P1 is discharged to the primary winding, and the level of the drive signal is pulled to 0V, so that the power switch tube S1 is turned off.
[0079] In some embodiments, the discharge speed of the first capacitor C1 is controlled by setting the third resistor R3.
[0080] In some embodiments, since the gate-source capacitance of the P-type switch tube P1 is smaller than the gate-source capacitance of the power switch tube S1, when the P-type switch tube P1 is turned on and discharges to the primary winding, the discharge current generated is smaller, so the power consumption of the isolation drive circuit can be reduced.
[0081] In some embodiments, the P-type switch tube is a PNP-type transistor, and the power switch tube is an NPN-type transistor. The gate of the P-type switch tube is the base of the PNP-type transistor, the drain of the P-type switch tube is the collector of the PNP-type transistor, and the source of the P-type switch tube is the emitter of the PNP-type transistor; the gate of the power switch tube is the base of the NPN-type transistor, the drain of the power switch tube is the collector of the NPN-type transistor, and the source of the power switch tube is the emitter of the NPN-type transistor.
[0082] On the one hand, the disclosed embodiment realizes electrical isolation between the control signal and the power circuit through the cooperation of the totem pole amplifier circuit and the transformer, thereby improving the stability and safety of the circuit. On the other hand, the first diode, the first resistor and the P-type switch tube of the secondary circuit are further provided, so that the drive signal output by the secondary circuit can stably drive the power switch tube, accurately control the conduction and cutoff of the power switch tube, reduce power consumption, improve the working efficiency of the circuit, and avoid misconduction of the power switch tube. In addition, the isolation drive circuit provided by the disclosed embodiment has a simple structure, is easy to manufacture and maintain, and reduces costs.
[0083] In some embodiments, Figure 8 As shown, the fifth resistor R5 can also be connected in parallel with a voltage regulator diode ZD1 to prevent Fig. 7A The peak voltage in the circuit will damage the power switch tube S1, which has the function of protecting the power switch tube S1.
[0084] In a second aspect, the present disclosure provides a switching power supply, such as Fig. 9 As shown, the switching power supply 10 includes: a dual-switch flyback circuit 11 and an isolation driving circuit 12 described in any of the above embodiments. The structure of the isolation driving circuit 12 can refer to the above embodiments and will not be described in detail here.
[0085] In some embodiments, the isolation driving circuit is used to control the dual-switch flyback circuit.
[0086] In some embodiments, the double-switch flyback circuit of the switching power supply includes two Figure 4 As shown in the power switch tube S1, the isolation drive circuit of the switching power supply includes two output circuits, for example, the isolation drive circuit of the switching power supply includes two Figure 4 The secondary circuit shown in FIG. 1 shows a gate and a source of one power switch tube S1 connected to a first output terminal out1 and a second output terminal out2 of an output circuit (secondary circuit) of the isolation drive circuit, respectively, and a gate and a source of another power switch tube S1 connected to a first output terminal out1 and a second output terminal out2 of another output circuit (secondary circuit) of the isolation drive circuit, respectively.
[0087] It can be understood that, since the switching power supply of this embodiment adopts the technical solution of the above-mentioned isolation driving circuit, the switching power supply has all the beneficial effects of the above-mentioned isolation driving circuit.
[0088] In a third aspect, an embodiment of the present disclosure provides an electronic device, which includes the switching power supply provided by the aforementioned embodiment.
[0089] It should be noted here that the description of the above device embodiment is similar to the description of the above isolation drive circuit embodiment, and has similar beneficial effects as the isolation drive circuit embodiment. For technical details not disclosed in the device embodiment of the present disclosure, please refer to the description of the embodiment of the isolation drive circuit of the present disclosure for understanding.
[0090] It should be understood that "one embodiment" or "some embodiments" mentioned throughout the specification means that specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the present disclosure. Therefore, "in one embodiment" or "in some embodiments" appearing throughout the specification does not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner. It should be understood that in the various embodiments of the present disclosure, the size of the serial number of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present disclosure. The serial numbers of the embodiments of the present disclosure are for description only and do not represent the advantages and disadvantages of the embodiments.
[0091] The above description is only a specific implementation mode of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure.
Claims
1. An isolation driving circuit, characterized in that: include: Primary circuit and secondary circuit; The primary circuit includes a totem pole amplifier circuit and a primary winding of a transformer, the output end of the totem pole amplifier circuit is connected to the same-name end of the primary winding, and the ground end of the totem pole amplifier circuit is connected to the opposite-name end of the primary winding; The secondary circuit includes a secondary winding of a transformer, a first diode, a first resistor and a P-type switching tube, wherein an anode of the first diode is connected to a first end of the first resistor and a like-name end of the secondary winding, and a cathode of the first diode is connected to a source of the P-type switching tube as a first output end of the isolation drive circuit, which is used to be connected to a gate of a power switching tube; a second end of the first resistor is connected to a gate of the P-type switching tube, and a drain of the P-type switching tube is connected to an unlike-name end of the secondary winding as a second output end of the isolation drive circuit, which is used to be connected to a source of a power switching tube.
2. The isolation driving circuit according to claim 1, characterized in that: The primary circuit also includes a first capacitor and a second resistor; The totem pole amplifier circuit includes a first switch tube and a second switch tube; the first electrode of the first switch tube serves as a power supply end of the totem pole amplifier circuit, the second electrode of the first switch tube is connected to the second electrode of the second switch tube as an input end of the totem pole amplifier circuit, the third electrode of the first switch tube is connected to the third electrode of the second switch tube as an output end of the totem pole amplifier circuit, and the first electrode of the second switch tube serves as a ground end of the totem pole amplifier circuit; A first end of the second resistor is connected to the output end of the totem pole amplifier circuit, a second end of the second resistor is connected to a first end of the first capacitor, and a second end of the first capacitor is connected to a same-name end of the primary winding; or, The first end of the second resistor is connected to the output end of the totem pole amplifier circuit, the second end of the second resistor is connected to the same-name end of the primary winding, the first end of the first capacitor is connected to the opposite-name end of the primary winding, and the second end of the first capacitor is connected to the first electrode of the second switch tube.
3. The isolation driving circuit according to claim 2, characterized in that: The primary circuit also includes a third resistor; A first end of the third resistor is connected to a first end of the first capacitor, and a second end of the third resistor is connected to a second end of the first capacitor.
4. The isolation driving circuit according to claim 2, characterized in that: The primary circuit further includes a second diode, a cathode of the second diode is connected to the first end of the first capacitor, and an anode of the second diode is connected to the second end of the first capacitor.
5. The isolation driving circuit according to claim 2, characterized in that: The capacitance value of the first capacitor ranges from 30nF to 500nF.
6. The isolation driving circuit according to claim 2, characterized in that: The first switch tube is an NPN type transistor, and the second switch tube is a PNP type transistor; wherein the first electrode is a collector, the second electrode is a base, and the third electrode is an emitter; or, The first switch tube is an NMOS transistor, and the second switch tube is a PMOS transistor; wherein the first electrode is a drain, the second electrode is a gate, and the third electrode is a source.
7. The isolation driving circuit according to claim 1, characterized in that: The P-type switch tube is a PMOS transistor, the power switch tube is an NMOS transistor, and the gate-source capacitance of the P-type switch tube is smaller than the gate-source capacitance of the power switch tube.
8. The isolation driving circuit according to claim 1, characterized in that: The material of the magnetic core body of the transformer includes high magnetic permeability powder, wherein the high magnetic permeability powder includes R5k powder and / or R10k powder.
9. A switching power supply, characterized in that: include: A dual-transistor flyback circuit and an isolation drive circuit as claimed in any one of claims 1 to 8.
10. An electronic device, characterized in that: Comprising the switching power supply as claimed in claim 9.