A power taking circuit and switching power supply

Abstract

The application relates to a power taking circuit and a switching power supply. The power taking circuit comprises a transformer T1, a first charging circuit, a first resonant circuit, a second charging circuit and a second resonant circuit. The transformer T1 comprises a first primary winding, a second primary winding and a secondary winding. The first charging circuit comprises a first capacitor and is used for storing positive half cycle energy input by a first alternating voltage input end and a second alternating voltage input end of the power taking circuit in the first capacitor. The first resonant circuit comprises a first switch circuit, the first capacitor and the first primary winding, and is used for transferring the energy stored in the first capacitor to the first primary winding and then to the secondary winding of the transformer T1. The second charging circuit is consistent with the first charging circuit. The second resonant circuit is consistent with the second resonant circuit. Two ends of the secondary winding are two output ends of the power taking circuit. The application can realize bidirectional utilization of alternating positive and negative half cycles, double the overall working frequency of the circuit and improve the circuit load capacity by more than 50%.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power supply, in particular to a power taking circuit and switching power supply. BACKGROUND

[0002] All electronic devices must work under the support of power supply circuit, and for this purpose, a corresponding power taking circuit needs to be designed. At present, there are many AC power taking schemes. For example, resistance-capacitance voltage reduction power taking, bridge rectifier power taking, half-wave rectifier power taking and a series of commonly used classic AC power taking schemes.

[0003] However, the above power taking schemes have various shortcomings. Resistance-capacitance voltage reduction power taking is cheap, but has no isolation and has the risk of electric shock; bridge rectifier power taking has good energy utilization rate, but the overall cost is high; half-wave rectifier power taking has slightly lower cost, but has low utilization rate, low output DC component and large output waveform pulsation; in addition, since the input is AC power frequency voltage which is a dangerous voltage, in order to prevent the risk of electric shock, a transformer needs to be added for isolation, so that the AC power frequency voltage is rectified into a DC voltage, and then converted into an AC pulsating energy that can be used by the transformer through a switching tube and then transmitted to the secondary side. The overall scheme is still relatively complex. SUMMARY

[0004] In view of this, the technical problem to be solved by the present application is to provide a power taking circuit and switching power supply, which at least solves the above-mentioned deficiencies of the prior art to some extent.

[0005] As a first aspect of the present application, the technical scheme of the provided power taking circuit embodiment is as follows:

[0006] A power taking circuit, comprising:

[0007] a transformer T1, comprising a first primary winding, a second primary winding and a secondary winding;

[0008] a first charging circuit, comprising a first capacitor, the first charging circuit being configured to store positive half-cycle energy input from a first AC voltage input end and a second AC input end of the power taking circuit in the first capacitor;

[0009] a first resonant circuit, comprising a first switching circuit, the first capacitor and the first primary winding, the first resonant circuit being configured to transfer the energy stored in the first capacitor to the first primary winding and then to the secondary winding of the transformer T1 for output;

[0010] a second charging circuit, comprising a second capacitor, the second charging circuit being configured to store negative half-cycle energy input from the first AC voltage input end and the second AC input end of the power taking circuit in the second capacitor;

[0011] a second resonant circuit comprising a second switching circuit, the second capacitor and the second primary winding, the second resonant circuit being configured to transfer energy stored in the second capacitor to the second primary winding and then to the secondary winding of the transformer T1 for output;

[0012] wherein two ends of the secondary winding are two output terminals of the power taking circuit.

[0013] Preferably, the first switching circuit comprises a thyristor S1 and a trigger circuit of the thyristor S1; and / or the second switching circuit comprises a thyristor S2 and a trigger circuit of the thyristor S2.

[0014] Preferably, the trigger circuit of the thyristor S1 obtains a supply voltage from the second AC input terminal; and / or the trigger circuit of the thyristor S2 obtains a supply voltage from the first AC input terminal.

[0015] Further, the power taking circuit further comprises a diode D3 and / or a diode D4; an anode of the diode D3 is connected to a cathode of the thyristor S1, and a cathode of the diode D3 is connected to an anode of the thyristor S1; an anode of the diode D4 is connected to a cathode of the thyristor S2, and a cathode of the diode D4 is connected to an anode of the thyristor S2.

[0016] A power taking circuit, comprising:

[0017] a transformer T1 comprising a first primary winding, a second primary winding and a secondary winding; a resistor R1, a resistor R2, a resistor R3, a thyristor S1, a thyristor S2, a diode D1, a diode D2, a capacitor C1 and a capacitor C2;

[0018] one end of the resistor R1 is a first AC voltage input terminal of the power taking circuit, the other end of the resistor R1 is connected to one end of the capacitor C1, the other end of the capacitor C1 is connected to a same name end of the first primary winding, a different name end of the first primary winding is connected to an anode of the diode D1, and a cathode of the diode D1 is a second AC voltage input terminal of the power taking circuit, so that the resistor R1, the capacitor C1, the first primary winding and the diode D1 form a first primary charging circuit;

[0019] an anode of the thyristor S1 is connected to one end of the capacitor C1, and a cathode of the thyristor S1 is connected to a different name end of the first primary winding, so that the thyristor S1, the capacitor C1 and the first primary winding form a first resonant circuit;

[0020] One end of the capacitor C2 is the second AC voltage input terminal of the power taking circuit, the other end of the capacitor C2 is connected to the same name terminal of the second primary winding, the different name terminal of the second primary winding is connected to the anode of the diode D2, and the cathode of the diode D2 is connected to the other end of the resistor R1, so that the capacitor C2, the second primary winding, the diode D2 and the resistor R1 form a second primary charging loop.

[0021] The anode of the thyristor S2 is connected to one end of the capacitor C2, and the cathode of the thyristor S2 is connected to the different name terminal of the second primary winding, so that the thyristor S2, the capacitor C2 and the second primary winding form a first resonance loop.

[0022] The resistor R2 is connected between the second AC voltage input terminal of the power taking circuit and the trigger electrode of the thyristor S1, and the resistor R3 is connected between the first AC voltage input terminal of the power taking circuit and the trigger electrode of the thyristor S2.

[0023] The two ends of the secondary winding are the two output terminals of the power taking circuit.

[0024] Further, the power taking circuit further comprises a diode D3 and / or a diode D4, the anode of the diode D3 is connected to the cathode of the thyristor S1, the cathode of the diode D3 is connected to the anode of the thyristor S1, the anode of the diode D4 is connected to the cathode of the thyristor S2, and the cathode of the diode D4 is connected to the anode of the thyristor S2.

[0025] Further, the power taking circuit further comprises a resistor R4 and / or a resistor R5, the resistor R4 is connected between the cathode and the trigger electrode of the thyristor S1, and the resistor R5 is connected between the cathode and the trigger electrode of the thyristor S2.

[0026] A power taking circuit, comprising:

[0027] A transformer T1, which comprises a first primary winding, a second primary winding and a secondary winding; a resistor R1, a resistor R2, a thyristor S1, a thyristor S2, a capacitor C1 and a capacitor C2.

[0028] One end of the resistor R1 is the first AC voltage input terminal of the power taking circuit, the other end of the resistor R1 is connected to one end of the capacitor C1, the other end of the capacitor C1 is connected to the same name terminal of the first primary winding, the different name terminal of the first primary winding is connected to the cathode of the thyristor S1, the trigger electrode of the thyristor S1 is connected to one end of the resistor R2, and the other end of the resistor R2 is the second AC voltage input terminal of the power taking circuit, so that the resistor R1, the capacitor C1, the first primary winding and the resistor R2 form a first primary charging loop.

[0029] The thyristor S1 anode is connected to one end of the capacitor C1, so that the thyristor S1, the capacitor C1 and the first primary winding form a first resonant circuit.

[0030] One end of the resistor R2 is connected to one end of the capacitor C2, the other end of the capacitor C2 is connected to the same end of the second primary winding, the different end of the second primary winding is connected to the cathode of the thyristor S2, and the trigger electrode of the thyristor S2 is connected to the other end of the resistor R1, so that the resistor R2, the capacitor C2, the second primary winding and the resistor R1 form a second primary charging circuit.

[0031] The thyristor S2 anode is connected to one end of the capacitor C2, so that the thyristor S2, the capacitor C2 and the second primary winding form a second resonant circuit.

[0032] Wherein, the two ends of the secondary winding are two output ends of the power taking circuit.

[0033] Further, the power taking circuit further comprises a diode D3 and / or a diode D4; the diode D3 anode is connected to the cathode of the thyristor S1, and the diode D3 cathode is connected to the anode of the thyristor S1; the diode D4 anode is connected to the cathode of the thyristor S2, and the diode D4 cathode is connected to the anode of the thyristor S2.

[0034] As a second aspect of the present application, the technical scheme of the switching power supply embodiment provided is as follows:

[0035] A switching power supply comprising the power taking circuit of any one of the first aspect.

[0036] The biggest difference between the power taking circuit of the present application and the prior art is that it directly uses AC power frequency high voltage to take power, and through the first charging circuit and the first resonant circuit and the second charging circuit and the second resonant circuit, it realizes staggered parallel operation in the full cycle of input AC power frequency voltage. Compared with the prior art, the present application has the following advantages:

[0037] (1) The staggered parallel resonant power taking can improve the working frequency of the circuit, and the working frequency of the circuit is increased from 1 time per power frequency cycle to 2 times per power frequency cycle, i.e. the working frequency of the circuit is increased by 1 times, so that the circuit can select a smaller transformer in the manufacturing process, which is beneficial to reduce the size of the circuit.

[0038] (2) using staggered parallel resonant power taking, the circuit's load capacity can be improved, the circuit transmits energy to the secondary side once in a power frequency cycle, and is optimized to transmit energy to the secondary side twice in a power frequency cycle, so that the load capacity of the overall circuit is improved by more than 50%, and the full use of energy in the whole cycle is realized. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 the principle diagram of the first specific embodiment of the power taking circuit of the present application;

[0040] Figure 2 the principle diagram of the second specific embodiment of the power taking circuit of the present application;

[0041] Figure 3 the principle diagram of the third specific embodiment of the power taking circuit of the present application;

[0042] Figure 4 the principle diagram of the fourth specific embodiment of the power taking circuit of the present application;

[0043] Figure 5 the principle diagram of the fifth specific embodiment of the power taking circuit of the present application;

[0044] Figure 6 the principle diagram of the sixth specific embodiment of the power taking circuit of the present application. DETAILED DESCRIPTION

[0045] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application is further described in detail below with reference to the 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.

[0046] It should be noted that the terms "comprising" and "having" and any variations thereof described in the specification and claims of the present application are intended to cover non-exclusive inclusion, for example, a series of components, unit circuits or control sequences do not have to be limited to those clearly listed, but can include components, unit circuits or control sequences that are not clearly listed or inherent to these circuits.

[0047] In addition, the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0048] It should be understood that in the specification and claims, when describing that an element is "connected" to another element, the element can be "directly connected" to the other element, or "connected" to the other element through a third element; when describing that a step is connected to another step, the step can be directly connected to the other step, or connected to the other step through a third step.

[0049] The application provides an embodiment of a power taking circuit.

[0050] The transformer T1 comprises a first primary winding, a second primary winding and a secondary winding.

[0051] The first charging circuit comprises a first capacitor, and is used for storing positive half-cycle energy input by the first AC voltage input end and the second AC input end of the power taking circuit in the first capacitor.

[0052] The first resonant circuit comprises a first switch circuit, the first capacitor and the first primary winding, and is used for transferring energy stored in the first capacitor to the first primary winding and then to the secondary winding of the transformer T1.

[0053] The second charging circuit comprises a second capacitor, and is used for storing negative half-cycle energy input by the first AC voltage input end and the second AC input end of the power taking circuit in the second capacitor.

[0054] The second resonant circuit comprises a second switch circuit, the second capacitor and the second primary winding, and is used for transferring energy stored in the second capacitor to the second primary winding and then to the secondary winding of the transformer T1.

[0055] The two ends of the secondary winding are two output ends of the power taking circuit.

[0056] The power taking circuit directly uses AC power frequency high voltage to work, and realizes staggered parallel work in the whole cycle of input AC power frequency voltage through the first charging circuit and the first resonant circuit and the second charging circuit and the second resonant circuit, so that the working frequency of the circuit is increased from one working frequency cycle to two working frequency cycles, which is beneficial to reducing the size of the power supply circuit; and the energy transmission from the circuit to the secondary winding is optimized from one working frequency cycle to two working frequency cycles, so that the load capacity of the overall circuit is increased by more than 50%, and the energy in the whole cycle is fully utilized.

[0057] Preferably, the first switch circuit comprises a thyristor S1 and a trigger circuit of the thyristor S1; and / or the second switch circuit comprises a thyristor S2 and a trigger circuit of the thyristor S2, since the thyristor can withstand bidirectional voltage and can realize opening and closing through AC bidirectional characteristics.

[0058] Further, the trigger circuit of the thyristor S1 obtains a supply voltage from the second AC input end; and / or the trigger circuit of the thyristor S2 obtains a supply voltage from the first AC input end, so that the thyristor can be automatically turned off through zero-crossing of AC power frequency high voltage, staggered work of the power taking circuit is realized, and the design of the trigger circuit is very simple.

[0059] Further, the power taking circuit further comprises: a diode D3 and / or a diode D4; the anode of the diode D3 is connected to the cathode of the thyristor S1, and the cathode of the diode D3 is connected to the anode of the thyristor S1; the anode of the diode D4 is connected to the cathode of the thyristor S2, and the cathode of the diode D4 is connected to the anode of the thyristor S2; due to the addition of the diode D3 and the diode D4, bidirectional resonant energy utilization can be achieved in some application scenarios, the utilization rate of the circuit is further improved, and the load capacity of the product is enhanced.

[0060] Figure 1 For the schematic diagram of the first embodiment of the power taking circuit of the present application, please refer to Figure 1 The power taking circuit comprises:

[0061] a transformer T1 comprising a first primary winding, a second primary winding and a secondary winding; a resistor R1, a resistor R2, a resistor R3, a thyristor S1, a thyristor S2, a diode D1, a diode D2, a capacitor C1 and a capacitor C2;

[0062] One end of the resistor R1 is the first AC voltage input terminal AC(L) of the power taking circuit, the other end of the resistor R1 is connected to one end of the capacitor C1, the other end of the capacitor C1 is connected to the same name terminal 1 of the first primary winding, the different name terminal 2 of the first primary winding is connected to the anode of the diode D1, and the cathode of the diode D1 is the second AC voltage input terminal of the power taking circuit, so that the resistor R1, the capacitor C1, the first primary winding and the diode D1 form a first primary charging circuit;

[0063] The anode of the thyristor S1 is connected to one end of the capacitor C1, and the cathode of the thyristor S1 is connected to the different name terminal 2 of the first primary winding, so that the thyristor S1, the capacitor C1 and the first primary winding form a first resonant circuit;

[0064] One end of the capacitor C2 is the second AC voltage input terminal AC(N) of the power taking circuit, the other end of the capacitor C2 is connected to the same name terminal 3 of the second primary winding, the different name terminal 4 of the second primary winding is connected to the anode of the diode D2, and the cathode of the diode D2 is connected to the other end of the resistor R1, so that the capacitor C2, the second primary winding, the diode D2 and the resistor R1 form a second primary charging circuit;

[0065] The anode of the thyristor S2 is connected to one end of the capacitor C2, and the cathode of the thyristor S2 is connected to the different name terminal of the second primary winding, so that the thyristor S2, the capacitor C2 and the second primary winding form a first resonant circuit;

[0066] The resistor R2 is a trigger circuit of the thyristor S1 and is connected between the second AC voltage input terminal of the power taking circuit and the trigger electrode of the thyristor S1; the resistor R3 is a trigger circuit of the thyristor S2 and is connected between the first AC voltage input terminal of the power taking circuit and the trigger electrode of the thyristor S2;

[0067] The two ends of the edge winding are two output terminals Vs1 and Vs2 of the power taking circuit.

[0068] It should be noted that, Figure 1 The power taking circuit can realize short-circuit self-recovery function because the resistance R1 limits the maximum power of the circuit.

[0069] Figure 1 The working principle of the power taking circuit is as follows:

[0070] The first AC voltage input terminal and the second AC input terminal input AC power frequency voltage positive half cycle: the current of the first AC voltage input terminal AC(L) gradually increases according to the sine curve of the positive half cycle, the current charges the capacitor C1 through the resistance R1, because the power frequency is low, the transformer T1 is in the saturation state, at this time the first primary winding charging circuit is connected, the capacitor C1 charging circuit current flow direction is: the first AC voltage input terminal AC(L)→resistance R1→capacitor C1→the same name end 1 of the first primary winding→the different name end 2 of the first primary winding→diode D1→the second AC voltage input terminal AC(N). When the current of the first AC voltage input terminal AC(L) increases to make the voltage Vgk of the trigger electrode G and the cathode K of the thyristor S1≥the threshold voltage Vth of the thyristor, because the voltage Vak of the anode A and the cathode K of the thyristor S1 is positive, at this time the thyristor S1 is triggered on. At the moment when the thyristor S1 is triggered on, the capacitor C1, the thyristor S1 and the primary winding form a resonant circuit, and at the same time the energy of the capacitor C1 is transferred to the first primary winding, then to the secondary winding and the transformer demagnetization is realized.

[0071] The first AC voltage input terminal and the second AC input terminal input AC power frequency voltage negative half cycle: the current of the first AC voltage input terminal AC(N) gradually increases according to the sine curve of the negative half cycle, the current charges the capacitor C2 through the resistance R1, because the power frequency is low, the transformer T1 is in the saturation state, at this time the second primary winding charging circuit is connected, the capacitor C2 charging circuit current flow direction is: the second AC voltage input terminal AC(N)→capacitor C2→the same name end 3 of the second primary winding→the different name end 4 of the second primary winding→diode D2→resistance R1→the first AC voltage input terminal AC(L). When the current of the second AC voltage input terminal AC(N) increases to make the voltage Vgk of the trigger electrode G and the cathode K of the thyristor S2≥the threshold voltage Vth of the thyristor, because the voltage Vak of the anode A and the cathode K of the thyristor S2 is positive, at this time the thyristor S2 is triggered on. At the moment when the thyristor S2 is triggered on, the capacitor C2, the thyristor S2 and the primary winding form a resonant circuit, and at the same time the energy of the capacitor C2 is transferred to the second primary winding, then to the secondary winding and the transformer demagnetization is realized.

[0072] Figure 2The schematic diagram of the second embodiment of the power taking circuit of the present application is shown in Fig. 2. Figure 2 The difference is that the power taking circuit further comprises diode D3 and diode D4; the anode of diode D3 is connected to the cathode of thyristor S1, and the cathode of diode D3 is connected to the anode of thyristor S1; the anode of diode D4 is connected to the cathode of thyristor S2, and the cathode of diode D4 is connected to the anode of thyristor S2. Figure 1 Due to the addition of diode D3 and diode D4, bidirectional resonant energy utilization can be achieved in some applications, further improving the utilization rate of the circuit and enhancing the load carrying capacity of the product. Figure 2 The working principle of the circuit is similar to that of the power taking circuit of the present application. Figure 1 Here, no further description is given. It should be noted that diode D3 and diode D4 can also be added alternatively, in which case the load carrying capacity is slightly worse than when diode D3 and diode D4 are added simultaneously.

[0073] Figure 3 The schematic diagram of the third embodiment of the power taking circuit of the present application is shown in Fig. 3. Figure 3 The difference is that the power taking circuit further comprises resistance R4 and resistance R5; resistance R4 is connected between the cathode and the trigger electrode of thyristor S1; and resistance R5 is connected between the cathode and the trigger electrode of thyristor S2. Figure 1 The power taking circuit of the present application, when capacitor C1 is charged, capacitor C2 discharges the residual charge to achieve reset, and the discharge path of capacitor C2 is: first AC voltage input end AC(L)→resistance R1→resistance R3→thyristor S2 trigger electrode G→thyristor cathode K→second secondary winding→capacitor C2→second AC voltage input end AC(N), so that the next AC power frequency voltage positive half cycle can work normally; similarly, capacitor C2 also needs to discharge the residual charge to achieve reset, and the discharge path of capacitor C1 is: second AC voltage input end AC(N)→resistance R2→thyristor S2 trigger electrode G→thyristor cathode K→first primary winding→capacitor C1→resistance R1→first AC voltage input end AC(L), Figure 1 The circuit, due to the addition of resistance R4 and resistance R5, which are connected in parallel between the corresponding thyristor cathode and trigger electrode, increases the corresponding capacitor reverse discharge loop current and improves the reliability of the circuit. Figure 3 The working principle of the circuit is similar to that of the power taking circuit of the present application. Figure 3 Here, no further description is given. Figure 1

[0074] Figure 4 The schematic diagram of the fourth embodiment of the power taking circuit of the present application is shown in Fig. 4. Figure 4 The difference is that diode D3, diode D4, resistance R4 and resistance R5 are added simultaneously, so that the advantages of the power taking circuit of the present application are integrated. Figure 1 Figure 2 Figure 3 The difference is that diode D3, diode D4, resistance R4 and resistance R5 are added simultaneously, so that the advantages of the power taking circuit of the present application are integrated.​​​Figure 4 The working principle of the circuit is as follows Figure 1 Similarly, details are not repeated here.

[0075] Figure 5 For the schematic diagram of the fifth embodiment of the power taking circuit of the application, please refer to Figure 5 The power taking circuit comprises:

[0076] A transformer T1 comprising a first primary winding, a second primary winding and a secondary winding; a resistor R1, a resistor R2, a thyristor S1, a thyristor S2, a capacitor C1 and a capacitor C2;

[0077] One end of the resistor R1 is an AC voltage input terminal AC(L) of the power taking circuit, the other end of the resistor R1 is connected to one end of the capacitor C1, the other end of the capacitor C1 is connected to a same name terminal 1 of the first primary winding, a different name terminal 2 of the first primary winding is connected to a cathode of the thyristor S1, one end of the resistor R2 connected to a trigger electrode of the thyristor S1, the other end of the resistor R2 is an AC voltage input terminal AC(N) of the power taking circuit, so that the resistor R1, the capacitor C1, the first primary winding and the resistor R2 form a first primary charging loop;

[0078] The anode of the thyristor S1 is connected to one end of the capacitor C1, so that the thyristor S1, the capacitor C1 and the first primary winding form a first resonance loop;

[0079] One end of the resistor R2 is connected to one end of the capacitor C2, the other end of the capacitor C2 is connected to a same name terminal 3 of the second primary winding, a different name terminal 4 of the second primary winding is connected to a cathode of the thyristor S2, the other end of the resistor R1 is connected to a trigger electrode of the thyristor S2, so that the resistor R2, the capacitor C2, the second primary winding and the resistor R1 form a second primary charging loop;

[0080] The anode of the thyristor S2 is connected to one end of the capacitor C2, so that the thyristor S2, the capacitor C2 and the second primary winding form a second resonance loop;

[0081] The two ends of the secondary winding are two output terminals Vs1 and Vs2 of the power taking circuit.

[0082] Figure 5 The resistor R1 is a trigger circuit of the thyristor S2, and the resistor R2 is a trigger circuit of the thyristor S1.

[0083] Figure 5 In the embodiment, since the resistor R1 and the resistor R2 limit the maximum power of the loop, the short-circuit self-recovery function can also be realized.

[0084] Figure 5 The working principle of the power taking circuit is as follows:

[0085] The first AC voltage input terminal and the second AC voltage input terminal are input to the positive half-cycle of the AC power frequency voltage. The difference from Figure 1 is that at this time, capacitor C2 is charging and capacitor C1 is discharging. The current path of the capacitor C2 charging circuit is: first AC voltage input terminal AC(L) → resistor R1 → thyristor S2 trigger electrode G → thyristor S2 cathode K → second primary winding → capacitor C2 → resistor R2 → second AC voltage input terminal AC(N); the current path of the capacitor C1 discharging circuit is: first AC voltage input terminal AC(L) → resistor R1 → capacitor C1 → first primary winding same-name terminal 1 → first primary winding opposite-name terminal 2 → thyristor S1 cathode K → thyristor S1 trigger electrode G → resistor R2 → second AC voltage input terminal AC(N).

[0086] The first AC voltage input terminal and the second AC voltage input terminal are input to the negative half-cycle of the AC power frequency voltage. The difference from Figure 1 is that at this time, capacitor C1 is charging and capacitor C2 is discharging. The current path of the capacitor C1 charging circuit is: second AC voltage input terminal AC(N) → resistor R2 → thyristor S1 trigger electrode G → thyristor S1 cathode K → first primary winding opposite terminal 2 → first primary winding same terminal 1 → capacitor C1 → resistor R1 → first AC voltage input terminal AC(L); the current path of the capacitor C2 discharging circuit is: second AC voltage input terminal AC(N) → resistor R2 → capacitor C2 → second primary winding same terminal 3 → second primary winding opposite terminal 4 → thyristor S2 cathode K → thyristor S2 trigger electrode G → resistor R1 → first AC voltage input terminal AC(L).

[0087] By comparison Figure 1 and Figure 5 It can be seen that, Figure 5 Its circuit structure is simpler, but Figure 5 When capacitors C1 and C2 are reset, the current path of the discharge circuit needs to go through the cathode to the emitter of the corresponding thyristor. The reverse leakage current of the PN junction between the cathode and emitter of the thyristor is very small. Therefore, the reverse reset current of capacitors C1 and C2 is very small. In order for capacitors C1 and C2 to be reset, the values ​​of resistors R1 and R2 must be very small. This will lead to greater circuit losses. Therefore, the two types of circuits each have their advantages and disadvantages. Those skilled in the art can choose which circuit scheme to use according to their needs in actual use.

[0088] Figure 6 This is a schematic diagram of the sixth specific embodiment of the power supply circuit of the present invention. Please refer to [link / reference]. Figure 6 ,and Figure 5The difference is that the power taking circuit further comprises: a diode D3 and a diode D4; the anode of the diode D3 is connected to the cathode of the thyristor S1, and the cathode of the diode D3 is connected to the anode of the thyristor S1; the anode of the diode D4 is connected to the cathode of the thyristor S2, and the cathode of the diode D4 is connected to the anode of the thyristor S2; due to the addition of the diode D3 and the diode D4, bidirectional resonant energy utilization can be achieved in some application occasions, the utilization rate of the circuit is further improved, and the load carrying capacity of the product is enhanced. Figure 6 The working principle is similar to Figure 5 and will not be described here. It should be noted that the diode D3 and the diode D4 can also be selectively added, in which case the load carrying capacity is slightly worse than when the diode D3 and the diode D4 are simultaneously added.

[0089] The application also provides a switching power supply comprising any one of the embodiments of the power taking circuit.

[0090] The switching power supply of the application directly utilizes AC power frequency high voltage for power taking by using the above-mentioned power taking circuit, and realizes staggered parallel operation in the whole cycle of input AC power frequency voltage through the first charging circuit and the first resonant circuit and the second charging circuit and the second resonant circuit, and has the beneficial effects compared with the prior art:

[0091] (1) The staggered parallel resonant power taking can improve the working frequency of the switching power supply, and the working frequency of the switching power supply is increased from 1 time per power frequency cycle to 2 times per power frequency cycle, i.e. the working frequency of the switching power supply is increased by 1 times, so that a smaller transformer can be selected in the manufacturing process of the switching power supply, which is beneficial to reducing the size of the switching power supply;

[0092] (2) The staggered parallel resonant power taking can improve the load carrying capacity of the switching power supply, and the energy transmission from the primary side to the secondary side of the switching power supply is optimized from 1 time per power frequency cycle to 2 times per power frequency cycle, so that the load carrying capacity of the overall switching power supply is increased by more than 50%, and the full utilization of energy in the whole cycle is realized.

[0093] The above is only an embodiment of the application, and it should be particularly pointed out that the above-mentioned embodiment should not be regarded as a limitation of the application, and for those skilled in the art, some improvements and refinements can be made without departing from the spirit and scope of the application, and these improvements and refinements should also be regarded as the protection scope of the application.

Claims

1. A power extraction circuit, characterized in that, include: Transformer T1 includes a first primary winding, a second primary winding, and a secondary winding; The first charging circuit includes a first capacitor, which is used to store the positive half-cycle energy input from the first AC voltage input terminal and the second AC input terminal of the power extraction circuit in the first capacitor. The first resonant circuit includes a first switching circuit, a first capacitor, and a first primary winding. The first resonant circuit is used to transfer the energy stored in the first capacitor to the first primary winding and then transmit it to the secondary winding of the transformer T1 for output. The second charging circuit includes a second capacitor, which is used to store the negative half-cycle energy input from the first AC voltage input terminal and the second AC input terminal of the power extraction circuit in the second capacitor. The second resonant circuit includes a second switching circuit, a second capacitor, and a second primary winding. The second resonant circuit is used to transfer the energy stored in the second capacitor to the second primary winding and then transmit it to the secondary winding of the transformer T1 for output. The two ends of the secondary winding are the two output terminals of the power supply circuit.

2. The power extraction circuit according to claim 1, characterized in that: The first switching circuit includes a thyristor S1 and a trigger circuit for the thyristor S1; and / or the second switching circuit includes a thyristor S2 and a trigger circuit for the thyristor S2.

3. The power extraction circuit according to claim 2, characterized in that: The trigger circuit of the thyristor S1 obtains its power supply voltage from the second AC input terminal; and / or the trigger circuit of the thyristor S2 obtains its power supply voltage from the first AC input terminal.

4. The power extraction circuit according to any one of claims 1 to 3, characterized in that: The power supply circuit further includes: diode D3 and / or diode D4; the anode of diode D3 is connected to the cathode of thyristor S1, and the cathode of diode D3 is connected to the anode of thyristor S1; the anode of diode D4 is connected to the cathode of thyristor S2, and the cathode of diode D4 is connected to the anode of thyristor S2.

5. A power extraction circuit, characterized in that, include: Transformer T1 includes a first primary winding, a second primary winding, and a secondary winding; resistors R1, R2, and R3; thyristor S1 and S2; diode D1 and D2; capacitor C1 and capacitor C2. One end of the resistor R1 is the first AC voltage input terminal of the power supply circuit, the other end of the resistor R1 is connected to one end of the capacitor C1, the other end of the capacitor C1 is connected to the same-name terminal of the first primary winding, the opposite-name terminal of the first primary winding is connected to the anode of the diode D1, and the cathode of the diode D1 is the second AC voltage input terminal of the power supply circuit, thereby forming a first primary charging circuit with the resistor R1, the capacitor C1, the first primary winding, and the diode D1. The anode of the thyristor S1 is connected to one end of the capacitor C1, and the cathode of the thyristor S1 is connected to the opposite end of the first primary winding, thereby forming a first resonant circuit with the thyristor S1, the capacitor C1, and the first primary winding. One end of the capacitor C2 is the second AC voltage input terminal of the power supply circuit, the other end of the capacitor C2 is connected to the same-name terminal of the second primary winding, the opposite-name terminal of the second primary winding is connected to the anode of the diode D2, and the cathode of the diode D2 is connected to the other end of the resistor R1, thereby forming a second primary charging circuit with the capacitor C2, the second primary winding, the diode D2, and the resistor R1. The anode of the thyristor S2 is connected to one end of the capacitor C2, and the cathode of the thyristor S2 is connected to the opposite end of the second primary winding, thereby forming a second resonant circuit with the thyristor S2, the capacitor C2, and the second primary winding. The resistor R2 is connected between the second AC voltage input terminal of the power supply circuit and the trigger electrode of the thyristor S1; the resistor R3 is connected between the first AC voltage input terminal of the power supply circuit and the trigger electrode of the thyristor S2. The two ends of the secondary winding are the two output terminals of the power supply circuit.

6. The power extraction circuit according to claim 5, characterized in that, The power supply circuit further includes: diode D3 and / or diode D4; the anode of diode D3 is connected to the cathode of thyristor S1, and the cathode of diode D3 is connected to the anode of thyristor S1; the anode of diode D4 is connected to the cathode of thyristor S2, and the cathode of diode D4 is connected to the anode of thyristor S2.

7. The power extraction circuit according to claim 5 or 6, characterized in that, The power supply circuit further includes: resistor R4 and / or resistor R5; resistor R4 is connected between the cathode and trigger electrode of thyristor S1; resistor R5 is connected between the cathode and trigger electrode of thyristor S2.

8. A power extraction circuit, characterized in that, include: Transformer T1 includes a first primary winding, a second primary winding, and a secondary winding; resistors R1 and R2; thyristor S1 and S2; capacitors C1 and C2; One end of resistor R1 is the first AC voltage input terminal of the power supply circuit. The other end of resistor R1 is connected to one end of capacitor C1. The other end of capacitor C1 is connected to the same-name terminal of the first primary winding. The opposite-name terminal of the first primary winding is connected to the cathode of thyristor S1. The trigger terminal of thyristor S1 is connected to one end of resistor R2. The other end of resistor R2 is the second AC voltage input terminal of the power supply circuit, thereby forming a first primary charging circuit with resistor R1, capacitor C1, the first primary winding, and resistor R2. The anode of the thyristor S1 is connected to one end of the capacitor C1, thereby forming a first resonant circuit with the thyristor S1, the capacitor C1, and the first primary winding. One end of the resistor R2 is connected to one end of the capacitor C2, the other end of the capacitor C2 is connected to the same-name terminal of the second primary winding, the opposite-name terminal of the second primary winding is connected to the cathode of the thyristor S2, and the trigger terminal of the thyristor S2 is connected to the other end of the resistor R1, thereby forming a second primary charging circuit with the resistor R2, the capacitor C2, the second primary winding and the resistor R1. The anode of the thyristor S2 is connected to one end of the capacitor C2, thereby forming a second resonant circuit with the thyristor S2, the capacitor C2, and the second primary winding. The two ends of the secondary winding are the two output terminals of the power supply circuit.

9. The power extraction circuit according to claim 8, characterized in that, The power supply circuit further includes: diode D3 and / or diode D4; the anode of diode D3 is connected to the cathode of thyristor S1, and the cathode of diode D3 is connected to the anode of thyristor S1; the anode of diode D4 is connected to the cathode of thyristor S2, and the cathode of diode D4 is connected to the anode of thyristor S2.

10. A switching power supply, characterized in that: Includes the power supply circuit as described in any one of claims 1 to 9.

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