A starting circuit and LED switch power supply system

Abstract

The present invention discloses a starting circuit and an LED switching power supply system, wherein the starting circuit comprises a starting module, an auxiliary power supply module, a shut-down module and a power supply module, wherein: the first input end of the starting module is an input end of high voltage alternating current, the second input end is connected to the output end of the shut-down module, and the output end is connected to the input end of the power supply module; the input end of the auxiliary power supply module is a voltage input end, the first output end is connected to the input end of the power supply module, and the second output end is connected to the input end of the shut-down module; the starting module is used to start the switching power supply system, the auxiliary power supply module is used to convert alternating current into direct current, the shut-down module is used to shut down the starting module when the auxiliary power supply module is in working state, and the voltage output by the power supply module is used to provide power to the electrical equipment. The embodiment of the present invention can shut down the starting module in time after the auxiliary power supply module works, thereby reducing the extra loss of the switching power supply system and improving the efficiency of the switching power supply system.

Description

Technical Field

[0001] The invention relates to the field of switching power supplies, and in particular to a starting circuit and an LED switching power supply system. Background Art

[0002] A switching power supply system is an input voltage source that provides operating voltage for electrical equipment. After obtaining the input voltage, the switching power supply system can convert the input voltage into the voltage required by the electrical equipment, thereby supplying power to the electrical equipment.

[0003] Typically, a switching power supply system may include a starting resistor, which may be used to start the switching power supply system. Furthermore, in order for the switching power supply system to obtain a larger starting current when starting, a starting resistor with a smaller resistance may be used.

[0004] However, after the switching power supply system is started, the starting resistor will still consume a certain amount of power in the process of supplying power to the electrical equipment, so that the switching power supply system has a large additional power consumption, resulting in poor overall efficiency of the switching power supply system. Summary of the invention

[0005] The embodiments of the present invention provide a starting circuit and an LED switching power supply system to solve the problem that when the switching power supply system is supplying power to an electrical device, a starting resistor in the switching power supply system consumes part of the power consumption, resulting in poor overall efficiency of the switching power supply system.

[0006] In order to solve the above-mentioned technical problems, the present invention is achieved as follows:

[0007] In a first aspect, a startup circuit is provided, which is applied to a switching power supply system, including a startup module, an auxiliary power supply module, a shutdown module and a power supply module, wherein:

[0008] The first input end of the start module is the input end of high voltage alternating current, the second input end is connected to the output end of the shutdown module, and the output end is connected to the input end of the power supply module;

[0009] The input end of the auxiliary power supply module is a voltage input end, the first output end is connected to the input end of the power supply module, and the second output end is connected to the input end of the shutdown module;

[0010] The startup module is used to start the switching power supply system, the auxiliary power supply module is used to convert AC power into DC power, the shutdown module is used to shut down the startup module when the auxiliary power supply module is in working state, and the voltage output by the power supply module is used to provide power to electrical equipment.

[0011] In a second aspect, an LED switching power supply system is provided, comprising the above-mentioned starting circuit.

[0012] In an embodiment of the present invention, the startup circuit includes a startup module, an auxiliary power supply module, a shutdown module and a power supply module, wherein an external voltage can be input into a high-voltage alternating current through a voltage input terminal of the startup module to start the switching power supply system, and after the switching power supply system is turned on, the auxiliary power supply module can convert the alternating current into direct current, and when the auxiliary power supply module is in a working state, the shutdown module can shut down the startup module. In this way, since the startup circuit provided by the embodiment of the present invention can shut down the startup module in a timely manner when the auxiliary power supply module is in a working state, the additional loss of the switching power supply system can be reduced, and the efficiency of the switching power supply system can be improved.

[0013] In addition, since the auxiliary power supply module can convert AC power into DC power and supply power to the input end of the power supply module, the auxiliary power supply module can not only meet the working voltage requirements of the power supply module, but also adjust the voltage level of the power supply module by adjusting the auxiliary power supply module, thereby improving the flexibility of the working process. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0015] Figure 1 is a schematic structural diagram of a starting circuit according to an embodiment of the present invention;

[0016] Figure 2 is a schematic structural diagram of a startup module of a startup circuit according to an embodiment of the present invention;

[0017] Figure 3 is a schematic structural diagram of an auxiliary power supply module of a starting circuit according to an embodiment of the present invention;

[0018] Figure 4 is a schematic structural diagram of an auxiliary power supply module of a starting circuit according to an embodiment of the present invention;

[0019] Figure 5 is a schematic structural diagram of an auxiliary power supply module of a starting circuit according to an embodiment of the present invention;

[0020] Figure 6 is a schematic structural diagram of a shutdown module of a startup circuit according to an embodiment of the present invention;

[0021] Figure 7 is a schematic structural diagram of a starting circuit according to an embodiment of the present invention;

[0022] Figure 8 is a schematic structural diagram of a starting circuit according to an embodiment of the present invention;

[0023] Fig. 9 It is a schematic structural diagram of an LED switching power supply system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] After the switching power supply system is currently turned on, the starting resistance in the switching power supply system still occupies a part of the loss, resulting in a large power supply loss, and the power supply voltage in the switching power supply system cannot be freely adjusted. Therefore, the main idea of ​​the embodiment of the present invention is: by adding a starting module, an auxiliary power supply module and a shutdown module to the switching power supply system, the starting module is used to quickly start the switching power supply system, and on the basis that the switching power supply system can be quickly started, the auxiliary power supply module is used to assist the switching power supply system, and the auxiliary power supply module is used to freely adjust the size of the power supply voltage, and the shutdown module is used to timely shut down the starting module, thereby reducing the additional loss of the switching power supply system and improving the efficiency of the switching power supply system.

[0026] The technical solutions provided by various embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0027] Figure 1 FIG. 1 is a schematic diagram of a starting circuit according to an embodiment of the present invention. Figure 1 As shown, the starting circuit may include a starting module, an auxiliary power supply module, a shut-down module and a power supply module.

[0028] exist Figure 1 In the embodiment, the startup module may include a first input terminal, a second input terminal and an output terminal, the auxiliary power supply module may include an input terminal, a first output terminal and a second output terminal, the shutdown module may include an input terminal and an output terminal, and the power supply module may include an input terminal and an output terminal, wherein:

[0029] The first input end of the start module is the input end of the high voltage alternating current, the second input end is connected to the output end of the shutdown module, and the output end is connected to the input end of the power supply module;

[0030] The input end of the auxiliary power supply module is a voltage input end, the first output end is connected to the input end of the power supply module, the second output end is connected to the input end of the shutdown module, and the voltage output by the output end of the power supply module can be used to provide power to the electrical equipment.

[0031] Figure 1 The startup module shown can be used to start the switching power supply system. Specifically, the external voltage can be input to the startup module through the first input terminal of the startup module. Under the action of the voltage, the startup module starts to work. At this time, the startup module can input voltage to the input terminal of the power supply module through the output terminal, thereby starting the switching power supply system. Among them, the above-mentioned external voltage is generally high-voltage alternating current, and the voltage input by the startup module to the power supply module is also high-voltage alternating current.

[0032] Since the high-voltage alternating current provided by the starting module is not compatible with the low-voltage direct current required by the input end of the power supply module, in order to meet the voltage requirement of the power supply module, the auxiliary power supply module can be used to provide auxiliary power.

[0033] Specifically, the startup circuit may include a power switch tube. When the switching power supply system is turned on and the startup module provides high-voltage AC power to the power supply module, the power switch tube will switch between the on state and the off state. During the switching process, an electric potential can be generated. The auxiliary power supply module can generate AC power according to the electric potential. At this time, the auxiliary power supply module starts to work. During the operation, the auxiliary power supply module can convert AC power into DC power, and output the converted DC power to the input end of the power supply module through the first output end, so as to achieve the function of auxiliary power supply.

[0034] It should be noted that the AC power generated in the auxiliary power supply module is related to the electric potential generated in the power supply module, and is numerically smaller than the high-voltage AC power in the power supply module. In addition, since the high-voltage AC power in the power supply module is provided by the starting module, the AC power generated in the auxiliary power supply module is smaller than the high-voltage AC power input to the first input terminal of the starting module.

[0035] After the auxiliary power supply module supplies power to the power supply module, the power supply module can provide power to the power-consuming device through the output terminal.

[0036] The auxiliary power supply module provided in this embodiment can also achieve the following technical effects:

[0037] When the high-voltage alternating current input to the first input terminal of the starting module changes, and the input terminal of the power supply module requires a constant voltage, the auxiliary power supply module can provide the power supply module with a constant low-voltage direct current; in addition, when the high-voltage alternating current input to the first input terminal of the starting module remains unchanged, and the input terminal of the power supply module requires a variable voltage, the auxiliary power supply module can also adjust the size of the low-voltage direct current output to the power supply module according to the needs of the power supply module.

[0038] The shutdown module can shut down the startup module when the auxiliary power supply module is in operation, thus preventing the components in the startup module from consuming power after the switching power supply system is started, thereby improving the overall efficiency of the switching power supply system.

[0039] Specifically, when the second output end of the auxiliary power supply module is connected to the input end of the shutdown module, the auxiliary module can input voltage to the shutdown module to start the shutdown module. That is to say, once the auxiliary power supply module starts working, the shutdown module starts working, and when the auxiliary power supply module is in working state, the shutdown module can shut down the start module through the first output end.

[0040] In the startup circuit provided by the embodiment of the present invention, after the switching power supply system is turned on, the auxiliary power supply module can convert AC power into DC power, and when the auxiliary power supply module is in a working state, the shutdown module can shut down the startup module. In this way, since the startup circuit provided by the embodiment of the present invention can shut down the startup module in a timely manner when the auxiliary power supply module is in a working state, the additional loss of the switching power supply system can be reduced and the efficiency of the switching power supply system can be improved.

[0041] In addition, since the auxiliary power supply module can convert AC power into DC power and supply power to the input end of the power supply module, the auxiliary power supply module can not only meet the working voltage requirements of the power supply module, but also adjust the voltage level of the power supply module by adjusting the auxiliary power supply module, thereby improving the flexibility of the working process.

[0042] In this embodiment, Figure 1 The startup module shown in the figure may include two current limiting resistors, a field effect transistor and two voltage regulator transistors. The specific connection structure can be referred to Figure 2 .

[0043] exist Figure 2 In the startup module, the startup module includes a first current limiting resistor R21, a second current limiting resistor R22, a first field effect transistor Q21, a first voltage zener diode ZD21 and a second voltage zener diode ZD23, wherein:

[0044] The first end of R21 ( Figure 2 A end shown) and the first end of R22 ( Figure 2 The second end of R21 ( Figure 2 The B end shown in the figure) is connected to the gate g of Q21, the cathode of ZD21 and the cathode of ZD23 respectively, and the second end of R22 ( Figure 2 The D terminal shown in the figure is connected to the drain d of Q21, and the anode of ZD21 is connected to the source s of Q21.

[0045] In this embodiment, the A terminal of R21 (i.e. the C terminal of R22) is the first input terminal of the startup module. Figure 2 The external voltage Vin shown can input high voltage AC to the startup module through the first input terminal; the gate g of Q21 is the second input terminal of the startup module, and the source s is the output terminal of the startup module.

[0046] Figure 2 The startup module shown works as follows:

[0047] After the external voltage Vin is input to the startup module, the startup module can start working. The external voltage Vin is input to the drain d of Q21 through R22 and to the gate g of Q21 through R21. When the voltage of the potential difference Vgs between the gate voltage and the source voltage is greater than the minimum turn-on voltage Vth of the gate g of Q21, Q21 is turned on and the source s of Q21 outputs an AC voltage.

[0048] It should be noted that Figure 2 The ZD21 and ZD23 shown play a clamping role in the startup module, which can limit the potential difference Vgs between the gate voltage and the source voltage of Q21. Specifically, under the clamping effect of ZD21 and ZD23, the maximum value of Vgs is the same as the voltage across ZD21, and the minimum value is the difference between the voltage across ZD23 and the anode voltage of ZD21.

[0049] Preferably, in order to quickly start the switching power supply system, R22 with a smaller resistance value can generally be selected. In this way, when the external voltage Vin charges the power supply module through R22, Q21 and D28, the input end of the power supply module can obtain a larger charging current, and the maximum value of the charging current can be (Vin-VQ21) / R22, where VQ21 is the on-state voltage drop of Q21.

[0050] Preferably, in order to prevent the breakdown of ZD23, a larger resistance value of R21 may be selected, wherein the resistance value of R21 may be greater than the resistance value of R22.

[0051] Optionally, Figure 2 The first field effect transistor Q21 shown can also be replaced by a triode. The function of the triode is the same as that of the first field effect transistor Q21 and will not be described in detail here.

[0052] In this embodiment, Figure 1 The auxiliary power supply module shown in the figure may specifically include a coil, a current limiting resistor, a diode and a capacitor. The specific connection structure can be referred to Figure 3 .

[0053] Figure 3 The auxiliary power supply module shown includes a first coil L21, a third current limiting resistor R26, a first diode D26, and a first capacitor C21, wherein:

[0054] The first end of L21 ( Figure 3 The E end shown) and the first end of C21 ( Figure 3 The G end shown in the figure) is connected to the second end of L21 ( Figure 3 The F end shown) and the first end of R26 ( Figure 3 The K end shown in the figure) is connected to the second end of R26 ( Figure 3 The L end shown in the figure) is connected to the anode of D26, and the cathode of D26 is connected to the second end of C21 ( Figure 3 H end shown).

[0055] In this embodiment, both ends of L21 are input ends of the auxiliary power supply module, which are used to input alternating current, and the cathode of D26 is the first output end and the second output end of the auxiliary power supply module.

[0056] Figure 3 The auxiliary power supply module shown works as follows:

[0057] When the switching power supply system is turned on, the power switch tube ( Figure 3 The auxiliary power supply module can sense the potential of the power switch tube through L21 and generate an induced voltage Vaux, that is, the potential is input to the auxiliary power supply module through L21, where Vaux can be alternating current. The auxiliary power supply module can enter the working state under the action of this potential.

[0058] After the auxiliary power supply module enters the working state, the auxiliary power supply module can convert AC power into DC power. Specifically, the AC power input at the L21 end can be converted into DC power through R26 and D26. Among them, R26 plays a role of current limiting, which can prevent the current in C21 from being too large and damaging C21, D26 plays a role of rectification, and C21 plays a role of filtering.

[0059] In this embodiment, in order to facilitate the auxiliary power supply module to adjust the voltage input to the power supply module, in one implementation, the auxiliary power supply module includes Figure 3 In the case of the device shown in the figure, it can also include a current limiting resistor, a triode, a voltage regulator diode, a diode and a capacitor. The specific connection structure can be referred to Figure 4 .

[0060] Figure 4 The auxiliary power supply module shown is Figure 3 The structure shown also includes a fourth current limiting resistor R25, a first transistor Q23, a third voltage stabilizing diode ZD24, a second diode D27 and a second capacitor C22, wherein:

[0061] The first end of R25 ( Figure 4 The M terminal shown in the figure) is connected to the cathode of D26 and the collector of Q23 respectively, and the second terminal of R25 ( Figure 4 The N end shown in the figure) is connected to the base of Q23 and the cathode of ZD24 respectively, and the anode of ZD24 is connected to the G end of C21 and the first end of C22 ( Figure 4 The anode of D27 is connected to the emitter of Q23, and the cathode of D27 is connected to the second end ( Figure 4 J terminal as shown) connection.

[0062] Figure 4 The cathode of D27 is the first output terminal of the auxiliary power supply module. 2 The cathode of 6 is the second output terminal of the auxiliary power supply module.

[0063] Figure 4 The auxiliary power supply module shown works as follows:

[0064] The auxiliary power supply module includes two paths, one of which is L 2 1. R 2 6.D 2 6 and C 2 1, which acts as a half-wave rectifier and can 2 The AC input at terminal 1 is converted into DC. The other path is from Q 23 , ZD 2 4. The path formed by D27 and C22 acts as a linear voltage regulator, which is used to adjust the voltage output to the power supply module. The voltage can be lowered according to the needs of the power supply module. Among them, R25 acts as a current limiter to prevent excessive current in C21 from damaging C21, and ZD24 acts as a voltage regulator.

[0065] Specifically, the voltage output from the auxiliary power supply module to the power supply module depends on the size of the ZD24 resistor, that is, the input voltage of the power supply module can be adjusted by controlling the size of the ZD24 resistor, wherein the larger the ZD24 resistor is, the larger the input voltage of the power supply module is, and the smaller the ZD24 resistor is, the smaller the input voltage of the power supply module is. In this way, since the input voltage of the power supply module can be adjusted by adjusting the size of the ZD24 resistor, different voltages can be provided to the power supply module according to the needs of the power supply module. In addition, when the voltage of the startup module changes, the auxiliary power supply module can still output a constant voltage to the power supply module, without affecting the normal external power supply of the power supply module.

[0066] After the auxiliary power supply module adjusts the input voltage of the power supply module by controlling the size of the ZD24 resistor, it can perform linear amplification through Q23 to make the electrical signal clearer, and then rectify it through D27. C22 can also filter the converted DC power to ensure that pure DC power can be obtained. In addition, the capacity of C22 can be increased, so that the DC power output by the auxiliary power supply module can be more stable and have less ripple.

[0067] After obtaining pure direct current, the auxiliary power supply module can input the direct current into the input end of the power supply module, so that the auxiliary power supply module can supply power to the outside.

[0068] In another implementation, in order to facilitate the auxiliary power supply module to adjust the voltage output to the power supply module, the auxiliary power supply module includes Figure 3 In the case of the device shown, it can also include a coil, a current limiting resistor, and a diode. The specific connection structure can refer to Figure 5 .

[0069] Figure 5 The auxiliary power supply module shown is Figure 3 The structure shown also includes a second coil (L22), a fifth current limiting resistor (R14) and a third diode (D12), wherein:

[0070] The first end of L22 ( Figure 5 The A end shown in FIG. 1 is connected to the F end of L21, and the second end of L22 ( Figure 5 The B end shown) and the first end of R14 ( Figure 5 The second end of R14 ( Figure 5 The D terminal shown) is connected to the anode of D12.

[0071] The second end of L21 ( Figure 5 The E end shown in FIG. 1 and the B end of L22 are input ends of the auxiliary power supply module for inputting alternating current. The cathode of D26 is the first output end of the auxiliary power supply module, and the cathode of D12 is the second output end of the auxiliary power supply module.

[0072] Figure 5 The auxiliary power supply module shown works as follows:

[0073] The auxiliary power supply module can sense the power switch tube in the startup circuit through L21 and L22 ( Figure 5The potential generated by the AC power supply (not shown) generates induced voltages Vaux and Vaux1, that is, the potential is input into the auxiliary power supply module through L21 and L22, wherein after Vaux1 passes through R14 and D12, D12 can rectify Vaux1, and after Vaux passes through R23 and D26, D26 can rectify Vaux, thereby assisting L22 and L21 to further convert AC power into DC power, and C21 can also filter the converted DC power to ensure that pure DC power can be obtained.

[0074] After obtaining pure direct current, the auxiliary power supply module can input the direct current into the input end of the power supply module, and the auxiliary power supply module supplies power to the outside.

[0075] It should be noted that L21 and L22 can adjust the voltage output to the power supply module, wherein the number of winding coils of L22 is positively correlated with the voltage value at the input end of the power supply module. In this way, the voltage value at the input end of the power supply module can be easily controlled by adjusting the number of winding coils of L22.

[0076] It should also be noted that the turn ratio of L22 and L21 can be determined according to the voltage level of the switching power supply system and the voltage required to shut down the startup module during actual operation. Preferably, the number of windings of L21 is greater than the number of windings of L22.

[0077] In this embodiment, Figure 1 The shutdown module shown in the figure may include a voltage stabilizing diode and a triode. The specific connection structure can be referred to Figure 6 .

[0078] Figure 6 The shutdown module shown includes a fourth voltage stabilizing diode ZD25 and a second triode Q22, wherein:

[0079] The anode of ZD25 is connected to the base of Q22, the cathode of ZD25 is the input end of the shutdown module, and the collector of Q22 is the output end of the shutdown module.

[0080] Figure 6 The shutdown module shown works as follows:

[0081] The second output terminal of the auxiliary power supply module inputs a voltage to the input terminal of the shutdown module. When the voltage exceeds the clamping voltage threshold of ZD25, Q22 will be triggered to turn on. Since the collector of Q22 in the shutdown module is connected to the second input terminal of the startup module, when Q22 is turned on, the shutdown module can control the startup module to stop working.

[0082] Optionally, Figure 6The Q22 shown can also be replaced by a field effect transistor. The function of the field effect transistor is the same as that of Q22 and will not be described in detail here.

[0083] In the embodiment of the present invention, based on the above Figures 2 to 6 The circuit structure shown in the figure can provide two better implementation methods. In the first implementation method, Figure 1 The startup module may include two current limiting resistors, a field effect transistor and two voltage regulators. The auxiliary power supply module may include a coil, two current limiting resistors, two diodes, two capacitors, a triode and a voltage regulator diode. The shutdown module may include a voltage regulator diode and a triode. The specific connection structure can refer to Figure 7 .

[0084] It should be noted that Figure 7 A voltage regulator diode D28 is added, the anode of D28 is connected to the source s of Q21, and the cathode is connected to the input end of the power supply module. D28 can isolate the interference signal generated between the starting module and the power supply module.

[0085] It should also be noted that Figure 7 The shutdown module shown may also include a sixth current limiting resistor (R24), wherein the first end ( Figure 7 The P end shown) is connected to the M end of R25, and the second end ( Figure 7 The O terminal shown in the figure is connected to the cathode of ZD25, and R24 plays a current limiting role in the circuit to prevent excessive current from breaking through ZD25.

[0086] In this embodiment, the A terminal of R21 (i.e. the C terminal of R22) is the first input terminal of the startup module. Figure 7 The external voltage Vin shown can input high voltage AC to the startup module through the first input terminal; the gate g of Q21 is the second input terminal of the startup module, and the source s is the output terminal of the startup module.

[0087] Both ends of L21 are input ends of the auxiliary power supply module, the voltage input to the input end is alternating current, the cathode of D27 is the first output end of the auxiliary power supply module, and the cathode of D26 is the second output end of the auxiliary power supply module.

[0088] The P end of R24 is the input end of the shutdown module, and the collector of Q22 is the output end of the shutdown module.

[0089] Figure 7 The startup circuit shown works as follows:

[0090] After the external voltage Vin is input to the startup module, the startup module can start working. The external voltage Vin is input to the drain d of Q21 through R22 and to the gate g of Q21 through R21. When the voltage of Vgs is greater than the minimum turn-on voltage Vth of the gate g of Q21, Q21 is turned on, and the source s of Q21 outputs a voltage, which is charged to the input end of the power supply module through D28 to start the switching power supply system.

[0091] Optionally, the starting circuit may include a power switch tube, wherein the input end of the power switch tube may be connected to the input end of the power supply module. After the starting module charges the input end of the power supply module, the power switch tube may enter a working state and begin to continuously turn on and off. Due to the continuous turning on and off of the power switch tube, an electric potential may be generated in the power switch tube.

[0092] The auxiliary power supply module can sense the potential of the power switch tube in the start-up circuit through L21 and generate an induced voltage Vaux, that is, the potential is input to the auxiliary power supply module through L21, where Vaux can be a high-voltage alternating current. Under the action of this potential, the auxiliary power supply module can enter the working state.

[0093] After the auxiliary power supply module enters the working state, the auxiliary power supply module can convert AC power into DC power. For details, please refer to Figure 4 The corresponding contents recorded in the illustrated embodiments will not be described in detail here.

[0094] After converting the DC power, the auxiliary power supply module can input the DC power into the input end of the power supply module (ie, input the low-voltage DC power to the Vcc end of the power supply module through the cathode of D27), so that the auxiliary power supply module can supply power to the outside.

[0095] Figure 7 In the embodiment, since the M end of R25 in the auxiliary power supply module is connected to the P end of R24 in the shutdown module, after the auxiliary power supply module enters the working state, the voltage at the M end of R25 can be output to the P end of R24, and under the action of this voltage, the shutdown module enters the working state.

[0096] When the shutdown module is in working state, when C21 in the auxiliary power supply module is charged to a voltage exceeding the clamping voltage threshold of ZD25, Q22 will be triggered to turn on. Since the collector of Q22 in the shutdown module is connected to the gate g of Q21 in the startup module, when Q22 is turned on, the level of the gate g of Q21 will be pulled down, causing Q21 to turn off, causing the startup module to stop working.

[0097] In this way, since the startup circuit provided by the embodiment of the present invention can shut down the startup module in time when the auxiliary power supply module is in a working state, the additional loss of the switching power supply system can be reduced and the efficiency of the switching power supply system can be improved.

[0098] In another preferred implementation, Figure 7 The components in the auxiliary power supply module shown can also be replaced by two coils, two current limiting resistors, two diodes and a capacitor. Figure 7 The resistor in the shutdown module shown can be replaced by a capacitor, and the transistor can be replaced by a field effect transistor. The specific connection structure is as follows: Figure 8 shown.

[0099] It should be noted that Figure 8 The third capacitor (C13) in the shutdown module is connected differently than Figure 7 The connection method of R24 in Figure 8 The first end of C13 ( Figure 8 The K terminal shown in the figure) is connected to the cathode of ZD14, and the second terminal ( Figure 8 The L terminal shown in the figure is connected to the source of Q12, and C13 is connected to the Figure 8 It plays the role of stabilizing the signal and can stabilize the signal between the shutdown module and the auxiliary power supply module.

[0100] In this embodiment, the B end of L22 and the D end of L21 are the input ends of the auxiliary power supply module, the voltage input to the input ends is AC, the cathode of D11 is the first output end of the auxiliary power supply module, and the cathode of D12 is the second output end of the auxiliary power supply module. The cathode of ZD14 is the input end of the shutdown module, and the drain of Q12 is the output end of the shutdown module.

[0101] Figure 8 The startup circuit shown works as follows:

[0102] Figure 8 The working principle of the startup module can be found in the above Figure 7 The working principle of the startup module is described in . The auxiliary power supply module can sense the potential of the power switch tube in the startup circuit through L21 and L22, and generate induced voltages Vaux1 and Vaux2, that is, the potential is input to the auxiliary power supply module through L21 and L22, where L21 and L22 are used to adjust the voltage output to the power supply module, and Vaux1 and Vaux2 can be low-voltage direct current. The auxiliary power supply module can enter the working state under the action of this potential.

[0103] Specifically, the two coils L21 and L22 can work together to stabilize the voltage obtained in L21 and L22 to adjust the voltage according to the needs of the power supply module, and after Vaux1 is generated in L22, it can pass through R14 and D12, and D12 can rectify Vaux1. After Vaux2 is generated in L21, it can pass through R26 and D26, and D26 can rectify Vaux2, thereby assisting L21 and L22 to further convert AC power into DC power. C21 can also filter the converted low-voltage DC power to ensure that pure low-voltage DC power can be obtained.

[0104] After obtaining pure low-voltage DC power, the auxiliary power supply module can input the low-voltage DC power into the input end of the power supply module (i.e., input the low-voltage DC power to the Vcc end of the power supply module through the cathode of D11), thereby the auxiliary power supply module supplies power to the outside.

[0105] Figure 8 In the embodiment, since the cathode of D12 in the auxiliary power supply module is connected to the cathode of ZD14 in the shutdown module, after the auxiliary power supply module enters the working state, the voltage of the cathode of D12 can be output to the cathode of ZD14, and under the action of this voltage, the shutdown module enters the working state.

[0106] When the shutdown module is in working state, when the sum of the voltages of L21 and L22 is greater than the sum of the voltage threshold of ZD14 and the minimum opening voltage of the gate g of Q12, Q12 is saturated and turned on. Since the drain of Q12 in the shutdown module is connected to the gate of Q21 in the startup module, when Q12 is turned on, the level of the gate of Q21 will be pulled down, causing Q21 to be turned off, so that the startup module stops working. Among them, C13 plays the role of stabilizing the signal, which can stabilize the electrical signal between the shutdown module and the auxiliary power supply module.

[0107] In this way, since the startup circuit provided by the embodiment of the present invention can shut down the startup module in time when the auxiliary power supply module is in a working state, the additional loss of the switching power supply system can be reduced and the efficiency of the switching power supply system can be improved.

[0108] Optionally, a capacitor C12 may be added to the startup circuit, and a first terminal of C12 ( Figure 8 The M terminal shown in the figure) is connected to the source s of Q12, and the second terminal of C12 ( Figure 8 The N terminal as shown is connected to the drain d of Q12. C12 can not only protect Q12, but also filter the voltage in the startup circuit to make the voltage in the startup circuit more stable.

[0109] In an embodiment of the present invention, the startup circuit includes a startup module, an auxiliary power supply module, a shutdown module and a power supply module, wherein an external voltage can be input into a high-voltage alternating current through a voltage input terminal of the startup module to start the switching power supply system, and after the switching power supply system is turned on, the auxiliary power supply module can convert the alternating current into direct current, and when the auxiliary power supply module is in a working state, the shutdown module can shut down the startup module. In this way, since the startup circuit provided by the embodiment of the present invention can shut down the startup module in a timely manner when the auxiliary power supply module is in a working state, the additional loss of the switching power supply system can be reduced, and the efficiency of the switching power supply system can be improved.

[0110] In addition, since the auxiliary power supply module can convert AC power into DC power and supply power to the input end of the power supply module, the auxiliary power supply module can not only meet the working voltage requirements of the power supply module, but also adjust the voltage level of the power supply module by adjusting the auxiliary power supply module, thereby improving the flexibility of the working process.

[0111] The embodiment of the present invention also provides an LED switching power supply system, such as Fig. 9 As shown, the LED switching power supply system includes the above-mentioned starting circuit.

[0112] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0113] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, a magnetic disk, or an optical disk), and includes a number of instructions for enabling a terminal (which can be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to execute the methods described in each embodiment of the present invention.

[0114] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A starting circuit, characterized in that: The startup circuit is applied to a switching power supply system, including a startup module, an auxiliary power supply module, a shutdown module and a power supply module, wherein: The first input end of the start module is the input end of high voltage alternating current, the second input end is connected to the output end of the shutdown module, and the output end is connected to the input end of the power supply module; The input end of the auxiliary power supply module is a voltage input end, the first output end is connected to the input end of the power supply module, and the second output end is connected to the input end of the shutdown module; The startup module is used to start the switching power supply system, the auxiliary power supply module is used to convert AC power into DC power, the shutdown module is used to shut down the startup module when the auxiliary power supply module is in working state, and the voltage output by the power supply module is used to provide power to the electrical equipment; The startup module includes a first current limiting resistor, a second current limiting resistor, a first field effect transistor, a first voltage stabilizing diode and a second voltage stabilizing diode, wherein: The first end of the first current limiting resistor is connected to the first end of the second current limiting resistor, and the second end is respectively connected to the gate of the first field effect transistor, the cathode of the first voltage zener diode, and the cathode of the second voltage zener diode; The second end of the second current limiting resistor is connected to the drain of the first field effect transistor, and the anode of the first voltage stabilizing diode is connected to the source of the first field effect transistor; The resistance value of the first current limiting resistor is greater than the resistance value of the second current limiting resistor, the first end of the first current limiting resistor is the first input end of the startup module, the gate of the first field effect transistor is the second input end of the startup module, and the source is the output end of the startup module; When the first field effect transistor is turned on, the startup module starts the switching power supply system; The auxiliary power supply module includes a first coil, a third current limiting resistor, a first diode and a first capacitor, wherein: The first end of the first coil is connected to the first end of the first capacitor, the second end is connected to the first end of the third current limiting resistor, the second end of the third current limiting resistor is connected to the anode of the first diode, and the cathode of the first diode is connected to the second end of the first capacitor; The two ends of the first coil are the input ends of the auxiliary power supply module, which are used to input alternating current, and the cathode of the first diode is the first output end and the second output end of the auxiliary power supply module; The path formed by the first coil, the third current-limiting resistor, the first diode and the first capacitor converts the alternating current into direct current.

2. The starting circuit according to claim 1, characterized in that: The startup circuit also includes a power switch tube, wherein: When the switching power supply system is turned on, the power switch tube switches between the on state and the off state and generates an electric potential, and the first coil induces the electric potential and generates the alternating current.

3. The starting circuit according to claim 1, characterized in that: The auxiliary power supply module further includes a fourth current limiting resistor, a first transistor, a third voltage stabilizing diode, a second diode and a second capacitor, wherein: The first end of the fourth current limiting resistor is respectively connected to the cathode of the first diode and the collector of the first transistor, the second end is respectively connected to the base of the first transistor and the cathode of the third voltage stabilizing diode, and the anode of the third voltage stabilizing diode is respectively connected to the first end of the first capacitor and the first end of the second capacitor; The anode of the second diode is connected to the emitter of the first transistor, and the cathode is connected to the second end of the second capacitor; The cathode of the second diode is the first output end of the auxiliary power supply module, the cathode of the first diode is the second output end of the auxiliary power supply module, and the path formed by the first transistor, the third voltage-stabilizing diode, the second diode and the second capacitor is used to adjust the voltage output to the power supply module.

4. The starting circuit according to claim 1, characterized in that: The auxiliary power supply module also includes a second coil, a fifth current limiting resistor and a third diode, wherein: The first end of the second coil is connected to the first end of the first coil, the second end is connected to the first end of the fifth current limiting resistor, and the second end of the fifth current limiting resistor is connected to the anode of the third diode; The second end of the first coil and the second end of the second coil are input ends of the auxiliary power supply module, which are used to input alternating current, and the cathode of the third diode is the second output end of the auxiliary power supply module; The first coil and the second coil are used to adjust the voltage output to the power supply module.

5. The starting circuit according to claim 4, characterized in that: The number of turns of the first coil is greater than the number of turns of the second coil, and the number of turns of the first coil is positively correlated with the voltage value of the input end of the power supply module.

6. The starting circuit according to claim 1, characterized in that: The shutdown module includes a fourth voltage stabilizing diode and a second triode, wherein: The anode of the fourth voltage stabilizing diode is connected to the base of the second transistor, the cathode of the fourth voltage stabilizing diode is the input end of the closing module, and the collector of the second transistor is the output end of the closing module; When the second transistor is turned on, the shut-down module shuts down the start-up module.

7. The starting circuit according to claim 6, characterized in that: The shutdown module further includes a sixth current limiting resistor, wherein: The first end of the sixth current limiting resistor is the input end of the shutdown module, and the second end is connected to the cathode of the fourth voltage stabilizing diode.

8. The starting circuit according to claim 6, characterized in that: The shutdown module further includes a third capacitor, wherein: The first end of the third capacitor is connected to the cathode of the fourth voltage-stabilizing diode, and the second end is connected to the source of the second transistor.

9. An LED switching power supply system, characterized in that: The invention comprises a starting circuit as claimed in any one of claims 1 to 8.

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