High-voltage starting circuit of switching power supply chip, switching power supply circuit and charger

Abstract

The utility model discloses a high-voltage starting circuit of a switching power supply chip, a switching power supply circuit and a charger. The high-voltage starting circuit of the switching power supply chip comprises a high-voltage starting end, a main power supply end, a constant current source module, a phase detection module and a low-voltage detection module. The phase detection module is connected with the high-voltage starting end and is used for outputting a first detection signal when the phase of a first power supply signal received by the high-voltage starting end is within a preset phase range; and the low-voltage detection module is connected with the main power supply end and is used for outputting a second detection signal when the voltage of a second power supply signal received by the main power supply end is smaller than a first preset voltage. The phase detection module in the high-voltage starting circuit can charge the main power supply end only when the phase of the received first power supply signal is within the preset phase range, so that excessive loss caused by direct charge through the high-voltage starting end can be avoided, and the input power is ensured not to generate large fluctuation.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of switching power supply, especially to a high voltage starting circuit of switching power supply chip, switching power supply circuit and charger. BACKGROUND

[0002] In the switching power supply circuit, the switching power supply chip is usually used to control the conduction and turn-off of the transformer primary winding in the switching power supply circuit, so as to utilize electromagnetic induction to transfer the energy of the primary winding side to the secondary winding to realize voltage output.

[0003] The electric energy of the switching power supply chip in the working process usually comes from the induced electric energy generated by the auxiliary winding coupled transformer, and when the switching power supply starts or the induced electric energy of the auxiliary winding is insufficient, the electric energy is obtained through the high voltage starting end connected with the AC voltage module in the switching power supply. However, since the AC voltage module outputs a steamed bun wave signal, the effective value of the voltage range is 90V to 264V, and if the switching power supply chip is directly powered through the high voltage starting end, great loss will be generated. SUMMARY

[0004] The utility model embodiment provides a high voltage starting circuit of switching power supply chip, switching power supply circuit and charger to solve the problem that the existing switching power supply chip obtains electric energy through the high voltage starting end and generates great loss.

[0005] The utility model embodiment provides a high voltage starting circuit of switching power supply chip, which comprises a high voltage starting end, a main power supply end, a constant current source module, a phase detection module and a low voltage detection module.

[0006] The phase detection module is connected with the high voltage starting end, and is used to output a first detection signal when the phase of a first power supply signal received by the high voltage starting end is within a preset phase range.

[0007] The low voltage detection module is connected with the main power supply end, and is used to output a second detection signal when the voltage of a second power supply signal received by the main power supply end is less than a first preset voltage.

[0008] The constant current source module is connected with the phase detection module and the low voltage detection module, and is also connected with the high voltage starting end and the main power supply end, and is used to be turned on when the first detection signal and the second detection signal are received at the same time, so that the high voltage starting end supplies power to the main power supply end.

[0009] Preferably, the phase detection module comprises a first comparator.

[0010] The first end of the first comparator is connected with the high voltage starting end, and the second end of the first comparator is used to connect a first reference voltage source to obtain a reference voltage corresponding to the preset phase range.

[0011] The third end of the first comparator is connected with the constant current source module, and is configured to output a first detection signal when the voltage of the first power supply signal is less than a reference voltage.

[0012] Preferably, the low-voltage detection module comprises a second comparator.

[0013] The first end of the second comparator is connected with the main power supply end, and the second end of the second comparator is configured to connect a second reference voltage source to obtain a first preset voltage.

[0014] The third end of the second comparator is connected with the constant current source module, and is configured to output a second detection signal when the voltage of the second power supply signal is less than the first preset voltage.

[0015] Preferably, the high-voltage starting circuit of the switching power supply chip further comprises an AND gate.

[0016] The first end of the AND gate is connected with the phase detection module, the second end of the AND gate is connected with the low-voltage detection module, and the third end of the AND gate is connected with the constant current source module, and is configured to output a power supply opening signal to the constant current source module when the first detection signal and the second detection signal are simultaneously received.

[0017] The constant current source module is configured to be opened when the power supply opening signal is received, so that the high-voltage starting end supplies power to the main power supply end.

[0018] Preferably, the high-voltage starting circuit of the switching power supply chip further comprises a fast starting module.

[0019] The first end of the fast starting module is connected with the main power supply end, the second end of the fast starting module is connected with the low-voltage detection module, and the third end of the fast starting module is connected with a connection node between the constant current source module and the AND gate.

[0020] The fast starting module is configured to be turned on when the voltage of the second power supply signal is less than a second preset voltage, to output the second detection signal to the constant current source module, so that the constant current source module is opened, and the high-voltage starting end supplies power to the main power supply end, wherein the second preset voltage is less than the first preset voltage.

[0021] Preferably, the fast starting module comprises a switch tube.

[0022] The first end of the switch tube is connected with the low-voltage detection module, the second end of the switch tube is connected with the connection node between the constant current source module and the AND gate, and the third end of the switch tube is connected with the main power supply end, and is configured to be turned on when the voltage of the second power supply signal is less than the second preset voltage.

[0023] Preferably, the fast starting module further comprises a first diode;

[0024] The anode of the first diode is connected with the second end of the switch tube, and the cathode of the first diode is connected with a connection node between the constant current source module and the AND gate.

[0025] Preferably, the high-voltage starting circuit of the switch power supply chip further comprises a second diode;

[0026] The anode of the second diode is connected with the AND gate, and the cathode of the second diode is connected with the constant current source module.

[0027] The utility model embodiment further provides a switch power supply circuit, including AC voltage module, rectifier module, transformer module, auxiliary winding and high voltage starting circuit of switch power supply chip of any one described above;

[0028] The input end of the AC voltage module is used for connecting the mains circuit, and the output end of the AC voltage module is a high-voltage signal input end connected with the high-voltage starting end in the high-voltage starting circuit of the switch power supply chip and also connected with the rectifier module, for outputting the first power supply signal to the high-voltage starting end;

[0029] The rectifier module is connected with the primary winding of the transformer module, the secondary winding of the transformer module is used for connecting external load, the auxiliary winding is coupled with the primary winding of the transformer module and connected with the main power supply end in the high-voltage starting circuit of the switch power supply chip, for outputting the second power supply signal to the main power supply end.

[0030] The utility model embodiment further provides a charger comprising the switch power supply circuit.

[0031] The utility model embodiment provides a high-voltage starting circuit of switch power supply chip, switch power supply circuit and charger, the phase detection module in the high-voltage starting circuit can make the high-voltage starting end only supply power to the main power supply end when the phase of the received first power supply signal is within the preset phase range, which can avoid excessive loss when directly supplying power through the high-voltage starting end and ensure that the input power does not fluctuate greatly. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical scheme of the utility model embodiment, the following will be briefly introduced the drawings needed to be used in the description of the utility model embodiment, and obviously, the drawings in the following description are only some embodiments of the utility model, and for those skilled in the art, other drawings can be obtained according to these drawings without creative labor.

[0033] Figure 1 is a circuit structure schematic diagram of a high-voltage starting circuit of a switching power supply chip in an embodiment of the utility model;

[0034] Figure 2 is a circuit structure schematic diagram of a switching power supply circuit in an embodiment of the utility model;

[0035] Figure 3 is a telecommunication signal waveform schematic diagram in a high-voltage starting circuit of a switching power supply chip in an embodiment of the utility model.

[0036] In the figure: 1, constant current source module; 2, phase detection module; 3, low voltage detection module; 4, fast starting module; 5, AC voltage module, 6, rectifier module; 7, transformer module; 8, auxiliary winding. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the utility model.

[0038] It should be understood that the utility model can be implemented in different forms, and should not be interpreted as being limited to the embodiments presented here. On the contrary, the presentation of these embodiments will make the disclosure complete and complete, and will fully convey the scope of the utility model to those skilled in the art. In the drawings, the size and relative size of the layers and regions may be exaggerated for clarity throughout the same reference signs represent the same elements.

[0039] It should be understood that when an element or layer is referred to as "on", "adjacent", "connected to", or "coupled to" other elements or layers, it can be directly on, adjacent to, connected or coupled to other elements or layers, or there can be intervening elements or layers. Conversely, when an element is referred to as "directly on", "directly adjacent", "directly connected to", or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, the first element, component, region, layer or part discussed below can be represented as the second element, component, region, layer or part without departing from the teachings of the utility model.

[0040] Spatially relative terms, such as "beneath", "below", "lower", "under", "above", "upper" and the like, can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use and / or operation in addition to the orientations depicted in the figures. For example, if a device in the figures is inverted, then a dependent element or feature that is described as "below" or "beneath" another element or feature is oriented "above" or "over" the other element or feature. Thus, the exemplary term "below" can encompass both an orientation of above and below. The device can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatial descriptions used herein interpreted accordingly.

[0041] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising", when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0042] For a thorough understanding of the present application, reference will be made to the following detailed description, in conjunction with the accompanying drawings, in which:

[0043] The embodiment of the present application provides a high-voltage starting circuit of a switching power supply chip, as shown in the figure, which can be arranged in a switching power supply circuit as shown in the figure, comprising a high-voltage starting end HV, a main power supply end VCC, a constant current source module 1, a phase detection module 2 and a low-voltage detection module 3. Figure 1 The phase detection module 2 is connected with the high-voltage starting end HV, and is used for outputting a first detection signal when a phase of a first power supply signal VA received by the high-voltage starting end HV is within a preset phase range. Figure 2 The low-voltage detection module 3 is connected with the main power supply end VCC, and is used for outputting a second detection signal when a voltage of a second power supply signal received by the main power supply end VCC is less than a first preset voltage Vth2. The constant current source module 1 is connected with the phase detection module 2 and the low-voltage detection module 3, and is also connected with the high-voltage starting end HV and the main power supply end VCC, and is used for starting when the first detection signal and the second detection signal are received at the same time, so that the high-voltage starting end HV supplies power to the main power supply end VCC.

[0044] As an example, the high-voltage starting circuit of the switching power supply chip can be arranged in the switching power supply circuit to provide a power supply voltage for the switching power supply chip arranged in the switching power supply circuit, and specifically includes a high-voltage starting end HV, a main power supply end VCC, a constant current source module 1, a phase detection module 2, and a low-voltage detection module 3. The high-voltage starting end HV can be connected to the output end of the AC voltage module 5 in the switching power supply circuit, and the AC voltage module 5 can include a diode and a resistor, for rectifying the alternating current signal output by the mains circuit to convert it into a steamed bun wave signal. When the switching power supply circuit starts and the auxiliary winding 8 cannot be coupled to obtain power, the high-voltage starting end HV can obtain the steamed bun wave signal output by the AC voltage module 5 and supply it as a first power supply signal VA to the switching power supply chip. The main power supply end VCC can be connected to the auxiliary winding 8 coupled to the transformer in the switching power supply circuit. When the switching power supply circuit is working, the main power supply end VCC can obtain power through the auxiliary winding 8 and supply it as a second power supply signal to the switching power supply chip. The phase detection module 2 is connected to the high-voltage starting end HV and the constant current source module 1, the low-voltage detection module 3 is connected to the main power supply end VCC and the constant current source module 1, and the constant current source module 1 is connected to the high-voltage starting end HV and the main power supply end VCC.

[0045] When the second power supply signal received by the main power supply end VCC is less than the first preset voltage Vth2, it proves that the current switching power supply circuit is in a starting state or a low-voltage no-load output state, and the power input to the main power supply end VCC is insufficient for the switching power supply chip, so the constant current source module 1 needs to be turned on to allow the first power supply signal VA input to the high-voltage starting end HV to supply power to the main power supply end VCC through the constant current source module 1. At this time, the low-voltage detection module 3 can output a second detection signal to the constant current source module 1 when it detects that the voltage of the second power supply signal is less than the first preset voltage Vth2, and the phase detection module 2 can output a first detection signal to the constant current source module 1 when the phase of the first power supply signal VA received by the high-voltage starting end HV is within the preset phase range. The constant current source module 1 can be turned on when it receives the first detection signal and the second detection signal at the same time, so that the high-voltage starting end HV supplies power to the main power supply end VCC through the constant current source module 1. In this example, the phase detection module 2 can only supply power to the main power supply end VCC when the phase of the first power supply signal VA received is within the preset phase range, which can avoid excessive power loss when directly supplying power through the high-voltage starting end HV, and ensure that the input power does not fluctuate greatly.

[0046] In an embodiment, the phase detection module 2 comprises a first comparator U1; a first end of the first comparator U1 is connected with the high-voltage starting end HV, a second end of the first comparator U1 is used for connecting a first reference voltage source to obtain a reference voltage Vth1 corresponding to the preset phase range; and a third end of the first comparator U1 is connected with the constant current source module 1, for outputting a first detection signal when the voltage of the first power supply signal VA is less than the reference voltage Vth1.

[0047] As an example, since the electrical signal output by the AC voltage module 5 in the switching power supply circuit is a steamed bun wave signal, the phase thereof is in a one-to-one correspondence with the voltage value, and thus the preset phase range detection can be converted into voltage value range detection, as shown in Figure 3 When the voltage of the first power supply signal VA is less than the reference voltage Vth1, the current phase of the first power supply signal VA is within the preset phase range (0°, 90°). Therefore, the phase detection module 2 can comprise the first comparator U1, a first end of the first comparator U1 is connected with the high-voltage starting end HV, a second end of the first comparator U1 is used for connecting a first reference voltage source to obtain the reference voltage Vth1, and a third end of the first comparator U1 is connected with the constant current source module 1; when the voltage of the first power supply signal VA is less than the reference voltage Vth1, the first comparator U1 outputs a high-level signal, that is, the first detection signal.

[0048] In an embodiment, the low-voltage detection module 3 comprises a second comparator U2; a first end of the second comparator U2 is connected with the main power supply end VCC, a second end of the second comparator U2 is used for connecting a second reference voltage source to obtain a first preset voltage Vth2; and a third end of the second comparator U2 is connected with the constant current source module 1, for outputting a second detection signal when the voltage of the second power supply signal is less than the first preset voltage Vth2.

[0049] As an example, the low-voltage detection module 3 can comprise the second comparator U2; a first end of the second comparator U2 is connected with the main power supply end VCC, a second end of the second comparator U2 is used for connecting a second reference voltage source to obtain the first preset voltage Vth2; and a third end of the second comparator U2 is connected with the constant current source module 1; when the voltage of the second power supply signal is less than the first preset voltage Vth2, the second comparator U2 outputs a high-level signal, that is, the second detection signal.

[0050] In an embodiment, the high-voltage starting circuit of the switching power supply chip further comprises an AND gate U3; a first end of the AND gate U3 is connected with the phase detection module 2, a second end of the AND gate U3 is connected with the low-voltage detection module 3, and a third end of the AND gate U3 is connected with the constant current source module 1, for outputting a power supply opening signal to the constant current source module 1 when the first detection signal and the second detection signal are simultaneously received; the constant current source module 1 is used for opening when the power supply opening signal is received, so that the high-voltage starting end HV supplies power to the main power supply end VCC.

[0051] As an example, the high-voltage starting circuit of the switching power supply chip further comprises an AND gate U3; a first end of the AND gate U3 is connected with the phase detection module 2, a second end of the AND gate U3 is connected with the low-voltage detection module 3, and a third end of the AND gate U3 is connected with the constant current source module 1. When the AND gate U3 detects that the signals output by the phase detection module 2 and the low-voltage detection module 3 are both high-level signals, that is, the first detection signal and the second detection signal are simultaneously received, a high-level signal, that is, a power supply opening signal, can be output to the constant current source module 1, so that the constant current source module 1 is opened, and the high-voltage starting end HV supplies power to the main power supply end VCC through the constant current source module 1. When the AND gate U3 detects that any one of the signals output by the phase detection module 2 and the low-voltage detection module 3 is not a high-level signal, a high-level signal cannot be output to the constant current source module 1, and the constant current source module 1 cannot be opened.

[0052] In an embodiment, the high-voltage starting circuit of the switching power supply chip further comprises a fast starting module 4; a first end of the fast starting module 4 is connected with the main power supply end VCC, a second end of the fast starting module 4 is connected with the low-voltage detection module 3, and a third end of the fast starting module 4 is connected with a connection node between the constant current source module 1 and the AND gate U3; the fast starting module 4 is used for conducting when the voltage of the second power supply signal is less than a second preset voltage, outputting a second detection signal to the constant current source module 1, so that the constant current source module 1 is opened, and the high-voltage starting end HV supplies power to the main power supply end VCC, wherein the second preset voltage is less than the first preset voltage Vth2.

[0053] As an example, the high-voltage starting circuit of the switching power supply chip further comprises a fast starting module 4; a first end of the fast starting module 4 is connected with the main power supply end VCC, a second end of the fast starting module 4 is connected with the low-voltage detection module 3, and a third end of the fast starting module 4 is connected with a connection node between the constant current source module 1 and the AND gate U3.

[0054] The second preset voltage is a voltage preset for judging whether the current switching power supply circuit is in a starting state, and the second preset voltage is less than the first preset voltage Vth2. When the voltage of the second power supply signal input to the main power supply end VCC from the auxiliary winding 8 is less than the second preset voltage, it indicates that the current switching power supply circuit is in a starting state. Since the phase detection module 2 provided in the current circuit only allows the first power supply signal VA to be in a specific phase to enable the high-voltage starting end HV to be powered by the main power supply end VCC, compared with directly powering the main power supply end VCC through the high-voltage starting end HV without the phase detection module 2, the power supply power is smaller, and the starting speed of the switching power supply circuit is slower. To speed up the starting speed and avoid the influence of the phase detection module 2 provided on the starting speed, when the voltage of the second power supply signal is less than the second preset voltage, the fast starting module 4 is turned on to directly connect the low-voltage detection module 3 and the constant current source module 1, so that the constant current source module 1 can be directly started under the control of the second detection signal output by the low-voltage detection module 3, that is, the high-level signal, so that the high-voltage starting end HV powers the main power supply end VCC. When the voltage of the second power supply signal is greater than the second preset voltage and less than the first preset voltage Vth2, the fast starting module 4 will not be turned on, and the phase detection module 2 and the low-voltage detection module 3 will normally control the constant current source module 1 to be started through the AND gate U3, and the first power supply signal VA will still be in a specific phase to enable the high-voltage starting end HV to power the main power supply end VCC.

[0055] In the example, by providing the fast starting module 4, the phase detection module 2 provided can avoid delaying the starting speed of the switching power supply circuit, so that the switching power supply circuit can be normally and quickly started.

[0056] In an embodiment, the fast starting module 4 includes a switch tube Q1, the first end of the switch tube Q1 is connected with the low-voltage detection module 3, the second end of the switch tube Q1 is connected with the connection node between the constant current source module 1 and the AND gate U3, and the third end of the switch tube Q1 is connected with the main power supply end VCC, for being turned on when the voltage of the second power supply signal is less than the second preset voltage.

[0057] As an example, the fast start module 4 includes a switch tube Q1. The switch tube Q1 can be a PMOS tube, the first end of the switch tube Q1 is the source of the PMOS tube, the second end of the switch tube Q1 is the drain of the PMOS tube, and the third end of the switch tube Q1 is the gate of the PMOS tube. The first end of the switch tube Q1 is connected with the low voltage detection module 3, the second end of the switch tube Q1 is connected with the connection node between the constant current source module 1 and the AND gate U3, and the third end of the switch tube Q1 is connected with the main power supply end VCC. When the switching power supply circuit is in the starting state, the voltage obtained by the main power supply end VCC through the auxiliary winding 8 is very small, so that the switch tube Q1 is turned on, and the high voltage starting end HV supplies power to the main power supply end VCC through the constant current source module 1. After the switching power supply circuit passes through the starting state, the main power supply end VCC can obtain power through the auxiliary winding 8, and the voltage of the second power supply signal input to the main power supply end VCC will continuously rise. At this time, the switch tube Q1 is turned off, and the phase detection module 2 and the low voltage detection module 3 normally control the opening of the constant current source module 1 through the AND gate U3.

[0058] In an embodiment, the fast start module 4 further includes a first diode D1; the anode of the first diode D1 is connected with the second end of the switch tube Q1, and the cathode of the first diode D1 is connected with the connection node between the constant current source module 1 and the AND gate U3.

[0059] As an example, the fast start module 4 further includes a first diode D1. The anode of the first diode D1 is connected with the second end of the switch tube Q1, and the cathode of the first diode D1 is connected with the connection node between the constant current source module 1 and the AND gate U3, for preventing the electrical signal output from the fast start module 4 to the constant current source module 1 from flowing back into the fast start module 4, and causing adverse effects on the fast start module 4.

[0060] In an embodiment, the high voltage starting circuit of the switching power supply chip further includes a second diode D2; the anode of the second diode D2 is connected with the AND gate U3, and the cathode of the second diode D2 is connected with the constant current source module 1.

[0061] As an example, the high voltage starting circuit of the switching power supply chip further includes a second diode D2; the anode of the second diode D2 is connected with the AND gate U3, and the cathode of the second diode D2 is connected with the constant current source module 1, for preventing the electrical signal output from the fast start module 4 to the constant current source module 1 from flowing back into the AND gate U3, and causing adverse effects on the AND gate U3.

[0062] The utility model discloses an embodiment further provides a switching power supply circuit, including AC voltage module 5, rectifier module 6, transformer module 7, auxiliary winding 8 and the high voltage starting circuit of switching power supply chip in above -mentioned embodiment, the input of AC voltage module 5 is used to connect the mains circuit, and the output of AC voltage module 5 is high voltage signal input, and is connected with the high voltage starting end HV in the high voltage starting circuit of switching power supply chip, still is connected with rectifier module 6, and is used to the first power supply signal VA output to high voltage starting end HV, rectifier module 6 is connected with the primary winding of transformer module 7, and the secondary winding of transformer module 7 is used to connect external load, and auxiliary winding 8 is coupled with the primary winding of transformer module 7, and is connected with the main power supply end VCC in the high voltage starting circuit of switching power supply chip, and is used to the second power supply signal output to main power supply end VCC.

[0063] As an example, the switching power supply circuit includes AC voltage module 5, rectifier module 6, transformer module 7, auxiliary winding 8 and the high voltage starting circuit of switching power supply chip in the above example. The input of AC voltage module 5 is used to connect the mains circuit, and the output of AC voltage module 5 is high voltage signal input, and is connected with the high voltage starting end HV in the high voltage starting circuit of switching power supply chip, still is connected with rectifier module 6, and is used to the first power supply signal VA output to high voltage starting end HV. Rectifier module 6 is connected with the primary winding of transformer module 7, and the secondary winding of transformer module 7 is used to connect external load, and auxiliary winding 8 is coupled with the primary winding of transformer module 7, and is connected with the main power supply end VCC in the high voltage starting circuit of switching power supply chip, and is used to the second power supply signal output to main power supply end VCC. In this example, the phase detection module 2 can make the high voltage starting end HV only supply power to the main power supply end VCC when the phase of the received first power supply signal VA is within the preset phase range, which can avoid excessive loss when directly supplying power through the high voltage starting end HV and ensure that the input power does not fluctuate greatly.

[0064] The utility model discloses an embodiment further provides a charger, including switching power supply circuit in above -mentioned embodiment.

[0065] As an example, in the switching power supply circuit, the phase detection module 2 of the switching power supply chip can make the high voltage starting end HV only supply power to the main power supply end VCC when the phase of the received first power supply signal VA is within the preset phase range, which can avoid excessive loss when directly supplying power through the high voltage starting end HV and ensure that the input power of the switching power supply circuit does not fluctuate greatly.

[0066] The above-described embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A high-voltage starting circuit of a switching power supply chip, characterized in that, The high-voltage starting end, the main power supply end, the constant current source module, the phase detection module and the low-voltage detection module are connected in series. The phase detection module is connected with the high-voltage starting end, and is configured to output a first detection signal when a phase of a first power supply signal received by the high-voltage starting end is within a preset phase range. The low-voltage detection module is connected with the main power supply end, and is configured to output a second detection signal when a voltage of a second power supply signal received by the main power supply end is less than a first preset voltage. The constant current source module is connected with the phase detection module and the low-voltage detection module, and is also connected with the high-voltage starting end and the main power supply end, and is configured to be turned on when the first detection signal and the second detection signal are received at the same time, so that the high-voltage starting end supplies power to the main power supply end.

2. The high-voltage starting circuit of a switching power supply chip according to claim 1, characterized in that, The phase detection module comprises a first comparator. A first end of the first comparator is connected with the high-voltage starting end, and a second end of the first comparator is configured to be connected with a first reference voltage source to obtain a reference voltage corresponding to the preset phase range. A third end of the first comparator is connected with the constant current source module, and is configured to output the first detection signal when a voltage of the first power supply signal is less than the reference voltage.

3. The high voltage starting circuit of a switching power supply chip according to claim 1, characterized in that, The low-voltage detection module comprises a second comparator. A first end of the second comparator is connected with the main power supply end, and a second end of the second comparator is configured to be connected with a second reference voltage source to obtain the first preset voltage. A third end of the second comparator is connected with the constant current source module, and is configured to output the second detection signal when a voltage of the second power supply signal is less than the first preset voltage.

4. The high voltage starting circuit for a switching power supply chip of claim 1, wherein, The high-voltage starting circuit of the switching power supply chip further comprises an AND gate. A first end of the AND gate is connected with the phase detection module, a second end of the AND gate is connected with the low-voltage detection module, and a third end of the AND gate is connected with the constant current source module, and is configured to output a power-on signal to the constant current source module when the first detection signal and the second detection signal are received at the same time. The constant current source module is configured to be turned on when the power-on signal is received, so that the high-voltage starting end supplies power to the main power supply end.

5. The high voltage starting circuit of a switching power supply chip according to claim 4, characterized in that, The high-voltage starting circuit of the switching power supply chip further comprises a fast starting module. A first end of the fast starting module is connected with the main power supply end, a second end of the fast starting module is connected with the low-voltage detection module, and a third end of the fast starting module is connected with a connection node between the constant current source module and the AND gate. The fast starting module is configured to be turned on when a voltage of the second power supply signal is less than a second preset voltage, and output the second detection signal to the constant current source module, so that the constant current source module is turned on, and the high-voltage starting end supplies power to the main power supply end, wherein the second preset voltage is less than the first preset voltage.

6. The high voltage starting circuit of a switching power supply chip according to claim 5, wherein, The fast starting module comprises a switch tube. The first end of the switch tube is connected with the low-voltage detection module, the second end of the switch tube is connected with a connection node between the constant current source module and the AND gate, and the third end of the switch tube is connected with the main power supply end, for turning on when the voltage of the second power supply signal is less than the second preset voltage.

7. The high voltage start-up circuit for a switching power supply chip of claim 6, wherein, The fast start module further comprises a first diode. The anode of the first diode is connected with the second end of the switch tube, and the cathode of the first diode is connected with the connection node between the constant current source module and the AND gate.

8. The high voltage starting circuit of a switching power supply chip according to claim 5, characterized in that, The high-voltage starting circuit of the switch power supply chip further comprises a second diode. The anode of the second diode is connected with the AND gate, and the cathode of the second diode is connected with the constant current source module.

9. A switching power supply circuit, characterized by comprising: The high-voltage starting circuit of the switch power supply chip further comprises an AC voltage module, a rectifier module, a transformer module, an auxiliary winding, and the high-voltage starting circuit of the switch power supply chip according to any one of claims 1-8. The input end of the AC voltage module is used for connecting a commercial power circuit, the output end of the AC voltage module is a high-voltage signal input end, which is connected with the high-voltage starting end in the high-voltage starting circuit of the switch power supply chip, and is further connected with the rectifier module, for outputting a first power supply signal to the high-voltage starting end; The rectifier module is connected with the primary winding of the transformer module, the secondary winding of the transformer module is used for connecting an external load, the auxiliary winding is coupled with the primary winding of the transformer module, and is connected with the main power supply end in the high-voltage starting circuit of the switch power supply chip, for outputting a second power supply signal to the main power supply end.

10. A charger characterized by comprising: The switch power supply circuit comprises the switch power supply circuit according to claim 9.

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