CN104918392B - System for supplying output current to one or more light emitting diodes - Google Patents

Abstract

A system for providing output current to one or more light emitting diodes is disclosed, comprising: a switch control assembly configured to generate a control signal based on information associated with a modulation signal, a demagnetization signal, and a reference signal, and utilize the The above control signal is used to control the cut-off and turn-on of the system power switch, wherein the system power switch is connected to the first diode terminal of the diode and the first inductor terminal of the inductor, the diode further includes a second diode terminal, the inductor The inductor also includes a second inductor terminal, and one or more light emitting diodes are connected in parallel with the output capacitor between the second diode terminal and the second inductor terminal. A method for controlling the output voltage of the system described above is also disclosed. The invention has precise overvoltage protection function.

Description

System for supplying output current to one or more light emitting diodes

technical field

The present invention relates to the field of circuits, and more particularly to a system for supplying output current to one or more light emitting diodes.

Background technique

At present, light-emitting diode (LED) lighting technology has matured day by day. Due to its high luminous efficiency and long service life, LEDs are widely used in the field of lighting to replace traditional incandescent lamps. However, when LEDs are used to replace incandescent lamps, because LED lamp driving circuits generally do not have an overvoltage protection function or the accuracy of overvoltage protection is not high, the LED lamp driving circuit is easily damaged or cannot be used efficiently. In order to achieve high-precision overvoltage protection, it is necessary to add complex peripheral circuits to the LED lamp drive circuit. On the one hand, the cost is high, and on the other hand, the printed circuit size is large, and it cannot be directly placed into the lamp socket.

Contents of the invention

In view of one or more of the problems described above, the present invention provides a system for providing output current to one or more light emitting diodes.

A system for providing output current to one or more light emitting diodes according to an embodiment of the present invention includes: a switch control component configured to generate a control signal based on information associated with the modulation signal, the demagnetization signal, and the reference signal, and Turning off and on of a system power switch is controlled by using the control signal, wherein the system power switch is connected to a first diode terminal of a diode and a first inductor terminal of an inductor, and the diode further includes a second diode terminal , the inductor further includes a second inductor terminal, and one or more light emitting diodes are connected in parallel with the output capacitor between the second diode terminal and the second inductor terminal.

According to an embodiment of the present invention, the method for controlling the output voltage of the above-mentioned system for providing output current to one or more light-emitting diodes includes: generating an input voltage detection signal by detecting the input voltage of the system; A first amount of time is generated for a duration that the system power switch is in an on state; a second amount of time is generated by detecting a demagnetization time of an inductor connected to the system power switch; based on the input voltage detection signal, the first amount of time, and For a second amount of time, calculating a characteristic voltage that characterizes the output voltage of the system using a predetermined equation that depends on the circuit structure of the system; and controlling the power switch of the system to be in a cut-off or normal operating state according to the characteristic voltage, thereby controlling the output of the system Voltage. The normal working state is a state in which the off and on of the system power switch is controlled by a pulse width modulation signal.

A system for providing output current to one or more light emitting diodes according to an embodiment of the present invention generates a control signal according to information associated with a modulation signal, a demagnetization signal, and a reference signal and uses the control signal to control the turn-off of a system power switch And conduction, provides a high-precision overvoltage protection function. In addition, the method for controlling the output voltage of the above-mentioned system for providing output current to one or more light emitting diodes according to the embodiment of the present invention also provides an overvoltage protection function with higher precision.

Description of drawings

The present invention can be better understood from the following description of specific embodiments of the present invention in conjunction with the accompanying drawings, wherein:

1 is a circuit diagram of a conventional system (BUCK circuit) for providing output current to one or more light emitting diodes;

2 is a circuit diagram of a system for providing output current to one or more light emitting diodes according to an embodiment of the present invention;

Fig. 3 is a working waveform diagram in the system circuit shown in Fig. 2;

Fig. 4 is the circuit diagram of the overvoltage protection (OVP) module in the system circuit shown in Fig. 2;

5 is a circuit diagram of a system for providing output current to one or more light emitting diodes according to another embodiment of the present invention;

Fig. 6 is a working waveform diagram in the system circuit shown in Fig. 5;

FIG. 7 is a circuit diagram of an overvoltage protection (OVP) module in the system circuit shown in FIG. 5 .

Detailed ways

Features and exemplary embodiments of various aspects of the invention will be described in detail below. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without some of these specific details. The following description of the embodiments is only to provide a better understanding of the present invention by showing examples of the present invention. The present invention is by no means limited to any specific configurations and algorithms presented below, but covers any modification, substitution and improvement of elements, components and algorithms without departing from the spirit of the invention. In the drawings and the following description, well-known structures and techniques have not been shown in order to avoid unnecessarily obscuring the present invention.

LED lamps are widely used in lighting applications. In order to keep the brightness of the LED lamp constant, generally a substantially constant current is supplied to the LED lamp. FIG. 1 is a circuit diagram of a conventional system (BUCK circuit) for supplying output current to one or more light emitting diodes.

As shown in FIG. 1 , a system 100 for providing output current to one or more LEDs includes an AC rectification component 102 , a controller component 104 , and a current output component 106 . Specifically, the AC rectifying component 102 receives an AC input voltage V _AC and converts the AC input voltage V _AC into a DC voltage V _BULK to provide current to one or more LED lamps. The controller component 104 outputs a control signal to the system power switch 1062 in the current output component 106 through the GATE terminal, so as to control the on and off of the system power switch 1062, thereby adjusting the current flowing through one or more LED lamps (or output current). When the system power switch 1062 is turned on, the current flowing through the inductor 1064 in the current output assembly 106 is sensed by the sense resistor 1066 in the current output assembly 106, so that the current sense signal is passed by the controller assembly 104 Received by the CS terminal. In response, the controller component 104 generates a control signal according to the current sense signal to control the turn-on and turn-off of the system power switch 1062 . When the system power switch 1062 is off, a current loop is formed between the inductor 1064 in the current output assembly 106 , the diode 1068 , and one or more LEDs connected between the two output terminals of the current output assembly 106 .

In the system shown in Figure 1, when there is no LED lamp connected between the two output terminals of the current output component 106 (that is, when the two output terminals are open), the output between the two output terminals of the current output component 106 The voltage V _OUT will be too high, and the output capacitor C _OUT in the current output component 106 will be easily damaged. Therefore, the system shown in FIG. 1 needs to provide overvoltage protection for when the two output terminals of the current output component 106 are open-circuited. However, in the system shown in FIG. 1, the controller component 104 cannot directly measure the output voltage V _OUT between the two output terminals of the current output component 106, and thus cannot accurately control the two output terminals of the current output component 106. output voltage at open circuit.

In order to solve one or more problems existing in the system shown in FIG. 1 , a system for providing output current to one or more light emitting diodes according to an embodiment of the present invention described in detail below with reference to FIGS. 2-7 is proposed.

2 is a circuit diagram of a system for providing output current to one or more light emitting diodes according to an embodiment of the present invention. As shown in FIG. 2 , the system 200 for providing output current to one or more LEDs includes an AC rectification component 202 , a resistor divider component 204 , a switch control component 206 , and a current output component 208 . The AC rectification assembly 202 includes first, second, third, and fourth rectification assembly terminals 202-1, 202-2, 202-3, 202-4. The resistor voltage divider 204 includes first, second, and third voltage divider terminals 204-1, 204-2, 204-3. The switch control component 206 includes first, second, third, and fourth control component terminals VIN, GATE, CS, GND. The current output assembly 208 includes first, second, third, fourth, and fifth output assembly terminals 208-1, 208-2, 208-3, 208-4, 208-5.

As shown in Figure 2, the first and second rectification component terminals 202-1, 202-2 of the AC rectification component 202 are respectively connected to both ends of the AC power supply, and the third and fourth rectification component terminals 202-3, 202-4 They are respectively connected to the first and second voltage dividing component terminals 204 - 1 and 204 - 2 of the resistor voltage dividing component 204 . The third voltage dividing component terminal 204 - 3 of the resistor voltage dividing component 204 is connected to the first control component terminal VIN of the switch control component 206 . The second control component terminal GATE of the switch control component 206 is connected to the second output component terminal 208-2 of the current output component 208, and the third control component terminal CS is connected to the third output component terminal 208-3 of the current output component 208. The terminal GND of the four control components is grounded. The first output component terminal 208-1 of the current output component 208 is connected to the first voltage dividing component terminal 204-1 of the resistor voltage dividing component 204, and the fourth output component terminal 208-4 is grounded. An output capacitor C _OUT in the current output assembly 208 is connected in parallel with one or more light emitting diodes (LEDs) between the first output assembly terminal 208-1 and the fifth output assembly terminal 208-5 of the current output assembly 208 (the first The output assembly terminal 208-1 and the fifth output assembly terminal 208-5 are the two output terminals of the current output assembly 208).

In the system shown in FIG. 2 , the AC rectification component 202 receives an AC input voltage V _AC and rectifies the AC input voltage V _AC into a DC voltage V _BULK to provide DC current to one or more LEDs. The resistor divider component 204 divides the DC voltage V _BULK through the resistors R1 and R2 to generate a voltage signal entering the switch control component 206 . The voltage signal obtained by dividing the DC voltage V _BULK by the resistor voltage divider 204 enters the voltage control module through the third voltage divider terminal 204-3 of the resistor voltage divider 204 and the first control module terminal VIN of the switch control module 206 206. The voltage control component 206 outputs a driving signal to the system power switch MOSFET in the current output component 208 through the GATE terminal, so as to control the turn-on and cut-off of the system power switch MOSFET. When the system power switch MOSFET is turned on, the current flowing through the inductor L1 in the current output component 208 is sensed by the sense resistor RS in the current output component 208, so that the sensed current is sensed by the switch control component 206 through the first Three control module terminals CS received. In response, the controller component 104 generates a control signal based on the information related to the sensed current to control the turn-on and turn-off of the system power switch MOSFET. When the system power switch MOSFET is turned off, a current loop is formed between the inductor L1 in the current output assembly 208 , the diode D1 , and one or more LEDs connected between the two output terminals of the current output assembly 208 .

Specifically, as shown in FIG. 2, the gate of the system power switch MOSFET is used as the third output component terminal 208-3 of the current output component 208; the drain of the system power switch MOSFET is connected to the first diode terminal of the diode D1 and the inductor The first inductor terminal of the device L1 is connected; the second diode terminal of the diode D1 is used as the first output assembly terminal 208-1 of the current output assembly 208; the collector of the system power switch MOSFET is used as the third output of the current output assembly 208 Component terminal 208-3, and ground via sense resistor RS; second inductor terminal of inductor L1 as fifth output component terminal 208-5 of current output component 208; one or more light emitting diodes and output capacitor C _OUT The parallel connection is between the first output assembly terminal 208 - 1 and the fifth output assembly terminal 208 - 5 of the current output assembly 208 .

In this embodiment, as shown in FIG. 2, the switch control component 206 may include an overvoltage protection module, a pulse width modulation (PWM) signal generation module, a logic control module, a gate drive module, a demagnetization detection module, and a current sensing module. module. Wherein, the overvoltage protection module generates an overvoltage protection signal based on the voltage signal from the resistance voltage divider assembly 204, the demagnetization signal from the demagnetization detection module, and the control signal from the logic control module, and the demagnetization detection module is based on the current output assembly 208. The current or voltage signal related to the demagnetization of the inductor L1 generates a demagnetization signal, the current sensing module generates a sensing signal based on the sensing current obtained through the sensing resistor RS in the current output component 208, and the PWM signal generating module generates a sensing signal based on the demagnetization signal and the sensing signal to generate an initial modulation signal, the logic control module performs logic operations based on the initial modulation signal and the overvoltage protection signal to generate a control signal, and the gate drive module generates a drive signal based on the control signal to control the system power switch in the current output component 208 MOSFET on and off. When the system power switch MOSFET in the current output component 208 is in a normal working state, its cut-off and turn-on are controlled by a primary modulation signal (PWM), so as to control and regulate the current flowing through one or more LEDs.

FIG. 3 is a working waveform diagram in the system circuit shown in FIG. 2 . In Figure 3, the PWM_G waveform is the output waveform of the logic control module after the PWM signal generation module, the GATE waveform is the output waveform of the gate drive module, the _IL waveform is the current waveform flowing through the inductor L1, and the VD waveform is the system power The voltage waveform at the drain of the switching MOSFET, and the Demag waveform is the output waveform of the demagnetization detection module. T _ON is the duration that the system power switch MOSFET is in the on state (that is, the conduction time of the system power switch MOSFET), and T _OFF is the duration that the system power switch MOSFET is in the off state (that is, the turn-off time of the system power switch MOSFET ), T _Demag is the demagnetization time of the inductor L1, and T _Demag is smaller than T _OFF .

In the system shown in FIG. 2, when the output voltage of the second control component terminal GATE of the switch control component 206 is high level (that is, the GATE waveform in FIG. 3 is logic high), the system in the current output component 208 The power switch MOSFET is turned on, and the current flowing through the inductor L1 in the current output component 208 rises linearly (the value of the current flowing through the inductor L1 can be obtained according to equation (1)). In the current output component 208, the current flowing through the inductor L1 passes through the system power switch MOSFET and flows through the sensing resistor RS to ground, and the voltage value generated on the sensing resistor RS (that is, at the first The voltage value V _CS sensed at the terminal CS of the three control components can be obtained according to equation (2). When V _CS reaches the set value or T _ON reaches the set value, the output voltage of the second control component terminal GATE of the switch control component 206 becomes low level (that is, the GATE waveform in FIG. 3 becomes logic low), The system power switch MOSFET in the current output component 208 is turned off. At this time, the inductor L1 in the current output component 208 is demagnetized through the diode D1, one or more light emitting diodes, and the output capacitor C _OUT , and the demagnetization ends after T _Demag time, and the current flowing through the inductor L1 becomes zero. The switch control component 206 can determine the demagnetization start point and end point of the inductor L1 by detecting the current flowing through the inductor L1 in the current output component 208, thereby obtaining the demagnetization time T _demag (demagnetization can be obtained according to equation (3) time, where I _PK is the maximum current value flowing through inductor L1). In addition, since the circuit system shown in FIG. 2 is essentially an improvement on the BUCK circuit, the relationship between the output voltage V _OUT and the DC voltage V _BULK output by the AC rectification component 202 is shown in equation (4).

Equation (1)

Equation (2)

Equation (3)

Equation (4)

That is to say, based on the information of the voltage V _BULK output by the AC rectification component 202, the turn-on time T _ON of the system power switch MOSFET, and the demagnetization time T _Demag of the inductor L1, the output can be calculated by equation (4). voltage V _OUT .

FIG. 4 is a circuit diagram of an overvoltage protection (OVP) module in the system circuit shown in FIG. 2 . As shown in FIG. 4 , the overvoltage protection module includes a first switch K1 , a second switch K2 , a low-pass filter, and a comparator. Wherein, the first switch K1 is connected between the third voltage dividing component terminal 204-3 of the resistor dividing component 204 and the first filter terminal of the low-pass filter, and the second switch K2 is connected between the first filter terminal of the low-pass filter. Between the filter terminal and the ground, the low-pass filter also includes a second filter terminal, the second filter terminal is connected to the first comparator terminal of the comparator, and the comparator also includes a second comparator terminal, the second The comparator terminal provides an overvoltage protection signal to the logic control module.

In the overvoltage protection module shown in FIG. 4 , when PWM_G is at a high level and the system power switch MOSFET in the current output component 208 is turned on, the first switch K1 is turned on, and the DC voltage V output by the AC rectification component 202 is The voltage signal generated by _BULK through the voltage division of the resistors R1 and R2 in the resistance voltage dividing component 204 is input to the low-pass filter. During the period from the cut-off of the system power switch MOSFET in the current output component 208 to the end of the demagnetization of the inductor L1 (that is, within T _demag ), the first switch K1 is turned off, the second switch K2 is turned on, and the ground signal is input to the low-pass filter. In other time periods, neither the first switch K1 nor the second switch K2 is turned on. The low-pass filter smoothes and filters the voltage signal from the resistor divider component 204, and outputs an approximate DC voltage signal. Here, the first switch K1 and the second switch K2 may be, for example, CMOS switches.

In the system shown in FIG. 2 , the actual output voltage value V _OUT can be obtained by detecting V _BULK through the resistors R1 and R2 in the resistor divider component 204 and then combining T _ON , T _Demag and other calculations. Specifically, the voltage signal V _VIN of the overvoltage protection module entering it via the first control component terminal VIN of the switch control component 206 is shown by equation (5), and the output signal V _{O_SENSE} of the low-pass filter shown in FIG. 4 From Equation (6). Combining equations (4)-(6), the relationship between V _{O_SENSE} and V _OUT shown in equation (7) can be obtained.

Equation (5)

Equation (6)

Equation (7)

When V _{O_SENSE is} higher than the predetermined reference voltage V _REF (ie, ), the system shown in FIG. 2 can recognize that the output voltage V _OUT has an overvoltage situation, so the switch control component 206 controls the output of the terminal GATE of the third control component, so that the system power switch MOSFET is cut off (turned off), and cut off immediately The energy transmission to the output terminal of the current output component 208 realizes high-precision overvoltage protection.

5 is a circuit diagram of a system for providing output current to one or more light emitting diodes according to another embodiment of the present invention. As shown in FIG. 5, the system 500 for providing output current to one or more light emitting diodes is basically the same as the system circuit shown in FIG. The component terminal 504-1 is connected to the drain of the system power switch MOSFET in the current output component 508, instead of the third rectifying component terminal 502-3 of the AC rectifying component 502; 2) The switch control component 506 includes an overvoltage protection module, In addition to the pulse width modulation (PWM) signal generation module, logic control module, gate drive module, demagnetization detection module, and current sensing module, it also includes a sampling pulse module.

In this embodiment, as shown in FIG. 5, the overvoltage protection module is based on the voltage signal from the resistor divider 504, the demagnetization signal from the demagnetization detection module, the sampling pulse signal from the sampling pulse module, and the logic control module. The control signal generates an overvoltage protection signal, the demagnetization detection module generates a demagnetization signal based on a current or voltage signal related to the demagnetization of the inductor L1 in the current output assembly 508, and the sampling pulse module generates a high level based on the demagnetization signal. The sampling pulse signal of the duration of the high level of the signal, the current sensing module generates a sensing signal based on the sensing current obtained by the sensing resistor RS in the current output assembly 508, and the PWM signal generating module is based on the demagnetization signal and sensing The signal generates an initial modulation signal, the logic control module performs logic operations based on the initial modulation signal and the overvoltage protection signal to generate a control signal, and the gate drive module generates a drive signal based on the control signal to control the conduction of the system power switch MOSFET in the current output component 508 pass and cutoff. When the system power switch MOSFET in the current output component 508 is in a normal working state, its turn-off and turn-on are controlled by a primary modulation signal (PWM), so as to control and regulate the current flowing through one or more LEDs.

In the system circuit shown in Fig. 5, when the system power switch MOSFET in the current output assembly 508 is turned on, the voltage V _D at the drain of the system power switch MOSFET is close to zero; when the system power switch MOSFET in the current output assembly 508 When the power switch MOSFET is turned off, the voltage V _D at the drain of the system power switch MOSFET is close to the DC voltage V _BULK obtained by rectifying the AC input voltage V _AC by the AC rectification component 502 (V _D =V _bulk +V _D1 , V _D1 is the forward conduction voltage of the diode D1 in the current output component 508 , eg, about 1V).

FIG. 6 is a working waveform diagram in the system circuit shown in FIG. 5 . In Fig. 6, the PWM_G waveform is the output waveform of the logic control module after the PWM signal generation module, the GATE waveform is the output waveform of the gate drive module (that is, the second control component terminal GATE of the switch control component 506), and the _IL waveform is the current waveform flowing through the inductor L1, the VD waveform is the voltage waveform at the drain of the system power switch MOSFET, the Demag waveform is the output waveform of the demagnetization detection module, and the SP waveform is the output waveform of the sampling pulse module. T _ON is the duration of the system power switch MOSFET in the on state, T _OFF is the duration of the system power switch MOSFET in the off state, T _Demag is the demagnetization time of the inductor L1, and T _Demag is less than T _OFF . The duration Tsp of the high level of the sampling pulse signal SP output by the sampling pulse module is shorter than the demagnetization time T _Demag. of the inductor L1, so as to ensure that the sampling ends within the demagnetization time period.

FIG. 7 is a circuit diagram of an overvoltage protection (OVP) module in the system circuit shown in FIG. 5 . As shown in FIG. 7 , the overvoltage protection module includes a first switch K0 , a capacitor C0 , a buffer, a second switch K1 , a third switch K2 , a low-pass filter, and a comparator. Wherein, the first switch K0 is connected between the third voltage dividing component terminal 504-3 of the resistor voltage dividing component 504 and the first buffer terminal of the buffer, and the capacitor C0 is connected between the first buffer terminal of the buffer and the ground Between, the buffer also includes a second buffer terminal, the second switch K1 is connected between the second buffer terminal of the buffer and the first filter terminal of the low-pass filter, and the third switch K2 is connected between the low-pass filter Between the first filter terminal and the ground, the low-pass filter also includes a second filter terminal, the second filter terminal is connected to the first comparator terminal of the comparator, the comparator also includes a second comparator terminal, the second The second comparator terminal provides an overvoltage protection signal to the logic control module.

In the overvoltage protection module shown in FIG. 7 , the sampling pulse signal SP provided to the first switch K0 is at a high level during the period from the cut-off of the system power switch MOSFET in the current output component 508 to the end of the demagnetization of the inductor L1 , the voltage V _D at the drain of the system power switch MOSFET in the current output component 508 is sampled to the capacitor C0 through the voltage signal generated by the voltage division of the resistors R1 and R2 in the resistor divider component 504; When low, the voltage of capacitor C0 is maintained. Here, the buffer may be, for example, an analog voltage follower.

In addition, when PWM_G is at a high level and the system power switch MOSFET in the current output component 508 is turned on, the second switch K1 is turned on, and the output of the buffer is connected to the input of the low-pass filter. During the period from the turn-off of the system power switch MOSFET in the current output component 508 to the end of the demagnetization of the inductor L1, the second switch K1 is turned off, the third switch K2 is turned on, and the ground signal is input to the low-pass filter. In other time periods, neither the second switch K1 nor the third switch K2 is turned on. The low-pass filter smoothes and filters the signal input to it, and outputs an approximate DC voltage signal. The first switch K0, the second switch K1, and the third switch K2 may be, for example, CMOS switches.

The system shown in FIG. 5 detects V _D through the resistors R1, R2 in the resistive voltage divider component 504 (during the demagnetization of the inductor L1 in the current output component 508, V _D =V _bulk +V _D1 , which is approximately V _bulk ) Combined with T _ON , T _Demag and other calculations, the actual output voltage V _OUT can be obtained. Here, V _{O_SENSE} output by the low-pass filter is approximated by Equation (8):

Equation (8)

When V _{O_SENSE is} higher than the predetermined reference voltage V _REF (ie, ), the system shown in Figure 5 can recognize that the output voltage V _OUT has overvoltage, so the switch control component 506 controls the output of the terminal GATE of the third control component, so that the system power switch MOSFET is cut off (turned off), and cut off immediately The energy transmission to the output terminal of the current output component 508 realizes high-precision overvoltage protection.

Those skilled in the art will understand that there are more optional implementations and improvements that can be used to implement the embodiments of the present invention, and the above implementations and examples are only illustrations of one or more embodiments. Accordingly, the scope of the invention is limited only by the appended claims.

Claims (9)

1. A system for supplying output current to one or more light emitting diodes, comprising: The switch control component is configured to generate an overvoltage protection signal according to information associated with the control signal, the demagnetization signal, and the reference signal, perform logic operations on the overvoltage protection signal and the modulation signal to generate a control signal, and use the control signal to control the cut-off and conduction of the system power switch, where the system power switch is connected to a first diode terminal of a diode and a first inductor terminal of an inductor, the diode further comprising a second diode terminal, the inductor further comprising a second inductor terminal, and said one or more light emitting diodes are connected in parallel with an output capacitor between said second diode terminal and said second inductor terminal, wherein The switch control assembly is further configured to generate the modulated signal based on information associated with a sense signal generated by sensing a current flowing through the system power switch, and the demagnetization signal of. 2. The system according to claim 1, wherein the switch control component enters the switch according to the duration of the high level of the control signal and the duration of the high level of the demagnetization signal. The voltage signal of the control component is low-pass filtered, and the low-pass filtered voltage signal is compared with the voltage value of the reference signal to generate the overvoltage protection signal. 3. The system according to claim 1, further comprising: an AC rectification component configured to rectify an AC signal from an AC power source to generate a rectified signal; a resistor divider component configured to divide the rectified signal to generate a voltage signal entering the switch control component, wherein The AC rectification assembly includes first, second, third, and fourth rectification assembly terminals, the first and second rectification assembly terminals are respectively connected to both ends of the AC power supply, and the third and fourth The terminals of the rectification assembly are respectively connected to the first and second terminals of the voltage division assembly of the resistance, wherein the terminal of the fourth rectification assembly is also connected to the ground, The resistor voltage divider component further includes a third voltage divider component terminal, and the third voltage divider component terminal provides the switch control component with the voltage signal entering the switch control component. 4. The system of claim 3, wherein the switch control assembly comprises a first control assembly switch, a second control assembly switch, a low pass filter, and a comparator, wherein The first control component switch is connected between the terminal of the third voltage dividing component of the resistor voltage dividing component and the first filter terminal of the low-pass filter, The second control component switch is connected between the first filter terminal of the low-pass filter and ground, The low-pass filter also includes a second filter terminal connected to the first comparator terminal of the comparator, The comparator also includes a second comparator terminal that outputs the overvoltage protection signal. 5. The system according to claim 4, wherein the first control component switch is in an on state when the control signal is at a high level, and is in an off state when the control signal is at a low level, The second control component switch is in an on state when the demagnetization signal is at a high level, and is in an off state when the demagnetization signal is at a low level. 6. The system according to claim 1, further comprising: an AC rectification component configured to rectify an AC signal from an AC power source to generate a rectified signal; a resistor divider component configured to divide the combined signal of the rectified signal and a predetermined voltage to generate a voltage signal entering the switch control component, wherein The AC rectification assembly includes first, second, third, and fourth rectification assembly terminals, the first and second rectification assembly terminals are respectively connected to both ends of the AC power supply, and the third and fourth The terminals of the rectifying component are respectively connected to the second diode terminal of the diode and the second voltage dividing component terminal of the resistance voltage dividing component, and the fourth rectifying component terminal is also connected to ground, The resistor divider assembly further includes a first voltage divider assembly terminal and a third voltage divider assembly terminal, wherein the first voltage divider assembly terminal is connected to the first diode terminal of the diode, and the system The drain of the power switch is connected, and the terminal of the third voltage dividing component provides the voltage signal entering the switch control component to the switch control component. 7. The system according to claim 6, wherein the switch control component comprises a first control component switch, a component capacitor, a buffer, a second control component switch, a third control component switch, a low-pass filter, and a comparator where The first control component switch is connected between the terminal of the third voltage dividing component of the resistor voltage dividing component and the first buffer terminal of the buffer, the component capacitor is connected between the first snubber terminal of the snubber and ground, The buffer also includes a second buffer terminal, the second control assembly switch is connected between the second buffer terminal of the buffer and the first filter terminal of the low pass filter, The third control component switch is connected between the first filter terminal of the low-pass filter and ground, The low-pass filter also includes a second filter terminal connected to the first comparator terminal of the comparator, The comparator also includes a second comparator terminal that outputs the overvoltage protection signal. 8. The system according to claim 7, wherein the switch control component is further configured to generate a sampling signal according to the demagnetization signal, and the duration of the sampling signal being at a high level is shorter than that of the demagnetization signal being at duration of high level, where The first control component switch is in an on state when the sampling signal is at a high level, and is in an off state when the sampling signal is at a low level, The second control component switch is in an on state when the control signal is at a high level, and is in an off state when the control signal is at a low level, The third control component switch is in an on state when the demagnetization signal is at a high level, and is in an off state when the demagnetization signal is at a low level. 9. The system according to claim 5 or 8, wherein the duration of the high level of the demagnetization signal is shorter than the duration of the low level of the control signal.