Dimming circuit and lighting system

Abstract

The invention provides a dimming circuit and a lighting system, and relates to the technical field of lighting control. The circuit comprises a light modulator, a rectifier bridge, a charging and discharging branch circuit and a load branch circuit, the light modulator is connected with the rectifier bridge; the rectifier bridge is connected with the charging and discharging branch and the load branch; the dimmer is used for controlling the charging and discharging branch and the load branch according to the input current and the input voltage; the rectifier bridge is used for shunting an input current into a first branch current input into the charge and discharge branch and a second branch current input into the load branch when the input voltage is greater than the working voltage of the load branch; wherein the first branch current is used for charging the charging and discharging branch, and the second branch current provides electric energy for the load branch; the charging and discharging branch circuit is also used for providing discharging current for the load branch circuit based on the electric energy stored by charging under the condition that the input voltage is smaller than or equal to the working voltage of the load branch circuit; wherein the discharge current provides electric energy for the load branch.

Description

Technical Field

[0001] The present application relates to the field of lighting control technology, and in particular to a dimming circuit and a lighting system. Background Art

[0002] With the development of the application of LED lighting fixtures, the application of dimmers for dimming LED lighting fixtures is becoming more and more widespread. However, due to the power difference between dimmers and LED lamps, the power of dimmers is larger than that of LED lamps, resulting in too little current flowing through the dimmer during operation, abnormal operation of the dimmer, and the need to reduce the conduction time of the LED lamp to increase the current. The compatibility is poor and the flicker is serious, resulting in poor lighting effect of the lighting system. Summary of the invention

[0003] In view of this, an object of the embodiments of the present application is to provide a dimming circuit and a lighting system to improve the problem of poor lighting effect of the lighting system in the prior art.

[0004] In order to solve the above problems, an embodiment of the present application provides a dimming circuit, the circuit comprising: a dimmer, a rectifier bridge, a charging and discharging branch, and a load branch;

[0005] The dimmer is connected to the rectifier bridge, and the rectifier bridge is connected to the charge and discharge branch and the load branch;

[0006] The dimmer is used to control the charge and discharge branch and the load branch according to the input current and the input voltage;

[0007] The rectifier bridge is used to divide the input current into a first branch current input to the charging and discharging branch and a second branch current input to the load branch when the input voltage is greater than the working voltage of the load branch; wherein the first branch current is used to charge the charging and discharging branch, and the second branch current provides electrical energy to the load branch;

[0008] The charging and discharging branch is also used to provide a discharging current for the load branch based on the charged and stored electric energy when the input voltage is less than or equal to the operating voltage of the load branch; wherein the discharging current provides electric energy for the load branch.

[0009] In the above implementation process, a dimmer is provided in the dimming circuit to perform dimming control on the load branch. When the input voltage is greater than the working voltage of the load branch, the input current output by the dimmer is split by the rectifier bridge to flow through the charging and discharging branch and the load branch respectively. The charging and discharging branch can be charged according to the first branch current flowing through, and the load branch can be turned on according to the second branch current flowing through to work. Moreover, when the input voltage is less than or equal to the working voltage of the load branch, the charging and discharging branch stops charging, and provides a discharge current to the load branch based on the electric energy stored in the charging, so that the load branch continues to turn on and work, thereby extending the on-time of the load branch, reducing the flicker on the load branch and the current ripple, improving the lighting efficiency, and effectively improving the compatibility of the dimming circuit.

[0010] Optionally, the circuit further comprises: a dimmer current bias branch; the dimmer current bias branch is connected to the rectifier bridge;

[0011] The rectifier bridge is used to input the initial current flowing through the dimmer into the dimmer current bias branch when the dimmer is turned off; the dimmer current bias branch is used to charge the dimmer based on the initial current, so that the input current flowing through the dimmer is greater than or equal to the maintenance current of the dimmer, so as to turn on the dimmer.

[0012] In the above implementation process, considering that when the current flowing through the dimmer is less than the dimmer's holding current, the dimmer cannot start normally, resulting in abnormal dimming and the like, a corresponding dimmer current bias branch is also set in the circuit. When the dimmer is turned off, the rectifier bridge inputs the initial current output by the dimmer into the dimmer current bias branch, and the dimmer current bias branch charges the dimmer based on the initial current, so that the final input current flowing through the dimmer is greater than or equal to the dimmer's holding current, thereby starting the dimmer to perform dimming work. The dimmer can be charged to enable the dimmer to start normally when the power difference between the dimmer and the load branch is large and the initial current flowing through the dimmer is small. It is suitable for a variety of dimmers and load lamps of different power sizes, and effectively improves the compatibility of the dimming circuit.

[0013] Optionally, the rectifier bridge is used to input the input current output by the dimmer into the dimmer current bias branch when the dimmer is turned on and the input voltage is lower than the operating voltage of the load branch; the dimmer current bias branch is used to maintain the dimmer turned on based on the input current.

[0014] In the above implementation process, since the input voltage will change periodically, after the dimmer is turned on, when the input voltage is lower than the working voltage of the load branch, the input current flowing through the dimmer will also decrease, and the reduced input current may be lower than the maintenance current of the dimmer, resulting in frequent switching of the dimmer during use, affecting the normal operation of the dimmer. The dimmer current bias branch can also continue to conduct to charge the dimmer when the dimmer is turned on and the input voltage is lower than the working voltage, thereby maintaining the dimmer continuously turned on when the input voltage is low, effectively reducing the frequent switching of the dimmer, optimizing the dimming effect of the dimmer, and improving lighting efficiency.

[0015] Optionally, the dimmer current bias branch comprises: a first transistor and a first comparator;

[0016] The first transistor is connected to the rectifier bridge and the ground, and the first comparator is connected to the first transistor;

[0017] The first comparator is used to control the first transistor to be turned on or off based on the input voltage and a first reference voltage.

[0018] In the above implementation process, a first transistor and a first comparator are provided in the dimmer current bias branch. The first comparator controls the on or off of the first transistor according to the input voltage and the first reference voltage, thereby controlling the on and off of the dimmer current bias branch. When charging is required, the dimmer current bias branch is turned on to charge the dimmer.

[0019] Optionally, the dimmer current bias branch further includes: an energy-saving controller;

[0020] The energy-saving controller is connected to the first comparator, and is used for controlling the first transistor to be turned off when the input voltage is greater than the working voltage.

[0021] In the above implementation process, when the input voltage is greater than the operating voltage of the load branch, the input current flowing through the dimmer is relatively large, which can maintain the dimmer to be turned on and work normally. Therefore, a corresponding energy-saving controller can be set in the dimmer current bias branch to control the first transistor to turn off during the time period that can maintain the normal operation of the dimmer, thereby turning off the dimmer current bias branch and reducing unnecessary power consumption in the dimmer current bias branch.

[0022] Optionally, the charge-discharge branch includes: a first diode, a charge-discharge component, a second diode, a second transistor and a second comparator;

[0023] The first diode is connected to the rectifier bridge and the charge-discharge component, the second diode is connected to the charge-discharge component, the second transistor is connected to the charge-discharge component and the ground, and the second comparator is connected to the second transistor;

[0024] The first diode is used to transmit the first branch current to the charging and discharging component;

[0025] The charging and discharging component is used for charging based on the first branch current;

[0026] The charging and discharging component is further used for discharging to the load branch based on the second diode when the input voltage is less than or equal to the working voltage, so as to provide the discharge current to the load branch;

[0027] The second comparator is used for controlling the second transistor to be turned on or off based on the input voltage and a second reference voltage.

[0028] In the above implementation process, two diodes, a second transistor, a second comparator, and a charging and discharging component for charging and discharging are provided in the charging and discharging branch. The first diode transmits the first branch current after diversion to the connected charging and discharging component, so that the charging and discharging component can charge based on the first branch current. When the input voltage is less than or equal to the working voltage of the load branch, the input source cannot provide enough voltage for the load branch to work, and the charging and discharging component stops charging, and discharges to the load branch based on the connected second diode to provide the load branch with a discharge current to continue working. The second comparator controls the conduction or cutoff of the second transistor according to the input voltage and the second reference voltage, thereby controlling the conduction and cutoff of the charging and discharging branch, controlling the charging and discharging component to discharge and discharge when discharge is required, and connecting the load branch to discharge when discharge is required, thereby filling the working current of the load branch, reducing the intermittent time and current ripple of the current on the load branch, and extending the conduction time of the load branch.

[0029] Optionally, the charge and discharge branch further includes: a first linear compensation component; the first linear compensation component is connected to the second comparator;

[0030] The first linear compensation component is used to reduce the second reference voltage when the input voltage increases.

[0031] In the above implementation process, since the input voltage will produce periodic changes, a corresponding first linear compensation component can be set in the charge and discharge branch to reduce the second reference voltage when the input voltage increases, so as to stabilize the power of each component in the charge and discharge branch and reduce the adverse effects of power changes on the components.

[0032] Optionally, the load branch comprises: a third transistor, a third comparator and at least one load component;

[0033] The load component is connected to the rectifier bridge, the third transistor is connected to the load component and the ground, and the third comparator is connected to the third transistor;

[0034] The load component is used to operate based on the second branch current when the input voltage is greater than the operating voltage;

[0035] The load component is further configured to operate based on the discharge current when the input voltage is less than or equal to the operating voltage;

[0036] The third comparator is used to control the third transistor to be turned on or off based on the input voltage and a third reference voltage.

[0037] In the above implementation process, a third transistor, a third comparator and at least one load component for lighting are provided in the load branch. When the input voltage is greater than the working voltage of the load component, the load component can work normally based on the shunted second branch current; when the input voltage is less than or equal to the working voltage of the load component, the input source cannot provide enough voltage for the load component to work, and the load component can obtain the discharge current in the charge-discharge branch to work. The third comparator controls the on or off of the third transistor according to the input voltage and the third reference voltage, thereby controlling the on and off of the load branch, turning on the load branch to work when it can work normally, and connecting the charge-discharge branch to continue working when the input voltage is reduced to the point where it cannot work normally, thereby reducing the intermittent time and current ripple of the current on the load branch and extending the on time of the load branch.

[0038] Optionally, the load branch further comprises: a second linear compensation component; the second linear compensation component is connected to the third comparator;

[0039] The second linear compensation component is used to reduce the third reference voltage when the input voltage increases.

[0040] In the above implementation process, since the input voltage will produce periodic changes, a corresponding second linear compensation component can be set in the load branch to reduce the third reference voltage when the input voltage increases, so as to stabilize the power of each component in the load branch and reduce the adverse effects of power changes on the components.

[0041] Optionally, the load branch further comprises: a ripple removal component; the ripple removal component is connected to the load component;

[0042] The ripple removal component is used to reduce the current ripple of the load component.

[0043] In the above implementation process, in order to further reduce the current ripple of the load component, a de-ripple component connected to the load component can also be set in the load branch to reduce the discontinuity of the current flowing through the load component, so that the current waveform flowing through the load component approaches a smooth straight line state, thereby reducing the current ripple and improving the lighting stability of the load component.

[0044] In a second aspect, an embodiment of the present application further provides a lighting system, which includes the dimming circuit described in any one of the above-mentioned first aspects.

[0045] In the above implementation process, dimming circuits are set in various types of lighting systems, which can be used with lighting fixtures compatible with various types of dimmers, effectively reducing the flicker during lighting without reducing lighting efficiency, and providing stable and efficient lighting functions.

[0046] In summary, the embodiments of the present application provide a dimming circuit and a lighting system. By setting a charging and discharging branch, charging is performed when the input voltage is large, and a discharge current is provided to the load branch based on the charged and stored electric energy when the input voltage is high, so that the load branch can continue to conduct and work, thereby extending the conduction time of the load branch, reducing the flicker and current ripple on the load branch, and improving the lighting efficiency. In addition, a variety of different types of dimmers can be set to perform dimming work, effectively improving the compatibility of the dimming circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0048] Figure 1 A schematic diagram of the structure of a dimming circuit provided in an embodiment of the present application;

[0049] Figure 2 A schematic diagram of the structure of another dimming circuit provided in an embodiment of the present application;

[0050] Figure 3 A schematic diagram of the specific structure of a dimming circuit provided in an embodiment of the present application.

[0051] Icon: 110-charge and discharge branch; 120-load branch; 130-dimmer current bias branch; AC-AC input source; Dimmer-dimmer; DB-rectifier bridge; Iin-input current; Vin-input voltage; V LED - working voltage; Ic- first branch current; I LED -second branch current; EA1-first comparator; MOS1-first transistor; VREF1-first reference voltage; con1-energy-saving controller; D1-first diode; C1-charge and discharge component; D2-second diode; EA2-second comparator; MOS2-second transistor; VREF2-second reference voltage; con2-first linear compensation component; If-discharge current; LEDn-load component; EA3-third comparator; MOS3-third transistor; VREF3-third reference voltage; con3-second linear compensation component; chip-ripple removal chip; C2-capacitor component; R1-first resistor; R2-second resistor; R3-third resistor; R4-fourth resistor. DETAILED DESCRIPTION

[0052] The technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments of the embodiments of the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the embodiments of the present application.

[0053] At present, there is a power difference between dimmers and LED lamps. The power of dimmers is larger than that of LED lamps. For example, the power of dimmers on the market is generally 40 to 600W, while the power of most LED lamps is only about 10W, resulting in too little current flowing through the dimmer and abnormal operation of the dimmer. For some low-power LED lamps, such as LED lamps with less than 5W, the input current is particularly small and cannot be used with most dimmers on the market. In order to better be compatible with more types of dimmers, the current solution is generally to reduce the conduction time of LED lamps to increase the current flowing through the dimmer, resulting in a long intermittent time of LED current, which leads to severe flicker during lighting. In order to solve the flicker, for the 50Hz power grid application scenario, it is necessary to add strong anti-flash circuit parameters, but this method will lead to low lighting efficiency of the lighting system, resulting in poor overall lighting effect of the lighting system, which cannot meet the current lighting needs.

[0054] In order to solve the above problems, an embodiment of the present application provides a dimming circuit, which can be set in various lighting systems, such as vehicle lighting systems, indoor / outdoor lighting systems, mobile device lighting systems, etc., and can be used in dimmers and lighting fixtures that are compatible with various different power levels to provide stable and efficient lighting functions.

[0055] See also Figure 1 , Figure 1 A structural schematic diagram of a dimming circuit provided in an embodiment of the present application, the dimming circuit may include: a dimmer Dimmer, a rectifier bridge DB, a charge and discharge branch 110 and a load branch 120, the dimmer Dimmer is connected to the rectifier bridge DB, and the rectifier bridge DB is connected to the charge and discharge branch 110 and the load branch 120.

[0056] Among them, the dimmer Dimmer is used to control the charge and discharge branch 110 and the load branch 120 according to the input current Iin and the input voltage Vin. The input voltage Vin is a voltage signal with periodic changes output after the alternating current emitted by the AC input source AC passes through the dimmer Dimmer. The voltage signal is rectified by the rectifier bridge DB to obtain the corresponding input current Iin with periodic changes. Optionally, the dimmer Dimmer can be a thyristor dimmer of various models and powers. The thyristor dimmer can include a front-cut dimmer and a rear-cut dimmer. When the current in the circuit changes, the resistance of the thyristor dimmer also changes accordingly to control the on and off of the alternating current and adjust the brightness of the light. For example, a thyristor can be composed of two thyristors connected in reverse for a second time. Its function is not only rectification, but also can be used as a contactless switch to quickly connect or disconnect, to achieve inversion of direct current into alternating current, to convert alternating current of one frequency into alternating current of another frequency, etc. The resistance value of the thyristor dimmer can be adjusted during the alternating current cycle to change the charging rate of the capacitor therein so as to advance or retarded the time for the thyristor to trigger conduction, that is, the purpose of dimming is achieved by changing the conduction angle of the thyristor.

[0057] The charge-discharge branch 110 and the load branch 120 can be connected in parallel, and the working voltage V LED The rectifier bridge DB is used to normally light up the load component LEDn in the load branch 120 when the input voltage Vin is greater than the working voltage V LED In the case of , the input current Iin is divided into a first branch current Ic of the input charge-discharge branch 110 and a second branch current Ic of the input load branch 120 LED The first branch current Ic is used to charge the charge-discharge branch 110, and the second branch current I LEDProvide electrical energy to the load branch 120 so that the load branch 120 can LED Normal operation, the first branch current Ic and the second branch current I LED The size of can be set and modified according to the actual situation of the charging and discharging branch 110 and the load branch 120.

[0058] Optionally, when the input voltage Vin is less than or equal to the operating voltage V of the load branch 120 LED In the case of the above, the charge-discharge branch 110 can stop charging and provide a discharge current I for the load branch 120 based on the electric energy stored in the charge. f The discharge current If provides electrical energy for the load branch 120 so that the load branch 120 can operate when the input voltage Vin is less than the operating voltage V LED The on-time of the load branch 120 can be extended, thereby reducing the flickering and current ripple on the load branch 120, improving the lighting efficiency, and effectively improving the compatibility of the dimming circuit.

[0059] Optionally, see Figure 2 , Figure 2 A structural schematic diagram of another dimming circuit provided in an embodiment of the present application, the dimming circuit may also include: a dimmer current bias branch 130, the dimmer current bias branch 130 is connected to the rectifier bridge DB, the dimmer current bias branch 130 and the charge and discharge branch 110 and the load branch 120 can be in a three-branch parallel connection state.

[0060] It should be noted that the dimmer has a corresponding holding current, for example, the holding current is 30mA. Considering that when the current flowing through the dimmer is less than the holding current of the dimmer, the dimmer cannot start normally, resulting in abnormal dimming, etc. Therefore, when the dimmer is turned off, the dimmer current bias branch 130 is turned on to form a loop with the dimmer. The rectifier bridge DB is used to input the initial current flowing through the dimmer into the dimmer current bias branch 130. The dimmer current bias branch 130 can charge the dimmer based on the initial current, so that the input current Iin flowing through the dimmer is greater than or equal to the holding current of the dimmer, so as to turn on the dimmer. The dimmer can be charged when there is a large power difference between the dimmer and the load branch 120 and when the initial current flowing through the dimmer is small so that the dimmer can start normally. This method is suitable for a variety of dimmers and load lamps of different power sizes, and effectively improves the compatibility of the dimming circuit.

[0061] Furthermore, since the input voltage Vin will change periodically, after the dimmer Dimmer is turned on, the input voltage Vin is lower than the working voltage V LED In this case, the input current Iin flowing through the dimmer Dimmer will also decrease, and the reduced input current Iin may be lower than the maintenance current of the dimmer Dimmer, which may cause the dimmer Dimmer to be frequently turned on and off during use, affecting the normal operation of the dimmer Dimmer. When the dimmer Dimmer is turned on and the input voltage Vin is lower than the operating voltage V LED , the dimmer current bias branch 130 is turned on to form a loop with the dimmer Dimmer, and the rectifier bridge DB is used to input the input current Iin output by the dimmer Dimmer into the dimmer current bias branch 130. The dimmer current bias branch 130 can maintain the dimmer Dimmer on based on the input current Iin, thereby maintaining the dimmer Dimmer on continuously when the input voltage Vin is small, effectively reducing the frequent switching of the dimmer Dimmer, optimizing the dimming effect of the dimmer Dimmer, and improving the lighting efficiency.

[0062] Optionally, see Figure 3 , Figure 3 A specific structural diagram of a dimming circuit provided in an embodiment of the present application, wherein the dimmer current bias branch 130 may include: a first transistor MOS1 and a first comparator EA1. The first transistor MOS1 is connected to the rectifier bridge DB and the ground terminal, and the first comparator EA1 is connected to the first transistor MOS1. Corresponding first resistors R1 and second resistors R2 may also be set at both ends of the first transistor MOS1 so that the dimmer current bias branch 130 can operate normally, and the resistance values ​​of the first resistor R1 and the second resistor R2 may be set and adjusted according to the actual conditions of the dimmer current bias branch 130.

[0063] The first comparator EA1 is connected to the first reference voltage VREF1, and can control the first transistor MOS1 to be turned on or off based on the input voltage Vin and the first reference voltage VREF1. For example, the first reference voltage VREF1 can be set to be equal to the working voltage V LED In the relevant voltage value interval, when the input voltage Vin is less than or equal to the first reference voltage VREF1, the first transistor MOS1 is controlled to turn on to charge the dimmer Dimmer, so as to turn on the dimmer current bias branch 130 to charge the dimmer Dimmer when charging is needed.

[0064] Optionally, the dimmer current bias branch 130 may further include: an energy-saving controller con1, the energy-saving controller con1 is connected to the first comparator EA1, and when the input voltage Vin is greater than the working voltage V LED In the case of , the input current Iin flowing through the dimmer Dimmer is large, which can maintain the normal conduction of the dimmer Dimmer. Therefore, the energy-saving controller con1 can be operated when the input voltage Vin is greater than the working voltage V LED In this case, the first transistor MOS1 is controlled to be turned off to turn off the dimmer current bias branch 130, thereby reducing unnecessary power consumption in the dimmer current bias branch 130 and further saving power consumption of the dimming circuit.

[0065] Optionally, the charge and discharge branch 110 may include: a first diode D1, a charge and discharge component C1, a second diode D2, a second transistor MOS2 and a second comparator EA2. The first diode D1 is connected to the rectifier bridge DB and the charge and discharge component C1, the second diode D2 is connected to the charge and discharge component C1, the second transistor MOS2 is connected to the charge and discharge component C1 and the ground terminal, and the second comparator EA2 is connected to the second transistor MOS2.

[0066] For example, the charge and discharge component C1 may be configured as a capacitor component C2 to achieve corresponding charging and discharging functions.

[0067] Optionally, one end of the second transistor MOS2 may also be connected to a corresponding third resistor R3 so that the charge and discharge branch 110 can operate normally. The resistance of the third resistor R3 may be set and adjusted according to the actual situation of the charge and discharge branch 110 .

[0068] It should be noted that the first diode D1 transmits the first branch current Ic after diversion to the connected charging and discharging component C1, so that the charging and discharging component C1 is charged based on the first branch current Ic. When the input voltage Vin is less than or equal to the working voltage V LED , the AC input source AC cannot provide enough voltage for the load branch 120 to work, the charge and discharge branch 110 and the load branch 120 are disconnected from the rectifier bridge DB, the charge and discharge component C1 stops charging, and forms a loop with the load branch 120 based on the connected second diode D2, thereby discharging to the load branch 120, so as to provide the load branch 120 with a discharge current If to continue working. The second comparator EA2 controls the conduction or shutoff of the second transistor MOS2 according to the input voltage Vin and the second reference voltage VREF2, thereby controlling the conduction and shutoff of the charge and discharge branch 110. For example, the second reference voltage VREF2 can also be set to be equal to the working voltage V LEDIn the relevant voltage value range, when the input voltage Vin is greater than the second reference voltage VREF2, the second transistor MOS2 is controlled to be turned on, so as to turn on the charge-discharge branch 110 for charging when charging is required; when the input voltage Vin is less than or equal to the second reference voltage VREF2, the second transistor MOS2 is controlled to be turned off, so as to control the charge-discharge component C1 to discharge and discharge when discharging is required, thereby filling the working current of the load branch 120, reducing the intermittent time and current ripple of the current on the load branch 120, and extending the conduction time of the load branch 120.

[0069] Optionally, the load branch 120 may include: a third transistor MOS3, a third comparator EA3 and at least one load component LEDn, the load component LEDn is connected to the rectifier bridge DB, the third transistor MOS3 is connected to the load component LEDn and the ground terminal, and the third comparator EA3 is connected to the third transistor MOS3.

[0070] For example, the load component LEDn can be configured as LED lamp devices of various models and powers.

[0071] Optionally, one end of the third transistor MOS3 may also be connected to a corresponding fourth resistor R4 so that the load branch 120 can operate normally. The resistance of the fourth resistor R4 may be set and adjusted according to the actual situation of the load branch 120 .

[0072] It should be noted that when the input voltage Vin is greater than the operating voltage V LED In the case of LED Normal operation; when the input voltage Vin is less than or equal to the working voltage V of the load component LEDn LED In the case of , the AC input source AC cannot provide enough voltage for the load component LEDn to work, the charge and discharge branch 110 and the load branch 120 are disconnected from the rectifier bridge DB, and the load component LEDn can obtain the discharge current If in the charge and discharge branch 110 to continue working. The third comparator EA3 controls the on or off of the third transistor MOS3 according to the input voltage Vin and the third reference voltage VREF3, thereby controlling the on and off of the load branch 120. For example, the third reference voltage VREF3 can also be set to be equal to the working voltage V LEDIn the relevant voltage value range, when the input voltage Vin is greater than the third reference voltage VREF3, the third transistor MOS3 is controlled to be turned on, so as to turn on the load branch 120 when it can work normally and light up the load component LEDn to work. When the input voltage Vin is less than or equal to the third reference voltage VREF3, the third transistor MOS3 is controlled to be turned off, so that when the input voltage Vin is reduced to the point where it cannot work normally, the input current Iin drops from the maximum value, and the load component LEDn can be compensated by the discharge current If, so that the current flowing through the load component LEDn does not drop immediately, so that the load component LEDn can continue to work, thereby reducing the intermittent time and current ripple of the current on the load branch 120, and extending the conduction time of the load branch 120.

[0073] For example, the first transistor MOS1, the second transistor MOS2 and the third transistor MOS3 can all be configured as various types of MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors). Figure 2 Only one feasible embodiment in which the first transistor MOS1, the second transistor MOS2 and the third transistor MOS3 are N-type MOS transistors is shown, and other types of transistor structures are not described in detail.

[0074] Optionally, since the input voltage Vin may change periodically, the charge-discharge branch 110 may further include: a first linear compensation component con2, the first linear compensation component con2 being connected to the second comparator EA2. The first linear compensation component con2 can reduce the second reference voltage VREF2 when the input voltage Vin increases, so as to stabilize the power of each component in the charge-discharge branch 110 and reduce the adverse effects of power changes on the components.

[0075] Optionally, since the input voltage Vin may change periodically, the load branch 120 may further include: a second linear compensation component con3, the second linear compensation component con3 is connected to the third comparator EA3. The second linear compensation component con3 can reduce the third reference voltage VREF3 when the input voltage Vin increases, so as to stabilize the power of each component in the load branch 120 and reduce the adverse effects of power changes on the components.

[0076] For example, the first linear compensation component con2 and the second linear compensation component con3 may be two functional interfaces arranged in the same linear compensation component, or may be two separate devices.

[0077] Optionally, in order to further reduce the current ripple of the load component LEDn, the load branch 120 may further include: a ripple removal component connected to the load component LEDn.

[0078] For example, the de-ripple component can also be connected to the second linear compensation component con3. The de-ripple component can include a capacitor component C2 and a de-ripple chip chip. The de-ripple chip chip is connected to the load component LEDn. The capacitor component C2 is arranged at both ends of the load component LEDn and the de-ripple chip chip, which constitute a complete de-ripple component to reduce the discontinuity of the current flowing through the load component LEDn, so that the current waveform flowing through the load component LEDn approaches a smooth straight line state, thereby reducing the ripple of the current and improving the lighting stability of the load component LEDn.

[0079] In addition, the various parts in the various embodiments of the present application can be integrated together to form an independent part, or the various parts can exist separately, or two or more parts can be integrated to form an independent part.

[0080] The above description is only an embodiment of the present application and is not intended to limit the scope of protection of the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0081] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application.

[0082] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, 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, article or device. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the existence of other identical elements in the process, article or device including the elements.

[0083] In several embodiments provided in the present application, it should be understood that the disclosed device can also be implemented in other ways. The device embodiments described above are merely schematic, for example, the block diagrams in the accompanying drawings show the possible architecture, functions and operations of the devices according to the multiple embodiments of the present application. In this regard, each box in the block diagram can represent a module, a program segment or a part of a code, and the module, a program segment or a part of the code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram, and the combination of the block diagrams, can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

Claims

1. A dimming circuit, characterized in that: The circuit comprises: a dimmer, a rectifier bridge, a charge and discharge branch and a load branch; The dimmer is connected to the rectifier bridge, and the rectifier bridge is connected to the charge and discharge branch and the load branch; The dimmer is used to control the charge and discharge branch and the load branch according to the input current and the input voltage; The rectifier bridge is used to divide the input current into a first branch current input to the charging and discharging branch and a second branch current input to the load branch when the input voltage is greater than the working voltage of the load branch; wherein the first branch current is used to charge the charging and discharging branch, and the second branch current provides electrical energy to the load branch; The charging and discharging branch is also used to provide a discharging current for the load branch based on the charged and stored electric energy when the input voltage is less than or equal to the operating voltage of the load branch; wherein the discharging current provides electric energy for the load branch.

2. The circuit according to claim 1, characterized in that The circuit further comprises: a dimmer current bias branch; the dimmer current bias branch is connected to the rectifier bridge; The rectifier bridge is used to input the initial current flowing through the dimmer into the dimmer current bias branch when the dimmer is turned off; the dimmer current bias branch is used to charge the dimmer based on the initial current, so that the input current flowing through the dimmer is greater than or equal to the maintenance current of the dimmer, so as to turn on the dimmer.

3. The circuit according to claim 2, characterized in that The rectifier bridge is used for inputting the input current output by the dimmer into the dimmer current bias branch when the dimmer is turned on and the input voltage is lower than the working voltage of the load branch; The dimmer current bias branch is used to maintain the dimmer conductive based on the input current.

4. The circuit according to claim 2, characterized in that in, The dimmer current bias branch includes: a first transistor and a first comparator; The first transistor is connected to the rectifier bridge and the ground, and the first comparator is connected to the first transistor; The first comparator is used to control the first transistor to be turned on or off based on the input voltage and a first reference voltage.

5. The circuit according to claim 4, characterized in that in, The dimmer current bias branch further includes: an energy-saving controller; The energy-saving controller is connected to the first comparator, and is used for controlling the first transistor to be turned off when the input voltage is greater than the working voltage.

6. The circuit according to any one of claims 1 to 5, characterized in that: in, The charging and discharging branch includes: a first diode, a charging and discharging component, a second diode, a second transistor and a second comparator; The first diode is connected to the rectifier bridge and the charge-discharge component, the second diode is connected to the charge-discharge component, the second transistor is connected to the charge-discharge component and the ground, and the second comparator is connected to the second transistor; The first diode is used to transmit the first branch current to the charging and discharging component; The charging and discharging component is used for charging based on the first branch current; The charge-discharge component is further used for discharging to the load branch based on the second diode when the input voltage is less than or equal to the working voltage, so as to provide the discharge current to the load branch; The second comparator is used for controlling the second transistor to be turned on or off based on the input voltage and a second reference voltage.

7. The circuit according to claim 6, characterized in that in, The charge and discharge branch further includes: a first linear compensation component; the first linear compensation component is connected to the second comparator; The first linear compensation component is used to reduce the second reference voltage when the input voltage increases.

8. The circuit according to any one of claims 1 to 5, characterized in that: in, The load branch comprises: a third transistor, a third comparator and at least one load component; The load component is connected to the rectifier bridge, the third transistor is connected to the load component and the ground, and the third comparator is connected to the third transistor; The load component is used to operate based on the second branch current when the input voltage is greater than the operating voltage; The load component is further configured to operate based on the discharge current when the input voltage is less than or equal to the operating voltage; The third comparator is used to control the third transistor to be turned on or off based on the input voltage and a third reference voltage.

9. The circuit according to claim 8, characterized in that in, The load branch further includes: a second linear compensation component; the second linear compensation component is connected to the third comparator; The second linear compensation component is used to reduce the third reference voltage when the input voltage increases.

10. The circuit according to claim 8, characterized in that in, The load branch further comprises: a ripple removal component; the ripple removal component is connected to the load component; The ripple removal component is used to reduce the current ripple of the load component.

11. A lighting system, characterized in that: The lighting system comprises the dimming circuit according to any one of claims 1-10.

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