Silicon controlled rectifier dimming control circuit, silicon controlled rectifier dimming control equipment and LED equipment

Abstract

The utility model provides a silicon controlled rectifier dimming control circuit, a silicon controlled rectifier dimming control device and an LED device, the silicon controlled rectifier dimming control circuit comprises a silicon controlled rectifier dimmer, a dimmer charging current control system and a constant current control system, the dimmer charging current control system is utilized to control the charging current of the dimmer, and when the conduction angle of the dimmer is smaller than the conduction angle of the LED, the constant current control system is utilized to control the charging current of the dimmer. The charging current of the silicon controlled rectifier light modulator is reduced, the time required for charging the capacitor of the silicon controlled rectifier light modulator to the silicon controlled rectifier opening threshold is longer, the conduction angle of the light modulator is increased, the opening time of the bidirectional silicon controlled rectifier of the silicon controlled rectifier light modulator is closer to the LED conduction point, the loss of the holding current required by the opening time of the bidirectional silicon controlled rectifier to the LED conduction point is reduced, and the service life of the light modulator is prolonged. And the system efficiency is improved.

Description

Technical Field

[0001] The present application relates to the field of LED driving technology, and in particular to a thyristor dimming control circuit, a thyristor dimming control device and an LED device. Background Art

[0002] At present, in the thyristor dimming system, the charging current and the holding current of the thyristor dimmer are reused. After the bus voltage passes through zero, the holding current will begin to be provided to the capacitor of the thyristor dimmer. When the voltage of the capacitor reaches a certain value (for example, 32V), the bidirectional thyristor is turned on. This will cause the time point when the thyristor dimmer is turned on to fall close to the zero point of the bus voltage, while the LED conduction voltage is large, and the LED conduction voltage is close to the peak position of the bus. Therefore, there is a long period of time between the thyristor turn-on time point and the LED turn-on time point, and the system needs to generate a holding current to make the dimmer work normally. The holding current is a system loss. Providing the holding current for a long time will greatly reduce the system efficiency and cause the system temperature to rise. Utility Model Content

[0003] The purpose of the embodiments of the present application is to provide a thyristor dimming control circuit, a thyristor dimming control device and an LED device to solve the problem of reduced system efficiency and increased system temperature due to long-term provision of maintenance current in the existing thyristor dimming system.

[0004] A thyristor dimming control circuit provided in an embodiment of the present application includes: a thyristor dimmer, a dimmer charging current control system and a constant current control system;

[0005] The thyristor dimmer is used to dim the LED module; the constant current control system is used to provide a stable current for the LED module;

[0006] The dimmer charging current control system is used to reduce the charging current of the thyristor dimmer when the dimmer conduction angle is smaller than the LED conduction angle, so as to increase the dimmer conduction angle.

[0007] In the above technical scheme, the thyristor dimming control circuit includes a thyristor dimmer, a dimmer charging current control system and a constant current control system. The dimmer charging current control system is used to control the dimmer charging current. When the dimmer conduction angle is smaller than the LED conduction angle, the charging current of the thyristor dimmer is reduced, and the time required for the capacitor of the thyristor dimmer to charge to the thyristor turn-on threshold is longer. The dimmer conduction angle is increased, so that the bidirectional thyristor turn-on time of the thyristor dimmer is closer to the LED turn-on point, reducing the loss of the maintenance current required from the bidirectional thyristor turn-on time to the LED turn-on point, thereby improving the system efficiency.

[0008] In some optional implementations, the dimmer charging current control system includes:

[0009] A conduction angle detection module, used for detecting the conduction angle of the dimmer of the thyristor dimmer, and controlling the output of a first modulation signal when the conduction angle of the dimmer is less than the conduction angle of the LED, wherein the first modulation signal is used for controlling the slope of the voltage to increase over time;

[0010] A bus voltage regulating module, configured to, when receiving a first modulation signal, output a voltage VP whose slope of the voltage value changing with time increases;

[0011] The charging current control module is used to utilize the virtual short and virtual break principle of the operational amplifier to make the bus voltage equal to the product of the voltage VP and the voltage dividing resistance ratio to control the charging current of the thyristor dimmer.

[0012] In some optional implementations, it further includes a rectifier, a first MOS tube, a second MOS tube, and a third MOS tube;

[0013] The AC voltage VAC is input into the rectifier through the thyristor dimmer, and the bus voltage is output after being rectified by the rectifier. The bus voltage is grounded after passing through the first MOS tube and the third resistor. The bus voltage is also grounded after passing through the first capacitor, the second MOS tube and the second resistor. The bus voltage is also grounded after passing through the LED module, the third MOS tube and the third resistor.

[0014] The gate of the first MOS tube is connected to the charging current control module, the first end of the constant current control system is connected to the gate of the second MOS tube, and the second end of the constant current control system is connected to the gate of the third MOS tube.

[0015] In some optional implementations, the conduction angle detection module is further used to:

[0016] Determine the dimmer on time Ton or the dimmer off time Toff according to the bus sampling voltage, the voltage VS2 of the first resistor, the voltage VS1 of the second resistor, the voltage VS0 of the third resistor or the bus voltage rising edge signal;

[0017] When the dimmer on time Ton is less than or equal to the first threshold, the second modulation signal is controlled to be output, and the second modulation signal is used to control the slope of the voltage to remain unchanged over time; when the dimmer on time Ton is greater than the first threshold, the first modulation signal is controlled to be output;

[0018] Or, when the dimmer off time Toff is greater than or equal to the second threshold, the second modulation signal is controlled to be output; when the dimmer off time Toff is less than the second threshold, the first modulation signal is controlled to be output.

[0019] The first threshold may be the LED on-time, or the LED on-time plus a smaller value T1; the second threshold may be 180 degrees minus the LED on-time, or 180 degrees minus the LED on-time minus a smaller value T1.

[0020] In the above technical solution, when the thyristor dimmer is turned on, the bus sampling voltage, the voltage VS2 of the first resistor, the voltage VS1 of the second resistor, and the voltage VS0 of the third resistor increase rapidly. Therefore, the dimmer on time Ton or the dimmer off time Toff can be determined according to the bus sampling voltage, the voltage VS2 of the first resistor, the voltage VS1 of the second resistor, the voltage VS0 of the third resistor, or the bus voltage rising edge signal. When the dimmer on time Ton is less than the LED on time, the charging current is no longer adjusted, and the control outputs the second modulation signal; when the dimmer on time Ton is greater than the LED on time, the charging current needs to be reduced, and the control outputs the first modulation signal.

[0021] In some optional implementations, the conduction angle detection module includes: a first comparator, a first current source, a second current source, a first switch, a second switch, a second capacitor, a second comparator, and a slope modulation signal generation module;

[0022] The first comparator is used to output a high level to control the first switch to close when the detection signal is greater than the reference voltage Vref1, and charge the second capacitor through the first current source; when the detection signal is less than the reference voltage Vref1, the first comparator outputs a low level, and after passing through the inverter, controls the second switch to close, and the second capacitor is discharged through the second current source;

[0023] The second comparator is used to output a high level to control the slope modulation signal generating module to output a first modulation signal when the voltage of the second capacitor is greater than the reference voltage Vref2, and the first modulation signal is used to control the slope of the voltage to increase over time; when the voltage of the second capacitor is less than the reference voltage Vref2, the second comparator is used to output a low level to control the slope modulation signal generating module to output a second modulation signal, and the second modulation signal is used to control the slope of the voltage to remain unchanged over time;

[0024] The detection signal includes a bus sampling voltage, a voltage VS1 of the second resistor, or a voltage VS0 of the third resistor.

[0025] In the above technical solution, when the thyristor dimmer is turned on, the bus sampling voltage, the voltage VS1 of the second resistor and the voltage VS0 of the third resistor increase rapidly. Different reference voltages Vref1 can be set for the bus sampling voltage, the voltage VS1 of the second resistor or the voltage VS0 of the third resistor to detect the time point when the thyristor dimmer is turned on. Using the first comparator, when the detection signal is greater than the reference voltage Vref1, the first current source charges the second capacitor, and when the detection signal is less than the reference voltage Vref1, the second capacitor is discharged through the second current source. Therefore, the voltage of the second capacitor is positively correlated with the dimmer on time Ton. When the dimmer on time Ton is greater than the first threshold, the voltage of the second capacitor is greater than the reference voltage Vref2, and the second comparator outputs a high level to control the slope modulation signal generation module to output the first modulation signal; when the dimmer on time Ton is less than the first threshold, the voltage of the second capacitor is less than the reference voltage Vref2, and the second comparator outputs a low level to control the slope modulation signal generation module to output the second modulation signal.

[0026] In some optional implementations, the bus voltage regulation module includes: a first operational amplifier, a third operational amplifier, a seventh resistor, an eighth resistor, a clock generation module, a fourth MOS tube, a DAC module and a second counter;

[0027] The voltage Vref is input to the positive input terminal of the first operational amplifier, the negative input terminal of the first operational amplifier is connected to the source of the fourth MOS tube, the output terminal of the first operational amplifier is connected to the gate of the fourth MOS tube, the source of the fourth MOS tube is connected to the power supply, and the source of the fourth MOS tube is connected to the first terminal of the DAC module;

[0028] The clock generation module is connected to the second counter, the second counter is connected to the third end of the DAC module, the second end of the DAC module is connected to the positive input end of the third operational amplifier, the negative input end of the third operational amplifier is grounded after passing through the eighth resistor, the output end of the third operational amplifier is grounded after passing through the seventh resistor, and the output end of the third operational amplifier outputs a voltage VP;

[0029] The slope of the curve of voltage VP changing with time is K, K = Vref / (CK×m×2 n ); wherein Vref is a reference voltage, n is the number of bits of the second counter, m is the coefficient of the number of bits of the second counter, and CK is the clock output by the clock generation module;

[0030] The output end of the conduction angle detection module is connected to the clock generation module, and the first modulation signal is used to control the value of CK;

[0031] Or, the output end of the conduction angle detection module is connected to the second counter, and the first modulation signal is used to control the value of m;

[0032] Alternatively, the output end of the conduction angle detection module is connected to the seventh resistor and / or the eighth resistor, and the first modulation signal is used to control the resistance ratio of the seventh resistor to the eighth resistor.

[0033] In some optional implementations, the charging current control module includes: a fourth resistor, a fifth resistor, and a second operational amplifier;

[0034] The first end of the fourth resistor is connected to the bus voltage, the second end of the fourth resistor is connected to the first end of the fifth resistor, the second end of the fifth resistor is grounded, the bus sampling voltage output by the second end of the fourth resistor is input to the positive input end of the second operational amplifier, the negative input end of the second operational amplifier inputs the voltage VP, and the output end of the second operational amplifier is connected to the gate of the first MOS tube.

[0035] In the above technical solution, the fourth resistor and the fifth resistor form a voltage-dividing resistor, and the bus voltage is sampled as the bus sampling voltage VM_DIV through the action of the voltage-dividing resistor. According to the virtual short and virtual break principle of the operational amplifier, the voltages of the two input terminals are forced to be equal by using the second operational amplifier, VP=VM_DIV=VM / K0, where K0 is the voltage-dividing resistor ratio of the voltage-dividing resistor formed by the fourth resistor and the fifth resistor.

[0036] In some optional implementations, the thyristor dimmer includes: a potentiometer, a trigger diode, a bidirectional thyristor and a third capacitor;

[0037] The AC voltage VAC is input to the first end of the potentiometer, the first end of the potentiometer is connected to the first end of the bidirectional thyristor, and the second end of the bidirectional thyristor is connected to the rectifier; the second end of the potentiometer is connected to the first end of the trigger diode, and the second end of the trigger diode is connected to the controlled end of the bidirectional thyristor; the second end of the potentiometer is also connected to the rectifier through a third capacitor.

[0038] In the thyristor dimmer of the above technical solution, after the bus voltage passes through zero, the third capacitor starts to charge until the voltage of the third capacitor reaches a certain value (for example, about 32V), triggering the diode to turn on, thereby turning on the bidirectional thyristor. When the bidirectional thyristor is turned on and the LED is not turned on, a maintenance current is required to make the dimmer work normally. However, the above embodiments of the present application can reduce the duration of the maintenance current and reduce system damage.

[0039] A thyristor dimming control device provided in an embodiment of the present application includes a thyristor dimming control circuit as described in any one of the above items.

[0040] An LED device provided in an embodiment of the present application includes a thyristor dimming control circuit as described in any one of the above items, and an LED module. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] 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.

[0042] Figure 1 A schematic diagram of a thyristor dimming control circuit structure provided in an embodiment of the present application;

[0043] Figure 2 A circuit diagram of a thyristor dimmer provided in an embodiment of the present application;

[0044] Figure 3 A schematic diagram of the time required to charge to the same charge value Q with different charging currents;

[0045] Figure 4 A schematic diagram comparing the waveform before and after adjustment provided in an embodiment of the present application;

[0046] Figure 5 A structural diagram of a dimmer charging current control system provided in a specific embodiment of the present application;

[0047] Figure 6 A schematic diagram of a first conduction angle detection module provided in an embodiment of the present application;

[0048] Figure 7 A schematic diagram of the working principle of the second conduction angle detection module provided in an embodiment of the present application;

[0049] Figure 8 A schematic diagram of the structure of a third conduction angle detection module provided in an embodiment of the present application;

[0050] Fig. 9 A schematic diagram of the working principle of the third conduction angle detection module provided in the embodiment of the present application;

[0051] Fig.10 A schematic diagram of the structure of a bus voltage regulation module provided in an embodiment of the present application;

[0052] Fig.11 A schematic diagram of the principle of adjusting the slope of a curve of voltage VP changing with time provided in an embodiment of the present application;

[0053] Fig.12 A schematic diagram of the charging current control module structure provided in an embodiment of the present application. DETAILED DESCRIPTION

[0054] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0055] Please refer to Figure 1 , Figure 1 A schematic diagram of the structure of a thyristor dimming control circuit provided in an embodiment of the present application, the thyristor dimming control circuit includes: a thyristor dimmer TRAIC, a dimmer charging current control system and a constant current control system.

[0056] Among them, the thyristor dimmer TRAIC is used to dim the LED module; the constant current control system is used to provide a stable current for the LED module; the dimmer charging current control system is used to reduce the charging current of the thyristor dimmer TRAIC when the dimmer conduction angle is smaller than the LED conduction angle, so as to increase the dimmer conduction angle.

[0057] Specifically, the thyristor dimming control circuit also includes a rectifier BD1, a first MOS tube M1, a second MOS tube M2 and a third MOS tube M3; the AC voltage VAC is input into the rectifier BD1 through the thyristor dimmer TRAIC, and the bus voltage is output after rectification by the rectifier BD1. The bus voltage is grounded after passing through the first MOS tube M1 and the third resistor R3, and the bus voltage is also grounded after passing through the first capacitor C1, the second MOS tube M2 and the second resistor R2. The bus voltage is also grounded after passing through the LED module, the third MOS tube M3 and the third resistor R3; the gate of the first MOS tube M1 is connected to the charging current control module, the first end of the constant current control system is connected to the gate of the second MOS tube M2, and the second end of the constant current control system is connected to the gate of the third MOS tube M3.

[0058] In an embodiment of the present application, a thyristor dimming control circuit includes a thyristor dimmer TRAIC, a dimmer charging current control system and a constant current control system. The dimmer charging current control system is used to control the dimmer charging current. When the dimmer conduction angle is smaller than the LED conduction angle, the charging current of the thyristor dimmer TRAIC is reduced, and the time required for the capacitor of the thyristor dimmer TRAIC to charge to the thyristor turn-on threshold is longer. The dimmer conduction angle is increased, so that the turn-on time of the bidirectional thyristor D2 of the thyristor dimmer TRAIC is closer to the LED turn-on point, reducing the loss of the maintenance current required from the turn-on time of the bidirectional thyristor D2 to the LED turn-on point, thereby improving the system efficiency.

[0059] Please refer to Figure 2 , Figure 2 This is a circuit structure diagram of a thyristor dimmer TRAIC provided in an embodiment of the present application. The thyristor dimmer TRAIC includes: a potentiometer R6, a trigger diode DB3, a bidirectional thyristor D2 and a third capacitor C3.

[0060] Among them, the AC voltage VAC is input to the first end of the potentiometer R6, the first end of the potentiometer R6 is connected to the first end of the bidirectional thyristor D2, and the second end of the bidirectional thyristor D2 is connected to the rectifier BD1; the second end of the potentiometer R6 is connected to the first end of the trigger diode DB3, and the second end of the trigger diode DB3 is connected to the controlled end of the bidirectional thyristor D2; the second end of the potentiometer R6 is also connected to the rectifier BD1 through the third capacitor C3.

[0061] In the thyristor dimmer TRAIC of the above technical solution, after the bus voltage passes through zero, the third capacitor C3 starts to charge until the voltage of the third capacitor C3 reaches a certain value (for example, about 32V), triggering the diode DB3 to turn on, thereby turning on the bidirectional thyristor D2. When the bidirectional thyristor D2 is turned on and the LED is not turned on, the maintenance current is required to make the dimmer work normally. However, the duration of the maintenance current can be reduced and the system damage can be reduced through the above embodiments of the present application, which is described in detail below:

[0062] The charge required to trigger the thyristor dimmer TRAIC is Q C3 , this value is fixed for each dimmer and has little difference, which can be expressed as:

[0063]

[0064] Among them, I CHG is the charging current of the thyristor dimmer TRAIC, which can be expressed as:

[0065]

[0066] Among them, VM is the voltage between the positive and negative ends of the rectifier output, called the bus voltage, VC3 is the voltage of the third capacitor C3, VR6 is the voltage of the potentiometer R6, is the instantaneous AC voltage.

[0067] The charge amount QC3 that the thyristor dimmer TRAIC can trigger can finally be expressed as:

[0068]

[0069] Therefore, the larger the VM value is, the smaller the voltage difference between VM and the sine wave is, and the smaller the charging current is. Figure 3 As shown, the smaller the charging current, the longer the time required for the capacitor to accumulate the same Q value.

[0070] Please refer to Figure 4 , Figure 4 A schematic diagram comparing the waveform before and after adjustment provided in the embodiment of the present application. Before adjustment, the charging current is large, and the charge amount is Q C3The time required is short. The duration Ta of the maintenance current required when the bidirectional thyristor D2 is turned on and the LED is not turned on is long. However, after adjustment, the charge amount is Q C3 The required time is longer, and the adjusted time Tb is shorter, so that the loss of this part of the maintenance current can be reduced and the system efficiency can be improved.

[0071] Please refer to Figure 5 , Figure 5 This is a structural diagram of a dimmer charging current control system provided in a specific embodiment of the present application. The dimmer charging current control system of this embodiment includes: a conduction angle detection module, a bus voltage regulation module and a charging current control module.

[0072] The conduction angle detection module is used to detect the conduction angle of the dimmer of the thyristor dimmer TRAIC, and when the dimmer conduction angle is less than the LED conduction angle, control the output of the first modulation signal, the first modulation signal is used to control the slope of the voltage to rise over time. The bus voltage regulation module is used to output the voltage VP after the slope of the voltage value changes over time increases when the first modulation signal is received. The charging current control module is used to use the virtual short and virtual break principle of the operational amplifier to make the bus voltage equal to the product of the voltage VP and the voltage divider resistor ratio to control the charging current of the thyristor dimmer TRAIC.

[0073] In some optional embodiments, the conduction angle detection module is specifically used to: determine the dimmer on-time Ton or the dimmer off-time Toff according to the bus sampling voltage, the voltage VS2 of the first resistor R1, the voltage VS1 of the second resistor R2, the voltage VS0 of the third resistor R3 or the bus voltage rising edge signal; when the dimmer on-time Ton is less than or equal to the first threshold, control the output of the second modulation signal, and the second modulation signal is used to control the slope of the voltage to remain unchanged over time; when the dimmer on-time Ton is greater than the first threshold, control the output of the first modulation signal; or, when the dimmer off-time Toff is greater than or equal to the second threshold, control the output of the second modulation signal; when the dimmer off-time Toff is less than the second threshold, control the output of the first modulation signal.

[0074] The first threshold may be the LED on-time, or the LED on-time plus a smaller value T1; the second threshold may be 180 degrees minus the LED on-time, or 180 degrees minus the LED on-time minus a smaller value T1.

[0075] In the embodiment of the present application, when the thyristor dimmer TRAIC is turned on, the bus sampling voltage, the voltage VS2 of the first resistor R1, the voltage VS1 of the second resistor R2, and the voltage VS0 of the third resistor R3 rise rapidly. Therefore, the dimmer on time Ton or the dimmer off time Toff can be determined according to the bus sampling voltage, the voltage VS2 of the first resistor R1, the voltage VS1 of the second resistor R2, the voltage VS0 of the third resistor R3, or the bus voltage rising edge signal. When the dimmer on time Ton is less than the LED on time, the charging current is no longer adjusted, and the control outputs the second modulation signal; when the dimmer on time Ton is greater than the LED on time, the charging current needs to be reduced, and the control outputs the first modulation signal.

[0076] Among them, according to the bus sampling voltage, the voltage VS2 of the first resistor R1, the voltage VS1 of the second resistor R2, the voltage VS0 of the third resistor R3 or the bus voltage rising edge signal, the dimmer on time Ton or the dimmer off time Toff is determined. The specific implementation method includes data encoding and analog voltage and current signal methods. The following is a detailed introduction to various implementation methods of the conduction angle detection module:

[0077] Please refer to Figure 6 , Figure 6 A schematic diagram of a first conduction angle detection module provided in an embodiment of the present application, the conduction angle detection module includes: a first comparator COMP1, a first current source I1, a second current source I2, a first switch K1, a second switch K2, a second capacitor C2, a second comparator COMP2 and a slope modulation signal generating module.

[0078] Among them, the first comparator COMP1 is used to: when the detection signal is greater than the reference voltage Vref1, output a high level to control the first switch K1 to close, and charge the second capacitor C2 through the first current source I1; when the detection signal is less than the reference voltage Vref1, output a low level, and after passing through the inverter, control the second switch K2 to close, and the second capacitor C2 is discharged through the second current source I2.

[0079] The second comparator COMP2 is used to: when the voltage of the second capacitor C2 is greater than the reference voltage Vref2, output a high level to control the slope modulation signal generating module to output a first modulation signal, and the first modulation signal is used to control the slope of the voltage to increase over time; when the voltage of the second capacitor C2 is less than the reference voltage Vref2, output a low level to control the slope modulation signal generating module to output a second modulation signal, and the second modulation signal is used to control the slope of the voltage to remain unchanged over time; wherein the detection signal includes the bus sampling voltage, the voltage VS1 of the second resistor R2 or the voltage VS0 of the third resistor R3.

[0080] In the embodiment of the present application, when the thyristor dimmer TRAIC is turned on, the bus sampling voltage, the voltage VS1 of the second resistor R2 and the voltage VS0 of the third resistor R3 increase rapidly, and different reference voltages Vref1 can be set for the bus sampling voltage, the voltage VS1 of the second resistor R2 or the voltage VS0 of the third resistor R3 to detect the time point when the thyristor dimmer TRAIC is turned on. Using the first comparator COMP1, when the detection signal is greater than the reference voltage Vref1, the first current source I1 charges the second capacitor C2, and when the detection signal is less than the reference voltage Vref1, the second capacitor C2 is discharged through the second current source I2. Therefore, the voltage of the second capacitor C2 is positively correlated with the dimmer on-time Ton. When the dimmer on-time Ton is greater than the first threshold, the voltage of the second capacitor C2 is greater than the reference voltage Vref2, and the second comparator COMP2 outputs a high level to control the slope modulation signal generating module to output the first modulation signal; when the dimmer on-time Ton is less than the first threshold, the voltage of the second capacitor C2 is less than the reference voltage Vref2, and the second comparator COMP2 outputs a low level to control the slope modulation signal generating module to output the second modulation signal.

[0081] Please refer to Figure 7 , Figure 7 The schematic diagram of the working principle of the second conduction angle detection module provided in the embodiment of the present application, the conduction angle detection module determines the conduction time point of the thyristor dimmer TRAIC by sampling the duty cycle of the detection signal (the detection signal includes the bus sampling voltage, the voltage VS2 of the first resistor R1, the voltage VS1 of the second resistor R2 or the voltage VS0 of the third resistor R3), the time when the voltage of the detection signal is higher than the reference voltage VREF1 is Ton, and the time when the voltage of the detection signal is lower than the reference voltage VREF1 is Toff. Among them, different detection signals correspond to different Ton and Toff, as shown in the following example. Figure 7 shown.

[0082] The control logic of this embodiment is: if Ton is less than or equal to the corresponding threshold, the second modulation signal is controlled to output and the bus voltage VM is stopped from being regulated; if Ton is greater than the corresponding threshold, the first modulation signal is controlled to output to gradually increase the slope of the bus voltage and control the charging current to decrease.

[0083] Alternatively, the control logic of this embodiment is: if Toff is greater than or equal to the corresponding threshold, the second modulation signal is controlled to be output and the bus voltage VM is stopped from being adjusted; if Toff is less than the corresponding threshold, the first modulation signal is controlled to be output to gradually increase the slope of the bus voltage and control the charging current to decrease.

[0084] Please refer to Figure 8 and Fig. 9 , Figure 8A schematic diagram of the structure of a third conduction angle detection module provided in an embodiment of the present application, Fig. 9 A schematic diagram of the working principle of the third conduction angle detection module provided in an embodiment of the present application.

[0085] The conduction angle detection module of this embodiment includes a rising edge detection module, a third comparator COMP3, a first counter CNT1 and a slope modulation signal generation module. This embodiment detects the time Toff1 from the zero point of the bus voltage to the dimmer conduction point through the rising edge detection module. If Toff1 is greater than or equal to the corresponding threshold, the slope modulation signal generation module outputs the second modulation signal to stop adjusting the bus voltage VM; if Toff1 is less than the corresponding threshold, the slope modulation signal generation module outputs the first modulation signal to gradually increase the slope of the bus voltage and control the charging current to decrease.

[0086] Please refer to Fig.10 , Fig.10 A schematic diagram of the structure of a bus voltage regulation module provided in an embodiment of the present application, the bus voltage regulation module comprising: a first operational amplifier, a third operational amplifier, a seventh resistor, an eighth resistor, a clock generation module, a fourth MOS tube, a DAC module and a second counter;

[0087] The voltage Vref is input to the positive input terminal of the first operational amplifier, the negative input terminal of the first operational amplifier is connected to the source of the fourth MOS tube, the output terminal of the first operational amplifier is connected to the gate of the fourth MOS tube, the source of the fourth MOS tube is connected to the power supply, and the source of the fourth MOS tube is connected to the first terminal of the DAC module;

[0088] The clock generation module is connected to the second counter, the second counter is connected to the third end of the DAC module, the second end of the DAC module is connected to the positive input end of the third operational amplifier, the negative input end of the third operational amplifier is grounded after passing through the eighth resistor, the output end of the third operational amplifier is grounded after passing through the seventh resistor, and the output end of the third operational amplifier outputs a voltage VP;

[0089] Please refer to Fig.11 , Fig.11 The schematic diagram of the principle of adjusting the slope of the curve of voltage VP changing with time provided in the embodiment of the present application. The slope of the curve of voltage VP changing with time is K, K = Vref / (CK × m × 2 n ); wherein Vref is a reference voltage, n is the number of bits of the second counter, m is the coefficient of the number of bits of the second counter, and CK is the clock output by the clock generation module;

[0090] The output end of the conduction angle detection module is connected to the clock generation module, and the first modulation signal is used to control the value of CK, specifically, the slope K is increased by controlling the value of CK to decrease;

[0091] Or, the output end of the conduction angle detection module is connected to the second counter, and the first modulation signal is used to control the value of m, specifically, the slope K is increased by controlling the value of m to decrease;

[0092] Or, the output end of the conduction angle detection module is connected to the seventh resistor and / or the eighth resistor, and the first modulation signal is used to control the resistance ratio of the seventh resistor to the eighth resistor, specifically by increasing the value of R7 / R8 to increase the slope K. It should be clear that, since VP=Kt, this embodiment controls the voltage VP by controlling the slope K, but the voltage VP can also be controlled by controlling the counting time t, that is, the time t is controlled by the modulation signal, and the faster the counting time is, the larger the value of the voltage VP is under the same counting voltage step.

[0093] In addition, the method of adjusting the bus voltage slope K includes but is not limited to using digital timing, or using VP=it / C, where i is the current, t is the charging time, C is the capacitance, and the slope K is expressed as i / C, wherein the value of the current i is determined by the modulation signal, and the modulation signal here includes digital coding or analog voltage and current signals. By adjusting the value of i, different slopes K can be obtained.

[0094] Please refer to Fig.12 , Fig.12 A schematic diagram of the structure of a charging current control module provided in an embodiment of the present application, wherein the charging current control module comprises: a fourth resistor R4, a fifth resistor R5 and a second operational amplifier OP2;

[0095] Among them, the first end of the fourth resistor R4 is connected to the bus voltage, the second end of the fourth resistor R4 is connected to the first end of the fifth resistor R5, the second end of the fifth resistor R5 is grounded, the bus sampling voltage output by the second end of the fourth resistor R4 is input to the positive input end of the second operational amplifier OP2, the negative input end of the second operational amplifier OP2 inputs the voltage VP, and the output end of the second operational amplifier OP2 is connected to the gate of the first MOS tube M1.

[0096] In the embodiment of the present application, the fourth resistor R4 and the fifth resistor R5 form a voltage-dividing resistor, and the bus voltage is sampled as the bus sampling voltage VM_DIV through the action of the voltage-dividing resistor. According to the virtual short and virtual break principle of the operational amplifier, the second operational amplifier OP2 is used to force the voltages of its two input terminals to be equal, VP=VM_DIV=VM / K0, where K0 is the voltage-dividing resistor ratio of the voltage-dividing resistor formed by the fourth resistor R4 and the fifth resistor R5.

[0097] A thyristor dimming control device provided in an embodiment of the present application includes a thyristor dimming control circuit as described in any one of the above items.

[0098] An LED device provided in an embodiment of the present application includes a thyristor dimming control circuit as described in any one of the above items, and an LED module.

[0099] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, and the indirect coupling or communication connection of the devices or units can be electrical, mechanical or other forms.

[0100] In addition, the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0101] Furthermore, the functional modules in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist independently, or two or more modules may be integrated to form an independent part.

[0102] In this document, relational terms such as first and second, etc. are used merely to distinguish one entity or operation from another entity or operation, but do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0103] The above description is only an embodiment of the present application and is not intended to limit the protection scope of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A thyristor dimming control circuit, characterized in that: include: Thyristor dimmers, dimmer charging current control systems and constant current control systems; The thyristor dimmer is used to dim the LED module; The constant current control system is used to provide a stable current for the LED module; The dimmer charging current control system is used to reduce the charging current of the thyristor dimmer when the dimmer conduction angle is smaller than the LED conduction angle, so as to increase the dimmer conduction angle.

2. The circuit according to claim 1, characterized in that The dimmer charging current control system comprises: A conduction angle detection module, used for detecting the conduction angle of the dimmer of the thyristor dimmer, and controlling the output of a first modulation signal when the conduction angle of the dimmer is less than the conduction angle of the LED, wherein the first modulation signal is used for controlling the slope of the voltage to increase over time; A bus voltage regulating module, configured to, when receiving a first modulation signal, output a voltage VP whose slope of the voltage value changing with time increases; The charging current control module is used to make the bus voltage equal to the product of the voltage VP and the voltage-dividing resistance ratio by utilizing the virtual short and virtual break principle of the operational amplifier, so as to control the charging current of the thyristor dimmer.

3. The circuit according to claim 2, characterized in that It also includes a rectifier, a first MOS tube, a second MOS tube and a third MOS tube; The AC voltage VAC is input into the rectifier through the thyristor dimmer, and is rectified by the rectifier to output a bus voltage, which is grounded after passing through the first MOS tube and the third resistor, and is also grounded after passing through the first capacitor, the second MOS tube and the second resistor, and is also grounded after passing through the LED module, the third MOS tube and the third resistor; The gate of the first MOS tube is connected to the charging current control module, the first end of the constant current control system is connected to the gate of the second MOS tube, and the second end of the constant current control system is connected to the gate of the third MOS tube.

4. The circuit according to claim 3, characterized in that The conduction angle detection module is also used for: Determine the dimmer on time Ton or the dimmer off time Toff according to the bus sampling voltage, the voltage VS2 of the first resistor, the voltage VS1 of the second resistor, the voltage VS0 of the third resistor or the bus voltage rising edge signal; When the dimmer on time Ton is less than or equal to the first threshold, control the output of a second modulation signal, wherein the second modulation signal is used to control the slope of the voltage to remain unchanged over time; When the dimmer on time Ton is greater than a first threshold, controlling the output of a first modulation signal; Or, when the dimmer off time Toff is greater than or equal to the second threshold, the second modulation signal is controlled to be output; when the dimmer off time Toff is less than the second threshold, the first modulation signal is controlled to be output.

5. The circuit according to claim 4, characterized in that The conduction angle detection module includes: a first comparator, a first current source, a second current source, a first switch, a second switch, a second capacitor, a second comparator and a slope modulation signal generating module; The first comparator is used to output a high level to control the first switch to close when the detection signal is greater than the reference voltage Vref1, and charge the second capacitor through the first current source; when the detection signal is less than the reference voltage Vref1, the first comparator outputs a low level, and after passing through the inverter, controls the second switch to close, and the second capacitor is discharged through the second current source; The second comparator is used to output a high level to control the slope modulation signal generating module to output the first modulation signal when the voltage of the second capacitor is greater than the reference voltage Vref2; and output a low level to control the slope modulation signal generating module to output the second modulation signal when the voltage of the second capacitor is less than the reference voltage Vref2; The detection signal includes a bus sampling voltage, a voltage VS1 of the second resistor, or a voltage VS0 of the third resistor.

6. The circuit according to claim 3, characterized in that The bus voltage regulation module includes: a first operational amplifier, a third operational amplifier, a seventh resistor, an eighth resistor, a clock generation module, a fourth MOS tube, a DAC module and a second counter; The voltage Vref is input to the positive input terminal of the first operational amplifier, the negative input terminal of the first operational amplifier is connected to the source of the fourth MOS tube, the output terminal of the first operational amplifier is connected to the gate of the fourth MOS tube, the source of the fourth MOS tube is connected to the power supply, and the source of the fourth MOS tube is connected to the first terminal of the DAC module; The clock generation module is connected to the second counter, the second counter is connected to the third end of the DAC module, the second end of the DAC module is connected to the positive input end of the third operational amplifier, the negative input end of the third operational amplifier is grounded after passing through an eighth resistor, the output end of the third operational amplifier is grounded after passing through a seventh resistor, and the output end of the third operational amplifier outputs a voltage VP; The slope of the curve of voltage VP changing with time is K, K = Vref / (CK×m×2 n ); wherein Vref is a reference voltage, n is the number of bits of the second counter, m is the coefficient of the number of bits of the second counter, and CK is the clock output by the clock generation module; The output end of the conduction angle detection module is connected to the clock generation module, and the first modulation signal is used to control the value of CK; Or, the output end of the conduction angle detection module is connected to the second counter, and the first modulation signal is used to control the value of m; Alternatively, the output end of the conduction angle detection module is connected to the seventh resistor and / or the eighth resistor, and the first modulation signal is used to control the resistance ratio of the seventh resistor to the eighth resistor.

7. The circuit according to claim 6, characterized in that The charging current control module includes: a fourth resistor, a fifth resistor and a second operational amplifier; The first end of the fourth resistor is connected to the bus voltage, the second end of the fourth resistor is connected to the first end of the fifth resistor, the second end of the fifth resistor is grounded, the bus sampling voltage output by the second end of the fourth resistor is input to the positive input end of the second operational amplifier, the negative input end of the second operational amplifier inputs the voltage VP, and the output end of the second operational amplifier is connected to the gate of the first MOS tube.

8. The circuit according to claim 7, characterized in that The thyristor dimmer comprises: a potentiometer, a trigger diode, a bidirectional thyristor and a third capacitor; The AC voltage VAC is input to the first end of the potentiometer, the first end of the potentiometer is connected to the first end of the bidirectional thyristor, and the second end of the bidirectional thyristor is connected to the rectifier; the second end of the potentiometer is connected to the first end of the trigger diode, and the second end of the trigger diode is connected to the controlled end of the bidirectional thyristor; the second end of the potentiometer is also connected to the rectifier through the third capacitor.

9. A thyristor dimming control device, characterized in that: A thyristor dimming control circuit comprising any one of claims 1 to 8.

10. An LED device, characterized in that: It comprises a thyristor dimming control circuit as described in any one of claims 1 to 8, and an LED module.

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