Control circuit for LED module

Abstract

According to the control circuit for the LED module, when the voltage of an external input power source is larger than the capacitor voltage Vin, the external input power source charges an energy storage capacitor through the energy storage capacitor, a charging control module and a sampling resistor, and meanwhile the external input power source provides energy for the LED module and a switch type control module, and the magnitude of the charging current for charging the energy storage capacitor is controlled by setting the resistance value of the sampling resistor. When the external input power supply voltage is smaller than the capacitor voltage Vin, the energy storage capacitor performs periodic discharge through the LED module and the switch type control module. The charging process of the energy storage capacitor is controlled through the charging control module, the conduction angle of the charging current of the energy storage capacitor is made to move forwards, the charging current serves as a part of the input current, the waveform consistency of the input current and the input voltage is improved, and therefore the DF value is increased so as to meet the requirement for the high DF value.

Description

Technical Field

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

[0002] LED light source is a light source based on light-emitting diodes, which has the advantages of using low-voltage power supply, low energy consumption, strong applicability, high stability, short response time, no pollution to the environment, and multi-color light emission. With the continuous development of LED technology, the performance requirements for LED drivers are getting higher and higher. The new standard proposes requirements for the displacement factor DF (Displacement factor), which usually requires the DF value to be greater than a certain threshold. The displacement factor is also called the fundamental wave displacement factor, which can be calculated by the power factor PF (Powerfactor) and the harmonic factor (Distortion factor). The calculation formula of the displacement factor DF is: Among them, K is the displacement factor, λ is the power factor, and THD is the total harmonic distortion.

[0003] However, it is difficult for the LED driving circuit in the prior art to effectively improve the DF value and cannot meet the DF value requirements of the new standard. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a control circuit for an LED module, so as to solve the problem that the LED driving circuit in the prior art is difficult to effectively improve the DF value and cannot meet the requirements of the DF value in the new standard.

[0005] A control circuit for an LED module provided in an embodiment of the present application includes: an energy storage capacitor, a charging control module, a sampling resistor and a switch type control module;

[0006] The first end of the energy storage capacitor is connected to the external input power supply, the second end of the energy storage capacitor is connected to the first end of the charging control module, and the second end of the charging control module is grounded after passing through the sampling resistor; wherein the charging control module is used to control the charging current Icharge of the energy storage capacitor through a linear constant current control method;

[0007] The first end of the energy storage capacitor is connected to the input end of the LED module, the output end of the LED module is connected to the first end of the switch type control module, and the second end of the switch type control module is grounded;

[0008] When the voltage of the external input power supply is greater than the voltage of the energy storage capacitor, the external input power supply charges the energy storage capacitor; when the voltage of the external input power supply is less than the voltage of the energy storage capacitor, the energy storage capacitor discharges. The charging control module is used to control the charging current Icharge of the energy storage capacitor so that the charging current conduction phase angle of the energy storage capacitor is shifted forward.

[0009] In the above technical solution, when the external input power voltage is greater than the capacitor voltage Vin, the external input power charges the energy storage capacitor through the energy storage capacitor, the charging control module and the sampling resistor. At the same time, the external input power provides energy for the LED module and the switch type control module, wherein the magnitude of the charging current for charging the energy storage capacitor is controlled by setting the resistance value of the sampling resistor. When the external input power voltage is less than the capacitor voltage Vin, the energy storage capacitor is periodically discharged through the LED module and the switch type control module.

[0010] The charging current of the energy storage capacitor is controlled by setting the reference voltage of the MOS tube in the charging control module, and specifically, a fixed reference voltage can be set to make the charging current a constant current. In this embodiment, the charging process of the energy storage capacitor is controlled by the charging control module, so that the charging current conduction angle of the energy storage capacitor is moved forward, and the charging current is used as a part of the input current to improve the consistency of the input current and input voltage waveforms, thereby improving the DF value to meet the requirement for a high DF value.

[0011] Moreover, in this embodiment, while the charging current conduction angle of the energy storage capacitor is moved forward, the capacitor voltage Vin is also reduced. Since the discharge current of the energy storage capacitor remains unchanged, the switching frequency of the switching device in the switch type control module is reduced, and the switching loss of the switching device is reduced, thereby saving costs and improving economy.

[0012] Among them, the switch type control module is used to control the on-off mode of the MOS tube of the switch type control module according to the PWM signal to control the current Iled or voltage Vled of the LED module. The switch type control module includes a switch type constant current module or a switch type constant voltage module. The switch type constant current module is used to control the on-off mode of the MOS tube according to the PWM signal to control the current Iled passing through the LED module to be a constant current. The switch type constant voltage module is used to control the on-off mode of the MOS tube according to the PWM signal to control the voltage Vled at both ends of the LED module to be a constant voltage.

[0013] In some optional embodiments, it further includes: a one-way passage module;

[0014] The input end of the unidirectional path module is grounded, and the output end of the unidirectional path module is connected to the second end of the energy storage capacitor.

[0015] In some optional implementations, a charging unidirectional module is also included; the energy storage capacitor, the charging unidirectional module, the charging control module, the sampling resistor and the ground wire form a charging circuit for the energy storage capacitor.

[0016] In some optional embodiments, the charging unidirectional module further includes: a capacitor charging diode; a unidirectional path module includes a capacitor discharging diode;

[0017] The second end of the energy storage capacitor is connected to the input end of the capacitor charging diode, and the output end of the capacitor charging diode is connected to the first end of the charging control module;

[0018] The second end of the energy storage capacitor is connected to the output end of the capacitor discharge diode, and the input end of the capacitor discharge diode is grounded.

[0019] In the above technical solution, when the external input power voltage is greater than the capacitor voltage Vin, the external input power charges the energy storage capacitor through the energy storage capacitor, the capacitor charging diode, the charging control module and the sampling resistor. At the same time, the external input power provides energy for the LED module and the switch type control module, wherein the magnitude of the charging current for charging the energy storage capacitor is controlled by setting the resistance value of the sampling resistor. When the external input power voltage is less than the capacitor voltage Vin, the capacitor discharge diode, the energy storage capacitor, the LED module and the switch type control module form a discharge circuit and perform periodic discharge.

[0020] In some optional embodiments, it also includes: a voltage sampling module; the voltage sampling module is used to sample the output voltage of the LED module and output the sampled voltage; the charging control module is also used to perform linear compensation of the reference voltage when the sampled voltage output by the voltage sampling module is greater than a threshold value, so as to reduce the charging current of the energy storage capacitor.

[0021] In some optional implementations, the charging control module includes a reference voltage module, a comparator, and a switch unit;

[0022] The comparator is used to compare the electrical signal of the energy storage capacitor with the reference voltage output by the reference voltage module to control the on and off of the switch unit.

[0023] The switch unit includes a triode or a MOS tube. In this embodiment, the switch unit adopts a first MOS tube to accurately control the charging current of the energy storage capacitor.

[0024] The output end of the LED module is connected to the first end of the voltage sampling module, the second end of the voltage sampling module is connected to the first end of the reference voltage module, the second end of the reference voltage module is connected to the positive input end of the comparator, the output end of the comparator is connected to the gate of the first MOS tube, the drain of the first MOS tube is connected to the output end of the capacitor charging diode, and the source of the first MOS tube is grounded after passing through the sampling resistor.

[0025] The reference voltage module is used to perform linear compensation on the output voltage of the reference voltage module when the output voltage of the voltage sampling module is greater than a threshold value, so as to reduce the charging current of the energy storage capacitor.

[0026] In the above technical solution, the reference voltage of the charging control module is obtained by sampling the cathode of the LED module to detect the voltage change of the LED module. When the voltage Vled of the LED module decreases, the cathode voltage Vled- of the LED module increases, and the sampling voltage Vfb of the voltage sampling module increases, so that the voltage sampling module and the reference voltage module enter linear compensation, so that the reference voltage Vref of the charging control module decreases, and the charging current Icharge of the energy storage capacitor decreases accordingly. In the face of different output voltage Vled scenarios, it can be guaranteed that within one half-wave, the input current Iin (Iin = Icharge + Iled) can reach the maximum value before the specified phase angle, for example, to meet the requirement of the new European standard that the input current maximum value corresponds to a phase angle of less than 65 degrees.

[0027] In some optional implementations, it also includes: a voltage stabilizing module; the input end of the voltage stabilizing module is connected to the bus, and the output end of the voltage stabilizing module is connected to the reference voltage module; the voltage stabilizing module is used to obtain the bus voltage from the bus and output it after stabilization.

[0028] In some optional embodiments, the voltage stabilization module includes: a junction field effect transistor, a power module and a bandgap reference module;

[0029] The drain of the junction field effect transistor is connected to the output end of the capacitor charging diode, the gate of the junction field effect transistor is grounded, the source of the junction field effect transistor is connected to the input end of the power module, the output end of the power module is connected to the third end of the reference voltage module, and the output end of the bandgap reference module is connected to the fourth end of the reference voltage module;

[0030] The junction field effect transistor is used to obtain the bus voltage from the bus; the power module is used to convert the bus voltage into the working voltage; the bandgap reference module is used to convert the working voltage into the zero temperature coefficient voltage; and the reference voltage module is used to obtain the reference voltage from the zero temperature coefficient voltage.

[0031] Among them, the voltage stabilizing module can be integrated into the IC chip of the charging control module.

[0032] In some optional embodiments, it further includes: an over-temperature adjustment module;

[0033] The output end of the power module is connected to the input end of the over-temperature regulation module, and the output end of the over-temperature regulation module is connected to the fourth end of the reference voltage module;

[0034] The over-temperature regulation module is used to set the output value of the reference voltage module to zero when the temperature is higher than a preset value.

[0035] Among them, the over-temperature regulation module can be integrated into the IC chip of the charging control module.

[0036] In some optional embodiments, the device further comprises: an inductor and an inductor discharge diode;

[0037] A first end of the inductor is connected to the output end of the LED module, and a second end of the inductor is connected to the first end of the switch type control module;

[0038] The second end of the inductor is also connected to the input end of the inductor discharge diode, and the output end of the inductor discharge diode is connected to the input end of the LED module.

[0039] In the above technical solution, when the external input power voltage is greater than the capacitor voltage Vin, the external input power charges the energy storage capacitor through the energy storage capacitor, the charging control module and the sampling resistor. At the same time, the external input power provides energy for the LED module and the switch-type control module. In this process, the switch-type control module controls the current Iled flowing through the LED module or the voltage Vled across the LED module by controlling the on-off of the MOS tube therein. Specifically, when the MOS tube of the switch-type control module is turned on, the external input power provides energy to the LED module through the LED module, the inductor and the switch-type control module, and the inductor stores energy at the same time; when the MOS tube of the switch-type control module is turned off, the inductor releases energy, and the inductor provides energy to the LED module after passing through the inductor discharge diode.

[0040] When the external input power supply voltage is less than the capacitor voltage Vin, the energy storage capacitor is discharged periodically through the LED module and the switch-type control module. In this process, the switch-type control module controls the current Iled flowing through the LED module or the voltage Vled across the LED module by controlling the on-off of the MOS tube therein. Specifically, when the MOS tube of the switch-type control module is turned on, the energy storage capacitor provides energy to the LED module through the LED module, the inductor and the switch-type control module, and the inductor stores energy at the same time; when the MOS tube of the switch-type control module is turned off, the inductor releases energy, and the inductor provides energy to the LED module after passing through the inductor discharge diode.

[0041] In some optional implementations, it further includes: a polarity capacitor;

[0042] The positive end of the polarity capacitor is connected to the input end of the LED module, and the negative end of the polarity capacitor is connected to the output end of the LED module.

[0043] In the above technical solution, due to the charging and discharging process of the inductor, the waveform of the current Iled flowing through the LED module is a triangular wave. In this embodiment, a polar capacitor is provided to achieve filtering to filter the triangular wave into a direct current.

[0044] In some optional embodiments, it further includes: a rectifier module;

[0045] The input end of the rectifier module is connected to an external AC power source, and the output end of the rectifier module is connected to the first end of the energy storage capacitor.

[0046] In some optional implementations, it further includes: a high-frequency filter capacitor;

[0047] The output end of the rectifier module is also connected to a high-frequency filter capacitor and then grounded.

[0048] In the above technical solution, the switch type control module realizes the periodic discharge of the circuit where the LED module is located, and the switching frequency of the switch type control module determines the discharge frequency. Therefore, the high-frequency switching action of the switch type control module causes high-frequency noise. In this embodiment, a high-frequency filter capacitor is provided to avoid high-frequency oscillation of the charging and discharging current, so as to improve the stability of the system.

[0049] A control device for an LED module provided in an embodiment of the present application includes a control circuit for an LED module as described in any one of the above items, and a shell surrounding the control circuit.

[0050] An LED device provided in an embodiment of the present application includes a control circuit for an LED module as described in any one of the above items, and an LED module; the control circuit is connected to the LED module.

[0051] An integrated circuit for an LED module provided in an embodiment of the present application includes: a control circuit for an LED module as described in any of the above items, a lead frame, and a plastic packaging material; the control circuit is arranged on the lead frame, and the plastic packaging material is used to seal the control circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] 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.

[0053] Figure 1 A schematic diagram of a control circuit for an LED module provided in an embodiment of the present application;

[0054] Figure 2 A waveform diagram of a first charging current Icharge provided in an embodiment of the present application;

[0055] Figure 3 A waveform diagram of a second charging current Icharge provided in an embodiment of the present application;

[0056] Figure 4 A waveform diagram of a third charging current Icharge provided in an embodiment of the present application;

[0057] Figure 5A schematic diagram of the waveform of the input current provided in an embodiment of the present application;

[0058] Figure 6 A structural diagram of a control circuit for an LED module provided in the first embodiment of the present application;

[0059] Figure 7 A schematic diagram of a charging control module provided in this embodiment;

[0060] Figure 8 A schematic diagram of a charging control module provided in another embodiment of the present application;

[0061] Fig. 9 A structural diagram of a control circuit for an LED module provided in the second embodiment of the present application;

[0062] Fig.10 This is a structural diagram of the control circuit provided in an embodiment of the present application.

[0063] Icon: 1-charging control module, 2-switch control module, 3-LED module, 4-voltage sampling module, 5-rectifier module, 6-one-way passage module. DETAILED DESCRIPTION

[0064] 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.

[0065] Please refer to Figure 1 , Figure 1 This is a schematic diagram of a control circuit of an LED module 3 provided in an embodiment of the present application. The control circuit specifically includes: an energy storage capacitor C1, a charging control module 1, a sampling resistor R and a switch type control module 2.

[0066] The first end of the energy storage capacitor C1 is connected to the external input power supply, the second end of the energy storage capacitor C1 is connected to the first end (IN end) of the charging control module 1, and the second end (CS end) of the charging control module 1 is grounded after passing through the sampling resistor R; wherein the charging control module 1 is used to control the charging current Icharge of the energy storage capacitor C1 through a linear constant current control method. The first end of the energy storage capacitor C1 is connected to the input end of the LED module 3, the output end of the LED module 3 is connected to the first end of the switch type control module 2, and the second end of the switch type control module 2 is grounded; wherein the switch type control module 2 is used to control the current Iled or voltage Vled of the LED module 3 by controlling the on and off of the MOS tube of the switch type control module 2 according to the PWM signal.

[0067] In the embodiment of the present application, when the external input power supply voltage Vm is greater than the capacitor voltage Vin, the external input power supply charges the energy storage capacitor C1 through the energy storage capacitor C1, the charging control module 1 and the sampling resistor R. At the same time, the external input power supply provides energy for the LED module 3 and the switch type control module 2, wherein the magnitude of the charging current for charging the energy storage capacitor C1 is controlled by setting the resistance value of the sampling resistor R. When the external input power supply voltage is less than the capacitor voltage Vin, the energy storage capacitor C1 is periodically discharged through the LED module 3 and the switch type control module 2.

[0068] The charging current of the energy storage capacitor C1 is controlled by setting the reference voltage of the MOS tube in the charging control module 1. Specifically, a fixed reference voltage can be set to make the charging current a constant current, such as Figure 2 In this embodiment, the charging process of the energy storage capacitor C1 is controlled by the charging control module 1, so that the charging current conduction angle of the energy storage capacitor C1 is moved forward, and the charging current is used as a part of the input current to improve the consistency of the input current and input voltage waveforms, thereby improving the DF value to meet the requirement for a high DF value.

[0069] Moreover, in this embodiment, while the charging current conduction angle of the energy storage capacitor C1 is moved forward, the capacitor voltage Vin is also reduced. Since the discharge current Ipk of the energy storage capacitor remains unchanged, the switching frequency of the switching device in the switch type control module is reduced. The reason is: Ipk = (Vin / L) × Ton, the output current Iled = Ipk / 2 is constant, so Ipk = 2 × Iled remains unchanged. Since Vin becomes smaller, Ton becomes larger, Toff = L × Ipk / Vled remains unchanged, T = Ton + Toff becomes larger, F = 1 / T becomes smaller, the switching frequency is reduced, the switching loss of the switching device is reduced, thereby saving costs and improving economy.

[0070] The switch type control module 2 includes a switch type constant current module or a switch type constant voltage module. The switch type constant current module is used to control the on / off mode of the MOS tube therein according to the PWM signal to control the current Iled passing through the LED module 3 to be a constant current. The switch type constant voltage module is used to control the on / off mode of the MOS tube therein according to the PWM signal to control the voltage Vled across the LED module 3 to be a constant voltage.

[0071] For details, please refer to Figure 5 , Figure 5A waveform diagram of the input current provided in the embodiment of the present application. Wherein, Iin is the input current in the control circuit provided with the charging control module 1 in this embodiment. Due to the action of the charging control module 1, within one half-wave, the charging current conduction angle of the energy storage capacitor C1 and the conduction angle of the input current are both θ, and the valley value of the capacitor voltage Vin is V1. Iin' is the input current in the control circuit without the charging control module 1. At this time, within one half-wave, the charging current conduction angle of the energy storage capacitor C1 and the conduction angle of the input current are both θ', and the valley value of the capacitor voltage Vin is V0. Therefore, compared with the circuit without the charging control module 1, the circuit provided with the charging control module 1 in this embodiment has a reduced input current conduction angle from θ' to θ, and a reduced valley value of the capacitor voltage Vin from V1 to V0, thereby improving the consistency of the input current and input voltage waveforms.

[0072] In addition, the charging current Icharge of the energy storage capacitor C1 is controlled by setting the reference voltage of the MOS tube in the charging control module 1. Alternatively, the reference voltage in the charging control module 1 is set to a value that varies with the phase angle, so that within a half-wave of the voltage Vm, a charging current begins to exist at a smaller phase angle, and the charging current quickly rises to a maximum value, and then the value of the charging current is always lower than the maximum value, so as to meet the requirement that the phase angle corresponding to the maximum input current is less than a certain threshold value, for example Figure 3 and Figure 4 The waveform of the charging current Icharge is shown in FIG.

[0073] Please refer to Figure 6 , Figure 6 This is a control circuit structure diagram of an LED module 3 provided in the first embodiment of the present application.

[0074] The control circuit of this embodiment also includes: a capacitor charging diode D1 and a capacitor discharging diode D2. The second end of the energy storage capacitor C1 is connected to the input end of the capacitor charging diode D1, and the output end of the capacitor charging diode D1 is connected to the first end (IN end) of the charging control module 1; the second end of the energy storage capacitor C1 is connected to the output end of the capacitor discharging diode D2, and the input end of the capacitor discharging diode D2 is grounded.

[0075] In the embodiment of the present application, when the external input power supply voltage is greater than the capacitor voltage Vin, the external input power supply charges the energy storage capacitor C1 through the energy storage capacitor C1, the capacitor charging diode D1, the charging control module 1 and the sampling resistor R. At the same time, the external input power supply provides energy for the LED module 3 and the switch type control module 2, wherein the magnitude of the charging current for charging the energy storage capacitor C1 is controlled by setting the resistance value of the sampling resistor R. When the external input power supply voltage is less than the capacitor voltage Vin, the capacitor discharge diode D2, the energy storage capacitor C1, the LED module 3 and the switch type control module 2 form a discharge circuit and perform periodic discharge.

[0076] In some optional embodiments, it also includes: an inductor L and an inductor discharge diode D3; wherein the first end of the inductor L is connected to the output end of the LED module 3, and the second end of the inductor L is connected to the first end of the switch type control module 2; the second end of the inductor L is also connected to the input end of the inductor discharge diode D3, and the output end of the inductor discharge diode D3 is connected to the input end of the LED module 3.

[0077] In the embodiment of the present application, when the voltage of the external input power supply is greater than the capacitor voltage Vin, the external input power supply charges the energy storage capacitor C1 through the energy storage capacitor C1, the charging control module 1 and the sampling resistor R. At the same time, the external input power supply provides energy for the LED module 3 and the switch type control module 2. In this process, the switch type control module 2 controls the current Iled flowing through the LED module 3 or the voltage Vled across the LED module 3 by controlling the on and off of the MOS tube therein. Specifically, when the MOS tube of the switch type control module 2 is turned on, the external input power supply provides energy to the LED module 3 through the LED module 3, the inductor L and the switch type control module, and the inductor L stores energy at the same time; when the MOS tube of the switch type control module 2 is turned off, the inductor L releases energy, and the inductor L provides energy to the LED module 3 after passing through the inductor discharge diode D3.

[0078] When the external input power supply voltage is less than the capacitor voltage Vin, the energy storage capacitor C1 is periodically discharged through the LED module 3 and the switch type control module 2. In this process, the switch type control module 2 controls the current Iled flowing through the LED module 3 or the voltage Vled across the LED module 3 by controlling the on and off of the MOS tube therein. Specifically, when the MOS tube of the switch type control module 2 is turned on, the energy storage capacitor C1 provides energy to the LED module 3 through the LED module 3, the inductor L and the switch type control module, and the inductor L stores energy at the same time; when the MOS tube of the switch type control module 2 is turned off, the inductor L releases energy, and the inductor L provides energy to the LED module 3 after passing through the inductor discharge diode D3.

[0079] In some optional implementations, it further includes: a polarity capacitor C2; the positive end of the polarity capacitor C2 is connected to the input end of the LED module 3, and the negative end of the polarity capacitor C2 is connected to the output end of the LED module 3.

[0080] In the embodiment of the present application, due to the charging and discharging process of the inductor L, the waveform of the current Iled flowing through the LED module 3 is a triangular wave. In the present embodiment, a polar capacitor C2 is provided to achieve filtering to filter the triangular wave into a direct current.

[0081] Furthermore, since the current loop where the LED module 3 of this embodiment is located adopts the switch type control module 2 to achieve constant current output, it also has the following advantages:

[0082] First, the input voltage range is wider and can adapt to larger grid voltage fluctuations.

[0083] Second, the input power is stable and basically does not change with the input voltage.

[0084] Third, high efficiency.

[0085] Fourth, the LED voltage setting is flexible and can be set according to actual needs.

[0086] Fifth, LED has no flicker.

[0087] In some optional embodiments, the device further comprises: a rectifier module 5; the input end of the rectifier module 5 is connected to an external AC power source, and the output end of the rectifier module 5 is connected to a first end of the energy storage capacitor C1. The rectifier module 5 rectifies the external AC voltage Vac into an external input voltage Vm.

[0088] In some optional implementations, it further includes: a high-frequency filter capacitor C3; the output end of the rectifier module 5 is also connected to the high-frequency filter capacitor C3 and then grounded. In the embodiment of the present application, the switch type control module 2 realizes the periodic discharge of the circuit where the LED module 3 is located, and the switching frequency of the switch type control module 2 determines the discharge frequency. Therefore, the high-frequency switching action of the switch type control module 2 causes high-frequency noise to be generated. In this embodiment, the high-frequency filter capacitor C3 is set to avoid high-frequency oscillation of the charging and discharging current to improve the stability of the system.

[0089] In an optional embodiment, the control circuit further includes: a voltage sampling module 4; please refer to Figure 7 , Figure 7The schematic diagram of the charging control module 1 provided in the present embodiment, the charging control module 1 in the present embodiment specifically includes a reference voltage module, a comparator and a first MOS tube M1. The output end of the LED module 3 is connected to the first end of the voltage sampling module 4, the second end of the voltage sampling module 4 is connected to the first end (FB end) of the reference voltage module, the second end of the reference voltage module is connected to the positive input end of the comparator, the output end of the comparator is connected to the gate of the first MOS tube M1, the drain of the first MOS tube M1 is connected to the output end of the capacitor charging diode D1, and the source of the first MOS tube M1 is grounded after passing through the sampling resistor R. When charging the energy storage capacitor C1, the value of Vref is higher than the threshold value of the first MOS tube M1, and the first MOS tube M1 is turned on; when the energy storage capacitor C1 is discharged, the value of Vref is lower than the threshold value of the first MOS tube M1, and the first MOS tube M1 is automatically disconnected.

[0090] In the embodiment of the present application, the reference voltage of the charging control module 1 is obtained by sampling the cathode of the LED module 3 to detect the voltage change of the LED module 3. When the voltage Vled of the LED module 3 decreases, the cathode voltage Vled- of the LED module 3 increases, and the sampling voltage Vfb of the voltage sampling module 4 increases, so that the voltage sampling module 4 and the reference voltage module enter linear compensation, so that the reference voltage Vref of the charging control module 1 decreases, and the charging current Icharge of the energy storage capacitor C1 decreases accordingly. In the face of different output voltage Vled scenarios, it can be guaranteed that within one half-wave, the input current Iin (Iin = Icharge + Iled) can reach the maximum value before the specified phase angle, for example, to meet the new European standard that the maximum input current corresponds to a phase angle of less than 65 degrees. In a specific embodiment, when the FB terminal voltage Vfb is greater than 1.8V, linear compensation of the output voltage is performed, and at this time Vref = 600-(Vfb-1.8) × 600 (mV).

[0091] It should be noted that the LED constant current driving circuit using a linear IC in the conventional solution also performs linear compensation. The difference between the linear compensation of the conventional solution and the linear compensation of this embodiment is that:

[0092] In conventional schemes, the linear compensation module (LN) generally samples the bus voltage and collects the change of the input voltage. Since the linear compensation module does not work when the terminal voltage Vln is less than 1.8V, the charging current Icharge is a constant current, and thus the input current is also a constant current, which cannot meet the requirement that the maximum input current corresponds to a phase angle of less than 65 degrees. Therefore, the input voltage must enter linear compensation (compensation method such as Vref = 600-(Vln-1.8) × 600 (mV)) at 230V to make the waveform of the input current meet the requirement that the maximum input current corresponds to a phase angle of less than 65 degrees. And due to the constant power effect of the linear compensation module, when the input voltage increases, if Icharge does not change, the bottom voltage of Vin will be very high. In addition, since the LED constant current chip uses a linear IC, the power P of the MOS tube in the chip is MOS =V MOS ×Iled=(Vin-Vled)×Iled, the input power will change greatly, after the linear compensation module works, Icharge will become smaller, Vin valley voltage will become lower, and P M2 The power changes are small, and the input power also changes small.

[0093] The present embodiment samples from the negative electrode of the LED module 3 in order to adapt to different output voltages for output voltage compensation. Thus, in the face of different output voltage Vled scenarios, it can be ensured that within one half-wave, the input current can reach the maximum value before the specified phase angle.

[0094] In some optional implementations, please refer to Figure 8 and Fig.10 ,in Figure 8 This is a schematic diagram of a charging control module 1 provided in another embodiment of the present application. The charging control module 1 further includes: a junction field effect transistor M0, a power module POWER and a bandgap reference module BG.

[0095] Among them, the drain of the junction field effect transistor M0 is connected to the output end of the capacitor charging diode D1, the gate of the junction field effect transistor M0 is grounded, the source of the junction field effect transistor M0 is connected to the input end of the power module POWER, the output end of the power module POWER is connected to the third end of the reference voltage module, and the output end of the bandgap reference module BG is connected to the fourth end of the reference voltage module; the junction field effect transistor M0 is used to obtain the bus voltage from the bus; the power module POWER is used to convert the bus voltage into an operating voltage; the bandgap reference module BG is used to convert the operating voltage into a zero temperature coefficient voltage; the reference voltage module is used to obtain a reference voltage from the zero temperature coefficient voltage.

[0096] In some optional embodiments, the charging control module 1 also includes: an over-temperature regulation module OTR; the output end of the power module POWER is connected to the input end of the over-temperature regulation module OTR, and the output end of the over-temperature regulation module OTR is connected to the third end of the reference voltage module; the over-temperature regulation module OTR is used to set the output value of the reference voltage module to zero when the temperature is higher than a preset value.

[0097] Please refer to Fig. 9 , Fig. 9 This is a control circuit structure diagram of an LED module 3 provided in the second embodiment of the present application. The control circuit specifically includes: an energy storage capacitor C1, a charging control module 1, a sampling resistor R, a switch control module 2 and a unidirectional path module 6.

[0098] The input end of the one-way passage module 6 is grounded, the output end of the one-way passage module 6 is connected to the second end of the energy storage capacitor C1, the first end of the energy storage capacitor C1 is connected to the external input power supply, the second end of the energy storage capacitor C1 is connected to the first end (IN end) of the charging control module 1, and the second end (CS end) of the charging control module 1 is grounded after passing through the sampling resistor R; wherein the charging control module 1 is used to control the charging current Icharge of the energy storage capacitor C1 through a linear constant current control method. The first end of the energy storage capacitor C1 is connected to the input end of the LED module 3, the output end of the LED module 3 is connected to the first end of the switch type control module 2, and the second end of the switch type control module 2 is grounded; wherein the switch type control module 2 is used to control the current Iled or voltage Vled of the LED module 3 by controlling the on and off of the MOS tube of the switch type control module 2 according to the PWM signal.

[0099] In the embodiment of the present application, when the external input power supply voltage is greater than the capacitor voltage Vin, the external input power supply charges the energy storage capacitor C1 through the energy storage capacitor C1, the charging control module 1 and the sampling resistor R. At the same time, the external input power supply provides energy for the LED module 3 and the switch type control module 2, wherein the magnitude of the charging current for charging the energy storage capacitor C1 is controlled by setting the resistance value of the sampling resistor R. When the external input power supply voltage is less than the capacitor voltage Vin, the unidirectional path module 6, the energy storage capacitor C1, the LED module 3 and the switch type control module 2 constitute a discharge circuit and perform periodic discharge. Among them, the unidirectional path module 6 can be a diode or other PN junction device with unidirectional conductivity, and the unidirectional path module 6 can also use the body diode of the switch device (MOS tube) of the charging control module 1. In this embodiment, the charging process of the energy storage capacitor C1 is controlled by the charging control module 1, so that the charging current conduction angle of the energy storage capacitor C1 is moved forward, and the charging current is used as a part of the input current to improve the consistency of the input current and input voltage waveforms, thereby improving the DF value to meet the requirements for high DF values.

[0100] The control circuit of this embodiment further includes: a polar capacitor C2, a rectifier module 5, a high-frequency filter capacitor C3, an inductor L and an inductor discharge diode D3.

[0101] Among them, the first end of the inductor L is connected to the output end of the LED module 3, and the second end of the inductor L is connected to the first end of the switch type control module 2; the second end of the inductor L is also connected to the input end of the inductor discharge diode D3, and the output end of the inductor discharge diode D3 is connected to the input end of the LED module 3. The positive end of the polarity capacitor C2 is connected to the input end of the LED module 3, and the negative end of the polarity capacitor C2 is connected to the output end of the LED module 3. The input end of the rectifier module 5 is connected to the external AC power supply, and the output end of the rectifier module 5 is connected to the first end of the energy storage capacitor C1. The output end of the rectifier module 5 is also connected to the high-frequency filter capacitor C3 and then grounded.

[0102] In the embodiment of the present application, when the voltage of the external input power supply is greater than the capacitor voltage Vin, the external input power supply charges the energy storage capacitor C1 through the energy storage capacitor C1, the charging control module 1 and the sampling resistor R. At the same time, the external input power supply provides energy for the LED module 3 and the switch type control module 2. In this process, the switch type control module 2 controls the current Iled flowing through the LED module 3 or the voltage Vled across the LED module 3 by controlling the on and off of the MOS tube therein. Specifically, when the MOS tube of the switch type control module 2 is turned on, the external input power supply provides energy to the LED module 3 through the LED module 3, the inductor L and the switch type control module, and the inductor L stores energy at the same time; when the MOS tube of the switch type control module 2 is turned off, the inductor L releases energy, and the inductor L provides energy to the LED module 3 after passing through the inductor discharge diode D3.

[0103] When the external input power supply voltage is less than the capacitor voltage Vin, the energy storage capacitor C1 is periodically discharged through the LED module 3 and the switch type control module 2. In this process, the switch type control module 2 controls the current Iled flowing through the LED module 3 or the voltage Vled across the LED module 3 by controlling the on and off of the MOS tube therein. Specifically, when the MOS tube of the switch type control module 2 is turned on, the energy storage capacitor C1 provides energy to the LED module 3 through the LED module 3, the inductor L and the switch type control module, and the inductor L stores energy at the same time; when the MOS tube of the switch type control module 2 is turned off, the inductor L releases energy, and the inductor L provides energy to the LED module 3 after passing through the inductor discharge diode D3.

[0104] Due to the charging and discharging process of the inductor L, the waveform of the current Iled flowing through the LED module 3 is a triangular wave. In this embodiment, a polar capacitor C2 is provided to achieve filtering, filtering the triangular wave into a direct current. The switch type control module 2 realizes the periodic discharge of the circuit where the LED module 3 is located. The switching frequency of the switch type control module 2 determines the discharge frequency. Therefore, the high-frequency switching action of the switch type control module 2 causes high-frequency noise to be generated. In this embodiment, a high-frequency filter capacitor C3 is provided to avoid high-frequency oscillation of the charging and discharging current, so as to improve the stability of the system.

[0105] A control device for an LED module provided in an embodiment of the present application includes a control circuit for an LED module as described in any one of the above items, and a shell surrounding the control circuit.

[0106] An LED device provided in an embodiment of the present application includes a control circuit for an LED module as described in any one of the above items, and an LED module; the control circuit is connected to the LED module.

[0107] An integrated circuit for an LED module provided in an embodiment of the present application includes: a control circuit for an LED module as described in any of the above items, a lead frame, and a plastic packaging material; the control circuit is arranged on the lead frame, and the plastic packaging material is used to seal the control circuit.

[0108] 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.

[0109] 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.

[0110] 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 separately, or two or more modules may be integrated to form an independent part.

[0111] 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.

[0112] 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 control circuit for an LED module, characterized in that: include: Energy storage capacitor (C1), charging control module (1), sampling resistor (R) and switch type control module (2); The first end of the energy storage capacitor (C1) is used to connect an external input power source and an input end of the LED module (3); the second end of the energy storage capacitor (C1) is connected to the first end of the charging control module (1); and the second end of the charging control module is grounded after passing through the sampling resistor (R); wherein the charging control module (1) is used to control the charging current Icharge of the energy storage capacitor (C1) so as to shift the charging current conduction phase angle of the energy storage capacitor (C1) forward; The first end of the switch type control module (2) is used to connect to the output end of the LED module (3), and the second end of the switch type control module (2) is grounded.

2. The control circuit according to claim 1, characterized in that: Also includes: One-way passage module (6); The input end of the one-way passage module (6) is grounded, and the output end of the one-way passage module (6) is connected to the second end of the energy storage capacitor (C1).

3. The control circuit according to claim 2, characterized in that: It also includes a charging unidirectional module; the energy storage capacitor (C1), the charging unidirectional module, the charging control module, the sampling resistor (R) and the ground wire form a charging circuit of the energy storage capacitor (C1).

4. The control circuit according to claim 1, characterized in that: Also includes: Voltage sampling module (4); The voltage sampling module (4) is used to sample the output voltage of the LED module (3) and output the sampled voltage; the charging control module (1) is also used to perform linear compensation of the reference voltage when the sampled voltage output by the voltage sampling module (4) is greater than a threshold value, so as to reduce the charging current of the energy storage capacitor (C1).

5. The control circuit according to claim 4, characterized in that: The charging control module (1) comprises a reference voltage module (VREF), a comparator and a switch unit; The comparator is used to compare the electrical signal of the energy storage capacitor (C1) with the reference voltage output by the reference voltage module (VREF) to control the on and off of the switch unit.

6. The control circuit according to claim 5, characterized in that: Also includes: Voltage regulator module; The input end of the voltage stabilizing module is connected to the bus, and the output end of the voltage stabilizing module is connected to the reference voltage module (VREF); the voltage stabilizing module is used to obtain the bus voltage from the bus and output it after stabilization.

7. The control circuit according to claim 6, characterized in that: The voltage stabilizing module comprises: a junction field effect transistor (M0), a power module (POWER) and a bandgap reference module (BG); The junction field effect transistor (M0) is used to obtain the bus voltage from the bus; the power module (POWER) is used to convert the bus voltage into the working voltage; the bandgap reference module (BG) is used to convert the working voltage into a zero temperature coefficient voltage; The reference voltage module (VREF) is also used to obtain a reference voltage from a zero temperature coefficient voltage.

8. The control circuit according to claim 5, characterized in that: Also includes: Over temperature regulation module (OTR); The output end of the over-temperature regulation module (OTR) is connected to the reference voltage module (VREF); The over-temperature regulation module (OTR) is used to set the reference voltage of the reference voltage module (VREF) to zero when the temperature is higher than a preset value.

9. The control circuit according to claim 1, characterized in that: The switch type control module (2) controls the current Iled or voltage Vled of the LED module (3) by controlling the on and off of its MOS tube; wherein the on and off control of the MOS tube is achieved by inputting a PWM signal to the gate of the MOS tube.

10. The control circuit according to claim 1, characterized in that: The energy storage capacitor (C1) is used to: when the voltage of the external input power supply is greater than the voltage of the energy storage capacitor (C1), the external input power supply charges the energy storage capacitor (C1); when the voltage of the external input power supply is less than the voltage of the energy storage capacitor (C1), the energy storage capacitor (C1) discharges.

11. The control circuit according to claim 1, characterized in that: Also includes: Inductor (L) and inductor discharge diode (D3); A first end of the inductor (L) is connected to the output end of the LED module (3), and a second end of the inductor (L) is connected to a first end of the switch type control module (2); The second end of the inductor (L) is also connected to the input end of the inductor discharge diode (D3), and the output end of the inductor discharge diode (D3) is connected to the input end of the LED module (3).

12. The control circuit according to claim 11, characterized in that: Also includes: Polarized capacitor (C2); The positive end of the polarity capacitor (C2) is connected to the input end of the LED module (3), and the negative end of the polarity capacitor (C2) is connected to the output end of the LED module (3).

13. The control circuit according to claim 1, characterized in that: Also includes: Rectification module (5) and high frequency filter capacitor (C3); The input end of the rectifier module (5) is connected to an external AC power source Vac, and the output end of the rectifier module (5) is connected to the first end of the energy storage capacitor (C1); the output end of the rectifier module (5) is also connected to the high-frequency filter capacitor (C3) and then grounded.

14. A control device for an LED module, characterized in that: It comprises a control circuit for an LED module as claimed in any one of claims 1 to 13, and a shell surrounding the control circuit.

15. An LED device, characterized in that: It comprises a control circuit for an LED module as described in any one of claims 1 to 13, and an LED module; the control circuit is connected to the LED module.

16. An integrated circuit for an LED module, characterized in that: include: A control circuit, a lead frame, and a molding compound for an LED module as claimed in any one of claims 1 to 13; The control circuit is arranged on the lead frame, and the plastic packaging material is used to seal the control circuit.

Images