A brightness adjustable non-stroboscopic LED control circuit and LED lighting equipment

Abstract

The present invention relates to an adjustable brightness non-stroboscopic LED control circuit and LED lighting equipment. The adjustable brightness non-stroboscopic LED control circuit comprises a command processing circuit, an output current control circuit, and a drive control circuit connected in sequence; the command processing circuit is used to receive and analyze a command signal provided by an external processor, and to generate a control signal according to the decoding of the command signal; wherein the control signal is a parallel output digital logic signal; the output current control circuit is used to receive the control signal, and to output an adjustment signal according to the control signal; the drive control circuit is used to receive the adjustment signal, and to adjust the output current according to the adjustment signal. The present invention can solve the stroboscopic problem existing in the existing design, avoid various adverse reactions caused by the stroboscopic light source to the human body, and improve the performance and stability of the product.

Description

Technical Field

[0001] The invention relates to the field of switch power supply LED driving, and more specifically to an adjustable brightness non-stroboscopic LED control circuit and LED lighting equipment. Background Art

[0002] Smart home connects various devices in the home (such as audio and video equipment, lighting system, curtain control, air conditioning control, security system, digital cinema system, audio and video server, movie cabinet system, network home appliances, etc.) through the Internet of Things technology, providing home appliance control, lighting control, telephone remote control, indoor and outdoor remote control, anti-theft alarm, environmental monitoring, HVAC control, infrared forwarding and programmable timing control and other functions and means. Compared with ordinary homes, smart homes not only have traditional residential functions, but also have architecture, network communication, information home appliances, equipment automation, provide a full range of information interaction functions, and even save money for various energy costs. As an important part of smart homes, smart LED lighting has received more and more attention. The most basic requirement of smart LED lighting is the controllable adjustment of the brightness of the lamp. The existing solution is usually to control the LED driver through PWM by a single-chip microcomputer or similar smart device, so as to control the average output current and obtain the predetermined brightness. However, the conventional PWM control method makes the output current pulsate at a specific low frequency (such as 400Hz), thus producing a stroboscopic phenomenon. Long-term use of this type of light source will cause a variety of adverse physiological reactions in the human body, such as headaches, eye fatigue and decreased vision. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a brightness-adjustable and flicker-free LED control circuit and an LED lighting device in view of the above-mentioned defects of the prior art.

[0004] The technical solution adopted by the present invention to solve the technical problem is: constructing an adjustable brightness non-stroboscopic LED control circuit, comprising a command processing circuit, an output current control circuit, and a drive control circuit connected in sequence;

[0005] The command processing circuit is used to receive and analyze the command signal provided by the external processor, and generate a control signal according to the decoding of the command signal; wherein the control signal is a parallel output digital logic signal;

[0006] The output current control circuit is used to receive the control signal and output a regulating signal according to the control signal;

[0007] The drive control circuit is used to receive the adjustment signal and adjust the output current according to the adjustment signal.

[0008] Preferably, the command signal includes a high level time command signal, a low level time command signal and an end time command signal;

[0009] The command processing circuit comprises:

[0010] an accumulator connected to the external processor and configured to update a current rising edge value upon receiving the high level time command signal; and

[0011] A timer connected to the external processor and used for generating timing according to the high-level time command signal and outputting a command end signal according to the end time command signal.

[0012] Preferably, the command processing circuit further includes a control unit and a data storage unit;

[0013] The control unit is connected to the accumulator and the timer respectively, and is used to send the current rising edge value of the accumulator to the data storage unit according to the command end signal;

[0014] The data storage unit is connected to the control unit and is used to receive and store the current rising edge value.

[0015] Preferably, the command processing circuit further includes:

[0016] A decoding circuit connected to the data storage unit and used for decoding the current rising edge value and converting it into the control signal.

[0017] Preferably, the digital logic signal includes a voltage control signal and / or a time control signal;

[0018] The output current control circuit comprises:

[0019] A dead time generating circuit connected to the first output terminal of the command processing circuit and used for generating a delay signal according to the time control signal;

[0020] A control logic circuit is connected to the dead time generating circuit, receives and performs a logic operation according to the delay signal and outputs a first driving signal.

[0021] Preferably, the output current control circuit further includes:

[0022] A reference voltage generating circuit connected to the second output terminal of the command processing circuit and configured to generate a reference voltage according to the voltage control signal;

[0023] A voltage comparison circuit connected to the reference voltage generating circuit and the control logic circuit respectively;

[0024] A voltage conversion circuit connected to the voltage comparison circuit is used to detect the current signal and convert the current signal into a voltage signal.

[0025] Preferably, the drive control circuit comprises:

[0026] A driving circuit connected to the control logic circuit and configured to receive and generate a second driving signal according to the first driving signal;

[0027] A switch circuit is respectively connected to the drive circuit, the voltage comparison circuit and the output circuit, and is used to adjust the output current according to the second drive signal.

[0028] Preferably, it also includes:

[0029] An output circuit connected to the switch circuit and used to generate an output current.

[0030] Preferably, the output circuit includes a freewheeling diode D7, an inductor L and a capacitor Co;

[0031] The anode of the freewheeling diode D7 is connected to the first end of the inductor L, the connection node between the anode of the freewheeling diode D7 and the first end of the inductor L is also connected to the switch circuit, the cathode of the freewheeling diode D7 is connected to the input signal, the second end of the inductor L is connected to the second end of the capacitor Co, and the first end of the capacitor Co is connected to the cathode of the freewheeling diode D7;

[0032] The first end of the capacitor Co is connected to the positive input end of the LED lamp, and the second end of the capacitor Co is connected to the negative input end of the LED lamp.

[0033] The present invention also provides an LED lighting device, comprising: a processor, and the above-mentioned adjustable brightness and flicker-free LED control circuit;

[0034] The processor is used to receive input information and generate a command signal according to the input information, and send the command signal to the adjustable brightness and flicker-free LED control circuit.

[0035] The implementation of the adjustable brightness non-stroboscopic LED control circuit of the present invention has the following beneficial effects: the adjustable brightness non-stroboscopic LED control circuit includes a command processing circuit, an output current control circuit, and a drive control circuit connected in sequence; the command processing circuit is used to receive and analyze the command signal provided by the external processor, and generate a control signal according to the command signal decoding; wherein the control signal is a parallel output digital logic signal; the output current control circuit is used to receive the control signal, and output an adjustment signal according to the control signal; the drive control circuit is used to receive the adjustment signal, and adjust the output current according to the adjustment signal. The present invention can solve the stroboscopic problem existing in the existing design, avoid various adverse reactions caused by the stroboscopic light source to the human body, and improve the performance and stability of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0037] Figure 1 It is a logic diagram of an adjustable brightness non-stroboscopic LED control circuit according to an embodiment of the present invention;

[0038] Figure 2 1 is a circuit schematic diagram of an adjustable brightness non-stroboscopic LED control circuit according to an embodiment of the present invention;

[0039] Figure 3 It is an electrical waveform diagram of the output inductor in the adjustable brightness non-stroboscopic LED control circuit according to an embodiment of the present invention;

[0040] Figure 4 It is a schematic diagram of the communication protocol format adopted by the processor in the LED lighting device according to the embodiment of the present invention. DETAILED DESCRIPTION

[0041] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0042] In order to avoid the low-frequency flicker problem existing in the existing design, the present invention constructs an adjustable brightness flicker-free LED control circuit, and the adjustable brightness flicker-free LED control circuit can realize flicker-free adjustment of the power supply output current.

[0043] like Figure 1As shown, an adjustable brightness non-stroboscopic LED control circuit provided by an embodiment of the present invention may specifically include a command processing circuit 10, an output current control circuit 20, and a drive control circuit 30 connected in sequence. The command processing circuit 10 is used to receive and analyze a command signal provided by an external processor, and to generate a control signal according to decoding of the command signal; the output current control circuit 20 is used to receive the control signal, and to output an adjustment signal according to the control signal; the drive control circuit 30 is used to receive the adjustment signal, and to adjust the output current according to the adjustment signal.

[0044] The control signal generated by the command processing circuit 10 of the embodiment of the present invention is a parallel output digital logic signal; alternatively, the parallel output digital logic signal may be a voltage control signal and / or a time control signal.

[0045] It should be noted here that in the embodiment of the present invention, the command signal received by the command processing circuit 10 is provided by an external processor, and the control of the LED current by the external processor is not achieved by the duty cycle of the PWM signal, but the external processor generates the command signal according to the output current requirement of the power supply and a pre-set communication protocol. The command signal is a command signal in a specific format, and the command processing circuit 10 then analyzes the received command signal and generates a corresponding control signal based on the decoding processing of the received command signal.

[0046] It can be understood that the output current demand of the power supply referred to here means that according to user or pre-defined requirements, such as the output current demand input by the user, after the external processor receives the output current demand input by the user, it combines the predetermined communication protocol driven by the power supply to generate a corresponding command signal and send it to the command processing circuit 10, wherein the external processor and the command processing circuit 10 can achieve communication connection via wired or wireless means.

[0047] The control signal generated by the command processing circuit 10 is sent to the output current control circuit 20 to adjust the output current control circuit 20, and then the output current control circuit 20 generates a corresponding adjustment signal to the drive control circuit 30 according to the received control signal, and finally the drive control circuit 30 performs corresponding operations according to the adjustment signal to realize the regulation and control of the output current. At the same time, it can also avoid the flicker problem caused by the output current changing with the frequency of the processor control signal (PWM control signal) in the conventional PWM control method, thereby eliminating the low-frequency flicker phenomenon.

[0048] Furthermore, the command signal provided by the external processor in the embodiment of the present invention includes a high-level time command signal, a low-level time command signal and an end time command signal.

[0049] like Figure 4FIG. 1 is a schematic diagram of the format of the communication protocol used by the adjustable brightness non-flicker LED control circuit of the embodiment of the present invention. Figure 4 It can be seen that there are 6 rising edges, which will be defined as 6 rising edge commands. Similarly, if there are 100 rising edges, it will be defined as 100 rising edge commands, and so on. Different rising edge commands represent different output current requirements. For ease of understanding, in this embodiment, 1 to 100 rising edge commands correspond to 1% to 100% output current requirements respectively. Therefore, 6 rising edge commands represent 6% output current requirements. In addition, there are three important time parameter signals in the command signal, T L 、T H and T END , these three time parameter signals correspond to the aforementioned low level time command signal, high level time command signal and end time command signal. Among them, the low level time command signal defines the low level duration, the high level time command signal defines the high level duration, and the end time command signal defines the end time of the operation. That is to say, the external processor sends the Figure 4 After the sixth rising edge in the command, the high level time must be maintained for at least the time specified by the end time command signal, so that the sending of these six rising edge commands is completed.

[0050] like Figure 2 As shown, the command processing circuit 10 of this embodiment may include an accumulator and a timer as an option.

[0051] The accumulator is connected to the external processor and is used to update the current rising edge value when receiving the high-level time command signal. The timer is connected to the external processor and is used to generate timing according to the high-level time command signal and output a command end signal according to the end time command signal.

[0052] Furthermore, the command processing circuit 10 also includes a control unit and a data storage unit;

[0053] The control unit is connected to the accumulator and the timer respectively, and is used to send the current rising edge value of the accumulator to the data storage unit according to the command end signal;

[0054] The data storage unit is connected to the control unit and is used to receive and store the current rising edge value.

[0055] In various embodiments of the present invention, the data storage unit can be implemented by using a memory such as an EEPROM memory, an MTP memory, etc., which can store information for a long time after power failure. The control unit can be implemented by using a conventional microprocessor (such as an MCU).

[0056] Specifically, after receiving the command signal, the command processing circuit 10 controls the control unit to analyze the command signal. If the received command signal is a high-level time command signal (i.e., a rising edge command), the control accumulator is controlled to update the value of its internal rising edge. At the same time, the high-level time command signal can also enable the timer, and the timer starts timing. If a low-level time command signal is received, the timer is reset. When the timer times to T END When the timer outputs the command end signal; if the control unit receives the command end signal output by the timer, it determines that the current command has been transmitted, and transmits the current value of the accumulator to the data storage unit, then clears the current value of the accumulator, and waits for the transmission of the next command signal. At this time, the data in the data storage unit is the data of the latest command signal, which is the current rising edge value, and the current rising edge value is decoded and converted into a corresponding control signal by the decoding processing circuit. The control signal is used to send to the output current control circuit 20 to control the operation of the output current control circuit 20.

[0057] Understandably, if the timer reaches T END Before the time, the command signal changes from a high-level time command signal to a low-level time command signal, the timer will be reset, and the timer will not generate an end time command signal until the next rising edge (high-level time command signal) arrives and remains at a high level for more than T END , the command signal transmission is completed.

[0058] Alternatively, the control signal is a parallel-output digital logic signal, and the parallel-output digital logic signal includes a voltage control signal and / or a time control signal.

[0059] The output current control circuit 20 may include: a dead time generating circuit 201 , a control logic circuit 202 , a reference voltage generating circuit 203 , a voltage comparing circuit 204 and a voltage converting circuit 205 .

[0060] The dead time generating circuit 201 is connected to the first output terminal of the command processing circuit 10, and is used to generate a delay signal according to the time control signal. The control logic circuit 202 is connected to the dead time generating circuit 201, receives and performs a logic operation according to the delay signal and outputs a first driving signal.

[0061] The reference voltage generating circuit 203 is connected to the second output terminal of the command processing circuit 10, and is used to generate a reference voltage according to the voltage control signal. The voltage comparison circuit 204 is respectively connected to the reference voltage generating circuit 203 and the control logic circuit 202. The voltage conversion circuit 205 is connected to the voltage comparison circuit 204, and is used to detect the current signal and convert it into a voltage signal according to the current signal.

[0062] Alternatively, the voltage comparison circuit 204 can be implemented using a comparator, and the voltage conversion circuit 205 can be implemented using a current detection resistor. The current detection resistor can convert the current of the inductor in the output circuit 40 into a voltage and send it to the voltage comparison circuit 204 for comparison and judgment.

[0063] The control logic circuit 202 may be implemented by a plurality of different logic gate combinations, such as an OR gate, a NOT gate, an AND-OR gate, a NAND gate, an AND gate, and the like.

[0064] Specifically, Figure 2 As shown, the first end of the current detection resistor Rs is connected to the non-inverting input end of the comparator, the second end of the current detection resistor RS is grounded, the inverting input end of the comparator is connected to the output end of the reference voltage generating circuit 203, and is used to receive the reference voltage output by the reference voltage generating circuit 203. The output end of the comparator is connected to the control logic circuit 202, and the detection voltage connected to the non-inverting input end is compared and processed with the reference voltage of its inverting input end by the comparator, and a corresponding signal is output to the control logic circuit 202 to adjust the output of the control logic circuit 202, thereby finally realizing the adjustment of the current of the inductor in the output circuit 40.

[0065] The driving control circuit 30 may include: a driving circuit 301 and a switching circuit 302 .

[0066] The driving circuit 301 is connected to the control logic circuit 202, and is used to receive and generate a second driving signal according to the first driving signal. The driving circuit 301 can be implemented by a buffer, which can be a buffer with high impedance input and low impedance output. Through the function of the buffer, the first driving signal can be enhanced to obtain an amplified second driving signal.

[0067] The switch circuit 302 is connected to the drive circuit 301, the voltage comparison circuit 204 and the output circuit 40 respectively, and is used to adjust the output current according to the second drive signal. The switch circuit 302 can be implemented by a MOS tube, and the inductor current of the output circuit 40 is adjusted by the on / off control of the MOS tube by the second drive signal.

[0068] The output circuit 40 is connected to the switch circuit 302 and is used to generate an output current.

[0069] like Figure 2 As shown, the output circuit 40 includes a freewheeling diode D7, an inductor L and a capacitor Co.

[0070] The anode of the freewheeling diode D7 is connected to the first end of the inductor L, and the connection node between the anode of the freewheeling diode D7 and the first end of the inductor L is also connected to the switching circuit 302. The cathode of the freewheeling diode D7 is connected to the input signal. The second end of the inductor L is connected to the second end of the capacitor Co, and the first end of the capacitor Co is connected to the cathode of the freewheeling diode D7. The first end of the capacitor Co is connected to the positive input end of the LED lamp, and the second end of the capacitor Co is connected to the negative input end of the LED lamp.

[0071] refer to Figure 3 , where the peak current of the inductor L is: The average current of the inductor L is:

[0072]

[0073] Among them, T0 is the time from the inductor current rising from 0 to I peak The time and inductor current required to change from I peak The sum of the time required to drop to 0, V cs , th is the reference voltage generated by the reference voltage generating circuit 203, which is used to control the current peak value of the inductor L. D is the time signal (i.e. the aforementioned delay signal) generated by the dead time generating circuit 201, which is used to delay a period of time T after the current of the inductor L drops to 0. D Then turn on the power switch (MOS tube) to charge the inductor L. From the above formula, it can be seen that the output current control circuit 20 can change the reference voltage V cs , th and T D The value of the inductor L is adjusted to adjust the average current of the LED, thereby achieving the adjustment of the average current of the LED, avoiding the problem of the output current changing with the frequency of the processor control signal (PWM control signal) in the conventional PWM control method, and effectively solving the low-frequency flicker phenomenon.

[0074] The present invention also constructs an LED lighting device, which may include: a processor, and the aforementioned adjustable brightness flicker-free LED control circuit. The processor is used to receive input information and generate a command signal based on the input information, and send the command signal to the adjustable brightness flicker-free LED control circuit. The input information received by the processor may be operation information input by the user on site, or may be an operation instruction pre-stored in the processor. The input information includes the output current demand. The processor controls the LED current not by the duty cycle of the PWM signal, but by the processor generating the command signal according to the output current demand of the power supply and the pre-set communication protocol. The command signal is a command signal of a specific format, and then the command processing circuit 10 analyzes the received command signal, and decodes the received command signal to generate a corresponding control signal.

[0075] It can be understood that the output current requirement of the power supply referred to here refers to the output current requirement input by the user or a predefined requirement, such as the output current requirement input by the user. After receiving the output current requirement input by the user, the processor generates a corresponding command signal in combination with the predetermined communication protocol driven by the power supply, and sends it to the command processing circuit 10, wherein the processor and the command processing circuit 10 can be connected to each other by wire or wirelessly. The processor here can be the same as the external processor mentioned above.

[0076] The LED lighting device can solve the stroboscopic problem existing in the existing design and avoid various adverse reactions caused by the stroboscopic light source to the human body. Long-term use of the LED lighting device will not cause headaches, eye fatigue and decreased vision.

[0077] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot limit the scope of protection of the present invention. All equivalent changes and modifications made to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

[0078] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A brightness adjustable non-stroboscopic LED control circuit, characterized in that: It includes a command processing circuit, an output current control circuit, and a drive control circuit connected in sequence; The command processing circuit is used to receive and analyze the command signal provided by the external processor, and generate a control signal according to the decoding of the command signal; wherein the control signal is a parallel output digital logic signal; The output current control circuit is used to receive the control signal and output a regulating signal according to the control signal; The drive control circuit is used to receive the adjustment signal and adjust the output current according to the adjustment signal; Wherein, the digital logic signal includes a time control signal and a voltage control signal; The output current control circuit comprises: A dead time generating circuit connected to the first output terminal of the command processing circuit and used for generating a delay signal according to the time control signal; A control logic circuit connected to the dead time generating circuit, receiving and performing a logic operation according to the delay signal and outputting a first driving signal; A reference voltage generating circuit connected to the second output terminal of the command processing circuit and configured to generate a reference voltage according to the voltage control signal; A voltage comparison circuit connected to the reference voltage generating circuit and the control logic circuit respectively; A voltage conversion circuit connected to the voltage comparison circuit is used to detect the current signal and convert the current signal into a voltage signal.

2. The adjustable brightness non-flicker LED control circuit according to claim 1, characterized in that: The command signal includes a high level time command signal, a low level time command signal and an end time command signal; The command processing circuit comprises: an accumulator connected to the external processor and used to update the current rising edge value when receiving the high-level time command signal; as well as A timer connected to the external processor and used for generating timing according to the high-level time command signal and outputting a command end signal according to the end time command signal.

3. The adjustable brightness non-flicker LED control circuit according to claim 2, characterized in that: The command processing circuit also includes a control unit and a data storage unit; The control unit is connected to the accumulator and the timer respectively, and is used to send the current rising edge value of the accumulator to the data storage unit according to the command end signal; The data storage unit is connected to the control unit and is used to receive and store the current rising edge value.

4. The adjustable brightness non-flicker LED control circuit according to claim 3, characterized in that: The command processing circuit also includes: A decoding circuit connected to the data storage unit and used for decoding the current rising edge value and converting it into the control signal.

5. The adjustable brightness non-flicker LED control circuit according to claim 1, characterized in that: The drive control circuit comprises: A driving circuit connected to the control logic circuit and configured to receive and generate a second driving signal according to the first driving signal; A switch circuit is respectively connected to the drive circuit, the voltage comparison circuit and the output circuit, and is used to adjust the output current according to the second drive signal.

6. The adjustable brightness non-flicker LED control circuit according to claim 5, characterized in that: Also includes: An output circuit connected to the switch circuit and used to generate an output current.

7. The adjustable brightness non-flicker LED control circuit according to claim 6, characterized in that: The output circuit includes a freewheeling diode D7, an inductor L and a capacitor Co; The anode of the freewheeling diode D7 is connected to the first end of the inductor L, the connection node between the anode of the freewheeling diode D7 and the first end of the inductor L is also connected to the switch circuit, the cathode of the freewheeling diode D7 is connected to the input signal, the second end of the inductor L is connected to the second end of the capacitor Co, and the first end of the capacitor Co is connected to the cathode of the freewheeling diode D7; The first end of the capacitor Co is connected to the positive input end of the LED lamp, and the second end of the capacitor Co is connected to the negative input end of the LED lamp.

8. An LED lighting device, characterized in that: include: A processor, and a brightness-adjustable, flicker-free LED control circuit as claimed in any one of claims 1 to 7; The processor is used to receive input information and generate a command signal according to the input information, and send the command signal to the adjustable brightness and flicker-free LED control circuit.

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