Control system

Abstract

This application discloses a control system, comprising: a constant current control device, a first terminal connected to a target load, a second terminal connected to a processing unit, and a third terminal connected to a voltage regulating circuit; the constant current control device feeding back the detected output voltage of the target load to the processing unit; the processing unit being connected to the constant current control device, the processing unit comparing the output voltage with a preset voltage threshold to send a control command to the constant current control device instructing it to turn on a constant current source; the constant current control device having an internal constant current source, the constant current control device receiving the control command to turn on the constant current source and output a control current to the voltage regulating circuit; and a voltage regulating circuit receiving the control current to adjust the input voltage of the target load downwards.

Description

Technical Field

[0001] This application relates to the field of control technology, and more particularly to a control system. Background Technology

[0002] Currently, the LED industry has increasingly stringent energy efficiency standards, placing higher demands on the efficiency of LED lighting control devices, such as constant current control devices. The industry primarily improves the efficiency of LED lighting control devices by introducing third-generation semiconductor gallium nitride (GaN) materials and technologies to reduce conduction losses and enhance control efficiency. However, the cost of this material is significantly affected by manufacturing processes and large-scale production, thus limiting its application.

[0003] How to reduce the wear and tear of control devices and improve control efficiency in a simple and effective way is a technical problem that needs to be solved. Utility Model Content

[0004] The purpose of this application is to provide a control system to solve the problem of low efficiency in LED lighting control devices.

[0005] To solve the above-mentioned technical problems, this specification is implemented as follows: Firstly, a control system is provided, including a constant current control device, a processing unit, and a voltage regulating circuit. The first terminal of the constant current control device is connected to the target load, the second terminal of the constant current control device is connected to the processing unit, and the third terminal of the constant current control device is connected to the voltage regulating circuit. The constant current control device feeds back the detected output voltage of the target load to the processing unit. The processing unit is connected to the constant current control device. When the output voltage exceeds a preset voltage threshold, the processing unit sends a control command to the constant current control device to instruct the constant current source to be turned on. The constant current control device has a constant current source inside. The constant current control device receives the control command to turn on the constant current source and outputs control current to the voltage regulating circuit. The voltage regulating circuit receives the control current to adjust the input voltage of the target load downwards.

[0006] In this embodiment, the control system includes a constant current control device, a processing unit, and a voltage regulating circuit. A first terminal of the constant current control device is connected to the target load, a second terminal is connected to the processing unit, and a third terminal is connected to the voltage regulating circuit. The constant current control device feeds back the detected output voltage of the target load to the processing unit. The processing unit is connected to the constant current control device and compares the output voltage with a preset voltage threshold to send a control command to the constant current control device instructing it to turn on the constant current source. The constant current control device internally... A constant current source is provided. The constant current control device receives the control command to turn on the constant current source and outputs a control current to the voltage regulation circuit. The voltage regulation circuit receives the control current to adjust the input voltage of the target load. Thus, the voltage value can be detected by the constant current control device, and the external input voltage of the target load can be adjusted by the internal algorithm of the processing unit combined with a simple current source circuit. This adjusts the voltage at the input terminal of the constant current control device to tend towards a preset voltage threshold, achieving low-cost and high-precision effective voltage control, significantly reducing the voltage drop loss generated by the constant current control device, and improving the control efficiency of the constant current control device. Attached Figure Description

[0007] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a structural block diagram of the control system according to an embodiment of this application.

[0008] Figure 2 This is an internal circuit diagram of the constant current control device according to an embodiment of this application.

[0009] Figure 3 This is a circuit diagram of a specific example of the control system of this application embodiment. Detailed Implementation

[0010] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. The drawing numbers in this application are only used to distinguish the various steps in the solution and are not used to limit the execution order of the various steps. The specific execution order is subject to the description in the specification.

[0011] To address the problems existing in the prior art, this application provides a control system including a constant current control device, a processing unit, and a voltage regulating circuit. A first terminal of the constant current control device is connected to a target load, a second terminal is connected to the processing unit, and a third terminal is connected to the voltage regulating circuit. The constant current control device feeds back the detected output voltage of the target load to the processing unit. The processing unit is connected to the constant current control device and compares the output voltage with a preset voltage threshold to send a control command to the constant current control device instructing it to turn on the constant current source. The constant current control device internally contains a constant current source. Upon receiving the control command, the constant current control device turns on the constant current source and outputs a control current to the voltage regulating circuit. The voltage regulating circuit receives the control current to adjust the input voltage of the target load.

[0012] Combination Figure 1 The control system 100 is applied to the constant current control device 120, which outputs a constant current of the required magnitude to control the brightness and / or color temperature of the target load 110, such as an LED lamp. The control system 100 is also used to adjust the input voltage of the target load 110 to reduce the control losses of the constant current control device 120 and improve control efficiency.

[0013] like Figure 1 As shown, the control system 100 includes a constant current control device 120, a processing unit 140, and a voltage regulating circuit 160. A first terminal of the constant current control device 120 is connected to a target load 110. In one embodiment, the target load includes multiple LED light sources connected in parallel. The constant current control device includes multiple first terminals, each corresponding to one of the LED light sources. The constant current control device is also used to detect the output voltage of the target LED light source at the corresponding first terminal when the target LED light source is lit.

[0014] Combination Figure 3 For example, the target load 110 is an LED lighting fixture, including four LED light sources connected in parallel, each LED light source consisting of LED1 to LED12. One end of each of the four LED light sources is connected to the input voltage Vbus, and the other end is an output port, corresponding to OUTA to OUTD respectively. The input voltage Vbus is initially a preset power supply voltage, used to provide current to the target load 110 to light up the corresponding LED light source.

[0015] The output terminals of the four LED light sources correspond to the four constant current ports of the constant current control device 120, enabling single-channel or multi-channel applications. For a single LED light source, when the input voltage Vbus of the constant current control device 120 is greater than the voltage drop across the corresponding LED chip, for example, in combination with... Figure 3The topmost LED light source includes LED1, LED2, and LED3. When the input voltage Vbus is greater than the sum of the voltage drops of these three LEDs, this LED light source is illuminated. Correspondingly, the voltage detection function of the OUT port of the constant current control device 120, i.e., the ports corresponding to OUTA to OUTD, is enabled. When this LED light source is illuminated, the constant current control device 120 internally detects the actual voltage value of the corresponding output port OUTA, i.e., the output voltage of the corresponding LED light source.

[0016] Similarly, if Figure 3 If multiple LED light sources are lit, the constant current control device 120 will detect the actual output voltage of each LED light source through its corresponding output port.

[0017] Combination Figure 1 The second terminal of the constant current control device 120 is connected to the processing unit 140, and is used to feed back the output voltage of the detected target load 110 to the processing unit 140. The processing unit 140 may include a microprocessor unit (MCU). After receiving the detected output voltage, the processing unit 140 compares whether the output voltage exceeds a preset voltage threshold. The preset voltage threshold is the internal operating voltage of the constant current control device 120 when it generates the required constant current. Ideally, it is the inflection point voltage when generating the corresponding constant current, or a smaller voltage greater than the inflection point voltage within a certain voltage range, and the closer to the inflection point voltage, the better. The inflection point voltage is determined by the chip parameters of the constant current control device 120, and different chips may correspond to different inflection point voltages. When the output voltage of the constant current control device 120 at the corresponding OUT port reaches the inflection point voltage, the constant current control device 120 can be triggered to output the required constant current, and the constant current size does not change with the increase of the output voltage; when the output voltage does not reach the inflection point voltage, the constant current control device 120 cannot output the required constant current.

[0018] If the output voltage is too large compared to the inflection point voltage, it will cause a large amount of power loss in the constant current control device 120. At this time, when the output voltage exceeds the preset voltage threshold, the processing unit 140 sends a control command to the constant current control device 120 to reduce the loss, instructing the constant current control device 120 to output control current to the voltage regulation circuit 160, thereby adjusting the output voltage of the OUT port of the constant current control device 120.

[0019] After receiving a control command from the processing unit 140, the constant current control device 120 turns on its internal constant current source and outputs a control current to the voltage regulation circuit 160 through the constant current source. Correspondingly, the voltage regulation circuit 160 adjusts the input voltage Vbus provided to the target load 110 based on the control current, thereby adjusting the output voltage of the OUT port of the constant current control device 120 to tend towards a preset voltage threshold. Here, the adjustment of the input voltage Vbus includes upward adjustment and downward adjustment. When the output voltage exceeds the preset voltage threshold, the input voltage Vbus of the target load is adjusted downward; when the output voltage does not exceed the preset voltage threshold, the input voltage Vbus of the target load is adjusted upward.

[0020] Optionally, the constant current control device includes a voltage regulator unit. The first terminal of the constant current source is connected to a power supply voltage, and the second terminal of the constant current source is connected to the third terminal of the constant current control device to provide a target current to the third terminal of the constant current control device. The reference terminal of the voltage regulator unit is connected to the third terminal of the constant current control device, the cathode of the voltage regulator unit is connected to the first terminal of the voltage regulating circuit, and the anode of the voltage regulator unit is grounded. The voltage regulator unit conducts based on the target current and outputs the control current to the voltage regulating circuit through the cathode.

[0021] Referring to the accompanying drawings, the constant current control device 120 internally includes a voltage regulator unit 1240, which comprises a reference terminal 1, a cathode terminal 2, and an anode terminal 3'. The reference terminal 1 of the voltage regulator unit 1240 is connected to the third terminal FB of the constant current control device 120, and the third terminal FB provides current to the reference terminal 1 of the voltage regulator unit. The cathode terminal 2 of the voltage regulator unit 1240 is connected to the fourth terminal TL of the constant current control device 120, and the fourth terminal TL is connected to the voltage regulating circuit 160. After current is supplied to the reference terminal 1, the voltage regulator unit 1240 is turned on, connecting the cathode terminal 2 of the voltage regulator unit 1240 to the voltage regulating circuit 160 and providing control current to the voltage regulating circuit 160.

[0022] In one embodiment, the voltage regulator unit 1240 is a controllable precision voltage regulator, including TL431 and TL432 types. The reference terminal 1 of the voltage regulator unit 1240 can provide a relatively stable reference voltage, ensuring the stability of the entire control system 100.

[0023] Combination Figure 2 One end of the constant current source 1220 is connected to the power supply voltage VDD, and the other end of the constant current source is connected to the third terminal FB of the constant current control device 120 to form the target circuit and provide power to the third terminal FB of the constant current control device 120, thereby turning on the voltage regulator unit 1240, so that the voltage regulator unit 1240 outputs control current to the voltage regulation circuit 160 through the cathode terminal 2.

[0024] After the processing unit 140 feeds back a control command to the constant current control device 120, the constant current control device 120 turns on the constant current source 1220. The constant current source 1220 then generates current based on the input power supply voltage VDD and outputs it through the third terminal FB of the constant current control device 120. That is, the constant current source 1220 flows back current to the third terminal FB, causing the voltage regulator unit 1240 to turn on. The cathode 2 of the voltage regulator unit 1240 forms a connection loop with the voltage regulation circuit 160 through the fourth terminal TL, and provides control current to the voltage regulation circuit 160.

[0025] The third terminal FB generates a voltage based on the current output by the constant current source 1220. The processing unit 140 sets the third terminal FB to have an intermediate state voltage. When the third terminal FB is in the intermediate state voltage, an intermediate state current is maintained. The intermediate state voltage is a reference used by the processing unit 140 to control the increase or decrease of the current output by the constant current source 1220. Specifically, if the processing unit 140 finds that the output voltage exceeds a preset voltage threshold, it sends a control command to the constant current control device 120, instructing the constant current control device 120 to output a control current to the voltage regulation circuit 160 that is larger than the intermediate state current. If the processing unit 140 finds that the output voltage does not exceed the preset voltage threshold, it sends a control command to the constant current control device 120, instructing the constant current control device 120 to output a control current to the voltage regulation circuit 160 that is smaller than the intermediate state current.

[0026] The conduction state of the voltage regulator unit 1240 is related to the current value provided by the constant current source 1220. It is fully conducting when the constant current source 1220 provides the maximum current value, and partially conducting when the current provided by the constant current source 1220 is less than the maximum current value. The greater the conduction depth of the voltage regulator unit 1240, the greater the control current output through the two-way voltage regulation circuit 160 at the cathode. By adjusting the current generated by the constant current source 1220, the conduction depth of the voltage regulator unit 1240 can be adjusted accordingly, thereby adjusting the magnitude of the control current output by the two-way voltage regulation circuit 160 at the cathode of the voltage regulator unit 1240.

[0027] Optionally, the constant current control device communicates with the processing unit via a digital interface. The constant current control device is used to convert the output voltage into a digital signal and feed it back to the processing unit through the digital interface. The processing unit is used to send control commands of digital signals to the constant current control device through the digital interface.

[0028] The processing unit 140 is responsible for communicating with the constant current control device 120 via a digital interface. It can send instructions to the constant current control device 120 to implement functions, and it can also report the status information of the constant current control device 120 through the digital interface.

[0029] In the embodiments of this application, such as Figure 3As shown, the constant current control device 120 and the processing unit 140 communicate bidirectionally via a digital interface. After detecting the output voltage, the constant current control device 120 converts the output voltage into a digital signal representing the voltage quantity and feeds it back to the processing unit 140 via the digital interface. When the processing unit 140 determines, based on a comparison of the digital signals, that the input voltage Vbus needs adjustment, it sends a digital signal representing a control command to the constant current control device 120 via the digital interface.

[0030] In one embodiment, the voltage regulation circuit includes a current adjustment unit, a voltage adjustment unit, and a voltage control unit. A first terminal of the current adjustment unit is connected to the input voltage, a second terminal of the current adjustment unit is connected to the voltage adjustment unit, and a third terminal of the current adjustment unit is connected to the reference terminal of the voltage regulator unit. The current adjustment unit receives the target current to adjust the current output to the reference terminal of the voltage regulator unit. A first terminal of the voltage adjustment unit is connected to the cathode of the voltage regulator unit, and a second terminal of the voltage adjustment unit is connected to the voltage control unit. The voltage adjustment unit receives the current output from the cathode of the voltage regulator unit to output a feedback voltage to the voltage control unit. The voltage control unit receives the feedback voltage to adjust the input voltage of the target load.

[0031] Combination Figure 3 The voltage regulation circuit 160 includes a current adjustment unit 1620, a voltage adjustment unit, and a voltage control unit 1660. For example... Figure 3 As shown, the first terminal of the current adjustment unit 1620 is connected to the input voltage Vbus, and the second terminal of the current adjustment unit 1620 is connected to the voltage adjustment unit. The third terminal of the current adjustment unit 1620 is connected to the cathode terminal 2 of the voltage regulator unit 1240 through the fourth terminal TL of the constant current control device 120. The current adjustment unit 1620 is used to adjust the conduction depth of the voltage regulator unit 1240 based on the current output from the third terminal FB of the constant current control device 120, thereby adjusting the control current output from the cathode terminal 2 of the voltage regulator unit 1240 to the voltage adjustment unit.

[0032] The first terminal of the voltage adjustment unit is connected to the cathode 2 of the voltage regulator unit 1240 via the fourth terminal TL of the constant current control device 120. The second terminal of the voltage adjustment unit is connected to the voltage control unit 1660. Based on the control current output from the cathode 2 of the voltage regulator unit, the voltage adjustment unit adjusts the feedback voltage output to the voltage control unit 1660. Based on the feedback voltage, the voltage control unit 1660 adjusts the input voltage Vbus provided to the target load 110.

[0033] Specifically, such as Figure 3As shown in the example, the current adjustment unit 1620 includes a first resistor R53, a second resistor R54, a third resistor R56, and a fourth resistor R62. The first terminal of the first resistor R53 is connected to the input voltage Vbus, and the second terminal of the first resistor R53 is connected to the first terminal of the second resistor R54. The second terminal of the second resistor R54 is connected to the first terminal of the third resistor R56, the first terminal of the fourth resistor R62, and the reference terminal 1 of the voltage regulator unit. The second terminals of the third resistor R56 and the fourth resistor R62 are grounded.

[0034] Combination Figure 3 It can be seen that the third resistor R56 and the fourth resistor R62 are connected in parallel, and the first resistor R53 and the second resistor R54 are connected in series, and then connected in parallel with the third resistor R56 and the fourth resistor R62. Furthermore, these resistors R53, R54, R56, and R62 are used to control the feedback regulation so that the input voltage Vbus is the set voltage value in the initial state. The initial state refers to the unadjusted input voltage. The formula for calculating the initial input voltage Vbus is Vbus=TLref / ((R62 / / R56)) / ((R62 / / R56)+R53+R54)), where TLref represents the reference voltage of the voltage regulator unit 1240.

[0035] In one embodiment, the current adjustment unit further includes a compensation circuit disposed between the first terminal of the voltage adjustment unit and the reference terminal of the voltage regulator unit. The compensation circuit includes a fifth resistor, a first capacitor, and a second capacitor. The first terminal of the fifth resistor is connected to the first terminal of the voltage adjustment unit and the cathode terminal of the voltage regulator unit, respectively. The second terminal of the fifth resistor is connected to the first terminal of the first capacitor. The second terminal of the first capacitor is connected to the third terminal of the constant current control device. The first terminal of the second capacitor is connected to the first terminal of the fifth resistor, and the second terminal of the second capacitor is connected to the second terminal of the first capacitor.

[0036] Specifically, such as Figure 3 As shown in the example, the compensation circuit of the current adjustment unit 1620 includes a fifth resistor R57, a first capacitor C30 and a second capacitor C31, which are disposed between the first terminal of the voltage adjustment unit and the fourth terminal TL of the constant current control device 120, i.e., the reference terminal 1 of the voltage stabilizing unit 1240.

[0037] One end of the fifth resistor R57 is connected to the fourth terminal TL of the constant current control device 120, and the other end of the fifth resistor R57 is connected in series with the first capacitor C30. The other end of the first capacitor C30 is connected to the third terminal FB of the constant current control device 120. The first end of the second capacitor C31 is connected to the first end of the fifth resistor R57, and the second end of the second capacitor C31 is connected to the second end of the first capacitor C30. Thus, the second capacitor C31 is connected in parallel with the series-connected fifth resistor R57 and the first capacitor C30.

[0038] Therefore, the fifth resistor R57, the first capacitor C30, and the second capacitor C31 form a compensation circuit, which is mainly used to compensate for voltage fluctuations, stabilize voltage output, and improve the dynamic response performance of the power supply system.

[0039] In one embodiment, the voltage adjustment unit includes an optocoupler, which includes a light-emitting diode (LED) and a phototransistor. The first terminal of the LED is connected to the input voltage, and the second terminal of the LED is connected to the cathode of the voltage regulator unit. The first terminal of the phototransistor is connected to the voltage control unit, and the second terminal of the phototransistor is grounded. The current adjustment unit further includes a sixth resistor disposed between the first and second terminals of the LED.

[0040] Combination Figure 3 The voltage adjustment unit includes an optocoupler U1. The optocoupler U1 includes a light-emitting diode (LED) and a phototransistor. The LED has a first terminal 11 and a second terminal 22. The first terminal 11 of the LED is connected to the input voltage Vbus, and the second terminal 22 is connected to the cathode 2 of the voltage regulator unit via a fourth terminal TL. The phototransistor has a first terminal 4 and a second terminal 3. The first terminal 4 of the phototransistor is connected to the voltage control unit 1660, and the second terminal 3 of the phototransistor is grounded to GND.

[0041] The first terminal 11 and the second terminal 22 of the light-emitting diode (LED) control the light intensity by controlling the magnitude of the current flowing through it, thereby controlling the switching characteristics of the phototransistor. The greater the current flowing through the LED, the greater the light intensity. The greater the light intensity, the greater the conduction depth of the phototransistor, bringing it closer to full conduction. Full conduction of the phototransistor is equivalent to a straight-line short circuit, where the voltage at the first terminal 4 is close to the ground voltage GND connected to the second terminal 3. Therefore, the greater the conduction depth of the phototransistor, the smaller the feedback voltage provided by the voltage adjustment unit to the voltage control unit 1660.

[0042] Conversely, the smaller the current flowing through the LED, the lower the light intensity. The lower the light intensity, the shallower the conduction depth of the phototransistor, bringing it closer to non-conductivity. A non-conducting phototransistor is equivalent to an open circuit, resulting in a larger voltage drop between terminal 4 and terminal 3. Therefore, the shallower the conduction depth of the phototransistor, the greater the compensation feedback voltage provided by the voltage adjustment unit to the voltage control unit 1660.

[0043] In one embodiment, when the output voltage exceeds the preset voltage threshold, the control current output by the constant current control device 120 increases, and the current adjustment unit 1620 adjusts the current output to the voltage adjustment unit to increase; when the current output by the voltage adjustment unit increases, the voltage adjustment unit adjusts the feedback voltage output to the voltage control unit 1660 to decrease; when the feedback voltage decreases, the voltage control unit 1660 adjusts the input voltage Vbus to decrease, so as to pull down the output voltage Vbus to approach the preset voltage threshold.

[0044] When the feedback voltage provided by the voltage adjustment unit to the voltage control unit 1660 decreases, the voltage control unit 1660 can control the input voltage Vbus to adjust downwards and approach the preset voltage threshold of the constant current control device 120. Thus, when the voltage at the input terminal of the constant current control device 120 approaches the preset voltage threshold, the corresponding voltage difference is small, thereby significantly reducing the voltage drop loss generated by the constant current control device and improving its control efficiency. Furthermore, input voltage control through the internal algorithm of the processing unit 140 has the advantages of low cost and high precision.

[0045] In another embodiment, when the output voltage does not exceed the preset voltage threshold, the control current output by the constant current control device 120 decreases, and the current adjustment unit 1620 adjusts the current output to the voltage adjustment unit to decrease; when the current output by the voltage adjustment unit decreases, the voltage adjustment unit adjusts the feedback voltage output to the voltage control unit 1660 to increase; when the feedback voltage increases, the voltage control unit 1660 adjusts the input voltage to increase, so as to pull the output voltage upward to approach the preset voltage threshold.

[0046] When the feedback voltage provided by the voltage adjustment unit to the voltage control unit 1660 increases, the voltage control unit 1660 can control the input voltage Vbus to adjust upwards and approach the preset voltage threshold of the constant current control device 120. Thus, when the voltage at the input terminal of the constant current control device 120 approaches the preset voltage threshold, the corresponding voltage difference is small, thereby significantly reducing the voltage drop loss generated by the constant current control device and improving its control efficiency. Furthermore, input voltage control through the internal algorithm of the processing unit 140 has the advantages of low cost and high precision.

[0047] like Figure 3 As shown, optionally, the sixth resistor R58 is disposed between the first terminal 11 and the second terminal 22 of the light-emitting diode. The function of the sixth resistor R58 is to limit current and supplement power. When there is no current in the photodiode, current can be generated by connecting the sixth resistor R58 to the input voltage Vbus, and the current is shunted to the photodiode. At the same time, the current is shunted to the voltage regulator unit 1240 through the fourth terminal TL of the constant current control device 120.

[0048] In one embodiment, the current adjustment unit 1620 further includes a Zener diode ZD1, the first end of which is connected to the first end 11 of the light-emitting diode, and the second end of which is connected to the input voltage Vbus.

[0049] The function of Zener diode ZD1 is to protect the voltage regulator unit 1240 in the constant current control device 120, so that the voltage division does not exceed the voltage of the cathode terminal 2 of the voltage regulator unit 1240, thereby preventing the voltage regulator unit 1240 from being over-voltaged and broken down.

[0050] In one embodiment, the current adjustment unit 1620 further includes a current limiting resistor R59, disposed between the second terminal of the Zener diode ZD1 and the input voltage Vbus.

[0051] The current-limiting resistor R59 is used to provide appropriate current to the Zener diode ZD1 and the optocoupler U1 so that they are in the corresponding operating state.

[0052] The voltage control unit 1660 can determine whether to adjust the current input voltage Vbus upward or downward based on the feedback voltage of the optocoupler U1, and send the adjusted PWM pulse signal by adjusting the duty cycle of the PWM pulse signal to control the current input voltage Vbus.

[0053] Optionally, the voltage control unit 1660 includes an AC-DC converter, and a current-following circuit is connected between the input terminal of the AC-DC converter and the power supply voltage. The current-following circuit includes a passive power factor correction circuit (PPFC).

[0054] The voltage control unit 1660 includes an AC-DC converter and a DC-DC converter. The AC-DC converter is used to filter and rectify the AC input to obtain DC power, while the DC-DC converter is used to convert the DC power to a voltage value. Based on the feedback voltage output from the voltage adjustment unit, the voltage control unit 1660 adjusts the output PWM pulse signal, and combines the PWM pulse signal to adjust the input voltage Vbus before supplying it to the target load 110.

[0055] In this embodiment, the multiple OUT ports of the constant current control device 120 are MOSFET transistors, which are used in the linear constant current region. At the AC-DC converter end of the voltage control unit 1660, it can be used with a high power factor current-gradient circuit, such as a PPFC passive power factor correction circuit, to achieve high-performance, low-cost, and high-efficiency applications with extremely high cost performance.

[0056] In summary, the working principle of the control system 100 in this embodiment is as follows: When the input voltage Vbus of the constant current control device 120 is greater than the voltage of the target LED light source, causing the target LED light source to start lighting up, the voltage detection function of the OUT port of the constant current control device 120 is activated, automatically detecting the actual output voltage value of the corresponding OUT port at this time, and feeding it back to the processing unit 140 for processing. The processing unit 140 has a preset voltage threshold. The significance of the preset voltage threshold is that it is the condition for the constant current control device 120 to enter the optimal working state of constant current, and it is also the inflection point voltage with low control loss and relatively optimal control efficiency.

[0057] Processing unit 140 compares and determines whether the actual output voltage value of the OUT port is greater than or exceeds a preset voltage threshold. If so, it sends a control command to constant current control device 120. Constant current control device 120 injects current into its third terminal FB through its internal constant current source 1220, increasing the current at the third terminal TL. This, in turn, increases the current flowing through the light-emitting diode in optocoupler U1, increasing the conduction depth of the first terminal 4 and the second terminal 3 of the phototransistor in optocoupler U1. This further reduces the feedback voltage output by optocoupler U1, causing the AC-DC controller of voltage control unit 1660 to adjust the output voltage Vbus. Ultimately, this reduces the input voltage Vbus until it approaches the preset voltage threshold.

[0058] Correspondingly, the processing unit 140 compares and determines that the actual output voltage value of the OUT port is not greater than or does not exceed the preset voltage threshold. If so, it sends a control command to the constant current control device 120. The constant current control device 120 injects current into its third terminal FB through its internal constant current source 1220, thereby reducing the current at the third terminal TL of the constant current control device 120. This reduces the current flowing through the light-emitting diode in the optocoupler U1, thereby reducing the conduction depth of the first terminal 4 and the second terminal 3 of the phototransistor in the optocoupler U1. This further increases the feedback voltage output by the optocoupler U1, which in turn causes the AC-DC controller of the voltage control unit 1660 to adjust the output voltage Vbus. Ultimately, this causes the input voltage Vbus to rise until it approaches the preset voltage threshold.

[0059] In this way, detection and control can be carried out in a simple and effective manner, thereby reducing the control loss of the constant current control device 120 and improving the control efficiency.

[0060] In this embodiment, the control system includes a constant current control device, a processing unit, and a voltage regulating circuit. A first terminal of the constant current control device is connected to the target load, a second terminal is connected to the processing unit, and a third terminal is connected to the voltage regulating circuit. The constant current control device feeds back the detected output voltage of the target load to the processing unit. The processing unit is connected to the constant current control device and compares the output voltage with a preset voltage threshold to send a control command to the constant current control device instructing it to turn on the constant current source. The constant current control device internally... A constant current source is provided. The constant current control device receives the control command to turn on the constant current source and outputs a control current to the voltage regulation circuit. The voltage regulation circuit receives the control current to adjust the input voltage of the target load. Thus, the voltage value can be detected by the constant current control device, and the external input voltage of the target load can be adjusted by the internal algorithm of the processing unit combined with a simple current source circuit. This adjusts the voltage at the input terminal of the constant current control device to tend towards a preset voltage threshold, achieving low-cost and high-precision effective voltage control, significantly reducing the voltage drop loss generated by the constant current control device, and improving the control efficiency of the constant current control device.

[0061] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A control system, characterized by, Includes a constant current control device, a processing unit, and a voltage regulation circuit. The first terminal of the constant current control device is connected to the target load, the second terminal of the constant current control device is connected to the processing unit, and the third terminal of the constant current control device is connected to the voltage regulating circuit. The constant current control device feeds back the detected output voltage of the target load to the processing unit. The processing unit is connected to the constant current control device, and the processing unit compares the output voltage with a preset voltage threshold to send a control command to the constant current control device to instruct the constant current source to be turned on. The constant current control device has a constant current source inside. The constant current control device receives the control command to turn on the constant current source and outputs control current to the voltage regulating circuit. The voltage regulating circuit receives the control current to adjust the input voltage of the target load.

2. The control system of claim 1, wherein, The constant current control device is equipped with a voltage stabilizing unit. The first terminal of the constant current source is connected to the power supply voltage, and the second terminal of the constant current source is connected to the third terminal of the constant current control device to provide the target current to the third terminal of the constant current control device; The reference terminal of the voltage regulator unit is connected to the third terminal of the constant current control device, the cathode terminal of the voltage regulator unit is connected to the first terminal of the voltage regulating circuit, the anode terminal of the voltage regulator unit is grounded, and the voltage regulator unit is turned on based on the target current and outputs the control current to the voltage regulating circuit through the cathode terminal.

3. The control system according to claim 2, characterized in that, The voltage regulation circuit includes a current adjustment unit, a voltage adjustment unit, and a voltage control unit. The first terminal of the current adjustment unit is connected to the input voltage, the second terminal of the current adjustment unit is connected to the voltage adjustment unit, and the third terminal of the current adjustment unit is connected to the reference terminal of the voltage regulator unit. The current adjustment unit receives the target current to adjust the current output to the reference terminal of the voltage regulator unit. The first terminal of the voltage adjustment unit is connected to the cathode terminal of the voltage regulator unit, and the second terminal of the voltage adjustment unit is connected to the voltage control unit. The voltage adjustment unit receives the control current output from the cathode terminal of the voltage regulator unit to output a feedback voltage to the voltage control unit. The voltage control unit receives the feedback voltage to adjust the input voltage of the target load.

4. The control system of claim 3, wherein, The current adjustment unit includes a first resistor, a second resistor, a third resistor, and a fourth resistor. The first end of the first resistor is connected to the input voltage, and the second end of the first resistor is connected to the first end of the second resistor; The second end of the second resistor is connected to the first end of the third resistor, the first end of the fourth resistor, and the reference end of the voltage regulator unit, respectively. The second terminals of the third resistor and the fourth resistor are respectively grounded.

5. The control system of claim 4, wherein, The current adjustment unit further includes a compensation circuit, which is disposed between the first terminal of the voltage adjustment unit and the reference terminal of the voltage regulation unit. The compensation circuit includes a fifth resistor, a first capacitor, and a second capacitor. The first end of the fifth resistor is connected to the first end of the voltage adjustment unit and the cathode end of the voltage stabilizing unit, respectively, and the second end of the fifth resistor is connected to the first end of the first capacitor; The second terminal of the first capacitor is connected to the third terminal of the constant current control device; The first terminal of the second capacitor is connected to the first terminal of the fifth resistor, and the second terminal of the second capacitor is connected to the second terminal of the first capacitor.

6. The control system of claim 4, wherein, The voltage adjustment unit includes an optocoupler, which comprises a light-emitting diode and a phototransistor. The first terminal of the light-emitting diode is connected to the input voltage, and the second terminal of the light-emitting diode is connected to the cathode terminal of the voltage regulator unit; The first terminal of the phototransistor is connected to the voltage control unit, and the second terminal of the phototransistor is grounded. The current adjustment unit also includes a sixth resistor, which is disposed between the first and second ends of the light-emitting diode.

7. The control system of claim 6, wherein, The current adjustment unit further includes: A Zener diode, the first end of which is connected to the first end of the light-emitting diode, and the second end of which is connected to the input voltage.

8. The control system of claim 7, wherein, The current adjustment unit further includes: A current-limiting resistor is placed between the second terminal of the Zener diode and the input voltage.

9. The control system of claim 1, wherein, The target load comprises multiple LED light sources connected in parallel, and the constant current control device comprises multiple first terminals, each corresponding to one of the LED light sources. The constant current control device is also used to detect the output voltage of the target LED light source at the corresponding first terminal when the target LED light source is lit.

10. The control system of claim 3, wherein, The voltage control unit includes an AC-DC converter, and a current-following circuit is connected between the input terminal of the AC-DC converter and the power supply voltage. The current-following circuit includes a passive power factor correction circuit (PPFC).

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