High-PF (power factor) stroboflash-free multi-section linear constant-current LED (light-emitting diode) driving circuit

Abstract

The utility model discloses a high PF stroboflash-free multi-segment linear constant current LED drive circuit, which comprises a rectification filter circuit, a segmentation control circuit and a stroboflash-removing circuit, and is characterized in that the rectification filter circuit is electrically connected with an AC power supply, and the rectification filter circuit is used for carrying out rectification and filtering processing on AC and outputting DC to the segmentation control circuit; the segmentation control circuit is electrically connected with the rectification circuit, and the segmentation control circuit is used for carrying out segmentation control on the current of the LED; the stroboscopic removing circuit is electrically connected with the rectification filter circuit, and the stroboscopic removing circuit is used for eliminating current ripples on the LED driver. According to the LED driving circuit, a specific chip and a multi-section linear constant-current driving technology are adopted, a high PF value and ultra-low THD are achieved, the requirements for the power factor and total harmonic distortion of the LED driving circuit are met, and the electric energy utilization efficiency and the current quality are improved.

Description

Technical Field

[0001] This invention relates to the field of LED technology, and in particular to a high PF flicker-free multi-segment linear constant current LED driving circuit. Background Technology

[0002] Existing single-segment and multi-segment linear constant current drivers are mainly used for high-voltage applications powered by mains electricity, maintaining a constant output current with a linear relationship between the output current and input voltage. In LED lighting fixtures, linear constant current driving is one of the commonly used driving methods. LEDs are current-sensitive devices; their luminous intensity and lifespan are closely related to the current flowing through them. Linear constant current driving ensures that LED chips operate under a stable current, thereby guaranteeing the stability and consistency of light emission.

[0003] Existing multi-segment linear constant current drive circuits, such as Figure 1 As shown, this includes a high-precision piecewise linear constant current LED control chip, integrating a high-voltage rectifier diode and a JFET (Junction Field-Effect Transistor) high-voltage power supply. It is primarily used to drive high-voltage, low-current LED strings powered by AC mains. This circuit eliminates the need for electrolytic capacitors and magnetic components, allowing for a small size and long lifespan for the LED driver. By precisely setting the LED current through an external resistor, the chip optimizes the current during segmented conduction, which helps reduce THD. It also integrates input line voltage compensation; when the input line voltage is too high, the output current is reduced according to the external compensation resistor, ensuring that the input power remains essentially unchanged with the line voltage. However, existing driver circuits exhibit flickering without electrolytic capacitors, which is unsuitable for demanding applications. With electrolytic capacitors, the power factor (PF) value is lowered, failing to meet national standards. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing LED driver circuits, which flicker when there is no electrolytic capacitor, making them unsuitable for high-requirement application scenarios, and the fact that the power factor (PF) value is lowered when there is an electrolytic capacitor, failing to meet national standards. This invention provides a high PF flicker-free multi-segment linear constant current LED driver circuit.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A high-PF flicker-free multi-segment linear constant current LED driver circuit includes a rectifier and filter circuit, a segmented control circuit, and a frequency-reducing lightning circuit. The rectifier and filter circuit is electrically connected to an AC power supply and is used to rectify and filter the AC power, outputting DC power to the segmented control circuit. The segmented control circuit is electrically connected to the rectifier circuit and is used to control the LED current in segments. The frequency-reducing lightning circuit is electrically connected to the rectifier and filter circuit and is used to eliminate current ripple on the LED driver.

[0007] Preferably, the segmented control circuit includes a driver chip U1 and an auxiliary control chip U2, which are electrically connected. The driver chip U1 is an ultra-high voltage linear input-output constant power LED driver chip used to drive high-voltage, low-current LED loads. The auxiliary chip U2 works in conjunction with the driver chip U1 to regulate the output current.

[0008] Preferably, the VIN pin of the driver chip U1 is connected to the rectifier filter circuit, the CS pin of the driver chip U1 is connected to one end of the resistor RS1, and the other end of the resistor RS1 is grounded; the SPC1 pin of the driver chip U1 is connected to the GA pin of the auxiliary control chip U2, the SPC2 pin of the driver chip U1 is connected to the GB pin of the auxiliary control chip U2, the VD pin of the auxiliary control chip U2 is connected to the positive terminal of the LED load, the VDD pin of the auxiliary control chip U2 is connected to the negative terminal of the LED load, and the DR pin of the driver chip is connected to the negative terminal of the LED.

[0009] Preferably, the flicker-free circuit includes several flicker-free chips, each chip being matched with a single LED load; the GND terminal of the flicker-free chip is connected to one end of resistor RV3, and the other end of resistor RV3 is grounded; the VC terminal of the flicker-free chip is connected to one end of capacitor C1a, the other end of capacitor C1a is connected to the positive terminal of the LED load, and the LED terminal of the flicker-free chip is connected to the negative terminal of the LED load.

[0010] Preferably, the output current is a peak current of 5mA to 280mA.

[0011] Preferably, the driver chip U1 is externally equipped with a resistor network to set the input constant power, and the input constant power is achieved by real-time monitoring of the network voltage.

[0012] Preferably, the turn-off temperature of the driver chip U1 is 160°C. If the internal junction temperature of the driver chip U1 exceeds 160°C, the resistor RS1 is set to short-circuit to trigger OTP protection, and the driver chip U1 shuts down the output.

[0013] The beneficial effects of this invention are: by using a specific chip and multi-segment linear constant current driving technology, this invention achieves a high PF value and ultra-low THD, meets the requirements for power factor and total harmonic distortion of LED driving circuits, and improves power utilization efficiency and current quality. Attached Figure Description

[0014] Figure 1 This is a diagram of a multi-segment linear constant current drive circuit in the prior art;

[0015] Figure 2 This is a circuit diagram of the present invention; Detailed Implementation

[0016] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art.

[0017] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0018] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0019] Example:

[0020] A high-PF flicker-free multi-segment linear constant current LED driver circuit, such as Figure 2 As shown, the device includes a rectifier and filter circuit, a segmented control circuit, and a frequency-reducing lightning circuit. The rectifier and filter circuit is electrically connected to the AC power supply and is used to rectify and filter the AC power, outputting DC power to the segmented control circuit. The segmented control circuit is electrically connected to the rectifier circuit and is used to control the LED current in segments. The frequency-reducing lightning circuit is electrically connected to the rectifier and filter circuit and is used to eliminate current ripples on the LED driver.

[0021] The segmented control circuit includes a driver chip U1 and an auxiliary control chip U2. The driver chip U1 and the auxiliary chip U2 are electrically connected. The driver chip U1 is an ultra-high voltage linear input-output constant power LED driver chip used to drive high voltage and low current LED loads. The auxiliary chip U2 works in conjunction with the driver chip U1 to adjust the output current, which is a peak current of 5mA to 280mA.

[0022] The VIN pin of the driver chip U1 is connected to the rectifier and filter circuit, the CS pin of the driver chip U1 is connected to one end of the resistor RS1, and the other end of the resistor RS1 is grounded; the SPC1 pin of the driver chip U1 is connected to the GA pin of the auxiliary control chip U2, the SPC2 pin of the driver chip U1 is connected to the GB pin of the auxiliary control chip U2, the VD pin of the auxiliary control chip U2 is connected to the positive terminal of the LED load, the VDD pin of the auxiliary control chip U2 is connected to the negative terminal of the LED load, and the DR pin of the driver chip is connected to the negative terminal of the LED.

[0023] The linear drive method of driver chip U1 eliminates the need for magnetic components, effectively avoiding EMI interference. Its closed-loop control achieves constant output current control, with excellent line regulation and load regulation, ensuring a constant average output current within a certain input voltage range. Driver chip U1 also integrates real-time monitoring of the grid voltage, achieving constant input power.

[0024] This embodiment employs a multi-segment linear constant current drive technology with an integrated analog multiplier to achieve a high power factor (PF) and ultra-low total current (THD). The LED chip is connected in series with the rectified power supply, forming a current loop. The output current is set by RS1. When the rectified voltage is sufficiently higher than the LED load voltage, the instantaneous output current follows the AC voltage, and the average current remains constant. The portion of the rectified voltage exceeding the LED load voltage is absorbed by the IC. The IC's maximum input voltage can reach 420V, satisfying most AC input applications.

[0025] The aforementioned flicker-free circuit includes three flicker-free chips, each matched with a single LED load. The GND terminal of the flicker-free chip is connected to one end of resistor RV3, and the other end of resistor RV3 is grounded. The VC terminal of the flicker-free chip is connected to one end of capacitor C1a, and the other end of capacitor C1a is connected to the positive terminal of the LED load. The LED terminal of the flicker-free chip is connected to the negative terminal of the LED load.

[0026] In this embodiment, pin DR1 of driver chip U1 is connected to flicker-reducing chip U3, pin DR2 of driver chip U1 is connected to flicker-reducing chip U5, and pin DR3 of driver chip U1 is connected to flicker-reducing chip U7. Flicker-reducing chips U3, U5, and U7 are used to drive LED strings and eliminate the 100-120Hz current ripple on the constant current AC / DC LED driver. They exhibit good ripple removal performance across the entire output current range and excellent system dynamic response speed during rapid dimming.

[0027] The driver chip U1 is externally configured with a resistor network to set a constant input power, and the constant input power is achieved by real-time monitoring of the network voltage.

[0028] The turn-off temperature of the driver chip U1 is 160°C. If the internal junction temperature of the driver chip U1 exceeds 160°C, the resistor RS1 will short-circuit and trigger the OTP protection, and the driver chip U1 will shut down the output.

[0029] Low-frequency closed-loop current control technology is introduced, eliminating the need for a COMP capacitor. The average output current is set by the CS pin of the driver chip U1 and resistor RS1. An external resistor network is used to set the input constant power, and the network voltage is monitored in real time to achieve the effect of constant input power. When some LEDs are short-circuited, the voltage across U1 will increase, leading to increased power consumption and a rise in the temperature of the driver chip U1. If the internal junction temperature of the driver chip U1 remains below 145°C, the output current will remain constant. In the worst case, if the positive and negative terminals of the LED load are short-circuited, all input voltage will be borne by U1, and the internal junction temperature of the driver chip U1 will rise sharply to 160°C. The driver chip U1 will shut down the output. LED short-circuit protection is achieved through temperature-induced current decay. A short circuit in the RS1 setting resistor triggers OTP protection, turning off the power transistor; an open circuit in RS1 breaks the current loop, and there is no current in the power transistor.

[0030] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the embodiments disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein.

[0031] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A high-PF flicker-free multi-segment linear constant current LED driver circuit, characterized in that, The rectification filter circuit is electrically connected with an alternating current power supply, and is used for rectifying and filtering alternating current and outputting direct current to the segmented control circuit; the segmented control circuit is electrically connected with the rectification circuit, and is used for segmenting control of the current of the LED; and the anti-flicker circuit is electrically connected with the rectification filter circuit, and is used for eliminating the current ripples on the LED driver.

2. The high PF no-flickering multi-section linear constant current LED driving circuit according to claim 1, characterized in that, The segmented control circuit comprises a driving chip U1 and an auxiliary control chip U2, the driving chip U1 and the auxiliary chip U2 are electrically connected, the driving chip U1 is a super-high-voltage linear input-output constant-power LED driving chip, and is used for driving a high-voltage small-current LED load; and the auxiliary chip U2 is used for cooperating with the driving chip U1 to adjust the output current.

3. The high PF no-flickering multi-segment linear constant current LED driving circuit according to claim 2, characterized in that, The VIN pin of the driving chip U1 is connected with the rectification filter circuit, the CS pin of the driving chip U1 is connected with one end of a resistor RS1, and the other end of the resistor RS1 is grounded; the SPC1 pin of the driving chip U1 is connected with the GA pin of the auxiliary control chip U2, the SPC2 pin of the driving chip U1 is connected with the GB pin of the auxiliary control chip U2, the VD pin of the auxiliary control chip U2 is connected with the positive pole of the LED load, the VDD pin of the auxiliary control chip U2 is connected with the negative pole of the LED load, and the DR pin of the driving chip is connected with the negative pole of the LED.

4. The high PF no-flickering multi-segment linear constant current LED driving circuit according to claim 3, characterized in that, The anti-flicker circuit comprises a plurality of anti-flicker chips, a single anti-flicker chip is matched with a single LED load; the GND end of the anti-flicker chip is connected with one end of a resistor RV3, and the other end of the resistor RV3 is grounded; the VC end of the anti-flicker chip is connected with one end of a capacitor C1a, the other end of the capacitor C1a is connected with the positive pole of the LED load, and the LED end of the anti-flicker chip is connected with the negative pole of the LED load.

5. The high PF no-flickering multi-segment linear constant current LED driving circuit according to claim 2, characterized in that, The output current is a peak current of 5mA to 280mA.

6. The high PF no-flickering multi-segment linear constant current LED driving circuit according to claim 3, characterized in that, The driving chip U1 is externally provided with a resistor network for setting input constant power, and realizes input constant power by real-time monitoring of line network voltage.

7. The high PF stroboscopic-free multi-segment linear constant current LED driving circuit according to claim 6, characterized in that, The turn-off temperature of the driving chip U1 is 160℃, if the internal junction temperature of the driving chip U1 exceeds 160℃, the resistor RS1 sets a resistor short circuit to trigger OTP protection, and the driving chip U1 is closed.

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