CN203225926U - LED lamp having self-adaptive drive circuit and self-adaptive drive circuit - Google Patents

Abstract

The utility model relates to the technical field related to LED (Light Emitting Diode), and especially relates to an LED lamp having a self-adaptive drive circuit and the self-adaptive drive circuit. The LED lamp comprises a plurality of LED lamp strings connected in series, and the each LED lamp string comprises at least one LED lamp bead connected in series. The self-adaptive drive circuit comprises a rectification unit, a current-limiting unit, a voltage detection and conduction control unit, and at least one controllable switch unit. The LED lamp having the self-adaptive drive circuit and the self-adaptive drive circuit provided by the utility model enable the LED to operate normally with an extremely simple drive mode, thereby removing a complicated constant-current drive circuit and an electrolytic capacitor having the limited service life, and simultaneously eliminating stroboflash, raising power factor, reducing harmonic distortion, eliminating electromagnetic interference, and reducing cost.

Description

A kind of LED lamp with self-adaptive driving circuit and self-adaptive driving circuit

technical field

The utility model relates to the LED related technical field, in particular to an LED lamp with an adaptive driving circuit and the adaptive driving circuit.

Background technique

LED has significant advantages such as high light efficiency, long life, solid light source, and no heavy metal elements that pollute the environment. It is a new generation of light source.

The Chinese name of LED is "light-emitting diode". Its electrical characteristics are similar to those of diodes. It is a constant voltage device and is very sensitive to the applied operating voltage. In order to work normally, the driving power supply with current effect is required to work normally. Generally, a dedicated LED power supply is used to convert the input mains power into a DC power with a constant output current to drive the LED to work stably.

LED drive power generally adopts flyback, LLC and other AC to DC circuits, which are composed of input filtering, rectification, constant current and control circuits, MOS tubes, transformers, output rectification and filtering, etc. There are many components, complex circuits, and difficult design. The cost is relatively high, and the cost price of a good-quality LED driving power supply is about 1.5 to 3 yuan/W. Due to the large number of circuit components, especially those with limited lifespan such as electrolytic capacitors, the lifespan of the driving power supply is limited, which limits the overall lifespan of the LED lamp, and the power supply often fails when the LED lamp bead has not reached its service life. , failed to give full play to the advantages of long life of LED. In addition, because the circuit works in a high-frequency switching state, electromagnetic interference will inevitably be generated, which will pollute the power grid and have a negative impact on the surrounding radio equipment. Therefore, the EMC design of the drive power supply is also a major problem that plagues engineers in the design process.

Recently, a kind of AC LED lamp without driving power has appeared on the market. The method is to use AC LED lamp beads (or ordinary lamp beads connected in reverse) to directly connect to the mains through resistor current limiting. The advantage of this method is that No driving power is needed, the cost is low, and the life is not limited by the power supply. However, this method often uses many LED lamp beads in series and then connected to the mains, so that the total voltage drop of the LED lamps is close to the effective value of the mains, which leads to a fatal The disadvantage is that the stroboscopic is more severe, and the power factor is low, and the pollution of harmonics to the power grid is relatively large.

Another patent "LED working mode control device [Publication (Announcement) No. 202503745U]" also proposes a LED driving method in which LEDs are connected to the power supply in segments to adapt to fluctuations in power supply voltage (such as after the mains has been rectified). Use the controllable switch to short-circuit the LED module to connect fewer LEDs when the power supply voltage is low, and open the controllable switch to connect more LEDs when the power supply voltage is high, so that the LED can adapt to the fluctuation of the power supply voltage. In this way, the controllable switches are all connected in series in the LED path. Because the controllable switches have a certain saturation voltage drop or on-resistance, they will consume some power. When the input voltage is lower, the more controllable switches are connected in series. At this time, the resistance of the controllable switch is also larger, and the power consumption is also higher, which will greatly reduce the efficiency of the circuit. At the same time, the voltage detection and switch control parts proposed in this patent are independent, and many components and complex circuits are used.

Utility model content

Based on this, it is necessary to provide a high-efficiency LED lamp with an adaptive drive circuit and an adaptive Drive circuit.

An LED lamp with an adaptive drive circuit, the LED lamp includes a plurality of LED lamp strings connected in series, and each LED lamp string includes a plurality of LED lamp beads connected in series, and the adaptive drive circuit includes: a rectification unit, A current limiting unit, a voltage detection and conduction control unit, and multiple controllable switching units;

The rectification unit is used to convert the AC voltage input by the AC power supply into a rectified driving voltage;

The voltage detection and conduction control unit is used to detect the comparison result of the driving voltage and multiple reference voltages to control the on-off of multiple controllable switch units, each reference voltage is associated with a controllable switch unit, and controls all The controllable switch unit whose associated reference voltage is higher than the driving voltage is turned off, and at least one controllable switch unit whose associated reference voltage is lower than the driving voltage is controlled to be connected;

The controllable switch unit is used to control the on-off of the LED light string connected in series to the negative terminal of the power supply of the rectifier unit;

The current limiting unit is configured to limit or constant the driving voltage and input it to the first LED light string of the plurality of LED light strings connected in series.

Further, the voltage detection and conduction control unit further includes a plurality of reference voltage dividing resistors and voltage stabilizing sources, and the reference voltage dividing resistors divide the voltage output by the stabilizing sources to obtain a plurality of the above reference voltage.

Further, the input end of the rectification unit is connected to an AC voltage, the output end is connected to the input end of the voltage detection and conduction control unit, the connection point of each LED light string is grounded through a controllable switch unit, and the rectification unit The output end of the unit is connected to the first LED light string of the plurality of series-connected LED light strings through the current limiting unit, and the output end of the voltage detection and conduction control unit is connected to the control end of the controllable switch unit .

Further, the voltage detection and conduction control unit includes a plurality of comparators connected to the controllable switch unit, and the comparators are used to control the controllable switches connected to the comparators according to the comparison results of the driving voltage and a plurality of reference voltages. Control the on-off of the switch unit.

Further, the voltage detection and conduction control unit includes a single-chip microcomputer, the analog-to-digital converter of the single-chip microcomputer is connected to the output terminal of the rectification unit, detects the comparison result between the driving voltage and multiple reference voltages in real time, and controls the The on-off of the controllable switch unit connected to the output port of the single-chip microcomputer is described.

An adaptive drive circuit for an LED lamp, used to supply power to the LED lamp, the LED lamp includes a plurality of LED lamp strings connected in series, and each LED lamp string includes at least one LED lamp bead connected in series, including: a rectification unit , a current limiting unit, a voltage detection and conduction control unit, and multiple controllable switch units;

The rectification unit is used to convert the AC voltage input by the AC power supply into a rectified driving voltage;

The voltage detection and conduction control unit is used to control the on-off of the plurality of controllable switch units according to the change of the driving voltage, each reference voltage is associated with a controllable switch unit, and the associated reference voltage is controlled to be higher than The controllable switch unit of the driving voltage is disconnected, and at least one controllable switch unit whose associated reference voltage is lower than the driving voltage is controlled to be connected;

The controllable switch unit is used to control the on-off of the LED light string connected in series to the negative terminal of the power supply of the rectifier unit;

The current limiting unit is used to limit or constant the driving voltage and input the first LED light string of the plurality of LED light strings connected in series;

The positive terminal of the power supply of the rectifying unit is respectively connected to the input terminals of the voltage detection and conduction control unit and the current limiting unit, and the output terminal of the voltage detection and conduction control unit is connected to the control terminals of a plurality of controllable switch units. connected, the output end of the current limiting unit is connected to the first LED light string of the plurality of series-connected LED light strings, and the plurality of series-connected LED light strings are respectively connected to the negative terminal of the power supply of the rectifier unit through a controllable switch unit .

Further, the voltage detection and conduction control unit further includes a plurality of reference voltage dividing resistors and voltage stabilizing sources, and the reference voltage dividing resistors divide the voltage output by the stabilizing sources to obtain a plurality of the above reference voltage.

Further, the input end of the rectification unit is connected to an AC voltage, the output end is connected to the input end of the voltage detection and conduction control unit, one end of each controllable switch unit is grounded, and the other end is used to connect with each two The connection points of adjacent LED light strings are connected, the output end of the rectification unit is connected to the first LED light string of the plurality of series connected LED light strings through a current limiting unit, and the voltage detection and conduction control unit The output terminal of is connected with the control terminal of the controllable switch unit.

Further, the voltage detection and conduction control unit includes a plurality of comparators connected to the controllable switch unit, and the comparators are used to control the controllable switches connected to the comparators according to the comparison results of the driving voltage and a plurality of reference voltages. Control the on-off of the switch unit.

Further, the voltage detection and conduction control unit includes a single-chip microcomputer, the analog-to-digital converter of the single-chip microcomputer is connected to the positive power supply terminal of the rectifier unit, the voltage detection and conduction control unit includes a single-chip microcomputer, and the analog-digital converter of the single-chip microcomputer The converter is connected to the positive power supply terminal of the rectifier unit, the output port of the single-chip microcomputer is connected to the controllable switch unit, and the comparison result between the driving voltage and multiple reference voltages is detected in real time, and the controllable switch connected to the output port of the single-chip microcomputer is controlled. On-off of the switch unit.

The LED lamp with self-adaptive driving circuit and self-adaptive driving circuit of the utility model make the LED lamp beads connected in series automatically adapt to the change of driving voltage by controlling the number of LEDs that are turned on. When the driving voltage is low, there are few LEDs that are turned on. , When the driving voltage is high, the number of LEDs turned on is large, so that the total voltage drop of the LED follows the change of the driving voltage. After a simple control circuit and a current limiting or constant current circuit, it can be connected to the mains, with a very simple driving method To make the LED work normally, the complex constant current drive circuit and the electrolytic capacitor with limited life are eliminated, and at the same time, the strobe is eliminated, the power factor is improved, the harmonic distortion is reduced, the electromagnetic interference is eliminated, and the cost is reduced.

Description of drawings

Fig. 1 is a structural schematic diagram of an LED lamp with an adaptive drive circuit of the present invention;

Fig. 2 is a schematic diagram of the turn-on and turn-off of the controllable switch unit and the change of the driving voltage of the utility model;

Fig. 3 is a circuit diagram of an LED lamp with an adaptive driving circuit according to the present invention.

Fig. 4 is another circuit diagram of an LED lamp with an adaptive driving circuit according to the present invention.

Fig. 5 is a flow chart of the single-chip microcomputer program in an example of the utility model.

Detailed ways

Below in conjunction with accompanying drawing and specific embodiment the utility model is described in further detail.

As shown in Figure 1, it is an LED lamp with an adaptive drive circuit, the LED lamp includes a plurality of series connected LED lamp strings L1, L2, ... Ln, and each LED lamp string includes a plurality of series connected LED lamps bead (not shown in the figure), the adaptive drive circuit includes: a rectification unit 1, a current limiting unit 2, a voltage detection and conduction control unit 3 and a plurality of controllable switch units K1, K2...Kn;

The rectification unit 1, that is, a rectification circuit composed of D1 to D4 in the figure, is used to convert the AC voltage output by the AC power supply into a rectified driving voltage;

The voltage detection and conduction control unit 3 is used to control the on-off of the controllable switch unit according to the change of the driving voltage. Each reference voltage is associated with a controllable switch unit, and the associated reference voltage is controlled to be higher than the driving voltage. The voltage controllable switch unit is disconnected, and at least one controllable switch unit whose associated reference voltage is lower than the driving voltage is controlled to be connected;

The controllable switch unit is used to control the on-off of the LED light string connected in series to the negative power supply terminal of the rectifier unit, wherein K1 controls the LED light string L1, K2 controls the LED light string L2... Kn controls the LED light string Ln;

The current limiting unit 2 is used for limiting or constant current of the driving voltage and then inputting the first LED light string of the plurality of LED light strings connected in series. It can be realized by using a constant current source circuit.

In one of the embodiments, the input end of the rectification unit 1 is connected to an AC voltage, the output end is connected to the input end of the voltage detection and conduction control unit 3, and the connection point of each LED light string is controlled by a controllable switch. The unit is grounded, the output end of the rectification unit 1 is connected to the first LED light string of the plurality of series-connected LED light strings through the current limiting unit 2, and the output end of the voltage detection and conduction control unit 3 is connected to the The control terminals of the above-mentioned controllable switch units K1, K2... Kn are connected.

Working principle: after rectification by the rectification unit 1, the mains power becomes a fluctuating direct current, that is, the AC voltage output by the AC power supply is converted into a rectified driving voltage. The voltage detection and conduction control unit 3 detects the change of the driving voltage in real time. When the driving voltage is low, Drive a part of the controllable switch unit to be turned on, and drive the other part of the controllable switch unit to be turned on when the driving voltage is high; LED light strings are connected in series in sections, and each section is connected to a controllable switch unit connected to a different voltage section, thereby realizing LED lighting. The number of strings connected in series follows the change of the driving voltage. When the driving voltage is low, the number of LED light strings connected in series is small. When the driving voltage is high, the number of LED light strings connected in series is large, so that some LED light strings are turned on when the voltage is low. , when the voltage is high, more LED light strings are turned on, so that the total voltage drop of LEDs is always close to the driving voltage, so that the LEDs will not be damaged by overcurrent due to too high driving voltage. The LED light string is turned on, thereby eliminating flicker, and maintaining a high power factor and low harmonic distortion. In this way, the power factor can easily reach more than 0.95, and the harmonic can also be kept below 20%.

Theoretically, the more segments the LED light string is divided into in this driving mode, the better it can closely follow the change of the driving voltage. At the same time, the voltage drop of the current limiting unit is smaller and the power consumed is smaller, which will improve the overall performance. Efficiency, but this also increases the number of voltage detection and drive units and thus increases the cost. After weighing, the low-power LED is divided into 4-6 segments, and the high-power LED is divided into 4-10 segments, which can better balance cost and performance. Since the controllable switch unit of this patent directly connects the corresponding strings of LEDs to the ground according to the size of the driving voltage, instead of short-circuiting or opening the LED light strings, no matter whether the driving voltage is high or low, only one or no LED lights are turned on at any time. The controllable switch is connected in series in the LED circuit, which means that only one or no controllable switch unit consumes power at any time, which improves the efficiency of the circuit.

As shown in Figure 1, there are L1, L2...Ln series of LED light strings and corresponding K1, K2...Kn controllable switch units. Each string of LED light strings is composed of several LED lamp beads in series, depending on the mains Depends on the size and number of strings. The AC mains is rectified by the rectification unit 1 and becomes a fluctuating direct current to drive the LED light string. The rectified voltage is the driving voltage. The voltage detection and conduction control unit 3 detects the magnitude of the driving voltage in real time, and conducts the control when the voltage is low. The circuit controls K1 to turn on, which is equivalent to the LED light string L1 (composed of several LED lamp beads connected in series, the same below) to turn on and emit light; when the voltage rises, the voltage detection and conduction control unit 3 controls K1 to turn off, K2 Turning on, at this time, it is equivalent to turning on and emitting light after L1 and L2 are connected in series. After L1 and L2 are connected in series, the total voltage drop also increases, which can adapt to the change of driving voltage increase, so that the LED will not be damaged due to overcurrent due to too high driving voltage. Can work normally and emit light; and so on, when the driving voltage rises to close to the maximum value, Kn is turned on and the rest are turned off. At this time, it is equivalent to connecting all LED light strings in series, and the voltage drop also reaches the maximum value. When the driving voltage starts to drop, the above process is repeated, and the turn-on and turn-off sequence of K1 to Kn is reversed, Kn is turned on first, and K1 is turned on last. The final result is that the voltage drop of the LED light string can follow the change of the driving voltage, cooperate with the current limiting unit 2, so that the LED can work normally within the allowable driving voltage and driving current range. FIG. 2 is a schematic diagram of the turn-on and turn-off of the controllable switch unit and the change of the driving voltage.

Assuming that the mains voltage is U, there are n strings of LED lights in total, and the voltage drop of each string of LED lights is Ul. The following relationship should be followed during design:

n*Ul<1.4*U

That is, the total voltage drop of all LEDs connected in series should be lower than the peak value of the commercial power.

For those of ordinary skill in the art, after reading this patent, a specific reference voltage acquisition method can be set, such as using multiple different voltage stabilization sources as reference voltages. In one embodiment, the voltage detection and conduction The control unit also includes a plurality of reference voltage dividing resistors and a voltage stabilizing source, and the reference voltage dividing resistor divides the voltage output by the stabilizing source to obtain a plurality of the reference voltages. A plurality of different reference voltages can be obtained through the reference voltage dividing resistors, so as to control the controllable switch unit. In this embodiment, only one stabilized voltage source is needed, and multiple different reference voltages are obtained through voltage division. Different ratios correspond to LED light strings with the same ratio, which can more accurately reflect the number of LED light strings that need to be connected, and the circuit efficiency is higher.

The voltage detection and conduction control unit 3 can be realized by a single-chip microcomputer or an analog circuit such as a comparator, and the controllable switch unit can be a bipolar transistor or a MOS tube.

In one of the embodiments, the voltage detection and conduction control unit 3 includes a plurality of comparators connected to the controllable switch unit, and the comparators are used to control and control the voltage with the The on-off of the controllable switch units K1, K2...Kn connected to the comparator.

In one of the embodiments, the output terminal of each comparator is connected to the control terminal of a controllable switch unit K1, K2...Kn, the first input terminal of the comparator detects the change of the driving voltage, and the voltage The detection and conduction control unit also includes a plurality of reference voltage dividing resistors and a voltage stabilizing source, the reference voltage dividing resistor divides the voltage output by the stabilizing source to obtain a plurality of reference voltages, and inputs the The second input terminal of the comparator.

In one of the embodiments, the voltage detection and conduction control unit further includes at least two driving voltage dividing resistors, and after the driving voltage dividing resistors divide the driving voltage, the voltage input to the comparator is first input.

In another embodiment, the voltage detection and conduction control unit 3 is composed of a single-chip microcomputer, and the output terminal (I/O) of the single-chip microcomputer is connected to the control terminals of the controllable switch units K1, K2...Kn, and the The analog-to-digital converter (ADC) of the single-chip microcomputer is connected to the positive power supply terminal of the rectification unit 1 to detect the change of the driving voltage in real time. The single-chip microcomputer is used to detect the LED driving voltage in real time, and control the on-off of the controllable switch units K1, K2...Kn according to the driving voltage.

The self-adaptive driving circuit of the LED lamp of the utility model is used for supplying power to the LED lamp, and its principle is consistent with the above, so it will not be repeated here.

As shown in Figure 3, it is an example of the utility model.

This example is designed as a 120VAC input, 24W LED dimmable ceiling light.

The mains power is 120V AC input, and the rectifier bridge stack B1 converts the input AC power into a fluctuating DC power VA after the fuse FUSE, which is used as the driving voltage of the LED lamp. RV1 is a varistor for lightning protection, and R1, R2 and C1 are used for freewheeling of the thyristor dimmer.

LED is composed of LED1, LED2, LED3, LED4, LED5, a total of 5 strings of LED lights connected in series. Each light string is composed of 9 Samsung 5630 lamp beads connected in series. One LED light string in the figure represents 9 LED lights connected in series beads. The voltage of a single 5630 is about 3.2V, and the voltage after 9 serial connections is:

9*3.2=28.8V

The total voltage of 5 strings of LED lamp beads is:

5*28.8=144V.

Lower than the peak value of mains electricity: 120*1.4=168V.

Considering the cost performance, this example uses LM2902 (IC1A, IC1B, IC1C and IC1D in Figure 3) single-supply four-op amp as a voltage comparator to detect the change of LED driving voltage VA in real time. R4, R5 and C2, D1 provide 15V power supply for the operational amplifier. The precision voltage regulator TL431 (D2 in Figure 3) and the voltage divider resistors (R7, R8, R9, R10) provide voltages of approximately 2.5V, 2V, 1.5V, and 1V for the "-" inputs of the four comparators, respectively. The reference voltage, VA is divided by resistors R3 and R11 and then connected to the "+" input terminal (Vi) of the op amp. The voltage division ratio is designed so that the relationship between VA and Vi and the output of the comparator is as follows:

Vi=VA*R11/(R3+R11)

Table 1

VA Vi Comparator A Comparator B Comparator C Comparator D <49.5V <1V output high output high output high output high >49.5V >1V output high output high output high output low >74.3V >1.5V output high output high output low output low >99V >2V output high output low output low output low >124V >2.5V output low output low output low output low

The current limiting circuit is composed of a constant current circuit composed of IC2 reference voltage source, MOS tubes T5, R12, and R13. The controllable switch unit is realized by MOS tubes (T1, T2, T3, T4 in Figure 3), and the output terminal of the comparator is connected to The gate of the MOS transistor is connected, so when the output of the comparator is high, the MOS transistor is turned on, and when the output of the comparator is low, the MOS transistor is turned off. The output state of the comparator directly controls the on and off of the MOS transistor. Corresponding to Table 1: When the driving voltage is less than 49.5V, T1 is turned on due to the high output of comparator D, which is equivalent to LED1 being connected to the power supply VA through the constant current circuit to emit light, because the driving voltage is low at this time and there is a constant current Due to the current limiting function of the circuit, LED1 can work normally within the allowable operating range; when the driving voltage is greater than 49.5V but less than 74.3V, the low output of comparator D will cause T1 to be cut off, and the output of comparator C to be high will cause T2 to be turned on, which is quite After LED1 and LED2 are connected in series, they are connected to the power supply VA through a constant current circuit. At this time, although VA increases, the voltage after LED1 and LED2 are connected in series also increases, and with the current limiting effect of the constant current circuit, the LED can still Work in the normal range; and so on, when VA is greater than 124V, T1-T4 are all cut off, at this time LED1-LED4 are all connected in series and connected to VA through the constant current circuit, and the LED voltage also reaches the maximum value, due to the limitation of the constant current circuit The LED can still work normally; when VA changes from high to low, the above process is repeated in the opposite direction. It can be seen that the voltage of the LED string can always follow the change of the driving voltage, so that the LED can work within the normal working range.

As shown in Figure 4, it is another example of the utility model.

This example is designed as a 120VAC input, 24W LED dimmable ceiling light.

The mains power is 120V AC input, and the rectifier bridge stack B1 converts the input AC power into a fluctuating DC power VA after the fuse FUSE, which is used as the driving voltage of the LED lamp. RV1 is a varistor for lightning protection, and R1, R2 and C1 are used for freewheeling of the thyristor dimmer.

LED is composed of LED1, LED2, LED3, LED4, LED5, a total of 5 strings of LED lights connected in series. Each light string is composed of 9 Samsung 5630 lamp beads connected in series. One LED light string in the figure represents 9 LED lights connected in series beads. The voltage of a single 5630 is about 3.2V, and the voltage after 9 serial connections is:

9*3.2=28.8V

The total voltage of 5 strings of LED lamp beads is:

5*28.8=144V.

Lower than the peak value of mains electricity: 120*1.4=168V.

This example uses a single-chip MCU to detect the change of the LED driving voltage VA in real time. R4, R5 and C2, D1 provide 5.1V power supply for the microcontroller. R3 and R11 divide and press VA to the ADC input terminal of the MCU. The ADC of the MCU detects the size of the VA in real time and controls the on and off of the MOS transistors T1~T4 through I/O1~I/O4, so that according to the size of the VA Control the number of LEDs connected to the loop, so that the LED voltage automatically adapts to the change of the driving voltage, and design circuit parameters and programs to satisfy the following relationship:

Vadc=VA*R11/(R3+R11)

Table 2

VA Vi I/O1 I/O2 I/O3 I/O4 <49.5V <1V output high output high output high output high >49.5V >1V output high output high output high output low >74.3V >1.5V output high output high output low output low >99V >2V output high output low output low output low >124V >2.5V output low output low output low output low

The current limiting circuit is composed of a constant current circuit composed of IC2 reference voltage source, MOS tubes T5, R12, and R13. The controllable switch unit is realized by MOS tubes (the same as T1, T2, T3, and T4 in Figure 3). (I/O) is connected to the gate of the MOS tube. Therefore, when the output of the microcontroller is high, the MOS tube is turned on, and when the output of the microcontroller is low, the MOS tube is turned off. The output state of the microcontroller directly controls the turn-on and off of the MOS tube.

The program flow chart is shown in Figure 5. The working principle is: the ADC of the single-chip microcomputer detects the driving voltage VA in real time and controls the on and off of the MOS. The relationship is designed as shown in Table 2, so that the LED can adapt to the fluctuation of the driving voltage and work normally. Specifically include:

Step S510, start the ADC to perform A/D conversion, perform analog-to-digital conversion on the driving voltage VA, and compare, if <49.5V, then perform step S521, if it is between 49.5V～74.3V, then perform step S522, in If it is between 74.3V and 99V, execute step S523; if it is between 99V and 124V, execute step S524; if it is >124V, execute step S525;

Step S521, T1~T4 are turned on (LED1 connected to VA), end;

Step S522, T1 is turned off, T2~T4 are turned on (LED1~LED2 connected to VA), and end;

Step S523, T1~T2 are turned off, T3~T4 are turned on (LED1~LED3 connected to VA), end;

Step S524, T1~T3 are turned off, T4 is turned on (LED1~LED4 connected to VA), end;

Step S525, T1-T4 are turned off, (LED1-LED5 are connected to VA), and end.

The above-mentioned embodiments only express several implementations of the utility model, and the description thereof is relatively specific and detailed, but it should not be construed as limiting the patent scope of the utility model. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the scope of protection of the utility model patent should be based on the appended claims.

Claims (10)

1. An LED lamp with an adaptive drive circuit, characterized in that, the LED lamp comprises a plurality of series-connected LED lamp strings, and each LED lamp string comprises a plurality of series-connected LED lamp beads, and the adaptive drive The circuit includes: rectification unit, current limiting unit, voltage detection and conduction control unit and multiple controllable switch units; The rectification unit is used to convert the AC voltage input by the AC power supply into a rectified driving voltage; The voltage detection and conduction control unit is used to detect the comparison result of the driving voltage and multiple reference voltages to control the on-off of multiple controllable switch units, each reference voltage is associated with a controllable switch unit, and controls all The controllable switch unit whose associated reference voltage is higher than the driving voltage is disconnected, and at least one controllable switching unit whose associated reference voltage is lower than the driving voltage is controlled to be connected; The controllable switch unit is used to control the on-off of the LED light string connected in series to the negative end of the power supply of the rectifier unit; The current limiting unit is configured to limit or constant the driving voltage and input it to the first LED light string of the plurality of LED light strings connected in series. the 2. The LED lamp with an adaptive drive circuit according to claim 1, wherein the voltage detection and conduction control unit further comprises a plurality of reference voltage dividing resistors and a voltage stabilizing source, and the reference voltage dividing The piezoresistor divides the voltage output by the voltage stabilizing source to obtain a plurality of the reference voltages. the 3. The LED lamp with an adaptive drive circuit according to claim 1, wherein the input end of the rectification unit is connected to an AC voltage, and the output end is connected to the input end of the voltage detection and conduction control unit , the connection point of each LED light string is grounded through a controllable switch unit, the output end of the rectification unit is connected to the first LED light string of the plurality of series-connected LED light strings through a current limiting unit, and the voltage detection and the output end of the conduction control unit is connected with the control end of the controllable switch unit. the 4. The LED lamp with an adaptive drive circuit according to claim 1, wherein the voltage detection and conduction control unit includes a plurality of comparators connected to the controllable switch unit, and the comparators are used for The comparison result of the driving voltage and multiple reference voltages controls the on-off of the controllable switch unit connected to the comparator. the 5. The LED lamp with an adaptive drive circuit according to claim 1, wherein the voltage detection and conduction control unit comprises a single-chip microcomputer, and the analog-to-digital converter of the single-chip microcomputer is connected to the output terminal of the rectification unit, Real-time detection of comparison results between the drive voltage and multiple reference voltages, and control the on-off of the controllable switch unit connected to the output port of the single-chip microcomputer. the 6. An adaptive drive circuit for an LED lamp, used to supply power to the LED lamp, the LED lamp includes a plurality of LED lamp strings connected in series, and each LED lamp string includes at least one LED lamp bead connected in series, its features It includes: rectification unit, current limiting unit, voltage detection and conduction control unit and multiple controllable switch units; The rectification unit is used to convert the AC voltage input by the AC power supply into a rectified driving voltage; The voltage detection and conduction control unit is used to control the on-off of the plurality of controllable switch units according to the change of the driving voltage, each reference voltage is associated with a controllable switch unit, and the associated reference voltage is controlled to be higher than The controllable switch unit of the driving voltage is disconnected, and at least one controllable switch unit whose associated reference voltage is lower than the driving voltage is controlled to be connected; The controllable switch unit is used to control the on-off of the LED light string connected in series to the negative end of the power supply of the rectifier unit; The current limiting unit is used to limit or constant the driving voltage and input the first LED light string of the plurality of LED light strings connected in series; The positive terminal of the power supply of the rectifying unit is respectively connected to the input terminals of the voltage detection and conduction control unit and the current limiting unit, and the output terminal of the voltage detection and conduction control unit is connected to the control terminals of a plurality of controllable switch units. connected, the output end of the current limiting unit is connected to the first LED light string of the plurality of series-connected LED light strings, and the plurality of series-connected LED light strings are respectively connected to the negative terminal of the power supply of the rectifier unit through a controllable switch unit . the 7. The adaptive drive circuit of LED lamp according to claim 6, characterized in that, the voltage detection and conduction control unit further comprises a plurality of reference voltage dividing resistors and voltage stabilizing sources, and the reference voltage dividing The resistor divides the voltage output by the voltage stabilizing source to obtain multiple reference voltages. the 8. The adaptive drive circuit for LED lamps according to claim 6, wherein the input end of the rectification unit is connected to an AC voltage, and the output end is connected to the input end of the voltage detection and conduction control unit, One end of each controllable switch unit is grounded, and the other end is used to connect with the connection point of every two adjacent LED light strings, and the output end of the rectification unit is connected to the plurality of series-connected LED light strings through a current limiting unit The first LED lamp string is connected, and the output terminal of the voltage detection and conduction control unit is connected with the control terminal of the controllable switch unit. the 9. The adaptive drive circuit for LED lamps according to claim 6, wherein the voltage detection and conduction control unit includes a plurality of comparators connected to the controllable switch unit, and the comparators are used for driving The comparison result of the voltage and multiple reference voltages controls the on-off of the controllable switch unit connected to the comparator. the 10. The adaptive drive circuit for LED lamps according to claim 6, wherein the voltage detection and conduction control unit includes a single-chip microcomputer, and the analog-to-digital converter of the single-chip microcomputer is connected to the positive power supply terminal of the rectification unit, The output port of the single-chip microcomputer is connected with the controllable switch unit. the

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