TW201526707A - Device for light emitting diode (LED) direct driver - Google Patents

Abstract

A device for LED direct driver comprises a major LED string, a minor LED string set, a pre-regulator, and a direct driver. The major LED string has multiple series-connected LED diodes which has a first end and a second end. The minor LED string set has a first end and a second end, and is formed with multiple series-connected minor strings. The first end of the minor LED string set is connected to the second of the major LED string. Each minor LED string has at least one LED diode. The direct driver is connected to the pre-regulator, the major LED string, the minor LED string, which is configured to short out selected minor LED strings for ensuring the most efficient LED driving configuration.

Description

Direct light emitting diode driving device

The present invention relates to a device for driving an LED driver, and more particularly to a device Direct LED drive unit.

There are two common types of light emitting diode (LED) driving circuits, one is a switch drive and the other is a direct driver. The switched drive circuit uses a magnetic component (eg, an inducer) to store power from a power supply and directly transfer this electrical energy directly to an LEC string. The disadvantage of the switched zone circuit is that it requires an additional EMI filter, requires more components to be installed, and has an obvious Output Current Ripple, but does not have a large capacitance.

The direct drive circuit can achieve up to 99% efficiency, requires fewer components, and is less expensive. However, the output current chopping of the direct drive circuit is significantly related to the power factor. In simple terms, if the power factor is effectively corrected, a direct drive circuit that produces almost no output current ripple can be designed.

Therefore, an LED driving device capable of driving a lamp which can be highly effective under various input voltages, having harmonic distortion (HD) characteristics, high power filter factor and low output current ripple is developed. It is very important.

An object of the present invention is to provide a direct light emitting diode driving device comprising a main LED string, a primary LED string, a presetting component, a power factor correction module and a direct driver.

The main LED light string comprises a plurality of LED units connected in series with each other and has a first end and a second end. The secondary LED string group has a first end and a second end, and includes a plurality of secondary LED strings connected in series with each other, the first end of the secondary LED string group being connected to the main LED string Second end. The presetting component includes a diode rectifier connected to a power source to convert an AC input voltage of the power source into a pulsed DC voltage. The power factor correction module is connected between the diode rectifier and the first end of the main LED string, and adjusts the pulse DC voltage to a stable regulated output voltage, wherein the stable voltage is output to drive the main The LED string, the secondary LED string group or the driving of the main LED string and the secondary LED string group. The direct drive has a current source and is coupled to each of the secondary LED strings to selectively turn off the selected secondary LED string.

In an embodiment, a pre-conditioning element and the direct drive further comprise a communication path.

In an embodiment, the direct drive further includes: a current feedback path connected to one of the preset components; and a current feedback module through the current feedback path to the preset component The controller generates a control voltage to regulate the regulated voltage of the output.

In an embodiment, the current feedback module further includes an integration circuit and a current channel, the integral power system is connected between the secondary LED light string group and the current source, and the current channel is connected to the integration circuit, and an indirect circuit is used. The diode selectively controls the current flowing into the current source. Current back The feed path further includes a first resistor, a second resistor, and a third resistor. The second resistor is a first resistor connected in series to the current feedback path. A contact of the first resistor and the second resistor is connected to an internal comparator inside the controller, and the internal comparator has an internal reference voltage. The third resistor has a first end and a second end. The first end is connected to a contact of the first resistor and the second resistor, and the second end is connected to the current channel.

In one embodiment, the comparator is comprised of an operational amplifier having a reference voltage, and the current path is an inverter that supplies current when the voltage of the current source is higher than the reference voltage.

In one embodiment, the integrating circuit is comprised of a transfer conductance that drives a comparator, and the current path is a buffer.

In one embodiment, the pre-conditioning component is coupled to a complex direct drive.

In one embodiment, each of the direct drivers has a current feedback module that causes current to flow out of the current feedback path and the current flowing out produces a control voltage.

In an embodiment, the current feedback path further includes a first resistor, a second resistor, and a third resistor. The second resistor is connected in series to the first resistor, and a contact of the first resistor and the second resistor is connected to an internal comparator inside the controller, and the internal comparator has an internal reference voltage. The third resistor has a first end for connecting to a junction of the first resistor and the second resistor.

In an embodiment, the direct-emitting diode driving device further includes a protection diode disposed between the third resistor and the current channel, and allowing the current to be pre-adjusted by the junction of the first resistor and the second resistor. The components flow.

In one embodiment, the direct light emitting diode driving device includes a current The sensing resistor is a current corresponding to a voltage of a main LED string to which a secondary LED string is attached, an internal current source having a preset current, and the preset current is equal to a minimum voltage value of the regulated output voltage. The current value sensed by the current sensing resistor, a diversion diode, and a first resistor. When the current sensed by the current sense resistor is higher than the current value preset by the internal current source, the first resistor has a large capacitance The current flowing into the diversion diode, an error amplifier, has a reference voltage source, an NOMS transistor, is connected to the error amplifier to form a current source, an offset resistor, and a REST resistor, which is connected to the The diode is diode-connected and produces a bias voltage between the reference voltage source and the REST resistor, wherein the bias voltage reduces the current flowing into the LED string.

In one embodiment, the current sensing resistor is connected to the first end of the main LED string and the presetting component, and the first resistor has a first end, a second end and a third end, wherein the first end The second end is connected to the second end of the secondary LED string, the internal current source is connected to the third end of the first resistor, and the diversion diode has an anode and a a cathode, wherein the anode is connected to the third end of the first resistor, the error amplifier has a positive input terminal, a negative input terminal and an output terminal, wherein the positive input terminal is connected to a reference voltage source, and the negative input terminal Connected to the cathode of the diversion diode, the NMOS transistor has a first end, a second end and a third end, wherein the first end is connected to the second end of the secondary LED string group, and the second The end is connected to the output terminal of the error amplifier, the third end is connected to the REST resistor, and the bias resistor is connected between the negative output of the error amplifier and the REST resistor.

Therefore, the driving device of the present invention is used to solve the problems encountered in current LED drivers. The pre-adjusting components can supply various ranges of output voltages, and have high power factor and low harmonic distortion characteristics, and the pre-conditioning components are only A stable regulated output voltage is required, so that power can be stably supplied to the LED driver, so that the LED driver provides a stable The voltage is output and does not output voltage ripple.

10‧‧‧Main LED light string

20‧‧‧Secondary LED string

200‧‧‧ secondary LED light string

30‧‧‧ Pre-adjustment components

301‧‧ Diode Rectifier

302‧‧‧Power Factor Correction Module

3021‧‧‧First capacitor

3022‧‧‧Inductors

3023‧‧‧ Controller

30231‧‧‧Internal comparator

3024‧‧‧Switching transistor

3025‧‧‧ diode

3026‧‧‧second capacitor

40‧‧‧Direct drive

401‧‧‧current source

50‧‧‧Connected path

60‧‧‧ Current feedback module

61‧‧‧Integral circuit

62‧‧‧current channel

63‧‧‧ Current feedback path

70‧‧‧ Current feedback module

71‧‧‧Integral circuit

72‧‧‧current channel

73‧‧‧ Current feedback path

80‧‧‧ Current sense resistor

81‧‧‧First transistor

82‧‧‧Internal current source

83‧‧‧ Diversion diode

84‧‧‧Error amplifier

85‧‧‧MONS transistor

86‧‧‧Offset resistance

87‧‧‧REST resistor

D‧‧‧Indirect diode

D1‧‧‧Protection diode

R1‧‧‧first resistance

R2‧‧‧second resistance

R3‧‧‧ third resistor

1 is a schematic view showing the structure of a direct LED driving circuit according to an embodiment of the present invention.

FIG. 2 is a diagram showing the circuit architecture of the direct LED driving device of FIG. 1.

3 is a block diagram of another embodiment of the present invention.

4 is a block diagram of another embodiment of the present invention.

Figure 5 is a block diagram showing still another embodiment of the present invention.

Fig. 6 is a view showing an embodiment of a direct type LED driving device in which a plurality of mutually arranged components are driven in parallel with each other by a single presetting element.

7 is an embodiment of a direct LED driving circuit

The apparatus or method of the present invention will now be described by way of example only. The following description of the embodiments is a description of the technical features of the present invention.

Referring to FIG. 1, FIG. 1 is a schematic structural view of a direct LED driving device according to an embodiment of the present invention. In the present embodiment, the direct LED driving device includes a main LED string 10, a primary LED string unit 20, a presetting element 30, and a direct driver 40. The main LED string 10 includes a plurality of LED units connected in series with each other and has a first end and a second end. The secondary LED string set 20 has a first end and a second end, and includes a plurality of secondary LED strings 200 connected in series with each other. The first end of the secondary LED string 20 is connected to the main LED. At the second end of the string 10, each time the LED string 200 is to include at least one LED unit.

The presetting element 30 includes a diode rectifier 301 and a power factor correction mode Group 302. The diode rectifier 301 is connected to a power source and converts the AC input voltage from the power source into a pulsed DC voltage. The power factor correction module 302 is disposed between the diode rectifier 301 and the first end of the main LED string 10, and adjusts the pulsed DC voltage to a stable regulated output voltage. And the pre-adjustment element 30 can supply a wide range of input voltages with high power factor and low harmonic distortion characteristics. It should be noted that the pre-conditioning component 301 does not need to provide a regulated input current. As long as a stable and regulated output voltage is provided, there is a small but reasonable current chopping of the output voltage.

In an embodiment of the invention, the preconditioning component 30 can have a boost-mode quasi-resonant architecture. The pre-adjusting component 301 with a boosted quasi-resonant architecture can be applied to a boundary mode and is the simplest application. The output voltage peak regulated by the pre-adjustment component 30 should fall at the maximum wave front position of the AC input voltage of the power supply. It will be readily appreciated by those skilled in the art that a component having a boost mode can only provide an output voltage that is the same or higher than the AC input voltage.

Please refer to FIG. 2, which illustrates the circuit architecture of the direct LED driving device of FIG. The diode rectifier 301 in the presetting element 30 is formed by four diodes. The power factor correction module 302 includes a first capacitor 3021, an inductor 3022, a controller 3023, a switching transistor 3024, a diode 3025, and a second capacitor 3026. The first capacitor 3021 is connected in parallel to the diode rectifier 301 and has a first end and a second end. The inductor 3022 has a first end and a second end. The first end of the switching transistor 3024 is coupled to the second end of the inductor, and the second end of the switching transistor 3024 is coupled to the controller 3023. The second capacitor 3026 has a first end and a second end. The diode 3025 is disposed between the first end of the switching transistor 3024 and the first end of the second capacitor 3026. First capacitor The second end of the 3021 and the second capacitor 3026, and the third end of the switching transistor 3024 are connected to a common ground.

The direct drive 40 includes a current source 401 and is coupled to the LED string 200 each time. The direct drive 40 selectively turns off the selected secondary LED string 200 to ensure maximum LED drive efficiency. The current source 401 is disposed between the second end of the secondary LED string unit 20 and the power factor correction module 302 of the presetting element 30. The direct drive 40 (and the accompanying primary LED string 10 and secondary LED string 20) has a predetermined operating voltage range that encompasses the expected maximum output voltage and expected minimum of the preconditioning element 30. The output voltage should also cover the range of output voltages regulated by the preconditioning element 30, as well as the LED voltage variations due to temperature, diode lifetime, and operational variables.

The direct drive 40 monitors the voltage across the entire primary LED string 10 and the secondary LED string 20 and adjusts the current so that the overall output power of the primary LED string 10 and the secondary LED string 20 are maintained. Is a constant.

As shown in FIG. 2, the direct LED driving device of the present invention further includes a communication path 50 disposed between the presetting element 30 and the direct driver 40. As the effective power range of the direct drive 40 increases, the number of secondary LED strings 200 can be reduced. For example, when the temperature rises such that the voltage flowing to the main LED string 10 becomes very small, the secondary LED string 20 can be connected in series to the main LED string 10. If the secondary LED string set 20 lacks sufficient secondary LED string 200 to counteract the voltage flowing to the LED, then the voltage flowing through the current source 401 of the direct driver 40 will increase, resulting in reduced overall power efficiency. Therefore, once the controller 3023 in the presetting element 30 can sense the voltage flowing through the main LED string 10 and the secondary LED string 20 through the communication path 50, the presetting element 30 can The regulated regulation voltage is reduced and the direct drive 40 is maximized. In addition, in order to sense the voltage flowing through the main LED string 10 and the secondary LED string group 20 through the communication path 50, and to adjust the overall brightness of the main LED string 10 and the secondary LED string group 20, the pre-adjusting components 30 will control the current source 401 of the direct driver 40 to maintain a steady light output.

On the other hand, assuming that the temperatures of the main LED string 10 and the secondary LED string group 20 are lowered, the voltage supply to the main LED string 10 and the secondary LED string group 20 needs to be more variable than usual. The direct drive 40 can gradually remove the voltage supplied to the secondary LED string set 20 from the primary LED string 10 until all of the secondary LED string sets 20 are turned off. The direct driver 40 causes the pre-conditioning component 30 to reduce the output of the regulated voltage and allows the device to maintain optimum operational efficiency.

The pre-adjustment element 30 and the direct drive 40 can be in a form of digitization, analog voltage or current. In order to avoid that when the number of secondary LED strings 200 has approached a critical value (that is, the maximum expected voltage or the minimum expected voltage of the pre-adjusted component 30 has been reached), the two values will be continuously "talked" back and forth. It is therefore necessary to add a hysteresis to a control method of the pre-tuning component 30 of its controller 3023.

Because the action of the pre-adjustment element 30 is only a single step, the overall operating efficiency can exceed 97%. If the direct driver 40 connected to the presetting element 30 can reach 98% or more, the combination of the presetting element 30 and the direct driver 40 according to the present invention can achieve an effective power supply efficiency of 95% (97%×98%). This kind of power supply is very efficient, and it is very important for those high power systems that reduce the 10% efficiency and cause a lot of power waste or heat loss.

Please refer to FIG. 3. FIG. 3 is an architectural diagram of another embodiment of the present invention? Because the efficiency of the high power supply system is reduced, it will cause waste of power or heat loss, so it is more prominent. The efficacy of the driving device disclosed by the present invention. In the present embodiment, a single pre-adjustment element 30 is coupled to a plurality of direct drives 40. Since the cost of the direct drive 40 is relatively inexpensive, it does not excessively increase the cost of the device. When the power supply is increased, it may be necessary to increase the volume of the presetting element 30. However, even if the amount of power supply is doubled, the volume and cost of the presetting element 30 will not be twice as high as the original, so the output voltage is generated. The cost can still be maintained at a low price.

Please refer to FIG. 4. FIG. 4 is a block diagram showing another embodiment of the present invention. The difference between this embodiment and FIG. 3 is that the pre-adjustment element 30 of the present embodiment does not use the hysteresis control method by the controller 3023. In the present embodiment, the LED direct drive device further includes a current feedback module 60 and a current feedback path 63 connected to the pre-tuning component 30 and an internal comparator 30231 in the controller 3023. The internal comparator 30231 has an internal reference voltage (Vrc). The current feedback module 60 is used to adjust the controller 3023 to change its regulated output voltage (Vout), and includes an integrating circuit 61 and a current passenger 62. The current feedback path 63 includes a first resistor R1, a second resistor R2, and a third resistor R3. The integrating circuit 61 is connected between the secondary LED string unit 20 and the current source 401. The current channel 62 is connected between the integrating circuit 61 and the third resistor R3, and selectively increases or decreases the current supply according to a control voltage (Vadj) value generated by the indirect diode D. The first resistor R1 and the second resistor R2 are connected in series to each other, and then connected in parallel to the second capacitor 3026. The first end of the third resistor R3 is connected to a junction of the first resistor R1 and the second resistor R2. In such a connection mode, an additional current can be injected through the third resistor R3 into the junction between the first resistor R1 and the second resistor R2, and between the regulated output voltage (Vout) and the control voltage (Vadj). The relationship can be expressed by the following equation: Vout = [(Vrc × R2 × R3 / R1) + (R3 × Vrc) + (R2 × Vrc) - (R2 × Vadj)] / R3.

In the embodiment disclosed in FIG. 4, the integrating circuit 61 is embedded in an operational amplifier (op-Amp) and has a comparison voltage (Vr). The current channel 62 is a unidirectional inverter because the current channel 62 only allows current to be introduced into the third resistor R3 to regulate the output voltage (Vout) to decrease, and the relationship to R1/R2 is considered, and the regulated The output voltage cannot be higher than its internal voltage value.

During the operation, if the average voltage value through the current source 401 is lower than the comparison voltage (Vr), the output of the boost integration circuit 61 is adjusted, and the output of the current channel 62 having the unidirectional inverter structure is adjusted to be lowered. And the current channel 62 will be locked and will not work. Once the average voltage value through current source 401 increases and is higher than the comparison voltage (Vr), then the output of current channel 62 begins to increase. During the operation, if the average voltage value through the current source 401 is lower than the comparison voltage (Vr), the output of the boost integration circuit 61 is adjusted, and the output of the current channel 62 having the unidirectional inverter structure is adjusted to be lowered. And the current channel 62 will be locked and will not work. Once the average voltage value through current source 401 increases 幷 above the comparison voltage (Vr), the output of current channel 62 begins to decrease. When the voltage of the power supply stream 401 is lower than an intermediate resistance value, the current channel 62 begins to supply current such that the regulated output voltage (Vout) of the preconditioning element 30 is lowered, and the intermediate resistance value is defined as between the first resistor R1 and the second resistor R2. The resistance value is affected by the comparison voltage (Vrc) of the internal comparator 30231 in the controller 3023. In many commercial controllers, the internal voltage of the comparison voltage (Vrc) is approximately 2.5 volts.

Please refer to FIG. 5. FIG. 5 is a structural diagram illustrating still another embodiment of the present invention. In this embodiment, the integrating circuit 61 is embedded in a transconductance structure, that is, a transfer conductance that drives a comparator, and the current channel 62 has a buffering function. This embodiment is identical to the embodiment of FIG. 4 in that the current channel 62 is either slow or slow. For the punch structure, the current can only be supplied according to the ratio of the resistance values of the first resistor R1 and the second resistor R2, so that the output voltage is gradually decreased from the maximum value.

Generally, in a general operation, the LED unit will heat up and the voltage flowing through the LED unit will decrease, and the voltage passing through the current source will increase, resulting in a decrease in power supply efficiency and an increase in waste heat generated by the lamp. 4 or the current feedback module 60 of the embodiment of FIG. 5 can sense the voltage increase condition of the current source 401 in response to lowering the output voltage (Vout). As with the regulation of the output voltage, the voltage through the current source 401 is also reduced to achieve an increase in power supply efficiency and a reduction in waste heat generation.

The embodiment of Figure 4 or Figure 5 demonstrates the superior efficacy of the present invention, particularly for an application similar to dimming lamps. In the process of analog dimming, when dimming to the brightest, the current through the LED will be reduced to a relatively small value, so the voltage flowing through each LED unit in the LED string will be full than the current through the LED. It is much lower, so it can produce higher operational efficiency when performing analog dimming.

In another similar state, if an overheat protection mechanism is applied to an LED module to reduce the current flowing through the LED in a superheated state, the output voltage regulated by the preconditioning component 30 will also flow through the LED. The voltage drops and decreases. This ensures that the (LED?) device does not have to counteract the rise in operating voltage during the overheating operation.

Further, when a single pre-adjusting element 30 is used to drive a plurality of direct-type LED driving devices arranged in parallel with each other, it is necessary to modify some of FIG. 4 or FIG. Because in such a situation, the required control voltage (Vadj) should be kept at the lowest voltage state, not the highest voltage state described in the previous paragraph.

In order to solve this problem, and to maintain an absolute maximum in the consideration of security For a large output voltage, please refer to FIG. 6. FIG. 6 illustrates an embodiment of the direct LED driving device of the present invention which uses a single pre-adjusting element to drive a plurality of parallel-connected LEDs. Each of the direct LED driving devices (not shown) is connected to a current feedback module 70, which is very similar to the current feedback module 60 described in FIG. 4 or FIG. Each current feedback module 70 includes an integrating circuit 71 and a current path 72 connected in series with the integrating circuit 71. The difference between FIG. 6 and FIG. 4 or FIG. 5 is that the direction of the indirect diode D in the current channel 72 is opposite. In such a state, the inverted indirect diode D in the current path 72 can only derive current. That is, the current path 62 in FIG. 4 or FIG. 5 is used to increase the current, and the current path 72 of the present embodiment is used to reduce the current.

When all of the current paths 72 are connected to each other, the lowest output voltage in the current path 72 is determined as a control voltage (Vadj). Because the output voltage of the current path 72 is minimal, when the current flows back to the preconditioning element 30, the output voltage regulated by the preconditioning element 30 is sufficient to supply sufficient voltage to the main LED string 10 and the secondary LED string group 20 to maintain The current required.

In the present embodiment, the current feedback path 73 (with no antecedent) further includes a securing diode D1. The protection diode D1 is disposed between the third resistor R3 and the current channel 72 and has an anode and a cathode. The anode of the protection diode D1 is connected to the third resistor R3, and the cathode is connected to the current channel 72. The protection diode D1 is only allowed to move current from the junction of the first resistor R1 and the second resistor R2 to the preconditioning element 30 to ensure that the regulated output voltage does not exceed the ratio of R1/R2.

Please refer to FIG. 7. FIG. 7 illustrates an embodiment of a direct LED driving circuit. As with many adaptive LED direct drivers, this embodiment requires modifying the LED current to provide a stable and appropriate output voltage to add or remove secondary LED strings that are attached to the primary LED string 10. 20 quantities.

In this embodiment, the direct LED driving device includes a current sensing resistor 80, a first transistor 81, an internal current source 82, an conducting diode 83, an error amplifier 84, and a MONS. A transistor 85, an offset resistor 86, and a REST resistor 87 are provided.

The current sensing resistor 80 is connected to the first end of the main LED string 10 and the presetting element 30. The first transistor 81 has three ends, wherein the first end is connected to the current sensing resistor 80 and the second end is connected to the second end of the secondary LED string unit 20. The connection of the current sensing resistor 80 and the first transistor 81 can sense the complete voltage flowing through the primary LED string 10 and the additional secondary LED string 200 (a portion of the current flowing through the current sensing resistor 80 is converted to supply the primary LED lamp) The string 10 and the voltage of the secondary LED string 200 are added). The internal current source 82 is connected to the third end of the first transistor, and the current value of the current source 82 is preset to be the minimum output voltage (that is, the minimum predicted voltage of the direct LED driver). The current sensed resistor 80 senses the same current value.

The diversion diode 83 has an anode and a cathode, wherein the anode is connected to the third end of the first transistor 81. The error amplifier 84 has a forward input terminal, a negative input terminal and an output terminal, wherein the forward input terminal of the error amplifier 84 is connected to a reference voltage source (Vrs), and the negative direction of the error amplifier 84 The input terminal is connected to the cathode of the diversion diode 83. The MONS transistor 85 has three ends, wherein the first end is connected to the second end of the secondary LED string unit 20, the second end is connected to the output of the error amplifier 84, and the third end is connected to the REST resistor 87. The offset resistor 86 is coupled between the negative input of the error amplifier 84 and the REST resistor 87. The error amplifier 84 and the MONS transistor 85 form a base current source, such as the current source 401 described in the previous paragraph.

When the current value flowing through the current sensing resistor 80 is greater than the preset value of the internal current source 82, excessive current will flow to the diode 83, and at this time, a voltage drop across the offset resistor 86 is generated, and further An offset voltage between the reference voltage source Vrs and the REST resistor 87 is generated and the current flowing through the LED is reduced. The reduced current value can be expressed by the following equation: I _LED = (Vrs - R ₈₆ × ((V _LED / R ₈₀ ) - I ₈₂ )) / R ₈₇ .

Wherein, Vrs is the voltage value of the reference voltage source, R ₈₆ is the resistance value of the offset resistor 86, R ₈₀ is the resistance value of the current sense resistor 80, I ₈₂ is the current value of the internal current source, and R ₈₇ is the REST resistor 87. resistance.

10‧‧‧Main LED light string

200‧‧‧ secondary LED light string

30‧‧‧ Pre-adjustment components

301‧‧ Diode Rectifier

302‧‧‧Power Factor Correction Module

Claims (12)

A direct light-emitting diode driving device includes: a main LED light string, comprising a plurality of LED units connected in series with each other, and having a first end and a second end; Having a first end and a second end, and comprising a plurality of secondary LED strings connected in series with each other, the first end of the secondary LED string set being connected to the second end of the main LED string; A pre-conditioning component includes: a diode rectifier connected to a power source for converting an AC input voltage of the power source into a pulsed DC voltage; and a power factor correction module coupled to the diode Between the rectifier and the first end of the main LED string, the pulsed DC voltage is adjusted to be a regulated regulated output voltage, wherein the stable voltage is output to drive the main LED string, the secondary LED string Grouping or driving the primary LED string and the secondary LED string set; and a direct drive having a current source coupled to each of the secondary LED strings to selectively turn off the selected secondary LED light post. The direct light emitting diode driving device of claim 1, wherein the presetting element and the direct driver further comprise a communication path. The direct-type light-emitting diode driving device of claim 1, wherein the direct-drive device further comprises: a current feedback path connected to one of the controllers of the preset component; and a current feedback a module that generates the controller of the presetting component through the current feedback path A control voltage is applied to regulate the stable voltage of the output. The direct light emitting diode driving device of claim 3, wherein the current feedback module further comprises: an integrating circuit connected between the secondary LED string group and the current source; And a current channel connected to the integrating circuit, and an indirect diode is used to selectively regulate the current flowing into the current source; the current feedback path further includes: a first resistor; a second resistor, Connected to the first resistor of the current feedback path in series, a contact of the first resistor and the second resistor is connected to an internal comparator of the controller, the internal comparator has an internal reference voltage; A third resistor has a first end and a second end. The first end is connected to a contact of the first resistor and the second resistor, and the second end is connected to the current channel. The direct light emitting diode driving device of claim 4, wherein: the comparator is composed of an operational amplifier having a reference voltage; and the current channel is an inverter when the current When the voltage of the source is higher than the reference voltage, current is supplied. The direct light emitting diode driving device of claim 4, wherein the integrating circuit is composed of a transfer conductance driving a comparator; and the current channel is a buffer. The direct light emitting diode driving device of claim 3, wherein the presetting element is coupled to a plurality of direct drivers. The direct light emitting diode driving device of claim 7, wherein each of the direct drivers has a current feedback module for causing current to flow out from the current feedback path, and the current flowing out generates a current Control voltage. The direct current LED driving device of claim 8, wherein the current feedback path further comprises: a first resistor; a second resistor connected in series to the first resistor, the first a contact of the resistor and the second resistor is connected to an internal comparator of the controller, the internal comparator has an internal reference voltage; and a third resistor has a first end connected to the first a junction of a resistor and the second resistor. The direct light emitting diode driving device of claim 9, wherein the direct light emitting diode driving device further comprises a protective diode, wherein the protective diode system is disposed on the third resistor and Between the current channels, and allowing current to flow from the junction of the first resistor and the second resistor to the preconditioning element. The direct light emitting diode driving device of claim 1, wherein the direct light emitting diode driving device comprises: a current sensing resistor, wherein the sensing corresponds to the addition of the secondary LED The main LED light string of the light string is a current of one of the voltages; an internal current source having a preset current, the preset current being equal to the minimum voltage value of the regulated output voltage, the current value sensed by the current sensing resistor; a diversion diode; a first resistor, when the current sensed by the current sense resistor is higher than the current value preset by the internal current source, the first resistor allows a large amount of current to flow into the diversion diode; an error amplifier , having a reference voltage source; an NOMS transistor connected to the error amplifier to form the current source; an offset resistor; and a REST resistor connected to the diversion diode and generating the reference voltage A bias voltage between the source and the REST resistor, wherein the bias voltage reduces current flow into the LED string. The direct light emitting diode driving device of claim 11, wherein: the current sensing resistor is connected to the first end of the main LED string and the presetting component; the first resistor, The first end, the second end and the third end, wherein the first end is connected to the current sensing resistor, and the second end is connected to the second end of the secondary LED string group; An internal current source is connected to the third end of the first resistor; the diversion diode has an anode and a cathode, wherein the anode is connected to the third end of the first resistor; the error amplifier, The system has a positive input terminal, a negative input terminal and an output terminal, wherein: the positive input terminal is connected to a reference voltage source; the negative input terminal is connected to the cathode of the current guiding diode; the NMOS battery The crystal has a first end, a second end and a third end, wherein the first end is connected to the second end of the secondary LED string set, and the second end is connected to the error amplification An output end, the third end is connected to the REST resistor; and the bias resistor is connected to The negative output of the error amplifier is between the REST resistor.