KR20120121320A - LED Driving Circuit having possible output stabilecurrent high-voltage DC and LED lamp using the same - Google Patents

Abstract

PURPOSE: A LED driving circuit capable of outputting a high voltage DC constant current and an LED lamp using the same are provided to maximize efficiency by forming 3V LED chips in serial to be operated as each LED properties as according to the change of a Vf value. CONSTITUTION: A bridge circuit(1) is combined with a power input terminal(11,12) through a filter(14,15) and a bypass condenser. The filter is composed of a fuse(13), a resistor(R1,R2), and an inductor(L1,L2). A power factor improvement circuit(17) is combined with the bypass condenser. The power factor improvement circuit includes a resistor(R4), a condenser(C4), and a Schottky diode(S1-S3). A drive circuit(2) includes a controller(21), an inductor(L) and a Schottky diode(S4). The cathode side of an LED is combined with a power output terminal(31). The anode side of the LED is combined with a power output terminal(32). Rectifying power from the bridge circuit flows through the drain terminal the controller.

Description

LED driving circuit capable of DC high voltage constant current output and LED lamp using same {LED Driving Circuit having possible output stabilecurrent high-voltage DC and LED lamp using the same}

The present invention relates to an LED driving circuit capable of outputting a DC high voltage constant current and an LED lamp using the same, and more specifically, to adopt a boosting (step-down or step-up) driving circuit to configure a 6V or 3V LED chip in series to form a Vf value. The present invention relates to an LED driving circuit capable of outputting a DC high voltage constant current and maximizing efficiency by operating each LED characteristic according to a change and securing sufficient reliability according to a high output constant current circuit, and an LED lamp using the same.

In general, the development of a light bulb using an LED chip (LED CHIP) is actively progressed as an energy saving method of the problem of inefficiency of the conventional filament incandescent bulb. Many companies are involved in the development of light bulbs and are being released to the market, but there are still unstable problems.

One of them is about reliability issues. The big advantage of LED chip is that it emits a lot of light. Because it emits 95% of light and 5% of heat, the energy saving is beyond imagination compared to 5% of light and 95% of heat of a conventional filament bulb. In this regard, even though the price of the bulb using the LED chip is many times higher, many users are changing one by one while having questions about energy saving.

However, LED chips are not the only advantages. If the circuit design is misconfigured and used, there is a problem in that a long life can be lost and reliability can be lost. That is, there is a problem that the life of the brightness, the life of the entire lamp is drastically shortened by the generation of a large amount of heat.

The present invention is to solve the above problems, by employing a boosting (step-down or step-up) driving circuit to configure a plurality of 6V or 3V LED chip in series to operate as each LED characteristic according to the change of the Vf value efficiency The purpose of the present invention is to provide a LED driving circuit capable of outputting a DC high voltage constant current capable of maximizing and securing sufficient reliability according to a high output constant current circuit and an LED lamp using the same.

In order to achieve the above object, the present invention provides a power supply stage based on a bridge circuit for full-wave rectification of AC input power, a smoothing capacitor coupled to the current output terminal of the bridge circuit, and a rectified power applied through the smoothing capacitor. In the LED driving circuit consisting of a driving circuit for outputting the LED driving power through;

The bridge circuit is coupled to a power input terminal to which an AC power is input, through a filter and a smoothing capacitor composed of a resistor and an inductor for shielding fuses and electromagnetic waves;

The smoothing capacitor is coupled to the rectifier power output terminal of the bridge circuit through a bypass capacitor and a filter for shielding electromagnetic waves, comprising a resistor and an inductor;

A power factor correction circuit having a resistor, a capacitor, and a schottky diode is coupled to the smoothing capacitor;

The driving circuit includes a controller, an inductor, and a schottky diode, wherein the rectified power output from the bridge circuit is coupled to a power output terminal and coupled to a drain terminal (DRAIN) of the controller through an inductor. It is supplied as the driving power of the controller, and the power output stage is coupled to the controller's drain stage (DRAIN) through a Schottky diode and coupled to the inductor so that the controller alternates between the drain stage (DRAIN) and the source stage (SOURCE) stage. Drive control a plurality of LEDs coupled to the power output terminal;

The cathode side of the LED is coupled to the power output stage, and the anode side of the LED is coupled to the power output stage. When the controller electrically couples the drain stage (DRAIN) and the source stage (SOURCE), the rectified power output from the bridge circuit is the power output stage. The LED is driven by flowing to the drain terminal (DRAIN) of the controller through the LED, power output terminal, and Schottky diode.

As described above, the present invention employs a boosting (step-down or step-up) driving circuit to configure a plurality of 6V or 3V LED chips in series to operate according to the characteristics of each LED according to the change of the Vf value to maximize the efficiency and high output constant current circuit. Therefore, there is an effect of ensuring sufficient reliability.

The present invention is not limited to the above-described specific preferred embodiments, and various modifications can be made by those skilled in the art without departing from the gist of the present invention as claimed in the claims. Of course, such changes will fall within the scope of the claims.

1 is an equivalent circuit diagram of a LED driving circuit capable of outputting a DC high voltage constant current according to an embodiment of the present invention and 20 6Watts of 6V 50mA of an LED lamp using the same.
2 is an LED lamp circuit of a DC high voltage constant current output according to an embodiment of the present invention and the LED lamp layout consisting of 20 6Watt 6V 50mA of the LED lamp using the same,
3 is an LED driving circuit capable of outputting a DC high voltage constant current according to an embodiment of the present invention and an LED driving circuit diagram of the LED lamp using the same;
Figure 4 is a perspective view showing a drive state of the LED lamp using the LED drive circuit capable of outputting DC high voltage constant current according to an embodiment of the present invention.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

For reference, in describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof is omitted.

In addition, terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to the intention or convention of a user or an operator.

Therefore, the definition should be made based on the contents throughout the specification.

In general, in LED lighting technology, reliability problems as well as light efficiency are the first things developers need to solve. Nevertheless, many developers are choosing to use easy methods to incorporate circuit design techniques.

In the case of a street lamp, for example, one streetlight goes out, and after a few days, the whole goes out and is replaced.By inserting a large amount of LED chips, it is inevitable to design a circuit in parallel or parallel structure. However, it is very difficult and inconvenient for the assembly process such as not only the cost but also the serial structure in pairs. Of course, the extra cost of this will also be a formidable problem.

The circuit configuration in the conventional lighting is mostly due to these problems, but the part that must be picked up is far from the circuit configuration in that it is a constant current drive due to the characteristics of the LED chip. can see. Of course, assuming that there are no errors in multiple chip characteristics, there will be no problem in selecting and applying constant voltage, constant and current operation.

(Figure A) and (Figure B) show the characteristics that operate in actual parallel and parallel structure.

(Figure A) 4-channel mixed series and parallel (Figure B) Serial structure

As shown in the above figure, the previous figure A shows the current flowing through each channel when it is composed of 4 channels (5 watts, 30V 50mA) in a series-parallel mixed structure using a 0.3Watt (6V 50mA) chip. As a result of measuring the change, each channel shows a different current flow.

Figure B shows the change of current in one channel in a 6Watt (120V 50mA) series structure. Therefore, in the serial and parallel structure, since the change of the current for each channel is large, the flow of current is concentrated to the LED chip having the bad characteristics. Then, the local heat is generated a lot and the probability of defect is very high.

In conclusion, first, as the current flows to the LED chip having poor characteristics, a large amount of heat is generated locally, and the light efficiency rapidly deteriorates with time.

Second, it is a factor that causes defects in long-term reliability. On the other hand, in LED lamp lighting, the design of the series structure can solve the above problems because it supplies a pure constant current source. Especially, when a large number of chips with high power and input voltage Vf are bundled together, high voltage input is performed. Is solved with high-voltage output driver (power) to achieve high efficiency and long-term reliability of rain.

In this regard, when looking at the LED bulbs of many manufacturers, it is convenient to design the lamp rather than configured according to the characteristics of the LED chip in the circuit configuration. The LED chip changes brightness rapidly as current flows and is very sensitive to thermal characteristics.

Figures 1a and 1b below show LED chip arrangements manufactured by many companies, and Figure 1a shows a 5Watt input and parallel mixed structure consisting of input voltage Vf 3V, 100mA or input voltage 6V, 50mA LED chips. Class LED lamp structure, Figure 1b is the LED lamp structure consisting of four 3V, 400mA 1.2Watt class in series.

        (Figure 1a) (Figure 1b)

LED chips are made of PN electrodes through a manufacturing process on various compound semiconductor substrates such as gallium arsenide and gallium nitride, which are called compound or mixture semiconductors, and these compound semiconductors are used in the process of manufacturing digital-based semiconductor devices. It is common to have more defects than the semiconductor of a board | substrate. These defects are very difficult to achieve uniform quality in the product's AD chip, but there are many parameters, but in particular, the relationship with the input voltage Vf which is closely related to the current chip LED chip.

(Figure 2) Typical current (I) and voltage (V) characteristic curve of LED chip

As shown in Figure 2, the characteristic of LED chip is that the change of current is very large according to the input voltage Vf. Therefore, when LED lamps are formed by mixing LED chips having different input voltage Vf values, the reliability of the LED lamps can be seriously affected. For example, as shown in Fig. 3 below, assuming that the 5W lamp is composed of the input voltage Vf 6V and 50mA chip in the equivalent circuit diagram, it can be said that if the entire LED chip is composed of Vf 6V or more, it can be efficient. There is no guarantee of this.

The reason for this is that different characteristics and characteristic changes with temperature change time occur. For this reason, even if the power supply device for driving the LED lamp of Figure 3 adopts positive, voltage circuit or constant and current circuit, it cannot solve the principle problem. That is, when the rated voltage and current are applied to the driving circuit, the loss of each insufficient part is generated by heat in the part with low Vf value, and this heat shortens the life of the whole product. If the configuration is lower than the current, there is a problem that the efficiency is lowered. This means that the deviation increases as the number of LED chips increases.

In other words, in the equivalent circuit, when driving in consideration of the pure rated voltage of 6V and 50mA at Rwatt = I · V, the total 4.8-4.725 = 0.075 (1.5%) is generated as heat.

(Figure 3) Equivalent circuit diagram with different input voltage Vf

The present invention is a method for solving such a conventional problem, by employing a boosting (step-down or step-up) driving circuit to fabricate the LED chip by configuring a plurality of 6V or 3V LED chip in series.

Table 1 shows 6V 50mA and Table 2 shows power consumption and output voltage by quantity when LED lamp is used with 3V 100mA LED chip.

Chip quantity, power consumption, and output voltage when 6V 50mA LED chip is used LED chip usage Power Consumption (Watt) Output voltage 16 4.8 96 20 6 120 22 6.6 132 27 8.1 162 40 12 240 50 15 300

Chip quantity, power consumption, and output voltage when 3V 100mA LED chip is used LED chip usage Power Consumption (Watt) Output voltage 16 4.8 48 20 6 60 22 6.6 66 27 8.1 81 40 12 120 50 15 150

As shown in Figures 1 and 2, the series structure can control the whole with a constant current flow. In Figure 2, the LED chip has a large current change according to the change of the Vf value. Therefore, even though there is a change in the LED chip Vf, the characteristics of each LED chip have a constant current flow. As long as it works, the efficiency can be maximized. This means that it is possible to secure sufficient reliability and high efficiency depending on the completeness of the high output constant current circuit diagram.

3 is a circuit diagram showing an LED driving circuit capable of outputting a DC high voltage constant current according to the present invention.

In FIG. 3, the LED driving circuit basically includes a bridge circuit 1 for full-wave rectifying AC input power, a bypass capacitor C1 coupled to a current output terminal of the bridge circuit 1, and a bypass capacitor C1. Comprising a driving circuit 2 for outputting the LED driving power through the power output stage (31, 32) based on the rectified power applied through.

The bridge circuit 1 is coupled to the power input terminals 11 and 12 through which the AC power is input, through the fuse 13, the filters 14 and 15, and the bypass capacitor C1. The filters 14 and 15 are for shielding electromagnetic waves, which are configured with resistors R1 and R2 and inductors L1 and L2, respectively.

The bypass capacitor C1 is coupled to the rectifier power output terminal of the bridge circuit 1 through a filter 16 and a bypass capacitor C3 for shielding electromagnetic waves having a resistor R3 and an inductor L3. . A power factor improving circuit 17 including a resistor R4, a capacitor C4, and a schottky diode S1-S3 is coupled to the bypass capacitor C1.

The drive circuit 2 includes a controller 21, an inductor L, and a schottky diode S4. The rectified power output from the bridge circuit 1 is coupled to the power output terminal 31 and coupled to the drain terminal DRAIN of the controller 21 through the inductor L. The rectified power is also supplied as the drive power of the controller 21. In addition, the power output terminal 32 is coupled to the drain terminal DRAIN of the controller 21 through the Schottky diode S4 and to the inductor L1. In the above configuration, the controller 21 alternately controls the drain stage DRAIN and the source stage SOURCE stage to drive control a plurality of LEDs coupled to the power output stages 31 and 32.

The cathode side of the LED is coupled to the power output stage 31 and the anode side of the LED is coupled to the power output stage 32. When the controller 21 electrically couples the drain terminal DRAIN and the source terminal SOURCE, the rectified power output from the bridge circuit 1 is connected to the power output terminal 31, the LED, the power output terminal 32, and the Schottky diode. The LED is driven by flowing to the drain terminal DRAIN of the controller 21 through S4.

At this time, the rectified power flows through the inductor L to the drain terminal DRAIN, whereby a current is accumulated in the inductor L.

On the other hand, when the controller 21 electrically disconnects the drain terminal DRAIN and the source terminal SOURCE, a counter electromotive force is generated in the inductor L, so that the current accumulated in the inductor L is stored in the power output terminal 31, the LED. , And flows through the power output terminal 32 and the schottky diode S4. Therefore, at this time, the LED coupled to the power output terminals 31 and 32 is driven by the current accumulated in the inductor L.

As such, the controller 21 drives the LED appropriately by interrupting the electrical path between the drain terminal DRAIN and the source terminal SOURCE at a constant cycle.

1: bridge circuit
2: drive circuit
11,12: power input terminal
13: fuse
14,15,16: filter
17: heat rate improvement circuit
21: controller
31,32: Power output terminal
C1, C2, C3, C4: Capacitor
L, L1, L2, L3: Inductor
R1, R2, R3, R4: Resistance
S1, S2, S3, S4: Schottky Diode

Claims (3)

In the LED driving circuit;
By adopting boosting (step-down or step-up) driving circuit, several 6V or 3V LED chips are configured in series and operate according to each LED characteristic according to the change of Vf value to maximize efficiency and secure sufficient reliability according to high output constant current circuit. LED (LED) driving circuit capable of outputting a DC high voltage constant current. On the basis of the bridge circuit 1 for full-wave rectification of AC input power, the bypass capacitor C1 coupled to the current output terminal of the bridge circuit 1, and the rectified power applied through the bypass capacitor C1. An LED driving circuit comprising a driving circuit 2 for outputting LED driving power through the power output stages 31 and 32;
In the power input terminals 11 and 12 into which AC power is input, filters 14 and 15 composed of resistors R1 and R2 and inductors L1 and L2 and a bypass capacitor C1 for shielding the fuse 13 and electromagnetic waves. The bridge circuit (1) is coupled through;
The bypass capacitor C1 is connected to the rectifier power output terminal of the bridge circuit 1 through a filter 16 and a bypass capacitor C3 for shielding electromagnetic waves, each of which includes a resistor R3 and an inductor L3. Combined;
A power factor improving circuit (17) having a resistor (R4), a capacitor (C4), and a schottky diode (S1-S3) is coupled to the bypass capacitor (C1);
The driving circuit 2 includes a controller 21, an inductor L, and a schottky diode S4, and the rectified power output from the bridge circuit 1 is coupled to the power output terminal 31. It is coupled to the drain terminal (DRAIN) of the controller 21 through the inductor (L), the rectified power is supplied as the driving power of the controller 21, the power output terminal 32 is the controller through the Schottky diode (S4). Coupled to the drain stage DRAIN of the 21 and coupled to the inductor L1, the controller 21 alternately intercepts the drain stage DRAIN and the source stage SOURCE stage to supply power to the output stages 31 and 32. Drive control a plurality of LEDs coupled to the plurality of LEDs;
The cathode side of the LED is coupled to the power output terminal 31 and the anode side of the LED is coupled to the power output terminal 32 so that the controller 21 electrically couples the drain terminal DRAIN and the source terminal SOURCE. The rectified power output from the circuit 1 flows to the drain terminal DRAIN of the controller 21 through the power output terminal 31 and the LED, the power output terminal 32, and the Schottky diode S4. LED (LED) driving circuit capable of outputting a DC high voltage constant current. LED lamp using the second term.

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