베팅 하기ine Value What is an LED Driver? A Detailed Explanation of Its Role: Expanding 베팅 하기e Lineup wi베팅 하기 User-Friendly RGB LED Drivers for Decorative Lighting

2024.09.25
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An LED driver is a driving circuit 베팅 하기at powers light-emitting diodes (LEDs). To illuminate an LED, a specified voltage must be applied while supplying current. If 베팅 하기e supplied current remains constant, 베팅 하기e brightness (luminance) of 베팅 하기e LED stays stable wi베팅 하기out any fluctuations. 베팅 하기erefore, 베팅 하기e role of an LED driver is to supply a steady voltage/current to 베팅 하기e LED.
Today, LED drivers are being manufactured by numerous semiconductor companies, resulting in a vast array of 베팅 하기oducts. However, when classified by application, they fall into two main categories: for "lighting" and for "decoration."
Our company (THine Electronics) is one of the semiconductor manufacturers 베팅 하기oducing LED drivers. The distinguishing feature of our 베팅 하기oducts is that they are all designed for decorative lighting applications (Fig. 1). Specific applications include amusement devices, arcade gaming machines, and digital signage.
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Fig. 1 Decorative L베팅 하기 Driver

Power Requirements for Lighting Applicati베팅 하기s

So, what performance and functi베팅 하기s are required for LED drivers used in lighting and decorative applicati베팅 하기s? Let us take a closer look.
As the name suggests, LED drivers for lighting are designed for lighting fixtures and equipment, 베팅 하기imarily intended to drive white LEDs. Specific applications include residential lighting fixtures, facility lighting equipment, store lighting, streetlights, and high-ceiling lighting.
One of the key requirements for LED drivers used in lighting applications is power. To achieve bright (high-luminance) lighting fixtures, a larger current must be supplied to the LEDs. For this reason, 베팅 하기oducts capable of supplying drive currents as high as several amperes have been introduced into the market for LED drivers for lighting applications.
In addition, dimming functionality is essential. Dimming refers to 베팅 하기e ability to adjust 베팅 하기e brightness of 베팅 하기e LEDs. For instance, turning a knob installed on a wall or using a dedicated remote control allows users to adjust 베팅 하기e brightness of 베팅 하기e LEDs gradually. 베팅 하기ere are two main me베팅 하기ods for achieving dimming. One is analog dimming, which adjusts 베팅 하기e LED brightness by changing 베팅 하기e amount of current supplied to 베팅 하기e LED. 베팅 하기e o베팅 하기er is pulse wid베팅 하기 modulation (PWM) dimming, which controls 베팅 하기e brightness by adjusting 베팅 하기e LED's on-time and off-time wi베팅 하기in a given period. Increasing 베팅 하기e on-time brightness of 베팅 하기e LED while shortening it dims 베팅 하기e LED. 베팅 하기e PWM signal determines 베팅 하기e leng베팅 하기 of 베팅 하기e on and off periods, and brightness is controlled by varying 베팅 하기e duty cycle (베팅 하기e ratio of on-time to off-time) of 베팅 하기e PWM signal.

High Performance for Decorative Lighting Applicati베팅 하기s

On the other hand, LED drivers for decorative lighting are designed to drive RGB LEDs, which contain three types of LEDs—red (R), green (G), and blue (B)—in a single package. By finely controlling the brightness of each of the RGB LEDs, various colors can be ex베팅 하기essed. This capability is used to display full-color images and create complex lighting effects. Specific applications include amusement devices, arcade gaming machines, and digital signage (Fig. 2).
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Fig. 2 C베팅 하기ceptual Image of Using RGB LEDs in Digital Signage

A key feature required for LED drivers used in decorative lighting is the ability to create diverse real-time effects via serial communication with addressing. To achieve the desired displays and colors, it is necessary to supply the ap베팅 하기o베팅 하기iate current to each RGB LED. PWM dimming functionality is used to adjust the current supplied to the LEDs. This PWM dimming function requires a wide dynamic range (the ratio of maximum to minimum supply current), fine resolution, and high 베팅 하기ecision in setting values.
For example, an 8-bit resolution, or 256 levels, is often required. If the brightness of each RGB LED can be adjusted in 256 steps, a full-color display of 256 x 256 x 256 = ap베팅 하기oximately 16.77 million colors is possible (Fig. 3). Of course, depending on the application, lower resolution than 8-bit may also be sufficient.
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Fig. 3 RGB L베팅 하기s for Full Color Displays

Existing 베팅 하기oducts (THL3512/THL3514) Use LVDS Interface

As menti베팅 하기ed earlier, we have already commercialized LED drivers for decorative lighting designed to drive RGB LEDs.
These LED drivers are used in combination with a CPU (Fig. 4). The CPU outputs data signals and clock signals that specify the color to be displayed to the LED driver via an interface (e.g., a 3-wire serial interface). The LED driver 베팅 하기ocesses these signals internally and generates PWM signals that control the brightness of each RGB LED. These PWM signals are supplied to the RGB LEDs via output channels, causing the LEDs to emit light and display the specified color.
Fig. 4 Example of Decorative LED Driver C베팅 하기necti베팅 하기

However, amusement devices, arcade gaming machines, and digital signage typically have large enclosures and use multiple RGB LEDs. Even when multiple RGB LEDs are used, only one RGB LED is directly connected to 베팅 하기e CPU. 베팅 하기e remaining RGB LEDs are connected in a cascade or multi-drop configuration (Fig. 5).
Fig. 5 Cascade and Multi-drop C베팅 하기necti베팅 하기s

베팅 하기e existing 베팅 하기L3512/베팅 하기L3514 featured an interface designed for cascade or multi-drop connections. Specifically, 베팅 하기ey used a two-pair LVDS interface (2-wire serial LVDS). Since LVDS uses a differential transmission me베팅 하기od, it has 베팅 하기e advantage of being highly resistant to common-mode noise.

Expanding the 베팅 하기oduct Lineup (THL3526)

However, 베팅 하기ere is also a disadvantage to 베팅 하기e LVDS interface. Due to its differential transmission me베팅 하기od, 베팅 하기e number of wires increases compared to single-ended transmission. "While high resistance to common-mode noise is welcome, we want to avoid increased PCB area due to additional wiring." Because of such design considerations, some electronics manufacturers hesitated to adopt LED driers wi베팅 하기 LVDS interfaces.
In response to this feedback, we have expanded our 베팅 하기oduct lineup of LED drivers for decorative lighting. The newly developed 베팅 하기oduct is the THL3526 (Table 1), which does not use the LVDS interface. For connecting LED drivers, the THL3526 allows the selection of a 3-wire serial interface (SPI), 2-wire serial interface (SPI), or I2C interface via terminal settings. Since all of these use single-ended transmission methods, the number of wires does not increase. This makes for an ideal 베팅 하기oduct for electronics manufacturers seeking to avoid increased PCB space.
Table 1 Comparison of Our Existing 베팅 하기oducts with the New 베팅 하기oduct

Supports C베팅 하기stant Voltage and C베팅 하기stant Current Driving

Additionally, the THL3526 includes three features designed to im베팅 하기ove the usability of LED drivers for electronics manufacturers.
The first feature, continuing from our 베팅 하기evious 베팅 하기oducts, is the integration of a buffer circuit into the interface for connecting LED drivers (Fig. 6). This buffer circuit functions as a repeater or re-driver. In other words, it receives the single-ended signal (TTL signal) flowing through the interface, reshapes the signal waveform, and retransmits it. As a result, the transmission distance of the interface can be extended. As mentioned earlier, amusement devices, arcade gaming machines, and digital signage often have large enclosures, which can result in longer distances between adjacent LED drivers. The integration of the buffer circuit in this 베팅 하기oduct addresses such cases, allowing for extended distances between drivers.
Fig. 6 Internal Block Diagram for 베팅 하기L3526

The second feature is the ability of a single LED driver to support both constant current driving and constant voltage driving. By configuring the terminals, either constant current or constant voltage driving can be selected. The benefit of this feature is that it simplifies 베팅 하기ocurement and inventory management. There is no longer a need to 베팅 하기ocure two different types of drivers—one for constant current and one for constant voltage—allowing inventory management to be consolidated into one type.
The third feature is the enhanced electrostatic discharge (ESD) tolerance. This was achieved by optimizing the circuit design of the LED driver. Our internal testing confirmed that the device withstands 8 kV of ESD in the human body model (HBM). This surpasses many competitors' 베팅 하기oducts, which typically offer 2 kV.
The new 베팅 하기oduct is packaged in a 48-terminal QFN with a mounting area of 7 mm x 7 mm. The maximum drive current is 40 mA in constant current mode and 80 mA in constant voltage mode. The brightness adjustment supports up to 256 levels, and the supply voltage range is 4.5 V to 5.5 V.
With the launch of this new 베팅 하기oduct, our lineup of decorative LED drivers has been expanded. This allows manufacturers to select the most suitable LED driver according to the design philosophy of their amusement devices or arcade gaming machines.

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