High power LEDs require high drive currents from 350 to 1000 mA. Using the latest technology, each LED can produce 40~80 lumens of light flux, typically 1~3W. According to the US Department of Energy website, the main LED manufacturers are Cree, Philips and Osram. The HBLED will be compared to the widely used white paper lamps and fluorescence, and an example of a circuit for a home application will be given.
Comparison light source
Consumers who know the benefits of HBLED (high-brightness LED) will find ways to use HBLED as much as possible. It can be seen from the comparison of the data in Table 1 that HBLED is the brightest lighting solution.
The energy efficiency of a light source is similar to efficiency. How much of the energy input into the bulb becomes light compared to the calorific value? Users want this value to be higher, and obviously HBLED does this. If the drive current fluctuates, the color tone of the incandescent lamp is most likely to change.
Compared to incandescent lamps, the main advantage of fluorescent lamps and HBLEDs is their longevity, so incandescent bulbs are being phased out in many countries. Next, HBLEDs may outperform fluorescent lamps in terms of penetration because HBLEDs are solid (made of silicon, not brittle), are very small in size, and contain no harmful chemical components (no special environmental treatment is required).
HBLED lighting design goals
To allow consumers to switch to HBLEDs, HBLEDs must be of high quality. Consumers require a power factor of at least 90% and an efficiency of 80% or higher. In DC applications, the maximum input voltage must not exceed 40V. In AC applications, an input voltage of 120V or 240V (270V maximum) may be used. HBLEDs must be driven with pulse width modulators operating at frequencies above 120 Hz to reduce annoying visible strobes. Sometimes this frequency needs to be variable. In addition to these design constraints, engineers and applications decide whether to use isolated or non-isolated designs. If necessary, you may also consider using a complicated dimming circuit.
As you can see, there is no one-size-fits-all solution. Things to consider in the design are interlocking. Each solution needs to be specifically designed based on the number of LEDs and the current flowing through the LEDs. Designers also need to adjust for different electromagnetic devices, as well as the power devices and output capacitors selected. Application circuit
The price of HBLED is about 1~2 dollars. Since the HBLEDs are used in series in each design, the cost constraint of the converter is not considered in the design.
The first introduced controller is the ISL6721. The ISL6721 is a single-ended pulse-width modulated current mode controller with peak current mode control that effectively resolves instantaneous power problems and provides built-in overcurrent protection. A large contract manufacturer has adopted the ISL6721 to produce a product that replaces the T8 circuit currently in use (replaces the traditional ballast circuit in a fluorescent starter). The ISL6721 can also be set as an alternative to incandescent lamps. The non-solid flyback solution is currently used in a shopping mall in Asia. The program uses 10 HBLEDs with an output of 10W and an efficiency of 82%.
To be truly competitive in the home market, HBLED lighting solutions must also provide dimming capabilities. Smart circuits can do this. Remember that the LED is driven by a pulse width modulation controller. In other words, the LED is not always in the "on" state. The number of pulses that power the LED is controlled by the controller and is variable. As it happens, this work is also done by the "controller."
The core of the complete circuit diagram design of a spotlight solution consisting of an adapter and dimming circuit with 6 LEDs (of course the HBLED is removed) is the ISL6745A controller. The device in the upper right corner constitutes a SEPIC controller that drives the six HBLEDs in series. The amplifiers around it perform current regulation, short-circuit protection and overvoltage protection. In the lower left corner, you can find the AC dimming circuit. The dimmer's amplifier output is filtered first and then used as a reference point for the current regulator, fed back into the control loop.
The ISL6745A's bias voltage, VDD, ranges from 6.5 to 20V, and the low-side FET driver's output is 12V, 1A, which can drive a low-side FET (Q1 in this design), the gate of a high-voltage driver IC, or It is a gate drive transformer.
Among the Intersil products, the ISL6745A is the most popular HBLED driver. In addition to the usage method shown in Figure 1, the switching frequency, soft start, and overtemperature protection of the ISL6745A can be adjusted, and the "dead time" can be precisely adjusted. The ISL6745A is available in a space-saving MSOP-10 package. The flexibility of the ISL6745A is also a feature of its ability to work in both isolated and non-isolated modes. Dimming is also optional.
in conclusion
HBLED is the greenest alternative to consumer lighting, and technological advances are enough to make it a viable option. Alternatives to incandescent and fluorescent lamps have emerged on the market. To save energy, extend service life, improve safety and increase reliability, please use HBLED.
5050 Rgb Color Strip ,Color Changing Strip Lights,Colored Led Light Strips,Multi Color Led Strip Lights
NINGBO SENTU ART AND CRAFT CO.,LTD. , https://www.lightworld-sentu.com