1. Scenario lighting: It is the scene lighting proposed by Philips in 2008. The lighting is designed according to the needs of the environment. The scene lighting is based on the place, aiming to create a beautiful and beautiful lighting environment to set off the scene effect and make people feel There is a scene atmosphere.

2. Emotional lighting: It is the mood lighting proposed by Kaisio in 2009, and the lighting is designed according to people's needs. Emotional lighting is based on human emotions, creating a mood-like lighting environment from a human perspective. The mood lighting is different from the scene lighting. The mood lighting is dynamic, the lighting method can meet the people's spiritual needs, making people feel the mood; and the scene lighting is static, it can only emphasize the needs of the scene lighting, but can not express Human emotions, in a sense, mood lighting covers scene lighting. Emotional lighting consists of four aspects: one is environmental protection and energy conservation, the other is health, the third is intelligent, and the fourth is humanization.

Second, in order to do a good job in LED lighting design, we must work hard in the following aspects.

1, do not use bipolar power devices

Doug Bailey pointed out that because bipolar power devices are cheaper than MOSFETs, typically around 2 cents, some designers use bipolar power devices to reduce LED drive costs, which can seriously affect circuit reliability because The temperature of the LED driver board increases, and the effective working range of the bipolar device will shrink rapidly. This will cause the device to malfunction when the temperature rises, which will affect the reliability of the LED lamp. The correct way is to use the MOSFET device and the MOSFET device. Lifespan is much longer than bipolar devices.

2. Do not use MOSFET withstand voltage of 600V

MOSFETs with a withstand voltage of 600V are relatively cheap. Many people think that the input voltage of LED lamps is generally 220V, so the withstand voltage of 600V is enough, but in many cases the circuit voltage will reach 340V. In the case of surge, the 600V MOSFET is easily broken down. Therefore, the life of the LED lamp is affected. In fact, the 600V MOSFET may save some cost but the cost of the whole circuit board. Therefore, do not use a 600V MOSFET, and it is better to use a MOSFET with a withstand voltage exceeding 700V.

3, try not to use electrolytic capacitors

Do you want to use electrolytic capacitors in the LED driver circuit? There are supporters and opponents. Supporters believe that if the temperature of the board can be controlled well, the purpose of extending the life of the electrolytic capacitor can be achieved in turn, for example, the high temperature of 105 degrees is 8000 hours. Electrolytic capacitor, according to the current electrolytic capacitor life estimation formula "every 10 degrees decrease in temperature, the life is doubled", then its working life is 16000 hours in a 95 degree environment, and the working life is 32000 hours in a 85 degree environment, at 75 The working life in the environment is 64000 hours. If the actual working temperature is lower, the life will be longer! From this point of view, as long as the selection of high-quality electrolytic capacitors has no effect on the life of the driving power supply!

Other proponents believe that the low-frequency flicker caused by the high ripple current caused by electroless capacitors will cause physiological discomfort to some people's eyes. The large amplitude of low-frequency ripple will also cause some digital camera equipment to appear poor. A brightly lit grid of flickering lights. Therefore, high-quality light source lamps still need electrolytic capacitors. However, opponents believe that electrolytic capacitors will naturally age. In addition, the temperature of LED lamps is extremely difficult to control, so the life of electrolytic capacitors will inevitably decrease, thus affecting the life of LED lamps.

In this regard, the industry's well-known people explained that in the LED driver circuit input part can be considered without electrolytic capacitors, in fact, using PI's linkSwitch-PH can save electrolytic capacitors, PI's single-stage PFC / constant current design can let designers save Large-capacity capacitors, in the output circuit, high-voltage ceramic capacitors can be used instead of electrolytic capacitors to improve reliability. Some people design a two-stage circuit, using a 400V electrolytic capacitor at the output, which will seriously affect For the reliability of the circuit, it is recommended to use a ceramic capacitor for a single-stage circuit. For industrial applications that do not pay much attention to dimming functions, high temperature environments, and high reliability, electrolytic capacitors are not recommended for design.

4, try to use integrated MOSFET

If the LED luminaires are not designed to be very powerful, it is recommended to use LED driver products with integrated MOSFETs because the benefit of this is that the integrated MOSFETs have less on-resistance and generate less heat than discrete ones. In addition, the integrated MOSFET is The controller and the FET together generally have a thermal shutdown function. When the MOSFET overheats, the circuit is automatically turned off to protect the LED luminaire. This is very important for the LED luminaire, because the LED luminaire is generally small and difficult to dissipate air.

5, try to use a single-stage architecture circuit

If the efficiency of the PFC is 95% and the efficiency of the DC/DC section is 88%, the efficiency of the entire circuit will be reduced to 83.6%! PI's linkSwitch-PH device will simultaneously PFC/CC controller, a 725 V MOSFET and MOSFET The driver is integrated into a single package, increasing the efficiency of the driver circuit to 87%. However, such devices greatly simplify board layout design, eliminating up to 25 components used in traditional isolated flyback designs. The components that are omitted include high voltage bulk electrolytic capacitors and optocouplers. The LED two-stage architecture is suitable for older drivers that must use a second constant current drive circuit to allow the PFC to drive the LEDs at constant current. These designs are outdated and no longer cost effective, so in most cases it is best to use a single stage design.

Linear Array Loudspeaker

Array Speakers,Line Array Speaker,Linear Array Loudspeaker,Linear Array Loudspeaker System

The ASI Audio Technology Co., Ltd , https://www.asi-sound.com