Common causes of LED lights flashing and approaches

Usually the human eye can perceive frequencies up to 70 Hz light flashes above this frequency is not perception. Therefore, in the LED lighting applications, if the pulse signal frequency is lower than the low frequency component of 70 Hz, the human eye will feel flicker. Of course, in the specific application, there are a variety of factors that could cause the LED blinks. For example, in the off-line low-power LED highbay light applications, a common power supply topology isolated flyback topology. ON Semiconductor 8 W the Offline-type LED solid-state lighting meet the "Energy Star" standard drive GreenPoint? Reference design, for example, due to the the flyback regulator sinusoidal square wave power conversion did not provide constant energy to the primary bias, dynamic Self-powered (DSS) circuit may activate and cause light flashes. In order to avoid this problem, it is necessary to make the primary bias able to discharge part in each half cycle, and accordingly, need to be appropriately selected form the magnitude of this capacitance and the resistance of the bias circuit. More LED lights product information please click: http://www.dzsc.com/product/info/3306.html

In addition, even if the LED drive applications in use provide an excellent power factor correction, to support the TRIAC dimmer, also requires the electromagnetic interference (EMI) filter. Transient currents caused by the TRIAC step (step) will stimulate the natural resonance of the inductance and capacitance in the EMI filter. If this resonance characteristics cause the input current is reduced under the TRIAC holding current, TRIAC will turn off. After a short delay, TRIAC usually will turned on to inspire the same resonance. Within a half cycle of the input power waveform, in this series of events may be repeated several times, so as to form a visible LED highbay light To cope with this problem, a key requirement for a very low input capacitance EMI filter TRIAC dimming, this capacitor decoupling by TRIAC and winding impedance. The capacitance decreases according to the formula, the dimming module, it is possible to increase the resistance of the resonant circuit, in principle, to suppress the oscillation, the restoration of the desired operation of the circuit.

PWM dimming LED life impact of

The LED itself long life the PWM dimming does not prejudice the life expectancy of the LED; even help reduce the LED heat PWM dimming, in fact, can also help prolong the LED life expectancy. Of course, the system design, the need for effective detection and control LED temperature to ensure LED work reliably, reflecting the advantages of long life and low maintenance costs.

TRIAC dimming of the LED brightness potential problems

TRIAC dimming is a popular the dimming market welcomed. TRIAC dimmer originally designed for incandescent TRIAC dimming LED driver but also launched this leading suppliers such as Semiconductor, TRIAC dimming ideal for LED lighting. But this approach also has its limitations where, such as increased circuit complexity, affect the power factor, the dimming level is relatively limited and other issues. The ON Semiconductor As the premier high-performance, energy efficient silicon solutions provider for green electronics, the latest LED driver for residential and commercial LED lighting applications the NCL30000 this device using a critical conduction mode (CrM) flyback architecture The single-stage topology power factor higher than 0.95, it is also avoided, DC - DC (DC-DC) switching segments, simplifying the circuit. This device, even in low also provide high energy efficiency, and compliance with various regulatory requirements and overall system luminous efficiency requirements. In addition, this device is compatible to leading edge TRIAC dimmer and the trailing edge transistor dimmer and dimmer depending adjustable LED light output to less than 2%, and provide excellent dimming performance.

Here are just look at the the Semiconductor Thermal push LED driver program

ON Semiconductor has introduced several important energy-efficient GreenPoint? LED driver reference design are:

1,3 W to 5 W LED driver reference design. This reference design uses the size and features for MR16 LED replacement configuration, has been carefully constructed and tested, and used to drive high-brightness LED reference design based on the buck - boost topology, non-isolated constant Semiconductor flow configuration, the work of about 150 kilohertz (kHz) frequency NCP3065 switching regulator. This reference design circuit for track lighting, automotive lighting and landscape lighting, 12 Vac or 12 Vdc applications, regardless of changes in input line and output LED voltage, flat current steady flow. This reference design also provides a unique auto-detection circuit, supports 12 Vdc or 12 Vac power input, while maintaining the target output current.

2, isolated 8 W constant current LED driver GreenPoint? Reference design. This reference design expectations in line with the U.S. "Energy Star" (an ENERGY STAR?) Residential lighting applications, the 1.1 version of the solid-state lighting (SSL) requirements designers, and the same has been carefully constructed and tested, and used to drive a portable table lamp, cabinet 1-8 power LED. applications within the lighting and outdoor porch light reference design uses a novel circuit configuration, no need to increase the the additional passive power factor correction (PFC) network, can provide high 115 Vac power factor of 0.85 to reduce the number of components, and easily meet the power factor requirements of residential LED applications. This design support from 90 Vac to 265 Vac universal input voltage the Semiconductor integrated fixed frequency current mode controller and a 700 V MOSFET NCP1014 switching regulator integrated circuit (IC).

3, the reference design for offline high power factor TRIAC Dimmable LED Driver GreenPoint? This reference design uses NCL30000 key device, intended for use in the United States, "Energy Star" commercial and residential lighting applications. NCL30000 working temperature range of -40 ° C to +125 ° C, to ensure the scope of work for most of the solid-state lighting (SSL) applications under the different environments. Low start-up current NCL30000 has a typical value of 24 microamps (μA) and the typical value of a low operating current of 2 mA, with the energy-efficient design. NCL30000 Other key features include programmable on-time limiter, zero current detection (ZCD) sensing module, gate driver, and application CrM switching power supply required for other PWM circuit and protection functions.

ON Semiconductor LED driver design advantages

ON Semiconductor provides many different LED driver solutions for a broad range of applications: automotive, mobile / portable (mobile phone and digital camera's LCD backlight and camera flash), large-size LCD screen (laptop, netbook, LCD TV) LCD backlighting, signs, buildings, as well as general lighting.

ON Semiconductor provides products cover three kinds of LED drive method: linear program (extremely simple and minimal external components), DC - direct current (DC-DC) inductive switching converter (used to provide energy-efficient and larger current) , as well as the charge pump switching converter (used to provide energy-efficient and compact size).

ON Semiconductor also offers different LED highbay light output modulation / dimming method: triac switching elements (TRIAC) dimmer, pulse-width modulation (PWM) dimming, analog dimming, digital dimming (DALI, the I2C etc.).

Semiconductor LED driver products can be different types of voltage source: AC high voltage from 120 Vac to 480 Vac (voltage specification of certain highways in the United States), the medium AC or DC voltage (such as cars 12 Vac or 12 the Vdc voltage), 0.9 to 5 V portable battery.

Overall, no matter what kind of LED lighting applications, regardless of what is required driver program, no matter what kind of dimming method, no matter what kind of common supply voltage, ON Semiconductor LED driver solution that can provide suitable to meet the different needs of customers.

More info you can visit: www.lead-lighting.com