LED fluorescent lamp power supply design knowledge
Date:2013-08-18 Hits:160
Lamp power supply is a very important component, also called: drive, a direct impact on the power supply to the lamp life. If the LED lamp than a man, then the LED light source lamp beads is the body of the lamp, and the lamp power is in the heart. The importance of visible power, so the power is also known as LED tube industry professionals soul.
LED drive power requirements of major
1, the double-height, namely: high power factor (PF), high conversion efficiency. PF = 0.9 and above, has been far more than the standard requirements of the world grid, thereby reducing the pollution of the grid; while the high conversion efficiency of products, in order to maximize the conversion of electrical energy into light energy, reducing heat loss.
2, the power to distinguish between the voltage at the electrical connection: Wide voltage power supply - the so-called wide voltage can adapt to most countries refers to the normal operating voltage range is generally wide voltage :85-265VAC or 100-265VAC;
3, narrow voltage supply: the so-called narrow voltage actually is a relative term, mostly narrow voltage range :175-265V (there are 185-265V), the different power suppliers differ.
4, according to distinguish between input and output: There are isolated and non-isolated power supply of the points.
Simple Tip: teach you a trick best way to determine soil LED driver is isolated or non-isolated power supply is isolated from the volume is too large, the safety factor in use is the highest; contrast, non-isolated smaller. Due to cost reasons, isolation products in the market as non-isolated wide market.
Isolated and non-isolated power supply
A non-isolated constant current power supply: non-isolated refers to the load terminal and the input terminal has a direct connection, so there is risk of electric shock load touch. Currently the most used non-isolated buck directly. Which is obtained after the AC rectified DC high voltage, then the direct use of antihypertensive (Buck) constant current control circuit buck and non-isolated constant current source has the advantage of simplicity and high efficiency.
2, isolated constant current power supply: Isolated refers to the input and output isolation transformer isolation transformer may be the frequency that may be high frequency. However, both the input and output isolated. After isolation, without danger to the earth after level voltage, output voltage can be equal to the input voltage or an input voltage range can contain not pose a threat to humans, wide voltage performance is very good. Isolated power Disadvantages: bulky, or an equivalent volume of less power.
LED power supply fundamentals
Generally, LED drive power mainly through the following three steps:
1, the buck: the access 220V (or 110V) AC mains buck becomes the low voltage.
2, rectified: After a low-voltage DC step-down and then through LED (LED diode characteristics: One-way conductivity) into a stable DC voltage electricity.
3, filter: by capacitive, inductive filter becomes stable after several low-voltage DC.
4, to the LED power supply.
Several Glossary about power
1, the power factor (PF): power factor is the cosine of the phase difference between voltage and current values. Because the current and voltage are the wave resistance map, a map is a sine, cosine a diagram difference waveform by two 1/4 cycles (i.e.: 90 °), thus forming a PF value, in order to increase the PF value, to A correction in the power supply circuit, a high PF value is also relatively high cost of power. PF correction circuit without PF value is generally about 0.6, with PF basic circuit can reach 0.9, or even higher. PF value is low when on the entire power system grid pollution, when the PF value is low, the electrical equipment for power generation efficiency becomes low, so the state for some big power with PF value of electrical equipment requirements, general it would be no less than 50W clear requirements. PF value state requirement is more than 0.6.
2, conversion efficiency: the popular talk is the output power and input power ratio, such as: a 10W electric power consumed by a lamp