The LED fluorescent lamp power constant current amount of accuracy to be the most appropriate?
Built-in led drive power supply is one of the most important parts of led fluorescent tube, suitable built-in led drive power supply for led fluorescent tube is equivalent to have a healthy heart. Choose a suitable led built-in driver power supply is very important to the delivery performance of the led fluorescent tube. NiuBao power below summarizes some knowledge about built-in LED fluorescent tube LED drive power supply some help to those in need.
1, LED fluorescent tube why constant-current LED built-in driver power supply
LED semiconductor are greatly influenced by the environment, temperature, LED the current will increase; The increase of the voltage, the LED current will increase. LED is current driven chip, has a rated current. More than rated current job for a long time, can greatly shorten the service life of the LED. Using the constant current led built-in led drive power supply can avoid current change with environment factors such as temperature and voltage.
2, LED fluorescent lamp power how to do with light plate matching
Some manufacturers to design good light board, again to find power supply, so find a power supply is not very appropriate. But also make do with, as a result of LED fluorescent tube severe fever, low efficiency or the input voltage range is not enough. In fact, in the design of the lamp board series and way can make the led and built-in drive power supply manufacturer communication, be customized.
3 what is the working current, LED light source is the most ideal
LED light source for encapsulation of LED chip size is different, its rated current also is distinguishing. We are now commonly used 3014 patch lamp bead rated current 30 ma, some 30 ma factory design from the start, actually this electrical work shed fever is very serious, through the contrast test for many times, designed to 27 ~ 29 ma is ideal, the recommended design for 28 ma.
4 what is the working voltage, LED light source
Generally recommend white LED working in 3.0 3.5 V voltage, practical application need to design according to the forward voltage of LED lamp bead, when purchasing LED light source into the Treasury to do incoming inspection, to ensure the consistency between the light source forward voltage. If a group of source voltage is close to 3.132 V, the M series lamp bead the total voltage = 3.132 * M
5, the LED board series parallel design with wide voltage
To make the LED fluorescent lamp work in the input voltage range is wide range (full voltage) AC85 ~ 265 v, the LED lamp board series parallel way is very important. NiuBao power points out that the current power generally is not isolation step-down type power supply, when the requirement of wide voltage, output voltage not over 72 v, the input voltage range is 85 ~ 265 v can reach. That is to say, the serial number of not more than 23 string. Parallel number not too much, otherwise the working current is too large, fever, recommended for 12 and 6 and 8 and / /. The total current is not more than 240 milliampere as well. Solution, there is a wide voltage is the voltage with L6561/7527 first push up to 400 v, and then step down, the equivalent of two switching power supply, cost is twice as expensive, the performance-to-price ratio is not high, no market.
6, leds series-parallel and PFC voltage is the relationship between power factor and wide
Currently on the market power PFC has three conditions: one is without special PFC circuit, the PFC general at around 0.65; One kind is with passive PFC circuit, light board horse well prepared, PFC general at around 0.92; And with a is made of active active 7527/6561 circuit, PFC can reach 0.99, but the cost of this solution more expensive than the second scheme. So the second solution is more. For passive PFC circuit, also called valley type PFC circuit, the working voltage range is half the peak of the ac input voltage. If input is 180 v, the peak is 180 * 1.414 = 254 v, half the peak voltage is 127 v, subtracting the step-down type differential pressure 30 v, its maximum output is 90 v, so the LED lamp bead series number up to 28 series. To get bigger of the power factor, therefore, lamp bead series number cannot too much, otherwise, to reach the requirements of low voltage.
7, LED fluorescent lamp power constant current accuracy how much the most appropriate
Some poor precision of constant current power supply in the market such as SMD802 constant current schemes, error of 8% plus or minus or plus or minus 10%, constant current error is too big. General requirements in the plus or minus 3%. According to the error of 3%, 6 road in parallel, each way of error of plus or minus 0.5%, about if parallel is 12 road, every road of error of plus or minus 0.25%, about the precision is enough. Precision is high, the cost will increase greatly. And for the LED, 17 milliampere and 17.5 milliampere.
8, the built-in led driver power supply isolation and the isolation
Isolated power supply in the input and output isolation transformer isolation, can avoid the risk of electric shock. CE certification and ul certification rules power are required to isolate the power LED fluorescent tube. Unfenced focus on high power factor and efficiency, reduce the energy consumption.
9, led internal driving power conversion efficiency
Built-in led drive power conversion efficiency must be high. In the LED fluorescent tube, electrical energy is converted into light energy and heat energy. The lower conversion efficiency means that the LED fluorescent tube light is smaller, the greater the heat. In the high temperature will affect the LED fluorescent tube, performance and life of electronic components. Shenzhen tomorrow photoelectric co., LTD. Production of LED fluorescent tube conversion rate is above 88%.
Restrictions on the size height is 10, LED fluorescent lamp power LEDled built-in power supply design of the main driving factors. LED fluorescent tube to heat dissipation is good, for T8 LED drive power supply inner height 9 mm or less, T10 tube height of 15 mm or less.