Where N Is The Number Of Led Tube

on Monday, December 31, 2012

To complete the cutting phase, mainly using two techniques: TRIAC (triac) switch or transistor switch. TRIAC dimmer and more for the cutting-edge phase dimmers cut. Transistor switch can be both cutting edge phase dimmers can also be cut along the phase dimmers. TRIAC dimmer problem is that it needs to meet special conditions to work properly: TRIAC can trigger the gate to open, once activated, still need a minimum current to maintain its in-state. The trigger current is known as "latch-current", and in order to maintain the TRIAC conduction current must be loaded for some time. Once the latch device is, there must be constant current supply. This current is called "keep current." If the current is broken or weakened, TRIAC will turn off. To be compatible with dimmers, somekeyword light dimmer must be absorbed to maintain the required current. For example, if a 6W of Led Tube light (roughly equivalent to 40W incandescent bulbs) to a minimum load is 10W with dimmer with the use of additional circuitry needed to provide enough to keep current. In this case, the light bulb efficiency will be reduced, but still high compared with the efficiency of 40W. Without this circuit, Led Tube light is not working properly. Dimmer to keep the different currents are different. Therefore, the additional loss of greater compatibility with dimmer the better. Application of tunable optical design difficulties is to find efficient lighting and dimmers best balance between compatibility.

NXP SSL2101 (and its derivatives SSL2102) has two integrated control of discharge from the IC switch. By external resistor, you can set two different discharge current. Selected for the current IC provides greater flexibility and optimize the dimmer compatibility. SSL2103 (SSL2101-only controller integrated version) integrated in the removed discharge switch, but can be low-cost external bipolar switch (still IC driver) instead, choose to provide higher discharge current. Meanwhile, the release also removes the built-in converter operation for MOSFET, but can be externally modified, adjusted to meet specific requirements to form a solution.

Select Size 1.2 Relationship with the topology

Led Tube light is essentially a current drive type. Their luminous intensity is roughly proportional by the current. Therefore, different topologies can be the use of electricity to drive. Topology selection is one of the key objectives of the application to determine the final dimensions. Less than 15W of low-power Led Tube light fixtures aimed at the improvement of existing applications. This means that the shape of the lamp must be similar to the existing conventional lighting. The major products currently marketed by the following three topologies:

1.2.1Led Tube and resistor in series

Led Tube in series with the resistance, the resistance is directly connected to mains. This topology is the simplest. As long as the power supply voltage higher than the diode forward voltage and, Led Tube is turned on. Led Tube maximum current determined by the resistance value: where n is the number of Led Tube, Vf is the forward voltage.

The solution is simple but inefficient. For example, a 12W application, the somekeyword may reach the maximum current 500mA. The total forward voltage will be 24V. For the 220V AC mains, the required resistor value is 574W. The resistance when the current is 500mA Power consumption 143W . Of course, we can consider using low-current diodes, but the power required to achieve the same Vf higher. A direct consequence of doing so is shortened open time, and there will be flashing.
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