The 8-inch tablet will have a big impact on the 7-inch and 10-inch tablet market. Because the portability of an 8-inch tablet is stronger than that of a 10-inch tablet, and the usable area is larger than that of a 7-inch tablet. The most important thing is that the price is more moderate, which is much cheaper than a 10-inch tablet. It can be said that the 8-inch tablet computer has a good balance between portability and screen display area, and is more likely to be favored by the majority of users.
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Hangzhou Silan Microelectronics recently released three high-power white LED driver chips with PWM dimming function - SB42511, SB42520 and SB42821. The input voltage of these three chips is 6V ~ 25V, the output current can reach 1A; built-in temperature protection circuit, current limiting protection circuit and PWM dimming circuit; system conversion efficiency is high, the efficiency can reach 95% when connecting multiple LEDs in series Above; the series of chips can be PWM dimming, the output current of the LED can be adjusted by an external PWM signal, and a good dimming effect can be achieved in the range of 100 Hz to 2 kHz; in addition, the bootstrap circuit inside the SB42511 and SB42520 chips adopts unique control. The method does not require an external Schottky, and can be started when a plurality of LEDs are connected in series, which greatly improves the performance compared with other similar products that work in the bootstrap mode.
From the steady current characteristics, the system control of SB42511 and SB42520 adopts the dual current loop control method, which makes the chip show good current adjustment capability and output current regardless of the input voltage change or the change of the number of driving LEDs. The rate of change is controlled within plus or minus 1%, and the performance has been significantly improved. The SB42821 uses constant shutdown control technology, which eliminates the need for loop compensation and requires fewer peripheral components. In addition, the SB42821 and SB42520 also have an internal enable function that has a quiescent current of only 25μA in the off state.
This series of chips are packaged in a small lead-free package, which is environmentally friendly and has low internal power consumption, which is more conducive to users' use. 
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