Hello~all Thank you for taking time to read my thread! I am in hot water now.Anyone can help me? There is a display board which need to control multi-LEDs ,I would like to use the microcontroller to drive 74HC595 and drive MOS to control LEDs by IO of 74HC595 (If I use one MOS to control four LEDs ,the resistance of every LED is 200ohm). After I switch them on current, I found that the output IO of 74HC595 is right,but all LEDs are opening! Then I review the circuit I found the resistance between source and drain of MOS is 193k, maybe the MOS is broken and can’t help the switches.The MOS I used is SI2306. (This is its datasheet .)The current of four LEDs may no exceed the range of MOS.I don’t know what it occurred? If i would like to use one MOS to control multi-LEDs, how should I design my circuit? All you help will be appreciated! Thanks a lot! NOTE: I have uploaded the picture ,please have a look!