EV1220 use for removing the 100/120Hz LED current ripple on AC/DC power.
The adaptive technology of JW1220 ensures minimum power dissipation on NMOSFET while removing LED current ripple.
JW1220 clamps the input voltage on VIN pin by 30V. Only one resistor is needed when the output voltage of AC/DC power is higher than 30V.
JW1220 allows user to setup maximum LED current by the sensing resistor between the source of NMOSFET and ground, which keeps NMOSFET damaged when LED short connected or hot-plug.
By sensing the drain voltage of NMOSFET via a resistor between the drain and VLMT pin, JW1220 allows user to setup the maximum cathode voltage of LED string, which could help limit the power dissipation on chip.
It’s considered that LED is shorted when the cathode voltage of LED is higher than short connecting threshold and remains over 0.5 second. JW1220 shuts down NMOSFET when LED is shorted.
JW1220 provides over thermal protection. When OTP is trigged, the current removing function is blocked, and then the temperature decreases.