MP3384- 50V, 4-STRING WHITE LED DRIVER

MP3384 Rev. 1.01

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9

1/29/2013

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part will maintain mark-off information until the

part shuts down.

Short String Protection

The MP3384 monitors the LEDX pin voltage to

judge if the short string condition occurs. If one or

more strings are short, the respective LEDX pins

will be pulled up to the boost output and tolerate

high voltage stress. If the LEDX pin voltage is

higher than 5.5V, the short string condition is

detected on the respective string. When the short

string fault (LEDX over-voltage fault) continues

for greater than 1.6ms, the string is marked off

and disabled. Once a string is marked off, its

current regulation is forced to disconnect from the

output voltage loop regulation. The marked-off

LED strings will be shut off totally until the part

restarts. If all strings in use are short, the MP3384

will shut down the step-up converter.