Help with LT3751

Thread Starter

MGPERF

Joined Jun 8, 2021
39
Hello,

I am trying to have the LT3751/ga3459 run continuously when supplied with 12V to make things a bit simpler I am also disabling over voltage and under voltage. My supply will be a steady 12 volts. The datasheet says connect to UVLO2 and UVLO1 to VCC however it does not mention any resistors or anything to do that. Would I need them? Any harm in having them/not having them? I cannot find an up to date and working LT Spice model for LT3751 so I'm kinda stuck ordering and hoping for the best.

Jon
 

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ronsimpson

Joined Oct 7, 2019
1,465
The datasheet says connect to UVLO2 and UVLO1 to VCC however it does not mention any resistors or anything to do that. Would I need them?
Data Sheet said:
UVLO2 (Pin 4/Pin 2): VCC Undervoltage Lockout Pin. Senses when VCC drops below:
VUVLO2 = 1.225 + 50µA •
RUVLO2 and trips the FAULT latch low, disabling switching. After VCC rises above VUVLO2, toggling the CHARGE pin reactivates switching
The pins have a 50uA pull down. A 1.22V trip point. And a external resistor that pulls up. Ohm's law.
1627647581315.png
 

Thread Starter

MGPERF

Joined Jun 8, 2021
39
Ron,
Great thanks my 100k resistors should do the trick then. Everything else look good? Mostly followed data sheet. More or less I’m looking for a simple hv power source. Niche application so I’m not super worried about core losses from running the transformer all the time.
 
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