I have implemented an LT6118 in a power supply and it is working pretty much as expected; when the current is over the specified limit, the pass transistor switches off. 12V input / 1.2A trip current. I attach a schematic (which looks blurry). I hope it is readable.
My issue is with the suggested method of LE transparency on start-up. I have used the circuit in the datasheet to delay the LE function using an RC delay (24k9 + 100n). This does not prevent the latch working when switched on.
Measuring the LE voltage shows that the voltage doesn't drop below 0.5V for a long time - far longer than the time between switch-ons. Therefore, the latch is always enabled.
Although the datasheet suggests a circuit for POR, this doesn't seem to function as expected. Even when starting from around 0V, the rise-time is extremely short. I have increased the value of R in the RC circuit but the rise time is still in the order of uS, not 100uS. The input is a switched 12V supply which is always present, so there is no rise-time - it is a step.
What is the expected behaviour of the POR? Nothing I've seen so far makes me think the POR actually works as per the data sheet.
Thanks in advance.
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