[req]the ic has some question when power on?

The regulator maximum load current is 500mA. It cannot go to stable state in some loading during 150mA~200mA when power on suddenly. But it is stable when power is applied slowly. And the loading is larger than 200mA, it is OK. What is the possible reason? Thanks.

a voltage regulator ... any voltage regulator say for talking
5v @ 1.5 amp output needs a 'shunt limiter' resistor in series with the input regulator supply pin

even this flaw in thinking creaps into my own designs and i know its wrong
and how to work it out

look for the maths { i am terrible at maths today}


so you need to work this out
i always remember the rule of 23 23 R is a good value for 1 amp @ 5v as a shunt limiter for a 9 - 10 v supply input




try this and check you dont have too much static capacitance

if the main psu is 5v or 12 try to lower the regulators resoviour caps a little

maybe a reset line somwhere rise too slowly etc ...

take a look some timings like this

esp oscillators

edit ... after thinking a little
upload a circuit part lets see the regulator stage and what it supplies is best... as a jpg file is best {i use psp {paint shop pro}}

staric said:

The regulator maximum load current is 500mA. It cannot go to stable state in some loading during 150mA~200mA when power on suddenly. But it is stable when power is applied slowly. And the loading is larger than 200mA, it is OK. What is the possible reason? Thanks.

Click to expand...

You check these item.
1.The start up circuit in Internal voltage or current reference circuit

2.Current limit error. whe when power on suddenly , the inrush current (VIN) is so large (The current come from load(you sink 150~200mA) and Charge Co current.
You can check this item by rdeduce Co. Or measurement the IOUT before Co and Loading .

When power on suddenly and load is 150mA~200mA ,test Iin and Iout. Analysis function of IC,whether other protection block has a effect or not .