I would like to have a very slow rise-up time by ADP7182.
It’s about 5msec @ - 5V, as slower.
Could you tell us if there is any good way?
It is possible to add a delay on the start-up time using the feedforward capacitor. You could refer to AN-1329 for more information. I'll post the EN input current once I have the information.
Unfortunately the ADP7182 doesn't have a programmable soft-start feature. If the purpose of the rise time is for delay or sequencing you could add an RC delay circuit at the EN pin.
t is the desired delay
Vth is the minimum voltage that the part will enable.
please note that the delay would deviate from part to part due to the differences in the Vth value. Hope this helps!
Thank you very much for your good idea.
I would like to know EN input current ,
Is it about 1uA or under?
And the other idea;
The big capacitor, between ADJ and VOUT.
It will be slow rise time.
Could you give your comment ?
I'll get back to you regarding the EN input current.
For the figure that you sent, that capacitor is actually called feed-forward capacitor. It doesn't slow down the rise time of the output instead it makes the feedback loop faster by adjusting the impedance of the top side of the feedback network.
> I'll get back to you regarding the EN input current.
Thank you for your support.
This information might help select the resistor.
I agree that it is actually feed-forward capacitor.
After power-up, Vout feed-back signal through this capacitor.
But that circuit is impossible to make slow power-up ?
and if it has any thinkable problem , please comment .
Thank you very much for your good support.
AN-1329 that you suggested is helpful for me.
The EN input current is estimated to be around 100nA though this is not being tested.
I understood EN input current is very low.
Thank you very much for you good support.
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