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30-25 volt converter ic other than 7805

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Newbie level 5
Jan 23, 2013
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is there any ic that will convert 30 volt to 5 volt other than 7805, reverse operation ulm2804 to interface 8 i/p of 89c51
also please suggest me a good transistor switch that will convert 30 volt to 5 volt to interface 89c51

7805 is not exactly a voltage converter.

what are you actually trying to do ? Just interfacing a 30v switching signal to uC input pins ? If so, wouldn't a simple resistive divider + zener protection be enough ?

please see my circuit diagram, i want to convert 8 sensor o/p voltage (voltage range 5 to 30) to 5 volt to interface 8 pins of microcontroller 89c51View attachment UC.bmp
also in circuit diagram i used a not gate at o/p of all transistor
AND+RC+NOT is for positive edge trigger, is it possible clear an input pin in uc89c51 programtically once the pin is declared as input.
i want to replace all transistor circuit with an ic
also suggest me proper transistor switch circuit to interface uc89c51

edge trigger is usually a term used for interrupts. Are your uC pins capable of accepting external edge-detect interrupts ?
If so, then just do the settings for edge detect, and throw away all your external circuits.

If not, then you have to poll / read the pins regularly and fast enough to see if they have gone active, and then take appropriate action. Then wait/ check for that pin to go inactive and active again before the next action.

Thats it.

To translate from 30v to 5v, you just need a resistive divi.... oh i already wrote that in post #2 :)

i want to convert i/p voltage range 6 to 30 voltage into constant 5volt

i want to convert i/p voltage range 6 to 30 voltage into constant 5volt

Use LM317 with a suitable resistor values. There's a nice online tool for calculating resistor values for LM317 here :
The regulator has a voltage drop of ~2V across the chip. Therefore it'll regulate the range ~7-30 V into 5V.

The maximum current it can provide is 1.5 A and when drawing currents more than 300 mA, a good heat sink is recommended

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