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Help regarding searching & choosing a Voltage converter & Relay

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Junior Member level 1
May 19, 2016
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I want do design a PCB that basically passes or stops the 12-24 AC/DC input voltage
I'm looking for the 5v Voltage converter (for MCU & other IC's) and for a Relay controlled by the MCU
A very high level block diagram attached

Any suggestions & tips will be helpful
Many Thanks

If cost is not a critical factor in your design, or if you do not want to spend time developing such a circuit, you may consider using any kind of transformerless SMPS DC/DC converter module for PCB mounting. At first sight, a voltage regulator-based solution could meet your need, since no electrical insulation is indicated in the circuit, but this approach wastes a lot of energy and requires a big space to accomodate the heat sink.

Hi Andre
Thanks for the reply

I need one converter for both AC & DC, is it possible ?
Lets say i don't know which type & level of voltage input will be... i need to prepare for 12-24 AC & DC

You'll use a bridge rectifier + filter capacitor in front of the voltage regulator/converter.

You don't show a control source for the power switch. If the control interface requires isolation against the power input, I would go for a standard isolated DC/DC module, e.g. wide range 9 - 36 V DC input, 5 V output. Otherwise a non-isolated buck converter or linear voltage regulator.


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Hi FvM
Thanks for the reply

Can you please elaborate regarding the rectifier + filter ? if it is possible an example (diagram, specific component) will be very helpful !
AC will be rectified, what about DC input voltage - just less 2 Vf of the diodes ?
Do i need to ensure enything regarding the rectifier output voltage ? so the DC/DC input will be valid ? (ripples etc')

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