Voltage step down

W

WyDiablo

Member
Well I ordered this one and right now I"m very stumped about how to solder it up for volts in and volts out.

Pololu 12V, 500mA Step-Down Voltage Regulator D24V5F12
Correct me if I"m wrong but the volts in would be (red) hot wire and volts out would be the (red) hot wire. And the grd would be the grnd wires from both the volts in and volts out correct? I just can't figure out what the "SHDN" is used for.
 
Tony

Tony

Staff member
SHDN is used to put the unit in a low power stand by mode. Below is per the site you linked.

The buck regulator has four connections: shutdown (SHDN), input voltage (VIN), ground (GND), and output voltage (VOUT). The SHDN pin can be driven low (under 0.3 V) to turn off the output and put the board into a low-power state that typically draws 20 μA, and it can be driven high (above 2.3 V) to enable the board.
Click to expand...

Not sure if that helped or not lol. From the sound of it, if you are going to unplug the battery every time, you may have to run a jumper from VIN to SHDN to power it on. That is what I'm getting from the above quote anyway.
 
W

WyDiablo

Member
Well I was planning on using the step down to power my led lights so I will only have the weight of one battery and not 2 to lighten the load. The leds are 12volt and I run 6S 3300 22.2 volt batteries. So you say that I will need to solder a jumper from the VIN over to the SHDN pin side?
 
Tony

Tony

Staff member
From what that quote states, that is what i would do. But i would call them or at least send an email with what you have planned and see what they say.
 
W

WyDiablo

Member
Tony here is the reply that I got from Pololu

Hello.

Thank you for your purchase. SHDN can be left disconnected; this will
leave the regulator permanently enabled. The SHDN pin provides a
convenient way to enable or disable the regulator. If SHDN is connected
to a voltage less than or equal to VIN, the regulator will be enabled,
and if SHDN is connected to ground, the regulator will be disabled.

Sincerely,
Nathan Bryant
(702) 262-6648
Pololu Robotics and Electronics
..............................
Pololu Corporation
920 Pilot Rd.
Las Vegas, NV 89119
USA
 
Tony

Tony

Staff member
So according to that, you can either leave it open or jump it to vin for it to run all the time. Leaving it open would be easiest.

Are you wanting to control something with this or are you ONLY looking for a voltage step down. If you are only needing a voltage step down, then leave it open and it will work just fine.
 
Tony

Tony

Staff member
He could, but they usually stop at about 6vDC.

As l I no ad you want the lights on all the time, leave the shdn open and only connect the 3 wires.
 
Tony

Tony

Staff member
I can understand that. If it were me, i would hook up the in and out as well as the common ground aand give it a shot.
 
W

WyDiablo

Member
Well when I get ready to solder and wire it to my led light hookup I will give it a shot and look for smoke lmaooooooooooooooooooooooooooo
 
W

WyDiablo

Member
This e-mail just came from Pololu Tech. Support

The state of the SHDN pin is not critical to the functionality of the
regulator when connecting and disconnecting input power. With the SHDN
pin disconnected, the regulator will turn on whenever input power is
connected and turn off whenever input power is disconnected. The primary
purpose of the SHDN pin is to allow the regulator to be turned on and
off without connecting and disconnecting the input power.
 
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