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I feel like I have seen many varieties of this question going in the other direction (powering a 24V solenoid with a 3V3 or 5V logic signal) but I'm having issues with finding answers about going in the other direction.

I have a small 5V solenoid (https://www.adafruit.com/product/2776) that I would like to incorporate into the end effector of a robot that I am working with. The robot has 24V power rails and 24V digital I/O (with a max current draw of 500mA per channel).

I have tried to use a 24V to 5V step-down buck converter (https://www.amazon.com/Alinan-Step-Down-Voltage-Converter-Adjustable/dp/B09MYNQLQB/), but have not gotten it to output anything (5V or otherwise) after bridging the 5V pads and supplying the "Enable" pin with ~4V via a voltage divider from either the 24V rail or 24V digital output.

Any suggestions, either as alternatives to the buck converter or ways to get the buck converter to function would be appreciated. The solenoid will be running at a low duty cycle, but has a peak current draw of 1.1A.

Thanks!

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  • \$\begingroup\$ You could PWM the solenoid at 5/24=20.8% and add a freewheeling diode. The solenoid becomes its own buck converter. I'm hoping the solenoid is okay with 24V maximum voltage - I think it probably is. \$\endgroup\$
    – Stack Exchange Supports Israel
    Commented Nov 8, 2022 at 0:20
  • \$\begingroup\$ This is the manufacturers page on the buck converter aideepen.com/products/… but it doesn'r have much more information, no proper data sheet. The 8 pin chip appears to have IAGCD on it, whilst In the Amazon images it's DKAAG, but neither lead to an identification. All I can think of is the enable may need a different voltage, what makes you think it should be ~4V? Or you've got a bad buck converter, try another one. Are you pulsing the converter with 24V? \$\endgroup\$
    – Peter Jennings
    Commented Nov 8, 2022 at 1:04
  • \$\begingroup\$ Or, have you considered buying a 24V solenoid? There are quite a few out there is you google it. \$\endgroup\$
    – Peter Jennings
    Commented Nov 8, 2022 at 1:59
  • \$\begingroup\$ powering or controlling? ... there is a difference \$\endgroup\$
    – jsotola
    Commented Nov 8, 2022 at 2:10
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    \$\begingroup\$ As a general rule, if someone makes a solenoid at one voltage, then they make basically that same solenoid at another voltage and it works out that it'll actuate at roughly the same power. So there's a really good chance that if you can find a distributor with a wider array of solenoids than AdaFruit (Newark is good, in the USA), then you can find the same or very similar part that's designed for 24V operation. \$\endgroup\$
    – TimWescott
    Commented Nov 8, 2022 at 5:13

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There's a good chance the solenoid's insulation doesn't break down at 24V i.e. it can handle 24V pulses.

If you add a flyback diode, and control it with PWM, at \$\frac{5}{24}\$ duty cycle (i.e. 20.8%), it will get the same current it's designed to handle.

This forms a buck converter where the solenoid is both the inductor and the load, with no extra components that you weren't going to use anyway. There is a risk of burning it out if the PWM signal gets stuck on.

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