Greetings all!

I'd like to invite comment, criticism, and recommendations on a small circuit project.

I haven't calculated values for many of the components at this time, in case major revisions are necessary.
Also, I apologize if the schematic doesn't conform to standards. I welcome any suggested improvements.

The concept: L1 is a 12v solenoid (part of a water valve) and will energized briefly (60 ms) with the power stored in a bank of capacitors (C5,C6,C7,C8). Charge sufficient for multiple discharges desired. 5V from Arduino pin 2 will be the trigger. Push button is pressed and held to energize capacitors. Voltage levels indicated by D3,D5,D8,D10.

Features: 2.1mm jack (J1) receives plug from a 9v, 1amp AC power adapter.
Voltage boosted by NJM2360D http://www.njr.com/semicon/PDF/NJM2360_E.pdf.
MOSFET Q1 is IRLZ24N http://www.irf.com/product-info/datasheets/data/irlz24npbf.pdf
Optocoupler V01, have not made a selection but looking at candidates.



I'm considering starting detailed work on the values.
Should I go back to drawing board, or can you suggest some modifications?

All comments, words of wisdom, and guidance welcome.
Many thanks.

 

Welcome to AAC!
You'll need a pull-down resistor on the FET gate, otherwise it will stay on for ages.
D13 seems redundant.
Depending on the solenoid, you may be surprised how much capacitance you need to energise it.

 

Thank you much for a kind welcome, sir.

Would R9 qualify as a pull-down resistor?

I agree with you on the need for a lot of capacitance. That's why I was thinking a bank.
Four was just a guess at the quantity. Maybe more would be advisable. To allow for utilizing smaller capacitors.

Given the discharge characteristics of capacitors, I'm guessing sizing will be no mean feat. The idea is to be able to energize the solenoid multiple times.

I plan to overpower the solenoid to 18V or higher.

I agree with you on D13; not sure why I thought it would be necessary.

 

Depending on how fast you want to re-energize, the D1 is going to slow the release, time dependent on energy stored.
Max.

 

Thank you, sir.

D1 is intended to be the primary protection for the MOSFET.

What guidance would you offer in specifying D1?

Aside from the voltage, what type? schottky?)
Recovery time?


Really, any suggestions regarding suitable choices for the components would be welcome, including the MOSFET and the optocoupler.

And I'm may need some help determining values for the components of the voltage boost circuit.

Thank you again.

 

I would feed and test the solenoid and diode direct from a P.S. and check to see if there is any appreciable drop out delay, I use mainly 1n4007 as these cover quite a few eventualities up to a certain power .
A 1k resistor from Mosfet gate to common would be a suitable value. R9 is usually around 10R.
Max.

 

Would R9 qualify as a pull-down resistor?

No, it only provides pull-up. You need a resistor (say 10k-47k, depending on the switching speed used) between gate and source (ground).

 

Hello,

Basicaly, the resistors 3 and 8 are in series, you can add the values and replace them with this value.
Also the resistors 4 and 9 are in series, you can add the values and replace them with this value.

Bertus

 

I would feed and test the solenoid and diode direct from a P.S. and check to see if there is any appreciable drop out delay, I use mainly 1n4007 as these cover quite a few eventualities up to a certain power .
A 1k resistor from Mosfet gate to common would be a suitable value. R9 is usually around 10R.
Max.

Thank you, sir!

No, it only provides pull-up. You need a resistor (say 10k-47k, depending on the switching speed used) between gate and source (ground).

I've added R15. I hope it reflects the intent your suggestion.

 

Hello,

Basicaly, the resistors 3 and 8 are in series, you can add the values and replace them with this value.
Also the resistors 4 and 9 are in series, you can add the values and replace them with this value.

Bertus

Has be rectified, sir. Thank you!

 

By way of introduction, my education and experience is in Mech Eng Technology.
Thank you all for your patient replies.

 

I'm considering different methods for increasing the voltage from the adapter.
I'm attaching some information for the NJM2360. Wondering if there is a simpler approach?

Any suggestions would be welcome.