8 replies to this topic

[rickh]

Folks,

I have been looking at a couple of Multi-Channel Power MOSFET output modules and discovered that there is a 4 output version that is plentiful on Amazon and on AliExpress.  I purchased one on Amazon https://www.amazon.c...asin_title&th=1 for ~$10.  From what I read, the boards need a simple modification for dependable 3.3V input.   The version I got from Amazon does not have flyback diodes, but I saw that a few versions did have this feature.  So why has this peaked my interest? Well, I think that many people that want a Pinscape Pico solution, may not want a time consuming project.  These modules take a lot of the labor out of building a Pinscape system and it is fairly scalable too.  So once I get to evaluate this module and find out what modifications and features are needed, I can contact a vendor on AliExpress and see if I can order a batch of these boards with the mods and features I desire.  Let me know if anyone is interested.

 

Regards,

 

Rick

[Tesla]

I'll be interested to see what you think of it.

 

I picked-up a similar-one, but haven't tried it yet. I was thinking it might work for something like flipper-solenoids (where all the components match).

 

So, without the "flyback diodes" ... does that just mean if we are using to control "something that moves" ... we just go ahead and install something like a 1N4007-diode (as previously recommended)?

Edited by Tesla, 20 November 2025 - 05:43 PM.

[rickh]

I'll be interested to see what you think of it.

 

I picked-up a similar-one, but haven't tried it yet. I was thinking it might work for something like flipper-solenoids (where all the components match).

 

So, without the "flyback diodes" ... does that just mean if we are using to control "something that moves" ... we just go ahead and install something like a 1N4007-diode (as previously recommended)?

Actually, I almost purchased the same one, but it would not arrive until mid December.  The flyback diodes can be placed directly on the load.  This is an ideal setup, as it prevents an EMF spike to develop across the hook-up wires causing a loud popping sound through your audio amplifier.  However, adding a diode is another hassle to deal with, so having the diodes on the board is a convenience.  BTW the IN4007 is an excellent choice.

[Suikazz]

I'll be interested to see what you think of it.

 

I picked-up a similar-one, but haven't tried it yet. I was thinking it might work for something like flipper-solenoids (where all the components match).

 

So, without the "flyback diodes" ... does that just mean if we are using to control "something that moves" ... we just go ahead and install something like a 1N4007-diode (as previously recommended)?

 

I can't tell exactly from the pictures but it looks like it has the diodes already installed?!

[rickh]

 

I'll be interested to see what you think of it.

 

I picked-up a similar-one, but haven't tried it yet. I was thinking it might work for something like flipper-solenoids (where all the components match).

 

So, without the "flyback diodes" ... does that just mean if we are using to control "something that moves" ... we just go ahead and install something like a 1N4007-diode (as previously recommended)?

 

I can't tell exactly from the pictures but it looks like it has the diodes already installed?!

 

Those diodes (MELFs) appear to be across the gate and source.  The flyback diode goes across the drain and source.

[rickh]

I just got my new MOSFET Board this morning and I was able to reverse engineer it. First glance, this board is very tiny.  As I went through the circuit I discovered that it does have flyback diodes.  They were so tiny, that I missed them.  Anyway, I created a schematic and circled an LED.  This LED should be replaced with a short to ensure this circuit works with 3.3V.  The MELF diodes mentioned earlier appear to be zeners.  The schematic is almost identical to the MOSFET driver circuit I created for my Bang Plus which you can find on my GitHub page, https://github.com/r...Bang-Board-Plus, except my design did not have that silly LED.  Below is a schematic.  

 

So far I am satisfied with this board.  Besides the diode issue, I think that R79 should be reduced to 4.7K, as this would produce better PWM performance.  However, I have not really placed this board through enough testing yet. 

 

Regards,

 

Rick 

Edited by rickh, 21 November 2025 - 10:42 PM.

[rickh]

Update

This board has more issues than I initially observed.  The zener diode is rated at 5.1V which is really stupid, as the MOSFET can withstand a gs voltage of 22V.  The 10K resistor needs to be lowered to 420, and the 100K needs to be reduced to 2.2k.  The 5.1V zener should be replaced with an 18V zener.   Just 90% of all the components. ;-)

 

EDIT - This board works great as-is (with diode shorted) for general switching, does not work well for PWM usage.

 

Rick

Edited by rickh, 14 January 2026 - 01:16 PM.

[fhjui]

yes, you are right Rick, this board is a little bit nonsense designed.

I would reduce R77 to 4,7Ohm - 10 Ohm and R78 to 1k - 2k2, as you mentioned, depending of the supply voltage at DC. The output Trans. nominal current is 5mA, max. current 30mA.

R77 has to charge the gate capacity quick as possible to avoid switching losses. R78 discharges the gate to ground.

The CQY99 is a IR-LED ? That makes no sense.

Edited by fhjui, 16 January 2026 - 06:21 PM.

[rickh]

yes, you are right Rick, this board is a little bit nonsense designed.

I would reduce R77 to 4,7Ohm - 10 Ohm and R78 to 1k - 2k2, as you mentioned, depending of the supply voltage at DC. The output Trans. nominal current is 5mA, max. current 30mA.

R77 has to charge the gate capacity quick as possible to avoid switching losses. R78 discharges the gate to ground.

The CQY99 is a IR-LED ? That makes no sense.

The zener P/N shown in this schematic is not correct, I basically used the one I'm using because I did not know the rating on the MELF zener used in this circuit.  Since this design is intended for use up to 30V those resistor values had to be really high so that they didn't kill the zener.  I think the reason they used the IR diode is that it had only a 1.1V drop.  Correction!!!  The LED is blue and has a drop of around 3V.  Anyway, I got it to work and the PWM looks okay.  Below is the output at 20kHz @ 15%.

Edited by rickh, 11 February 2026 - 08:53 PM.