I'm thinking the internal body diode in the 2N7000 is providing a path holding the trigger low.
Replaced the 2N7000 with a 2N3904 and increase the value of C1 to 10uf.

 

Add a 250K resistor from pin4 to ground.

Okay. Here you go--

 

Currently I'm out of town and can't do any testing on a breadboard.
Can you sim the circuit in post 41 when you have time?

 

Can you sim the circuit in post 41 when you have time?

Okay, finally success.
Seems to work but I had to change R1 to 100kΩ and C1 to 100µF.

 

Thanks for doing the sim.

 

@crutschow could you please share the sim source file?

 

@crutschow could you please share the sim source file?

See attached:
I didn't have a working LMC555 model so I used the ideal NE555 one, which should give results close to what the LMC555 will do in this circuit.

 

So this circuit works ?
I will use it in JLCPCB.

 

It does according to the simulator.

 

For your amusement, here's a simple toggle circuit that operates from a grounded PB trigger, using just one IC and only three passive parts besides the output MOSFET driver.
I used the CD4040 counter since it is one of the few CMOS circuits that toggles from the negative going trigger that a grounded NO PB circuit generates.
C1, R1 and R2 provide the needed switch bounce suppression.

As an added bonus, as long as power is maintained, it keeps track of how many times you've pressed the button (up to 4095 times).

The advantages of this circuit over the 555 one are:

• Fewer parts.
• No restrictions for the push-button pressed time.

Edit: If you need the circuit to power up in an off state, a power-up reset circuit can be added with a resistor and capacitor.
Edit2: The CD4020 and CD4024 counters can also be used, since they have a negative-going clock trigger as well.

 

Thanks. Will have to breadboard test it first. Then JLCPCB

 

Is c1 100 uF or nF and how many volt ?

 

Is c1 100 uF or nF and how many volt ?

It's nF on the schematic.
10V for a 5V supply.

 

Could I simply replace the IRLZ44N with a AO3400 ?

 

Could I simply replace the IRLZ44N with a AO3400 ?

Yes, that should work fine.

 

Sorry, I think I asked this before, but is C1 in this schematic 100 uF or 100 nF ? It is just because the first version was 100 nF, but we seem to have ended up with 100 uF ?

 

Sorry, I think I asked this before, but is C1 in this schematic 100 uF or 100 nF ? It is just because the first version was 100 nF, but we seem to have ended up with 100 uF ?

For that circuit its 100µF.

 

Can a lmc555 run at 3.3v ?

 

Can a lmc555 run at 3.3v ?

Yes.
But the output might not be high enough to trigger the mosfet fully ON depending on the mosfet.

 

AO3400