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I'm looking to make a soft-latching interface with a single momentary push button.

Required features for my build are (edited, sorry for bad description) :

  • Circuit should always start in OFF position (hence auto reset) ;

  • Should work as press to power ON, hold to shut down ;

  • Must be compatible up to 60V ;

  • Must be able carry the battery's nominal voltage to the module it switches ON and OFF (said module needs high voltage to go HIGH else it stays LOW)

Can you please tell me if anything is wrong ? How should I solve it ?

Thanks

Edit (2) : For the 5v regulator I use a LM317HVT with a pair of resistors. NAND used is a CD4011 and mosfet used to switch ON/OFF is an irf510.

Soft-latch switch with momentary push button LM317HVT based

Vanarian
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With a little bit of cooperation from the host, you can do this entirely with discrete devices. See this answer here: How can I make this "automatic turn off" work using some GPIO pins on a MCU?

These circuits will need a bit of modification to work with 60V: voltage dividers to limit the FET gate-source voltages. But otherwise they meet your criteria for reliable power-on state and switch denounce: instant-on with the first button press, and the micro can then monitor the button and implement the hold-for-off function.

I would also recommend using a step-down DCDC, maybe even a flyback type, as the regulator losses for a linear type will be large. Here’s an example that’s just $3. https://www.ebay.com/itm/152828093871

hacktastical
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This "analogic" circuit simply delays switch contact >0.5s and debounces the switch. There are far simpler ways to do this with a single RC filter and Schmitt trigger gate.

There is no latch.

Tony Stewart EE75
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  • If the argument is that they will not, it might be useful to explain why the cross connected NANDs do not function as a toggle element. – Chris Stratton Mar 10 '18 at 22:51
  • The spec is "auto-reset itself in OFF position (always need to press button to power ON) " so no latch function defined. Only the title incorrectly defines it this way. If it were defined as a push-push delayed switch then a toggle latch is spec'd – Tony Stewart EE75 Mar 10 '18 at 23:08
  • That sounds more like an argument for a close vote than an answer. – Chris Stratton Mar 10 '18 at 23:10
  • Yes the Specs are very poorly defined for transfer function – Tony Stewart EE75 Mar 10 '18 at 23:34
  • My bad for describing it wrong, I corrected the features required ; I indeed look for a press ON / hold OFF single button layout which always starts first in OFF first when wired to my battery. I simulated the NAND without a live wire first and ended with an always OFF state no matter if button was pressed. Could please elaborate on how I should correct this to make the latch functional? – Vanarian Mar 11 '18 at 02:16
  • So short press ON and long press OFF t1=? t2=? – Tony Stewart EE75 Mar 11 '18 at 02:45
  • Yes, T1 = less than 1s ; T2 = at least 2s – Vanarian Mar 11 '18 at 03:04
  • Why not instant ON /OFF push/push toggle? with OFF as POR initial state? – Tony Stewart EE75 Mar 11 '18 at 06:15
  • Instant ON push as you suggest is right ; delayed OFF with hold press is a safety to prevent accidental shut down (it will be used as power button for e-scooter and e-skateboard, the momentary push button might be exposed to debris and vibrations). – Vanarian Mar 11 '18 at 11:20