Above my pay grade, but that looks like a nice component.
I do know enough to say you should slavishly follow all the recommendations gleaned from careful perusal of the data sheet, including and especially the physical layout of the parts and the PCB pattern on offer in the reference design.
You could also look for a pre-built step-up regulator that had an ability to turn itself almost completely off.
I've usually had better luck with step-down regulators, which sometimes I place after an off the shelf power switch.
But those don't typically afford an ability to otherwise use the pushbutton as you intend.
Thank you for the alerts! Both issues are current: the assembled step-up converter indeed consumes power even when there is no load on it. And indeed, the current circuit requires a minimum input voltage of 3.6 volts to switch stably. (3x AAA cell? I would try to avoid that). So my question would be:
a. How can I modify the circuit to switch stably at an input voltage of 2.7-3V? In this case, I would place the voltage regulator inside the circuit.
b. How can I modify the circuit to have a separate 2.7-3V branch when the switch is pressed, which I would use to "turn on" the voltage regulator?
Didn't read the whole thread, but that chip is obsolete, and the manufacturer does not have a good replacement.
I also wanted to use that chip for a project, and ordered some NCP1402 from China.
Sadly the CE part of the clones was not working.
Low voltage startup was also not like an original I had.
Leo..
Hey! I also came up with another idea, that I could replace the SPST switch with a DPST (DPDT) switch, and this way I would have an independently switchable voltage branch, which switches on the voltage regulating boost circuit, then the ESP power hold pin takes over the CE (chip enable) circuit. Something like this:
Since U1 is a boost converter, even if EN is low, current will still flow through L1 and D3.
And then you would need a diode on the Power Hold Pin to prevent current from flowing back through the protection diode on that pin when the processor is powered down and you turn on the switch manually.
I think this version is not no great. If you want the boost converter to be completely shut down when power is off, then I think it may be better to put it on the drain side of the mosfet. Which means you would need to replace your mosfet with a logic level part.
I have completed the latest design. I replaced the MOSFET and the BJT with their low-voltage counterparts. I hope I chose the right components! Additionally, I placed the voltage regulator step-up converter inside the power-on circuit.
Thank you for the suggestions! Based on them, I constructed the latch circuit, and it switches perfectly without load with a 2.5-3V input voltage!
I will soon work on the step-up converter part as well, following your suggestions!
I managed to assemble the entire circuit on the prototype panel. Soldering the SMD components onto the test board wasn't easy!
The circuit and voltage boosting are working perfectly. It provides a stable 5 volts from the lab power supply, ranging from 2.3 volts to 3.0 volts, which allows the ESP32 to boot up.
@ShermanP : Thank you for the suggestions. I replaced the diode and resistors, and I'm attaching the new circuit diagram! D3: 1N5711
Congratulations. But just for future reference, I still don't think R1 should be there. It creates a voltage divider, so the gate voltage isn't brought down as low as it could be, and potentially the same issue exists on the button state pin. That's on top of what the two diodes are doing. Perhaps R1 is there as protection in case the button state pin is set to high output instead of input, but if that's the case, maybe it should be in that line. In any case, the main thing is that it works. It's good when things work.
Thank you, I will try tomorrow to see what happens if I omit the R1 resistor! "It's good when things work." Yes, it would be great to gather more knowledge. I just started an Udemy course on the topic, and I've also stocked up on CircuitBread YouTube channel!
