Help me assess the correctness of the task

Projects General Guidance
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  1. Modular central unit with ESP32-PICO-D4 processor (3 pcs)
    power module: 5V input (USB) + battery connection with charging circuit processor module with ISP and JTAG inputs, and two buttons (boot and reset)
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  • Say what ?

:face_with_spiral_eyes:

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The proverbial crystal ball is still in the dishwasher...

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➜ Please do yourself a favor and read How to get the best out of this forum. Post accordingly,

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Didn't know they had gone digital as well... Obviously not IP67 rated if the condensation is anything to go by...

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What is the question?

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I do not see three.

I do not see a charging circuit, only a voltage regulator.

I see the USB micro.

I do not see a power module.

I see ISP and JTAG (pin 18 TDI, 21 TDO, 20 TCK, 17 TMS and 49 GND)

I see pin 23 IO0 and pin 9 EN

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@kz6789 the schematic is incomplete. There is no ground coming from the external (USB?) connector to ground.

Also you have shown a 10uF capacitor as the output capacitor on that regulator, where as the data sheet shows a 22uF value. The data sheet says:-

The circuit design used in the AMS1117 series requires the use of an output capacitor as part of the device frequency compensation. The addition of 22μF solid tantalum on the output will ensure stability for all operating conditions.

When the adjustment terminal is bypassed with a capacitor to improve the ripple rejection, the requirement for an output capacitor increases. The value of 22μF tantalum covers all cases of bypassing the adjustment terminal. Without bypassing the adjustment terminal smaller capacitors can be used with equally good results.

To further improve stability and transient response of these devices larger values of output capacitor can be used.

It is vital with a low drop out regulator to use not only the correct values, but also the correct quality of components.

By the way having a tantalum capacitor across the power supply output is a bad idea. This is because when a tantalum capacitor fails its normal failure mode is a short circuit. This constitutes a fire hazard, and so would never get UL approval, no matter what the data sheet says.

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Any recommendations??? Ceramic plus electrolytic maybe???

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  • MLCC 22uF are easily found these days, cheap like borscht.
    Mind you borscht is not that cheap now.
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I would never object to a ceramic capacitor, but in this case I am not sure it would help. LDRs often break conventional rules, and need special consideration.

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Same user, same subject, different topic...