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| Boilerplate USB single Lithium cell battery power supply for DIY projects |
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| jonovid:
Lithium Li-ion 18650 3.7V 4.2V Battery Charger Board DC-DC Step Up Boost Module TP4056 as sold this Module see image has anyone added a soft latch power switch circuit to this particular USB battery board DC-DC step Up boost module? if so? can we see your reverse engineering work of this particular boost module? why so we can have an auto power off at low Battery & a soft latch power switch for the step Up boost part of the circuit. the idea here is to have a single Li-ion 18650 with USB Charger and power 50 to 200Ma 6 to 9 volt projects boilerplate USB battery power supply circuit for 6 to 12 volt projects with its own soft latch power switch . I have seen and know about soft latch power switch circuits, Dave did a video on them. so how would you go about modifying this particular USB battery board DC-DC step Up boost module? I would cut in to the power rail tracks on the PCB in between the TP4056 battery charge part of the circuit A and the DC-DC step Up boost part B of the on the PCB and add a power MOSFET & two npn in a soft latch. but the part I do not know, is the best way to trip off any modified soft latch circuit when the battery gets low. so if any of you have reverse engineered this module? :-/O can pin 8 on the TP4056 be used as an On Off switch? so no auxiliary power MOSFET is needed simplifying a soft latch power switch. my USB TP4056 boost modules are still in the post & no one online has reverse engineered the circuit as far as I know. |
| Peabody:
I have one of these modules, but haven't had a chance to play with it. You may find more information by searching for "J5019 module". The mystery chip is an MT3608. The module has no protection function, so you would have to add that or use protected batteries. There are three plated-through holes near the output headers, but I don't know what purpose they have. In addition to protection, the module is also missing a power sharing circuit (also known as power path). I agree that the best place for the soft latch circuit is between the battery + terminal and the input to the boost regulator. You want to be able to charge the battery while the load power is switched off. |
| thm_w:
I use the dedicated MT3608 module then USB charger + protection in one board, with a hard power switch on OUT+, from what I remember: https://www.aliexpress.com/item/32649780468.html https://www.aliexpress.com/item/4001066566291.html There is probably a way to logic level trip the DW01 used on those boards, but, I didn't consider that method. |
| MegaVolt:
Information on a typical protection board with Ali. |
| JohanH:
MT3608 pin 4 EN is probably connected to incoming voltage to DC converter. You could cut the trace and use pin 4 to enable/disable the converter (min. 1.5V to enable). |
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