How are you doing?
I am reaching out to seek assistance with a critical issue I am facing with my system. Below are the details of my setup and the problem:
Sensor Communication: Receiving sensor data via a radio module using UART2.
Data Transmission: Sending received UART sensor data to my server using MQTT.
Battery Management: Using embedded IP5306 coded for battery management and to provide backup power when USB (adapter) power is unavailable (i.e. power cut on adapter side). see the datasheet here
The Problem: As the power cut happens, the IP5306 comes into action with the boosted battery power. When the battery drains completely, the IP5306 stops providing power to the TTGO board. Upon USB power restoration, the IP5306 does not resume normal operation unless the reset button is manually pressed (I mean if again a power disruption on the adapter side happens it does not resume with battery power). This TTgo board reset button (which resets the ESP32) is connected to the KEY pin of the IP5306, and pressing it shorts the KEY pin to GND, re-enabling the battery backup functionality.
The issue is exacerbated because my setup is deployed 126 km away on my farm, making manual intervention to press the reset button impractical.
Proposed Solution:
I am considering adding an ATTiny microcontroller to detect when the battery was fully drained before the last power cut. The ATTiny would then briefly pull the TTGO board's EN (enable) pin low for a few milliseconds to simulate a reset when the USB power is restored.
Request for Suggestions:
Is the proposed ATTiny chip solution viable for this scenario? If it is viable then is there any recommendation for a designing PCB?
Are there alternative approaches to solve this issue? For instance, can the IP5306 be configured differently to re-enable power delivery automatically when USB power is restored?
I would greatly appreciate your guidance or insights on resolving this challenge. Thank you in advance for your time and assistance.
If I am understanding you what you have here is a classic UPS issue. UPS means you are charging and using at the same time. If so, there is lot's of chips, circuits and tutorials. If not, then nevermind.
Yes @ sonofcy You are correct; this is indeed a UPS-like setup. The IP5306 chip, commonly used in backup power banks, is embedded in the TTGO T-Call board as part of its design. While replacing the chip is theoretically an option, I prefer to work within the constraints of the existing board since it comes preassembled with the IP5306 from production. My focus is on modular solutions rather than custom board development.
Thank you for your input, and I’m open to additional suggestions that align with this modular approach.
Thank you @sonofcy for sharing your insights and the link. I appreciate your perspective and your experience in electronics—it’s always valuable to learn from someone with such a rich background.
I understand the point raised in the discussion you linked, which highlights that the IP5306 may not be a pure UPS chip. However, for my specific application, it has been effective in managing power outages by leveraging its VBUS voltage drop detection to activate backup power during USB power loss.
The only limitation I’m facing is the manual reset requirement tied to the KEY button after a full battery drain, which is what I’m working to resolve. Beyond that, the IP5306 has been serving my purpose well.
Thank you again for your thoughtful input and kind wishes!
I wasn't sure if you were aware of the glitch in that chip. I have no experience with that chip so can't judge myself. You sound like you have a fair amount of experience with that chip so I will leave it with you. Good luck.
