Lilygo released V8 of the TTGO T-Beam board in August 2019. This rework included several changes mainly targetted at reducing power consumption by using integrating the AXP192 power controller IC. A list of the changes is as follows:
- User button Pin GPIO39 pin is replaced with GPIO38
- Replace the charging IC (TP5400) with the power management AXP192
- GPS TX (12), RX (34) pin replacement
- Power on switch removed and replaced with push button
- Reduced sleep current
- GPS battery replacement
The AXP193 controls the board's power domains and has 4 linear voltage regulators (LDO) and 3 Buck DC-DC converters.
- DCDC1 powers OLED if installed
- DCDC2 not connected
- DCDC3 now controls the 3.3v to the board and to header 2 Pin7 & pin11
- LDO2 provides LoRa power
- LDO3 provides GPS power
- AXP Charge Led replaces Led on GPIO
https://github.com/Xinyuan-LilyGO/TTGO-T-Beam
Experiments indicate that
| Mode | Pwer (mA) |
|---|---|
| Deep sleep | 5.3 |
| GPS and LoRa powered off | 42mA |
| GPS and LoRa powered on | 44mA |
| Blue LED charge light | +20mA |