-
Notifications
You must be signed in to change notification settings - Fork 0
Power
VIN
The voltage at the battery terminal
V+
The regulated output power (VBATT - 4.4V) of the BQ24074 battery charger.
VBUS
4.35 V - 10.5 V
VBATT
The measured voltage of the battery?
| Teensy | OLED | mA | mW |
|---|---|---|---|
| F0 | y | 134 | 546 |
F0 : Full Power, minimal processing
| Device | Current (mA) | Power (mW) | Method |
|---|---|---|---|
| SD | 20 | 80 | Regulator off |
| WIO-E5 | 9 | 36 | Low Power Mode |
| Total | 29 | 116 |
|---|
The SD Card power consumption was tested by turning the SD Card regulator on and off and measuring the difference in current and power using the built-in fuel gauge.
In SDIO mode using the SDFat library, the SD Card was initialise using sd.begin(SdioConfig(FIFO_SDIO)) and the power was measured for 20 seconds. Then the power was measured for 20 seconds with the power to the SD Card's 3.3v regulator turned off.
| Mode | Current (mA) | Power (mW) |
|---|---|---|
| Dis | -126 | -505 |
| En | -146 | -585 |
| Dis | -126 | -505 |
| En | -146 | -584 |
| Dis | -126 | -505 |
| En | -146 | -584 |
It seems like there's a 20 mA (80 mW) difference in draw with the SD card enabled over a measured span of 20 s. So it might be worth keeping the independent regulator.
The WIO-E5 power consumption was tested by switching the chip to low power mode using the AT+LOWPOWER command. The command and mode was verified by echoing the command and response via Serial to a laptop before disconnecting the laptop to log power consumption.
| Mode | Current (mA) | Power (mW) |
|---|---|---|
| Dis | -115 | -462 |
| En | -124 | -498 |
| Dis | -115 | -461 |
| En | -124 | -497 |
| Dis | -115 | -461 |
| En | -124 | -497 |
A difference of 9 mA (36 mW) was measured over a span of 20 s. It's unclear if an additional regulator would further reduce this.
I have not tested auto low power mode or the impact of turning the serial connection off (which is recommended). There seems to be a Serial.end() function, which should do the trick.
NB: Snooze v6.3.9 does not work on Teensy MM. It will not program properly. It requires modifications listed in https://github.com/duff2013/Snooze/issues/114. I have forked the library and applied these and overridden the Teensy library version and it seems to work (at least partially).
Teensy sleep modes are tested with 5V USB power though the USB Power monitor (battery not attached).
| Mode | Voltage (V) | Current (mA) | Power (mW) |
|---|---|---|---|
| On | 5.07 | 112 | 570 |
| Sleep. | 5.10 | 27 | 140 |
| Deep Sleep | 5.10 | 17 | 86 |
| Hibernate | 5.10 | 16 | 83 |
In theory, this seems like the Teensy could run for 11 days on low power.