Flight Core v2 Power
Table of contents
Hardware
J13 - VOXL Power Module v3 Input
The main power input is J13 and is typically paired with a VOXL Power Module v3, which provides two I2C based power monitoring ICs, providing PX4 the battery status.
Recommended is MCBL-00062 (Flight Core v2 to Power Module Cable) for this interface.
J3 - USB Power Input
New to v2 of Flight Core, is the ability to power the system off USB power (note that the main power input at J13 takes precedence when both are present). Note there is no power monitoring via this interface.
Recommended is MCBL-00010 (JST-to-micro-USB) for this interface, when adding your own micro USB cable.
Software
PX4 Driver Source
An open source PX4 driver is available at /src/drivers/power_monitor/voxlpm
PX4 Driver Overview
(Reused from the header file, DRY!)
* - VOXLPM v3 (QTY2 INA231) -
*
* +~~~~~~~~~~~~~~+
* VBATT -----| RSENSE_VBATT | ----------+---------------------> VBATT TO ESCS
* | +~~~~~~~~~~~~~~+ |
* | | +--------+------+
* +----+ +----+ | 5/12V REGULATOR |
* | | +--------+------+
* | | | +~~~~~~~~~~~~~~+
* | | +---| RSENSE_5VOUT |---> 5/12VDC TO COMPUTE/PERIPHERAL
* | | | +~~~~~~~~~~~~~~+
* | | | |
* V| |A V| |A
* ################# #################
* # INA231, 0x44 # # INA231, 0x45 #
* ################# #################
*
*
* Publishes: Publishes:
* - ORB_ID(battery_status)
* - ORB_ID(power_monitor) - ORB_ID(power_monitor)
*
The driver periodically queries two INA231 devices, and calculates the battery voltage and amperage draw (e.g. ESC power + compute power), along with the regulated 5VDC output and amperage draw (e.g. compute power).
There are parameters that can adjust shunt resistance values if rework is done to the power module to change the fullscale range.