FW-PM1 · digital power module
The board between the battery and the autopilot.
FW-PM1 measures pack voltage, current, power and temperature over I²C and powers a Pixhawk-class flight controller. PX4 and ArduPilot read it with drivers they already ship, so there's no custom firmware.
Rev A · engineering review · not yet for sale
Rev A engineering render (shunt and connector bodies not modeled)
Specifications
Design targets for rev A. Final ratings come from qualification testing.
| Input | 3–8S LiPo (9–33.6 V) |
|---|---|
| Battery current | 60 A continuous (design target; thermal qualification pending) |
| Current sensing | 0.2 mΩ four-terminal (Kelvin) shunt · TI INA238 monitor, ±204.8 A range |
| Telemetry | Bus voltage, current, power and die temperature over I²C, address 0x45 |
| Autopilot supply | 5.2 V, 3 A (TI LM76003 synchronous buck, 60 V class) |
| Input protection | 600 W TVS (36 V standoff) |
| Autopilot connector | 6-pin Molex CLIK-Mate, 2.00 mm (Pixhawk POWER port) |
| Battery leads | Solder pads for 12 AWG, in and out |
| Board | 50 × 35 mm · 4 layers · 2 oz outer copper |
Works with
| PX4 | Enable SENS_EN_INA238, set INA238_SHUNT = 0.0002 |
|---|---|
| ArduPilot | BATT_MONITOR = 21 (INA2XX), BATT_SHUNT = 0.0002 |
Settings from each autopilot's INA238 driver; confirmed on hardware once rev A is built.
POWER port pinout
| Pin 1, 2 | 5.2 V |
|---|---|
| Pin 3 | I²C SCL (3.3 V logic) |
| Pin 4 | I²C SDA (3.3 V logic) |
| Pin 5, 6 | GND |
Provenance
The active parts on FW-PM1. Each one's wafer fab and packaging site is published per production lot before a board ships.
| Power monitor | Texas Instruments INA238 |
|---|---|
| 5.2 V buck converter | Texas Instruments LM76003 |
| 3.3 V regulator | Texas Instruments TLV75533 |
| TVS diode | Littelfuse SMBJ36A |
| Bare board | U.S. fabricator |
| Assembly and test | Ohio |
Top and bottom
Want evaluation units?
Rev A is in engineering review. Tell us your airframe, cell count and current, and we'll line you up for the first build.
Email us