Strix PSU

The Strix PSU is a test board created to test both the new PSU chips (required due to the chip shortage) and test the process of creating a board from scratch, post-COVID. Project files can be found on GitHub.

Background

The Strix PSU is a prototype for the proposed Project Strix (Martlet IV) power supply, and as such is required to be compact, rechargeable, and store a high energy density.

The core architecture is a 2S Li-Ion battery pack, connected to a balancer, charger, and two voltage regulators. The regulators create 3.3V and 1.8V voltage outputs at up to 300mA, to accomodate a large safety factor over the power budget of the proposed Strix subsystems. The system is designed to be recharged by a 12V lead-acid battery - so that the avionics system can be recharged on the pad.

Li-Ion Battery Charging

There are two key phases to Li-Ion battery charging: the constant current and constant voltage regimes.

Experimental Testing Log

Day 1: 22/11/21

Initial Testing

Cheap DuPont jumper wires were soldered up to the underside of the right-angle headers to make connections easily in lieu of actually buying receptables and crimps.
- Male to male connectors were attached to the battery, 3v3, and 1v8 connectors on the board.
- Male to female connectors were attached to the cells themselves.
Regulator outputs were tested with multimeter, correct voltages measured.
VBatt measured at 7.9V, within spec.
Regulators and board temp were measured with fingers, warm to the touch but no burning.

Charger Testing

Male to male DuPont jumpers were soldered to the charger input of the board.