VOXL 2 DS1 LED Flicker Problem?

[czarsimon]

Hi, we're seeing the DS1 LED flicker when we have some additional peripherals connected to the same 5V supply. When they are disconnected the LED is a solid green. The VOXL has been functioning just fine, how big of a problem is this? Is anything other than a solid green light completely unacceptable and risky to use? Thanks!

[Vinny]

Hi @czarsimon
Flickering is not acceptable and it is worth chasing before you fly it. DS1 is driven by the 5 V eFuse on VOXL 2. Solid green means power good with no fault. Any flicker means the eFuse is toggling power-good or asserting a fault and recovering, so you are operating right at the edge of a trip. The system may look fine on the bench and then brown out when something shifts, such as a colder battery, a warmer ambient, or a transient load.

Two questions before we can tell you which fault it is. Are your peripherals powered from the same upstream VBAT supply as VOXL 2, or from VOXL 2’s own 5 V output connectors? And can you scope VDCIN_5V at J4 pin 1 while the flicker is happening?

What you are looking for is whether the rail is sagging or spiking. Sagging points at supply capacity: VOXL 2 expects 5 V ±5%, and the power module is set to 5.08 V no-load specifically to absorb cable drop. Adding load on the same supply eats that margin. Spiking above 5.6 V trips the eFuse overvoltage protection instead, which is a transient problem at the peripheral rather than a capacity problem.

Also note our cable-connector power outputs are rated 1 A each and the system cannot supply 1 A on all connectors simultaneously: https://docs.modalai.com/voxl2-connectors/#power-inputoutput-important-note

If it is droop and the total load is genuinely beyond one power module, separate the peripherals onto their own supply (using a second power module regulated from your VBAT) rather than sharing the VOXL 2 feed. If it is overvoltage, more supply capacity will not help.