search

baylibre-acme / ACME

Migrated to gitlab - BayLibre's ACME repo Manifests
https://gitlab.com/baylibre-acme/ACME
2 stars 0 forks source link

USB probe problem #4

Closed kdub closed 6 years ago

kdub commented 6 years ago

The problem here may just be a lack of understanding on my part, but I'm trying to measure a device that will shut off at about 3.6V. My power source is set to 4.0V. As the device boots, the voltage starts to drop, with the last reading being:

vshunt 15.6 mV vbus 3643.8 mV 5675.0 mW 1558.0 mA

before the target device reboots from a brownout condition. The power source reports itself as staying at 4.0V the whole time, and removing the ACME probe avoids any brownout condition on the target device. Any idea why there's a 0.4V drop across the acme probe?

kdub commented 6 years ago

Actually, a bit more investigation revealed that the significant drop was not in the probe, but in the wires. The problem only became apparent when workload drove current > 1.5A. Closing issue.