- Full breakout to access signals from USB B, Mini or Micro cables
- Output standard USB A port for low cost connection cable to desired termination
- Current sense header to quickly insert current meter to measure device current
- D+ and D‐ test points to easily access data or measure DC bias levels
- Switch to attach biasing rheostats to set DC levels on data lines for charger emulation
The USB breakout/converter is intended for designers who need a fast and unobtrusive method of examining USB signals between two devices. Common applications include USB power bus monitoring and test or emulation of DC bias levels typically used with charging devices where D+ and D‐ lines are repurposed to provide analog signalling to the target charger.
All standard USB signals (VBUS, D+, D‐, GND) are interconnected to all connectors. D+ and D‐ impedance is equalized and tested to support USB 2.0 High Speed data rates without disrupting signal integrity. Please note that high current devices like external hard drives will not typically function with cables longer than 18″ so will not be able to draw enough current through an additional cable and this adapter.
The breakout not only enables fast and easy measurement of existing signals, but also allows DC levels to be set on the USB data lines for testing / emulation purposes. Biasing rheostats are connected to D+ and D‐ by toggling the slider switch on the board. The rheostats are adjusted to individually set voltage to any level between VUSB and ground. Data line connection to the rheostats is through 100k resistors to prevent loading and can be adjusted if required by the application.
Target current is measured by removing jumper J2 and inserting a current meter. Test points give easy access to measure 5V_IN and 5V_OUT across the meter to check voltage drop from the test.