The load at VOUT can be increased up to 2.5 W. A 10 Ω purely resistive load (i.e. 2.5 W load at 5 V) is usually
managed without problems also at ping-up. In some case (e.g. a following DC-DC converter stage) the load could
show a remarkable capacitive behavior and a relatively high initial current may trigger the over-current protection
or may exceed the dynamic capability of the transmitter. To avoid this, the load should be smoothly increased, or
its capacitive component should be reduced.
Several parameters of the receiver module can be temporary changed through the GUI. Just to give an example,
the output voltage can be changed on-the-fly by acting on the slider and writing the new value into the related
register (
).
Figure 12.
Changing the output voltage to 6 V via GUI
Note that increasing the output voltage may impact on the external components (e.g. proximity to maximum
voltage rating of VRECT and VOUT capacitors or to clamping voltage of protection TVS diodes) and on some
setting (the OVP threshold, for example, could be triggered if not conveniently adapted to the new operating
conditions). Some transmitters may have inherent limitations and could terminate the power transfer if significant
changes in the output voltage are applied.
An extensive description of the GUI and its functionalities can be found in the related user manual, while the
complete register map of STWLC68JRH can be found in its datasheet.
reports the typical TX-to-RX efficiency of the paired STEVAL-ISB68WAM and STEVAL-ISB045V1T kits.
Although the graph in
has been extended to an output power of 3.5 W (0.7 A @ 5 V), the 2.5 W limit
prevents over-heating of the RX coil.
UM2693
STEVAL-ISB68WA test setup
UM2693
-
Rev 1
page 12/18