FIG. 1 is a front, top, right side perspective view of a first embodiment of a USB charger, showing my new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a top plan view thereof;
FIG. 5 is a bottom plan view thereof;
FIG. 6 is a left side elevational view thereof; and
FIG. 7 is a right side elevational view thereof.
FIG. 8 is a front, top, right side perspective view of a second embodiment of a USB charger, showing my new design;
FIG. 9 is a front elevational view thereof;
FIG. 10 is a rear elevational view thereof;
FIG. 11 is a top plan view thereof;
FIG. 12 is a bottom plan view thereof;
FIG. 13 is a left side elevational view thereof; and,
FIG. 14 is a right side elevational view thereof.
The broken lines depict portions of the USB charger and form no part of the claimed design.