iPad Giv

I used Pianoteq 8 with my iPad and with an E. piano over MIDI. As a MIDI interface I used an E-MU Midi 2x2 from Creative. The power for the MIDI interface always came via USB. Until last Saturday shortly before my performance. The power for the interface no longer flows. The interface and the cable are fine. Why is there no more power coming out of the iPad? I have no explanation. Who can give me advice? Is there something witH the IPad?