A projection display apparatus may include a light source, a power supply unit, a detecting unit, a nonvolatile memory, a capacitor, and a control unit. The power supply unit supplies power from an external power supply to the light source power derived from the received power. The detecting unit detects a cut-off state in which no or no sufficient power is being received by the power supply unit. The capacitor accumulates charges in response to power being received. Following detection of the cut-off state and even after turning off the light source, the control unit is operable to carry out a data storage operation in which at least part of the data is stored in the nonvolatile memory, wherein power to carry out the data storage operation is obtained from the charges previously accumulated by the capacitor.