This invention is a portable electronic device (100) including a display
(212), an input device (210), a lighting circuit (204), a light sensor
(206) and a control circuit (208). The lighting circuit (204) includes a
light source (214) to illuminate the display (212) and the input device
(210). The light sensor (206) determines the ambient lighting conditions
about the display (212) and/or the input device (210) and generates an
ambient lighting signal based on the ambient lighting conditions. The
control circuit (208) is coupled to the lighting circuit (204) and the
light sensor (206) and has a delayed operation mode in which a first
activation of the input device (210) illuminates the display (212)
without performing any other operation of the device (100) and a second
activation of the input device performs an operation of the device other
than illuminating the display. The control circuit (208) of the portable
electronic device (100) may receive a reverse bias signal generated by
the lighting circuit (204) when incident with ambient lighting about the
user interface (202) to supplement or eliminate the light sensor (206).