Patent ID: 6979086
Filing Date: 2005-12-27
Classification: H04N

Abstract:
1. A projector, comprising: a power supply; a lamp for providing a projector light source; a starter for turning on the lamp; an image processing system for outputting projected images according to a video signal; a CPU for controlling the image processing system; at least one cooling fans generating pulse signals according to the rotational speed of the cooling fan; a charging circuit coupled to the cooling fan for generating a continuous charging signal; a comparator for comparing the voltage level of the continuous charging signal with a reference voltage and generating a comparison signal with different voltage levels responding to the comparison result; a signal generating circuit for generating a boot-delay signal after starting the lamp for a predetermined delay period; an AND logic gate for receiving the comparison signal and the boot-delay signal and outputting a logic signal with a logic level; and a status latch and protection drive circuit for receiving the logic signal output from the AND logic gate and outputting a protection active signal to reset the CPU, shut down the power supply or the lamp when the logic level of the logic signal changes.