Navigation device and power saving method thereof

摘要

A navigation device includes an image sensor, a processing unit, a main clock circuit and an auxiliary clock circuit, wherein a clock frequency of the auxiliary clock circuit is much lower than that of the main clock circuit. The image sensor captures a predetermined number of image frames in a burst period. The processing unit is configured to calculate a displacement according to the image frames, to disable the main clock circuit after the predetermined number of image frames have been captured by the image sensor and to restart the main clock circuit with the auxiliary clock circuit before the end of the burst period.

主权项

1. A navigation device, configured to report a displacement with a burst mode in a normal operation mode, the navigation device comprising:
a main clock circuit configured to generate a first clock signal with a first frequency; an auxiliary clock circuit configured to generate a second clock signal with a second frequency, wherein the second frequency is lower than the first frequency; an image sensor configured to capture a first image, a second image and a third image according to the first clock signal within a burst period of the burst mode; and a processing unit configured to
calculate the displacement according to the first image, the second image and the third image, anddisable the main clock circuit to stop generating the first clock signal at a predetermined time after receiving the third image from the image sensor, wherein a start point of a next burst period is counted by using the second clock signal generated by the auxiliary clock circuit.