Patent ID: 8832480

Claim:
A portable electronic device having automatic power supply mode switching, comprising: a micro-sensor, for sensing whether the portable electronic device is worn by a user to generate a sensing signal accordingly; and a control circuit, coupled to the micro-sensor, for determining whether to switch a power supply mode according to the sensing signal and a present mode, wherein, if the sensing signal changes when the control circuit operates in a normal mode, the control circuit switches to a standby mode, wherein the control circuit includes a timer, for generating a timing result, and when the control circuit operates in the standby mode, the control circuit is configured to switch to the normal mode according to the timing result and whether the sensing signal changes, wherein the timer is configured to begin operation in response to a change of the sensing signal, and wherein, if the timing result is less than a first time length when the control circuit operates in the standby mode while the sensing signal changes, the control circuit is configured to switch to the normal mode.