Patent ID: 8085613

Claim:
A power detecting circuit adapted for a portable device, wherein the portable device includes a power input terminal, the power detecting circuit comprising: a data latch, coupled to the power input terminal, for receiving a voltage inputted from the power input terminal; a discharge unit, comprising a first terminal, a second terminal and a control terminal, wherein the first terminal of the discharge unit is coupled to the power input terminal, the second terminal of the discharge unit is coupled to a common voltage, the control terminal of the discharge unit receives a power detecting signal, wherein the first terminal and the second terminal of the discharge unit are electrically connected when the power detecting signal is enabled; and a switch circuit, comprising a first terminal, a second terminal, a first control terminal and a second control terminal, wherein the first terminal of the switch circuit is coupled to the power input terminal, the first control terminal of the switch circuit is coupled to the data latch, the second control terminal receives the power detecting signal, wherein, during a detecting period, the power detecting signal is enabled, the first terminal and the second terminal of the switch circuit are disconnected, if a power low signal outputted from the data latch and received from the first control terminal of the switch circuit is altered from a first state to a second state during the detecting period, the circuit between the first terminal and the second terminal of the switch circuit is kept disconnecting.