Semiconductor device and control method thereof

A method of controlling a semiconductor device including a power circuit supplied with a first voltage from a host, the power circuit including first and second channels, a semiconductor memory, and a controller for the semiconductor memory, the method comprising:

• generating a second voltage from the first voltage in the first channel;
• generating a third voltage from the first voltage in the second channel;
• supplying the generated second voltage to the semiconductor memory;
• supplying the generated third voltage to the controller;
• and
• upon detecting that the first voltage is less than a first threshold, turning off the first and second channels.

A semiconductor device comprising:

• a connector configured for connection to a host;
• a switch supplied with a first voltage from the host via the connector;
• a power circuit including first and second channels configured to generate second and third voltages, respectively, from the first voltage output by the switch;
• a semiconductor memory supplied with the second voltage via the first channel;
• and
• a controller for the semiconductor memory, supplied with the third voltage via the second channel,
• wherein when the first voltage is less than a first threshold, the power circuit turns off the first channel and the second channel.