Mobile terminal

1. A mobile terminal comprising:

a control unit;

a power managing unit coupled to said control unit; and

a switch unit coupled to said control unit and said power managing unit, said switch unit comprising a single switch which is operable so as to enable said power managing unit to supply electric power to said control unit, said switch being further operable so as to enable said control unit to perform one of controlling said power managing unit to stop supply of electric power thereto and a predetermined operation in response to a duration of user actuation of said switch;

wherein said power managing unit includes first, second and third nodes, and is operable in one of:

a non-power supplying mode, where said power managing unit provides

a logic-high voltage signal at each of said first and third nodes, and

a logic-low voltage signal at said second node, and

a power supplying mode, where said power managing unit provides

a logic-high voltage signal at each of said first and second nodes

and where said power managing unit supplies electric power to said control unit;

said switch unit including:

a first voltage-controlled switch having

a first end coupled to said third node of said power managing unit,

a second end, and a first control end coupled to said first node of said power managing unit,

a second voltage-controlled switch having

a third end coupled to said first node of said power managing unit,

a grounded fourth end, and

a second control end coupled to said second node of said power managing unit,

a third voltage-controlled switch having

a fifth end coupled to a first terminal of said control unit,

a grounded sixth end, and

a third control end coupled to said first node of said power managing unit,

a fourth voltage-controlled switch having

a seventh end coupled to a second terminal of said control unit,

an eighth end coupled to said second end of said first voltage-controlled switch, and

a fourth control end coupled to said second node of said power managing unit, and

a manually-operable switch having

a ninth end coupled to said second end of said first voltage-controlled switch and said eighth end of said fourth voltage-controlled switch,

a tenth end coupled to said fifth end of said third voltage-controlled switch and said first terminal of said control unit, and

a manually-operable end;

wherein said power managing unit switches from the non-power supplying mode to the power supplying mode when said switch unit is operated, so as to provide a logic-low voltage signal to said third node of said power managing unit.

2. The mobile terminal as claimed in claim 1 , wherein said control unit enables said power managing unit to switch from the power supplying mode to the non-power supplying mode when the duration of user actuation of said switch exceeds a predetermined period.

3. The mobile terminal as claimed in claim 2 , wherein the predetermined operation is one of on-hook and off-hook operations.

4. The mobile terminal as claimed in claim 2 , wherein each of said first, second, third and fourth voltage-controlled switches is an NMOS transistor, and said manually-operable switch is a push button switch.

5. The mobile terminal as claimed in claim 1 , further comprising an I2C interface interconnecting said power managing unit and said control unit.