Methods for initiating operating voltages for subscriber identity cards and systems utilizing the same

A method for initiating operating voltages of a first subscriber identity card and a second subscriber identity card of a mobile station, the mobile station further comprising a Baseband unit and an RF module, the method comprising:

• coupling the Baseband unit to the first subscriber identity card and providing a voltage variable signal to the first subscriber identity card;
• receiving a first code from the first subscriber identity card when the voltage variable signal is provided to the first subscriber identity card;
• providing a first operating voltage corresponding to the first code to the first subscriber identity card;
• coupling the Baseband unit to the second subscriber identity card and providing the voltage variable signal to the second subscriber identity card after the first operating voltage is provided;
• receiving a second code from the second subscriber identity card when the voltage variable signal is provided to the second subscriber identity card;
• and
• providing a second operating voltage corresponding to the second code to the second subscriber identity card;
• wherein the voltage variable signal is an analog signal with a first voltage level during a first time period and a second voltage level during a second time period, a voltage level of the first operating voltage is equal to the first or second voltage level, and a voltage level of the second operating voltage is equal to the first or second voltage level.

A method for initiating operating voltages of a first subscriber identity card and a second subscriber identity card of a mobile station, the mobile station further comprising a Baseband unit, a controller and an RF module, the method comprising:

• providing a first signal from the Baseband unit to the controller via a first interface;
• coupling a second interface of the Baseband unit to the first subscriber identity card by the controller after the first signal is provided;
• providing a voltage variable signal to the first subscriber identity card by a first regulator of the controller when the second interface of the Baseband unit is coupled to the first subscriber identity card;
• receiving a first code from the first subscriber identity card by the Baseband unit via the second interface when the voltage variable signal is provided to the first subscriber identity card;
• performing voltage level settings to the first regulator and a first level shifter according to the first code, wherein the first regulator and the first level shifter are coupled to the first subscriber identity card;
• providing a second signal from the Baseband unit to the controller via the first interface after the voltage level settings of the first regulator and the first level shifter are completely performed;
• coupling the second interface of the Baseband unit to the second subscriber identity card by the controller after the second signal is provided;
• providing the voltage variable signal to the second subscriber identity card by a second regulator of the controller when the second interface of the Baseband unit is coupled to the second subscriber identity card;
• receiving a second code from the second subscriber identity card by the Baseband unit via the second interface when the voltage variable signal is provided to the second subscriber identity card;
• and
• performing voltage level settings to the second regulator and a second level shifter according to the second code, wherein the second regulator and the second level shifter are coupled to the second subscriber identity card;
• wherein the voltage variable signal is an analog signal with a first voltage level during a first time period and a second voltage level during a second time period, and a voltage level of the first operating voltage is equal to the first or second voltage level, and a voltage level of the second operating voltage is equal to the first or second voltage level.