Power source switching apparatus and method thereof

Abstract

A power source switching apparatus and method thereof are provided. The example power source switching apparatus may include a battery storing charges received from an external power source and outputting a voltage corresponding to the stored charges, a voltage adjuster outputting a first power source voltage having a voltage level, corresponding to the output voltage of the battery, during an external power source mode where the battery is being charged, the first power source voltage based at least in part on the external power source and the output voltage of the battery, a controller outputting a first control signal and a second control signal, the first control signal enabled if the battery is operating in the external power source mode and the second control signal is enabled if the battery is not operating in the external power source mode, a first switch outputting the first power source voltage if the first control signal is enabled and a second switch outputting the output voltage of the battery if the second control signal is enabled. In an example method, a first power source voltage may be provided if a battery is not being charged by an external power source voltage, the first power source voltage output by the battery. A second power source voltage may be provided if the battery is being charged by the external power source voltage, the second power source voltage corresponding to a voltage level of the first power source voltage and not provided from the battery.

1 . A power source switching apparatus, comprising:
 a first power source unit supplying a first voltage which is applied to a system load during a first power source mode;   a second power source unit supplying a second voltage which is applied to a system load during a second power source mode and charged by the first voltage; and   a voltage adjuster controlling that the first voltage has the same voltage level of the second voltage while the second voltage is being charged so as to maintain a level of voltage applied to the system load during a transition between the first power source mode and the second power source mode.   
   
   
       2 . The power source switching apparatus of  claim 1 , wherein the first voltage is an external power source voltage. 
   
   
       3 . The power source switching apparatus of  claim 1 , wherein the second voltage is an output voltage of a battery. 
   
   
       4 . The power source switching apparatus of  claim 1 , further comprising:
 a battery charger supplying charges from the first power source unit to the second power source unit.   
   
   
       5 . The power source switching apparatus of  claim 1 , further comprising:
 a first switch applying the first voltage to the system load in responding to a first control signal; and   a second switch applying the second voltage to the system load in responding to a second control signal.   
   
   
       6 . The power source switching apparatus of  claim 1 , further comprising:
 a controller outputting a first control signal enabled during the first power source mode and a second control signal enabled during the second power source mode.   
   
   
       7 . The power source switching apparatus of  claim 1 , wherein the voltage adjuster comprises:
 an operational amplifier including a first input terminal receiving the first voltage and a second input terminal connected to the system load; and   a MOS transistor including a first terminal applied the first voltage, a second terminal connected to the system load.   
   
   
       8 . The power source switching apparatus of  claim 7 , wherein the voltage adjuster further includes:
 a load including a first terminal connected to the second input terminal of the operational amplifier and the second input terminal of the MOS transistor.