cpu 22 outputs the open signal at the third gpio port 28 to u201c open u201d the first switch 118 if the output of the comparator 102 changes to be the logical high control signal indicating that the battery voltage v b is between v f 5 r 12 iir 14 r 12 iir 14 r 11 iir 13 and v f 5 r 12 iir 14 r 11 r 12 iir 14 the cpu 22 outputs a second low power indication signal to the display device if the comparator 102 still outputs the logical low control signal indicating that the battery voltage v b is less than v f 5 r 12 iir 14 r 11 r 12 iir 14 the cpu 22 outputs a first low power indication signal to the display device the resistors from first to fourth must have resistances such that r 12 iir 14 r 12 iir 14 r 11 iir 13 is smaller than r 12 r 12 r 11 the first and second power segment detection circuits 114 and 120 mentioned above are connected in parallel with the first and second resistors 110 and 112 respectively alternatively the power detection circuit 100 can have a variety of connections of the first and second power segment indication circuits 114 and 120 and the first and second resistors 110 and 112 for example the first and second power segment indication circuits 114 and 120 can be connected in parallel with the first or second resistors 110 and 112 at the same time since power detection circuits of such connections have operations similar to those of the voltage detecting circuit 100 further description is omitted the voltage detecting.