| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to output a stable internal source voltage by setting a 1st border voltage, which is switched from variable voltage characteristics to fixed-voltage characteristics, lower than a 2nd border voltage which is switched from fixed-voltage characteristics to variable-voltage characteristics. SOLUTION: A divided voltage Va1=(VEXT×R6/(R4+R5+R6) based upon a 1st voltage division ratio of a voltage dividing circuit 120 is compared with a reference voltage VREF to switch a 2nd voltage section to a 3rd voltage section when an external source voltage VEX is as high as a 2nd border voltage VT2 , and a divided voltage Va2=VEXT×R6/(R5+R6) based upon a 2nd voltage division ratio is compared with VREF to switch the 3rd voltage section to the 2nd voltage section when VEXT is as high as a 1st border voltage VT1 <VT2 . Namely, the external source voltage which is switched from the 3rd voltage section to the 2nd voltage section is set lower than the external source voltage which is switched from the 2nd voltage section to the 3rd voltage section to give hysteresis characteristics to the section switching between the 2nd and 3rd voltage sections.
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