A power gating system including: a first power line coupled to a first pad; a second power line coupled to a second pad; a third power line coupled to a plurality of logic gates in common; a first power gating switch coupled between the first and third power lines; and a second power gating switch coupled between the second and third power lines. When a double power mode is set, the first and second power gating switches may be turned on to couple the first and second power lines to the third power line at the same time.