Hydraulic control system of automatic transmission for vehicle provided with idle stop and go system

A hydraulic control system of an automatic transmission for a vehicle provided with an idle stop and go (ISG) system, the hydraulic control system supplying hydraulic pressure to a friction member operated at a gear stage when starting control is performed, the hydraulic control system comprising:

• a mechanical hydraulic pump driven by a torque of an engine, the mechanical hydraulic pump pumping a fluid stored in an oil pan;
• a regulator valve for regulating an operating hydraulic pressure fed from the mechanical hydraulic pump to be stable;
• a manual valve for receiving the hydraulic pressure from the regulator valve through a first hydraulic line and supplying the hydraulic pressure to a second hydraulic line by manipulation of a shift lever;
• a linear solenoid valve for controlling the hydraulic pressure supplied from the manual valve through the second hydraulic line and for supplying the controlled hydraulic pressure to a third hydraulic line;
• a switch valve for selectively supplying the hydraulic pressure supplied from the linear solenoid valve through the third hydraulic line to the friction member through a fourth hydraulic line;
• and
• an electric hydraulic pump driven by electric energy for pumping the fluid stored in the oil pan through a fifth hydraulic line and for feeding the pumped fluid to a sixth hydraulic line connected to the fourth hydraulic line,
• wherein the switch valve is controlled by the hydraulic pressure supplied from the manual valve through the second hydraulic line.