Hydraulic pressure supply system of automatic transmission for vehicle

A hydraulic pressure supply system of an automatic transmission for a vehicle generating a low hydraulic pressure and a high hydraulic pressure using oil stored in an oil pan and supplying the low hydraulic pressure and the high hydraulic pressure respectively to a low pressure portion and a high pressure portion, the hydraulic pressure supply system comprising:

• a low-pressure hydraulic pump generating the low hydraulic pressure using the oil stored in the oil pan;
• a low-pressure regulator valve regulating the low hydraulic pressure supplied from the low-pressure hydraulic pump to be stable hydraulic pressure and supplying the regulated hydraulic pressure to the low pressure portion;
• a high-pressure hydraulic pump generating the high hydraulic pressure using the oil Stored in the oil pan and supplying the high hydraulic pressure;
• a high-pressure regulator valve regulating the high hydraulic pressure supplied from the high-pressure hydraulic pump to be stable hydraulic pressure and supplying the regulated hydraulic pressure to the high pressure portion;
• a first switch valve disposed between the low-pressure hydraulic pump and the low-pressure regulator valve, and selectively communicating the low-pressure hydraulic pump to the low-pressure regulator valve;
• a second switch valve selectively opening or closing a first circulating line connecting a downstream of the low-pressure hydraulic pump to an upstream of the high-pressure regulator valve;
• and
• a third switch valve selectively opening or closing a second circulating line connecting a downstream of the high-pressure regulator valve to an upstream of the low-pressure regulator valve.