Hydraulic pressure supply system of automatic transmission for vehicle

A hydraulic pressure supply system of an automatic transmission for a vehicle which generates a low hydraulic pressure and a high hydraulic pressure using oil stored in an oil pan and supplies 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 receiving the oil stored in the oil pan through an input line, generating the low hydraulic pressure, and discharging the low hydraulic pressure to a first low-pressure line;
• a low-pressure regulator valve connected to the first low-pressure line and regulating the hydraulic pressure of the first low-pressure line to stable low hydraulic pressure and supplying the stable low hydraulic pressure to a second low-pressure line;
• a first switch valve selectively connecting the second low-pressure line to a third low-pressure line connected to the low pressure portion;
• a first bypass line bypassing the first switch valve and connecting the first low-pressure line with the second low-pressure line;
• a high-pressure hydraulic pump connected to the first low-pressure line and increasing the hydraulic pressure supplied through the first low-pressure line to generate the high hydraulic pressure, and discharging the high hydraulic pressure to a high-pressure line connected to the high pressure portion;
• a second bypass line bypassing the high-pressure hydraulic pump and connecting the first low-pressure line with the high-pressure line;
• a second switch valve disposed on the second bypass line and selectively supplying the hydraulic pressure of the first low-pressure line to the high-pressure line;
• and
• a high-pressure regulator valve disposed on the high-pressure line, regulating the hydraulic pressure supplied from the high-pressure hydraulic pump and the hydraulic pressure selectively supplied through the second switch valve to stable high hydraulic pressure, and supplying the regulated hydraulic pressure to the high pressure portion.