Circuit for controlling hydraulic pressure of torque converter

A circuit for controlling hydraulic pressure of a torque converter, wherein the torque converter includes an engagement hydraulic pressure chamber independently installed in a fluid operation chamber enclosed by a front cover and an impeller and having engagement hydraulic pressure supplied thereto in order to engage a lock-up clutch, the circuit comprising:

• a torque converter control valve exhausting a portion of line pressure, stably adjusting hydraulic pressure to supply operation hydraulic pressure of the torque converter, and receiving fed-back exhaust hydraulic pressure of the torque converter at the time of controlling the engagement of the lock-up clutch to decrease supply hydraulic pressure of the torque converter;
• a torque converter pressure control valve controlled by a linear solenoid valve to control engagement and disengagement pressure of the lock-up clutch and receiving fed-back supply hydraulic pressure of the torque converter at the time of controlling the engagement of the lock-up clutch to control engagement hydraulic pressure of the lock-up clutch;
• and
• a lock-up switch valve controlled by the linear solenoid valve to directly supply the hydraulic pressure supplied from the torque converter control valve connected to the lock-up switch valve, as control pressure of the torque converter pressure control valve and supply exhaust hydraulic pressure of the torque converter as control pressure of the torque converter control valve.