QUICK COUPLER CIRCUIT OF CONSTRUCTION MACHINE WITH AUTOMATIC PRESSURIZATION SYSTEM

Provided is a quick coupler circuit of a construction machine with an automatic pressurization system. The quick coupler circuit includes a quick coupler cylinder configured to attach and/or detach an attachment to and/or from the construction machine by expansion and/or contraction, a flow pump configured to supply fluid to the quick coupler cylinder, a quick coupler valve through which fluid for operating the quick coupler cylinder passes, a spool valve which includes a spool, configured to move along an axial direction, and to form a pressure at a node of the flow pump according to movement of the spool, an electronic proportional pressure reducing valve configured to control the spool valve, a quick coupler switch configured to perform an ON/OFF operation, and a controller configured to output a control current to the electronic proportional pressure reducing valve in response to the operation of the quick coupler switch, wherein the controller is further configured to maintain control current which it ou