In the Functional Block Diagram of the HIP4020, the four switches and a load are arranged in an H-Configuration so that the drive voltage from terminals OUTA and OUTB can be cross-switched to change the direction of current flow in the load. This is commonly known as 4-quadrant load control. As shown in the Block Diagram, switches Q1 and Q4 are conducting or in an ON state when current flows from VDD through Q1 to the load, and then through Q4 to terminal VSSB; where load terminal OUTA is at a positive potential with respect to OUTB. Switches Q1 and Q4 are operated synchronously by the control logic. The control logic switches Q3 and Q2 to an open or OFF state when Q1 and Q4 are switched ON. To reverse the current flow in the load, the switch states are reversed where Q1 and Q4 are OFF while Q2 and Q3 are ON. Consequently, current then flows from VDD through Q3, through the load, and through Q2 to terminal VSSA, and load terminal OUTB is then at a positive potential with respect to OUTA.
