Schematic Volt

In the Safe Constant Current Source Circuit Diagram shown, a CMOS op amp controls the current through a p-channel HEXFET power transistor to maintain a constant voltage across RL The current is given by: 1 ~ VREF/Rl. The advantages of this configuration are: (a) in the event of a component failure, the load current is limited by Rl; and (b) the overhead voltage needed by the op amp and the HEXFET is extremely low.