A switching converter IC without a built-in power switching device includes a first terminal serving as a power supply positive connection, a second terminal serving as a power supply return connection, a third terminal serving as the switch-driving connection for controlling the switching duty of an external bipolar or MOSFET power switching device and also serving as a conduit for detection of current drawn by the power switching device to thereby provide overcurrent protection. Feedback information is derived from voltage between the first and the second terminals.