Patent ID: 7936202

Claim:
An integrated circuit controller for a power supply, the controller comprising: a selector terminal, wherein a first mode of operation of the integrated circuit controller is selected when there is no connection to the selector terminal external to the integrated circuit controller and wherein a second mode of operation of the integrated circuit controller is selected when a voltage at the selector terminal is fixed by a regulated voltage external to the integrated circuit controller; a voltage comparator coupled to compare the voltage at the selector terminal to a voltage threshold and coupled to provide a signal in response to comparing the voltage at the selector terminal to the voltage threshold; and a variable current limiting circuit coupled to the voltage comparator and coupled to limit a current through the selector terminal to a fixed current limit value, wherein the variable current limiting circuit selects the fixed current limit value from a plurality of fixed current limit values in response to the signal provided by the voltage comparator, and wherein the variable current limiting circuit comprises: a variable current source to be coupled between the selector terminal and a voltage bus; and a switch coupled to engage the variable current source when the voltage at the selector terminal reaches a voltage boundary.