Controllers for controlling switching converters

A power conversion system comprising:

• a switching converter configured to convert an input power to an output power to power a load when a power switch in said switching converter is turned on and turned off alternately;
• and
• a controller coupled to said power switch, said controller comprising:
• a drive terminal configured to provide a drive signal to alternately turn on and turn off said power switch at a frequency of said drive signal;
• a multi-function terminal, wherein in a normal mode, said multi-function terminal is configured to provide a control current to control said frequency of said drive signal, and wherein in a protection mode, said multi-function terminal is configured to provide a control voltage indicating that an abnormal condition is present in said power conversion system;
• and
• control circuitry, coupled to said drive terminal and said multi-function terminal, configured to activate an alert signal if said abnormal condition is detected in said normal mode and to switch operation to said protection mode and generate said control voltage at said multi-function terminal when said alert signal is active.

A method comprising:

• controlling a controller to operate in a normal mode when an alert signal is inactive;
• in said normal mode, said controller providing a drive signal to alternately turn on and turn off a power switch in a switching converter at a frequency of said drive signal;
• in said normal mode, providing, through a multi-function terminal of said controller, a control current to control said frequency of said drive signal;
• activating, using said controller, said alert signal if an abnormal condition is detected;
• switching operation of said controller from said normal mode to a protection mode when said alert signal is activated;
• and
• in said protection mode, providing, through said multi-function terminal of said controller, a control voltage indicating that an abnormal condition is present in a system comprising said controller.