CONTROLLER
A secondary side controller for a power converter configured to provide a control signal to an emitter element of an opto-coupler for control of a primary side controller of the power converter, the secondary side controller configured to operate with the primary side controller for controlling the voltage output of the power converter, the secondary side controller configured to, based on; a first control value configured to instruct the power converter to output its present voltage output; and a second control value configured to instruct the power converter to provide a requested target voltage output; provide said control signal in accordance with a transition profile over a predetermined transition time period to effect a change between the first control value and the second control value, the transition profile comprising at least a first rate of change in the control signal followed by an end time period leading to the end of the transition time period during which the rate of change in the control signal is less than a threshold rate based on a characteristic of the opto-coupler and/or the power converter with which the controller is rated to operate, the first rate of change greater than the threshold rate of change.