Apparatus and method for isolated current mode controller

A control circuit for a switched mode voltage converter that includes a transformer providing a primary winding on a first side of a galvanic isolation medium and a secondary winding on a second side of the galvanic isolation medium, the control circuit comprising:

• an initialization signal source on the first side and configured to provide an initialization signal;
• a switch, on the first side, coupled to the primary winding;
• a switch control circuit, on the first side, coupled to and configured to control the switch using a comparison of a primary winding parameter with one of the initialization signal during startup and a feedback signal received from the second side during steady state operation;
• and
• a feedback signal generator circuit, on the second side, configured to provide the feedback signal during steady state operation based on a comparison of a reference voltage signal and an output on the second side of the converter.

A method to control a switched mode converter circuit to provide a secondary side output signal, wherein the converter circuit includes primary and secondary sides that are coupled using respective primary and secondary windings of a transformer, the method comprising:

• at the primary side, controlling a switch to modulate a current in the primary winding of the transformer, the controlling based on a first feedback signal from the secondary side or on an initialization signal;
• at the secondary side, during a converter startup phase, generating the first feedback signal based on the output signal and, during a converter steady-state phase, generating the first feedback signal based at least in part on a reference signal source;
• and
• transitioning from the startup phase to the steady-state phase in response to the first feedback signal substantially matching the initialization signal during the startup phase.