Patent ID: 8243477

Claim:
A controller, comprising: a switched element to be coupled to a second winding of an energy transfer element of a power supply; a secondary control circuit coupled to the switched element, the secondary control circuit to be coupled across an output of the second winding to switch the switched element in response to a difference between an actual output value at the output of the second winding and a desired output value to force a current in a third winding of the energy transfer element that is representative of the difference between the actual output value at the output of the second winding and the desired output value; a primary switch to be coupled to a first winding of the energy transfer element; and a primary control circuit coupled to the primary switch, the primary control circuit to be coupled to receive the current forced in the third winding of the energy transfer element in response to the secondary control circuit, the primary control circuit coupled to switch the primary switch to regulate an output of the power supply coupled to the output of the second winding in response to the forced current.