Control Circuit for a Switched-Mode Power Supply with Regulation Based on the Secondary-Side Current Flow Time Period

摘要

A control circuit for a primary controlled switched-mode power supply that has a primary-side switch and a transmitter. It also relates to an associated switched-mode power supply. The control circuit can be connected to a control input of the primary-side switch so that the primary-side switch is controlled based on a secondary-side current flow time period in which a current flows through the secondary-side winding of the transmitter in order to regulate the output voltage. The secondary-side current flow time period can be used as a control parameter instead of the actual output voltage in order to then control the primary-side switch. Because the secondary-side current flow time period can be determined indirectly on the primary side, no direct feedback is necessary between the output voltage on the secondary side and the control circuit on the primary side.