Patent ID: 11942871
Assignee: CYPRESS SEMICONDUCTOR CORPORATION
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  G | IPC G  H

Claim 8:
9. An integrated circuit for an alternating current to direct current (AC-DC) converter, the integrated circuit comprising:
a primary side controller on a primary side of a transformer and configured to receive a rectified alternating current (AC) voltage and coupled to a discharge circuit to discharge an external capacitor based on an undervoltage threshold, the primary side controller comprising:
a gate driver configured to turn on a primary field effect transistor (FET) that operates at a duty cycle; and
a startup controller coupled to the gate driver, the startup controller configured to:
determine whether a control signal has been received from a secondary side controller on a secondary side of the transformer;
in response to determining that the control signal has not been received, increase the duty cycle of a primary FET;
determine whether the rectified AC voltage of the AC-DC converter is below the undervoltage threshold;
in response to determining that the voltage of the AC-DC converter is below the undervoltage threshold:
determine a current duty cycle of the primary FET; and
turn off the primary FET.