The ADP1043A is a secondary side power supply controller IC designed to provide all the functions that are typically needed in an ac-to-dc or isolated dc-to-dc control application. The ADP1043A is optimized for minimal component count, maximum flexibility, and minimum design time. Features include remote voltage sense, local voltage sense, primary and secondary side current sense, pulse-width modulation (PWM) generation, and hot-swap sense and control. The control loop is digital with an integrated programmable digital filter. Protection features include current limiting, ac sense, undervoltage lockout (UVLO), and overvoltage protection (OVP). The built-in EEPROM provides extensive programming of the integrated loop filter, PWM signal timing, inrush current, and soft start timing and sequencing. Reliability is improved through a built-in checksum and redundancy of critical circuits.