Abstract: In one embodiment, a power supply controller generates a PWM control signal that is subsequently used to control a portion of current flow in a primary side of a power supply system. THE PWM control signal is coupled to a secondary of the power supply system and used to control a synchronous rectifier that is coupled within the secondary side.

Abstract: In one embodiment, a power supply controller generates a PWM control signal that is subsequently used to control a portion of current flow in a primary side of a power supply system. THE PWM control signal is coupled to a secondary of the power supply system and used to control a synchronous rectifier that is coupled within the secondary side.

Abstract: A ring generator circuit provides both a ring signal and talk battery to a subscriber telephone line. The ring generator recognizes whether talk battery voltage or a ring signal voltage is required and supplies the right voltage without the use of external relays. A switching network is coupled to the primary of a transformer to generate AC power at the transformer secondary. The switches intermittently conduct current from a DC power source through the primary of the transformer at a frequency substantially greater than the ring signal. A rectifier circuit converts the generated AC power into DC power to be provided to the telephone line. A sampling circuit samples the AC power, and the sampled power is additively combined with the DC power from the rectifier to form a ring signal component whose frequency is equal to the difference between the sampling frequency and the AC power frequency.