Abstract: A circuit for use with a Universal Serial Bus (USB) socket includes a power converter coupled to receive an input voltage at an input terminal and coupled to provide an output voltage at an output terminal. A transistor is coupled between the output terminal of the power converter and a bus voltage terminal of the USB socket. A USB communication controller is coupled to the USB socket. The USB communication controller includes an output terminal coupled to a control terminal of the transistor. A bleeder circuit is coupled between the output terminal of the USB communication controller and the bus voltage terminal of the USB socket.

Abstract: A circuit for use with a Universal Serial Bus (USB) socket includes a power converter coupled to receive an input voltage at an input terminal and coupled to provide an output voltage at an output terminal. A transistor is coupled between the output terminal of the power converter and a bus voltage terminal of the USB socket. A USB communication controller is coupled to the USB socket. The USB communication controller includes an output terminal coupled to a control terminal of the transistor. A bleeder circuit is coupled between the output terminal of the USB communication controller and the bus voltage terminal of the USB socket.

Abstract: An interface module for use in a power conversion system includes a first current circuit coupled to a single external programming terminal to conduct a programming current through an external programming circuitry coupled to the single external programming terminal. A current comparator is coupled to the first current circuit to compare a current representative of the programming current with an internal current. A mode select circuit is coupled to the current comparator to generate a select signal to select one of a plurality of modes in response to a comparison of the current representative of the programming current with the internal current by the current comparator. A second current circuit is coupled to the first current circuit and the mode select circuit to generate a reference current in response to the programming current and the select signal from the mode select circuit.

Abstract: An interface module for use in a power conversion system includes a first current circuit coupled to a single external programming terminal to conduct a programming current through an external programming circuitry coupled to the single external programming terminal. A current comparator is coupled to the first current circuit to compare a current representative of the programming current with an internal current. A mode select circuit is coupled to the current comparator to generate a select signal to select one of a plurality of modes in response to a comparison of the current representative of the programming current with the internal current by the current comparator. A second current circuit is coupled to the first current circuit and the mode select circuit to generate a reference current in response to the programming current and the select signal from the mode select circuit.

Abstract: A timing circuit of a controller generates a clock signal having a switching period for use by a pulse width modulation (PWM) circuit to control a switch of a power supply. The switching period of the clock signal is based on a charging time plus a discharging time of a capacitor included in the timing circuit. A first current source charges the capacitor while the timing circuit is in a normal charging mode. A second current source charges the capacitor while the timing circuit is in an alternative charging mode that is when the on time of the switch exceeds a threshold time. The current provided by the second current source is less than the current provided by the first current source such that the switching period of the clock signal is increased in response to the timing circuit entering the alternative charging mode.

Abstract: A timing circuit of a controller generates a clock signal having a switching period for use by a pulse width modulation (PWM) circuit to control a switch of a power supply. The switching period of the clock signal is based on a charging time plus a discharging time of a capacitor included in the timing circuit. A first current source charges the capacitor while the timing circuit is in a normal charging mode. A second current source charges the capacitor while the timing circuit is in an alternative charging mode that is when the on time of the switch exceeds a threshold time. The current provided by the second current source is less than the current provided by the first current source such that the switching period of the clock signal is increased in response to the timing circuit entering the alternative charging mode.

Abstract: A single-switch ac-to-ac converters for driving ac loads which are particularly suitable for gas discharge lamp ballast applications based upon integration of automatic current shapers and converters that resemble a class-E converter, both parts sharing a single active switch. The first part comprises a high power factor (HPF) converter having automatic input current-shaping means and internal energy storage means operated by the single active switch driven at a constant frequency and duty ratio, and the second part comprises a resonant converter means operated by the aforesaid single active switch as it is being driven. Integration of the HPF converter having automatic current shaping means and the resonant converter through the single active switch operation brings advantages from both parts into the whole circuit, such as soft-switching characteristics so that the combined circuit can shape the input current without switching losses in a compact structure.