Abstract: A controller includes: an input terminal, coupled to a power switch, operable for generating a parameter signal indicating an on/off state of the power switch; a power terminal, coupled to a power source, operable for receiving electric power supplied by the power source to power the controller; an output terminal, coupled to a forwarding module, operable for outputting an indicating signal and a control signal, to enable the forwarding module to read the control signal based on the indicating signal, thus selecting an operating mode of an intelligent device, where both the control signal and the indicating signal are generated by the controller based on the parameter signal.

Abstract: A controller includes a current input terminal, a switch monitoring terminal, a first control terminal, a second control terminal and a current monitoring terminal. The current input terminal is coupled to a power source through a rectifier and receives electric power from the power source. The switch monitoring terminal is coupled to a power switch and receives a switch monitoring signal indicating the on/off state of the power switch. The power switch is coupled between the rectifier and the power source. Based on the switch monitoring signal, the first control terminal turns on or turns off a first light source in a light source module and the second control terminal turns on or turns off a second light source in the light source module. The current monitoring terminal monitors a current flowing through the first light source and a current flowing through the second light source.

Abstract: A controller includes a current input terminal, a switch monitoring terminal, a first control terminal, a second control terminal and a current monitoring terminal. The current input terminal is coupled to a power source through a rectifier and receives electric power from the power source. The switch monitoring terminal is coupled to a power switch and receives a switch monitoring signal indicating the on/off state of the power switch. The power switch is coupled between the rectifier and the power source. Based on the switch monitoring signal, the first control terminal turns on or turns off a first light source in a light source module and the second control terminal turns on or turns off a second light source in the light source module. The current monitoring terminal monitors a current flowing through the first light source and a current flowing through the second light source.

Abstract: A controller is coupled to a first light source in a light source module through a power converter. The controller includes a monitoring terminal and a control terminal. The monitoring terminal is coupled to a power switch and is operable for receiving a switch monitoring signal indicating an on/off state of the power switch. The power switch is coupled between a power source and a rectifier. The power converter is operable for receiving input electric power from the rectifier and for supplying electric power to the first light source. A control terminal is operable for outputting an enable signal based on the switch monitoring signal to control a second controller coupled to a second light source in the light source module to turn on and turn off the second light source.

Abstract: A switching power supply includes a power converter which includes a transformer and a switch, a current sensor, a switch controller and a compensation resistor. The current sensor is operable for generating a current monitoring signal indicating a current through a primary winding of the transformer. The switch controller is operable for receiving a feedback signal indicating an output voltage of the power converter, generating a driving signal based on the feedback signal to control an input power and an output power of the transformer, receiving a line voltage signal indicating an input voltage of the power converter, and generating a compensation current corresponding to a peak value of the line voltage signal. The compensation resistor is coupled between the current sensor and the switch controller. A voltage of the current monitoring signal is inversely proportional to the input voltage under control of the compensation current and the compensation resistor.

Abstract: A switching power supply includes a power converter which includes a transformer and a switch, a current sensor, a switch controller and a compensation resistor. The current sensor is operable for generating a current monitoring signal indicating a current through a primary winding of the transformer. The switch controller is operable for receiving a feedback signal indicating an output voltage of the power converter, generating a driving signal based on the feedback signal to control an input power and an output power of the transformer, receiving a line voltage signal indicating an input voltage of the power converter, and generating a compensation current corresponding to a peak value of the line voltage signal. The compensation resistor is coupled between the current sensor and the switch controller. A voltage of the current monitoring signal is inversely proportional to the input voltage under control of the compensation current and the compensation resistor.

Abstract: A flyback converter includes a transformer and a controller operable for controlling a switch coupled in series with a primary winding of the transformer. The controller is configured to operate in multiple modes including a burst mode and a standby mode. In the burst mode, the controller generates a first plurality of discrete pulse groups to turn on the switch and a duration of each pulse in the first plurality of discrete pulse groups is determined by a first reference signal having a first predetermined voltage. In the standby mode, the controller generates a second plurality of discrete pulse groups to turn on the switch and a duration of each pulse in the second plurality of discrete pulse groups is determined by a second reference signal having a second predetermined voltage which is greater than the first predetermined voltage of the first reference signal.

Abstract: A controller for controlling a power converter includes a signal generator and a driver. The power converter receives an input voltage and provides an output voltage to power a load. The signal generator receives a sense signal indicating a current flowing through the power converter, receives a detection signal indicating whether the power converter operates in a predetermined state, and generates a square wave signal according to the sense signal and the detection signal. The square wave signal has a first voltage level proportional to a peak level of the current when the power converter operates in the predetermined state; otherwise, the square wave signal has a second voltage level. The driver generates a driving signal based on the square wave signal to control a current flowing through the load.

Abstract: A circuit includes a transformer and a controller. The transformer includes a primary winding and a secondary winding, and operates in multiple switching cycles. A switching cycle includes a charging period and a discharging period. During the charging period, the transformer is powered by the input voltage and a current flowing through the primary winding increases. During the discharging period the transformer discharges to power the load and a current flowing through the secondary winding decreases. The controller includes a pin that receives a first feedback signal indicating the input voltage during the charging period and receives a second feedback signal indicating an electrical condition of the secondary winding during the discharging period. The controller generates a first control signal and a second control signal to regulate the input voltage and an output current flowing through the load, respectively.

Abstract: A flyback converter includes a transformer and a controller operable for controlling a switch coupled in series with a primary winding of the transformer. The controller is configured to operate in multiple modes including a burst mode and a standby mode. In the burst mode, the controller generates a first plurality of discrete pulse groups to turn on the switch and a duration of each pulse in the first plurality of discrete pulse groups is determined by a first reference signal having a first predetermined voltage. In the standby mode, the controller generates a second plurality of discrete pulse groups to turn on the switch and a duration of each pulse in the second plurality of discrete pulse groups is determined by a second reference signal having a second predetermined voltage which is greater than the first predetermined voltage of the first reference signal.

Abstract: Embodiments of the invention provided a driving circuit for powering a light-emitting diode (LED) light source. The driving circuit includes a rectifier, a filter capacitor, and a control circuit. The rectifier converts an AC voltage from an AC power source to a rectified AC voltage. The filter capacitor coupled to the rectifier filters the rectified AC voltage to provide a DC voltage. The control circuit controls power supplied to the LED light source. The control circuit enables a discharging current periodically to discharge the filter capacitor if a switch coupled between an AC power source and a rectifier is turned off and disables the discharging current if the control circuit determines that the switch is turned on.

Abstract: A controller for controlling a power converter includes a signal generator and a driver. The power converter receives an input voltage and provides an output voltage to power a load. The signal generator receives a sense signal indicating a current flowing through the power converter, receives a detection signal indicating whether the power converter operates in a predetermined state, and generates a square wave signal according to the sense signal and the detection signal. The square wave signal has a first voltage level proportional to a peak level of the current when the power converter operates in the predetermined state; otherwise, the square wave signal has a second voltage level. The driver generates a driving signal based on the square wave signal to control a current flowing through the load.

Abstract: A power converter includes a transformer operated in multiple switching cycles. At least one switching cycle includes a charging period, a discharging period, and an adjusting period. The transformer has a primary winding coupled to a power source and a secondary winding coupled to a load. During the charging period the transformer is powered by the power source and a current flowing through the primary winding increases. During the discharging period the transformer discharges to power the load and a current flowing through the secondary winding decreases. A ratio of a duration of the discharging period to a total duration of the charging period, the discharging period and the adjusting period is constant.

Abstract: A driving circuit for driving a light source includes a power converter, a controller and a voltage-controlled current source. The power converter is coupled to the light source, and receives an input voltage from a power source and provides an output voltage to the light source. The power converter includes a switch coupled in series with the light source. The controller is coupled to the power converter and controls a power of the light source by controlling the switch. The voltage-controlled current source is coupled to the controller and provides a first current. The controller controls the switch based on the first current.

Abstract: A circuit includes a transformer and a controller. The transformer includes a primary winding and a secondary winding, and operates in multiple switching cycles. A switching cycle includes a charging period and a discharging period. During the charging period, the transformer is powered by the input voltage and a current flowing through the primary winding increases. During the discharging period the transformer discharges to power the load and a current flowing through the secondary winding decreases. The controller includes a pin that receives a first feedback signal indicating the input voltage during the charging period and receives a second feedback signal indicating an electrical condition of the secondary winding during the discharging period. The controller generates a first control signal and a second control signal to regulate the input voltage and an output current flowing through the load, respectively.

Abstract: A controller for controlling power to an LED light source includes a control terminal and control circuitry coupled to the control terminal. The control terminal provides a control signal to control a transformer. A cycle of the control signal includes a charging period, a discharging period, and an adjusting period. The control circuitry controls a primary winding of the transformer to receive power during the charging period and controls a secondary winding of the transformer to discharge power to the LED light source during the discharging period. The control circuitry further varies a frequency of the control signal periodically by controlling the adjusting period.

Abstract: Embodiments of the invention provided a driving circuit for powering a light-emitting diode (LED) light source. The driving circuit includes a rectifier, a s filter capacitor, and a control circuit. The rectifier converts an AC voltage from an AC power source to a rectified AC voltage. The filter capacitor coupled to the rectifier filters the rectified AC voltage to provide a DC voltage. The control circuit controls power supplied to the LED light source. The control circuit enables a discharging current periodically to discharge the filter capacitor if a switch coupled between an AC power source and a rectifier is turned off and disables the discharging current if the control circuit determines that the switch is turned on.

Abstract: A power supply system includes a power converter, a switch, and a controller. The power converter is operable for providing power to a load. The switch is coupled to the power converter and is operable for adjusting the power to the load. The switch has a gate, a source and a drain. The controller is coupled to the switch and is operable for controlling a state of the switch. The controller has a first control terminal for providing a gate voltage to the gate of the switch, a second control terminal for providing a source voltage to the source of the switch, and an input terminal for receiving a supply voltage via the source of the switch. The controller is also operable for limiting the supply voltage within a predetermined maximum level by regulating the gate voltage to a preset level.

Abstract: A circuit for driving a light source, e.g., an LED light source, includes a converter, a sensor, and a controller. The converter converts an input voltage to an output voltage across the LED light source based upon a driving signal. A duty cycle of the driving signal determines an average current flowing through the LED light source. The sensor is selectively coupled to and decoupled from the converter based upon the driving signal. The sensor generates a sense voltage indicative of a current flowing through the LED light source when the sensor is coupled to the converter. The controller is coupled to the converter and sensor. The controller compares the sense voltage to a reference voltage indicative of a predetermined average current through the LED light source to generate a compensation signal and generates the driving signal based upon the compensation signal.

Abstract: A controller for controlling power to an LED light source includes a control terminal and control circuitry coupled to the control terminal. The control terminal provides a control signal to control a transformer. A cycle of the control signal includes a charging period, a discharging period, and an adjusting period. The control circuitry controls a primary winding of the transformer to receive power during the charging period and controls a secondary winding of the transformer to discharge power to the LED light source during the discharging period. The control circuitry further varies a frequency of the control signal periodically by controlling the adjusting period.