Abstract:
A circuit for driving a light source includes a voltage converter, a switch and a controller. The voltage converter converts an AC input voltage signal to a first rectified AC voltage signal. The voltage converter further generates an average signal proportional to an average voltage level of the first rectified AC voltage signal. The switch is coupled to the light source in series. The controller coupled to the voltage converter and the switch compares the first rectified AC voltage signal with the average signal to generate a pulse signal. The controller further generates a dimming control signal based on the pulse signal to control the switch thereby controlling dimming of the light source.
Abstract:
A controller for controlling dimming of a light-emitting diode (LED) light source includes a switch monitoring pin, a current monitoring pin, and a control pin. The switch monitoring pin monitors an operation of a power switch which transfers an AC voltage to a rectifier when the power switch is on. The current monitoring pin receives a current monitoring signal indicating a current flowing through the LED light source. The control pin generates a control signal to control a second switch coupled in series with the LED light source to adjust the brightness of the LED light source according to the operation of the power switch.
Abstract:
A driving circuit for controlling power of a light source includes a power converter coupled to a power source and the light source, and a dimming controller coupled to the power converter. The power converter can receive power from the power source and provide a regulated power to the light source. The power converter includes a control switch coupled in series with the light source. The dimming controller can monitor a power switch coupled between the power source and the driving circuit, and receive a dimming request signal and a dimming termination signal. The dimming request signal can indicate a first set of operations of the power switch. The dimming termination signal can indicate a second set of operations of the power switch. The dimming controller can continuously adjust the regulated power from the power converter by controlling the control switch if the dimming request signal is received, and can stop adjusting the regulated power from the power converter if the dimming termination signal is received.
Abstract:
A driving circuit for controlling power of a light-emitting diode (LED) light source includes a transformer, a switch controller, and a dimming controller. The transformer has a primary winding that receives input power from an AC/DC converter and a secondary winding that provides output power to the LED light source. The switch controller coupled between an optical coupler and the primary winding receives a feedback signal indicative of a target level of a current flowing through the LED light source from the optical coupler, and controls input power to the primary winding according to the feedback signal. The dimming controller coupled to the secondary winding receives a switch monitoring signal indicative of an operation of a power switch coupled between an AC power source and the AC/DC converter, and regulates the output power by adjusting the feedback signal according to the switch monitoring signal.
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 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. The duty cycle of the driving signal is adjusted based upon the compensation signal to adjust the average current flowing through the LED light source to the predetermined average current.
Abstract:
In a cylinder lock assembly, a latch operating tube has an enlarged end portion extending into an outer drive tube disposed in an outer handle. A locking spindle is disposed in the latch operating tube and has a locking tongue extending radially and outwardly through the outer drive tube to interlock with an outer rose when the locking spindle is pressed by a push button to move to a locked state. A locking plate is sleeved around the locking spindle and has a radial locking part to engage a protrusion that projects radially and inwardly from an inner surface of the enlarged end portion so that the locking spindle is locked against movements to an unlocked state when the locking spindle is in its locked state.
Abstract:
A controller for controlling power to a light source includes a first sensing pin, a second sensing pin, a third sensing pin, and a driving pin. The first sensing pin receives a first signal indicating an instant current flowing through an energy storage element. The second sensing pin receives a second signal indicating an average current flowing through the energy storage element. The third sensing pin receives a third signal indicating whether the instant current decreases to a predetermined current level. The driving pin provides a driving signal to a switch to control an average current flowing through the light source to a target current level. The driving signal is generated based on one or more signals selected from the first signal, the second signal and the third signal.
Abstract:
In one embodiment, a controller includes a first comparator, a second comparator and a control unit coupled to the first and second comparators. The first comparator is operable for comparing a first sense signal indicative of an output current flowing through an energy storage component of the power converter with a first threshold, and for generating a first comparison signal. The second comparator is operable for comparing a second sense signal indicative of the output current with a second threshold and for generating a second comparison signal. The control unit is operable for turning a switch of the power convertor on and off according to the first and second comparison signals. The energy storage component is coupled to a power source for storing energy from the power source if the switch is turned on, and is decoupled from the power source for releasing stored energy to a load if the switch is turned off.
Abstract:
A re-keyable cylinder lock has a control member to permit or restrict transverse movement of a re-keying unit. The control member is movable axially between first and second positions and transversely to a third position from the second position. In the third position, the re-keying unit moves transversely and disengages from first tumbler pieces. A limit member is provided to prevent the control member from moving axially when no right key is inserted into a plug. A security arm is connected to the control member and is breakable so that destructive forces cannot reach the control member.