GREEN MARK TECHNOLOGY INC. Patent applications |
Patent application number | Title | Published |
20110234110 | LED DRIVER CIRCUIT - A light-emitting diode (LED) driver circuit is provided, which includes a transistor, a current regulator, a release diode, and a voltage clamping device. The transistor is coupled in series with an LED string. The LED string is coupled between the transistor and a bus voltage. The current regulator is coupled to the transistor for regulating the current through the transistor and the LED string to a predetermined current. The release diode has an anode coupled between the LED string and the transistor. The voltage clamping device is coupled to the cathode of the release diode for clamping the voltage level at the cathode of the release diode to a predetermined voltage. The voltage clamping device protects the transistor from breakdown when the transistor is turned off for dimming control. | 09-29-2011 |
20110109249 | DIMMABLE LED LAMP AND DIMMABLE LED LIGHTING APPARATUS - A dimmable light-emitting diode (LED) lamp and a dimmable LED lighting apparatus thereof are provided. The dimmable LED lamp includes a bridge rectifier, a toggle detector, a sustain voltage supply circuit, a counter, an LED light source, and an LED lighting driver. The bridge rectifier receives a source alternating current (AC) voltage through a wall switch and provides a rectified direct current (DC) voltage. The toggle detector monitors a toggle action of the wall switch. The sustain voltage supply circuit provides a sustain voltage. The counter receives the sustain voltage for operation. Moreover, the counter stores and provides an counting value that changes when the toggle detector detects the toggle action. The LED lighting driver converts the rectified DC voltage to a constant current to drive the LED light source. The LED lighting driver also provides multi-level dimming to the LED light source according to the counting value. | 05-12-2011 |
20090316836 | SINGLE-WIRE, SERIAL, DAISY-CHAIN DIGITAL COMMUNICATION NETWORK AND COMMUNICATION METHOD THEREOF - A digital communication network including several receivers and a communication method for the digital communication network are provided. Each of the receivers includes a first port and a second port. The first port of the first receiver is coupled to the microcontroller. The first port of each of the receivers except the first receiver is coupled to the second port of the previous receiver. Each receiver further includes a chain register. The chain registers of the receivers are mutually connected through the first ports and the second ports, forming a virtual global queue. By utilizing the characteristics of the virtual global queue, the system and the method achieve bi-directional, single-wire, serial communication without the encumbrance of assigning addresses or identification codes to the receivers. | 12-24-2009 |
20090257250 | SYNCHRONOUS RECTIFIER DC/DC CONVERTERS USING A CONTROLLED-COUPLING SENSE WINDING - A synchronous rectifier DC/DC converter is provided. The synchronous rectifier DC/DC converter includes a power transformer, a first diode, a first MOSFET, and a first controller. The power transformer includes a core, a primary winding, a secondary winding, and a sense winding. The primary winding is wrapped around the core and receives an input voltage of the synchronous rectifier DC/DC converter. The secondary winding is wrapped around the core and provides the energy of an output current of the synchronous rectifier DC/DC converter. The sense winding is wrapped around the core and provides a sense signal. The first diode is coupled to the secondary winding for rectifying the output current. The first MOSFET is coupled in parallel with the first diode. The first controller is coupled to the sense winding and the first MOSFET for turning on and turning off the first MOSFET according to the sense signal. | 10-15-2009 |
20080316781 | BUCK CONVERTER LED DRIVER CIRCUIT - A buck converter LED driver circuit is provided. The driver circuit includes a buck power stage, a rectified AC voltage source, a voltage waveform sampler, and a control circuit. The buck power stage includes at least one LED and provides a first signal directly proportional to the current through the LED. The rectified AC voltage source is coupled to the buck power stage for driving the buck power stage. The voltage waveform sampler is coupled to the rectified AC voltage source for providing a second signal directly proportional to the voltage provided by the rectified AC voltage source. The control circuit is coupled to the voltage waveform sampler and the buck power stage for turning on and turning off the buck power stage according to a comparison between the first signal and the second signal. | 12-25-2008 |
20080219648 | CIRCUIT AND METHOD FOR CONTROLLING THE ROTATING SPEED OF A BLDC MOTOR - A circuit and a method for controlling the rotating speed of a brushless direct current (BLDC) motor are provided, whose goal is solving the stall problem encountered by conventional BLDC motors driven by pulse width modulation (PWM). The circuit includes a closed-loop control mechanism for adjusting the duty cycle of the motor current of the BLDC motor, thus controlling the rotating speed of the motor. The closed-loop control is based on the comparison of a signal proportional to the actual rotating speed and another signal proportional to the predetermined target rotating speed. | 09-11-2008 |