Abstract:
An LED-based lighting apparatus comprises a rectified AC voltage source having a rectified output connected to a storage capacitor through a switching device, a plurality of LED segments controlled by a linear driving circuit and at least one charging path connected between the LED segments and the storage capacitor. One or more controllable linear LED driving units may be connected in parallel with the storage capacitor to provide balance between reducing flicker and increasing power factor of the lighting apparatus.
Abstract:
An LED-based lighting apparatus is powered by multi-phase AC voltages to reduce flicker. A multi-phase AC-to-AC power generator is used to generate a plurality of AC voltages from an AC power source. The plurality of AC voltages each having a different phase are rectified by a plurality of rectifiers to provide a plurality of rectified AC voltages for a plurality of LED lighting units. Each LED lighting unit has voltage dependent brightness and reaches maximum brightness at different time due to the phase difference in the rectified AC voltage. The peak-to-peak variation in the total brightness is reduced and therefore the LED-based lighting apparatus has low flicker.
Abstract:
An apparatus comprises a plurality of controllable LED strings interposed with a plurality of switching units with each switching unit being connected between a leading controllable LED string and a trailing controllable LED string. A controller controls the switching units so that controllable LED strings are connected in a combination of series and parallel connections by connecting two adjacent leading and trailing controllable LED strings in series or parallel or by-passing the leading controllable LED string based on an automatically detected input voltage range. Each controllable LED string includes a plurality of LEDs connected in series between positive and negative ends of the controllable LED string and a plurality of controlling switches each corresponding to an LED. The number of LEDs connected in series in each controllable LED string is further adjusted by the controller as the input voltage varies with time.
Abstract:
A plurality of switching units interleaves with a plurality of LED-based lighting units to configure the interconnection of the LED-based lighting units for providing multiple lighting modes. Each switching unit disposed between a leading lighting unit and a trailing lighting unit is separately controlled by a controller. The switching unit can be configured to connect the two LED-based lighting units in parallel or in series, or to bypass the leading LED-based lighting unit. All the LED-based lighting units are connected in series when an input voltage supply is at a maximum voltage level, and connected in parallel when the input voltage supply is at a minimum voltage level. As the input voltage level decreases, the number of LED-based lighting units connected in parallel increases, and vice versa.
Abstract:
A constant current regulator includes a current sensing circuit loop connected to a switch unit of the constant current regulator to detect a current flowing through the switch unit and to generate a detection current that is in proportion to the current flowing through the switch unit. The detection current flows through a detection resistor to induce a detection voltage. A differential amplifier bases on a set voltage and the received detection voltage to generate an error voltage to a pulse width modulation controller, which in turn causes a gate driver circuit to control the switching operation of the switch unit thereby supplying a constant current to a load connected to an output voltage of the regulator.
Abstract:
A driving method for LCD panels is disclosed, wherein the driver circuit includes multiple data line drivers and at least two gate line drivers, and the first gate line driver produces a normal image with sequential line scanning starting from the beginning of a frame, and the second gate line driver produces a dimmed image starting from a predetermined number of lines below at the same time to emulate one full sweep across a CRT. Therefore, a dimmed image is inserted into every digitized image, where a dimmed image is defined to be a digitized image with each pixel having a fraction 1/N of the original pixel value. The LCD panel drive using this driving method achieves performance closer to the impulse approach used in CRT displays, and the flickering phenomenon can be significantly rectified.
Abstract:
A dynamic driving device is disclosed. The device enhances the display effect of a dynamic image on a liquid crystal display by dynamically adjusting the driving voltage applied to a liquid crystal display's Graphic Processing Unit (GPU) or Central Processing Unit (CPU). The device utilizes a driving path selection unit to allow a user to specify a driving path through an operation interface, which in turn affects the variation of driving voltage applied on the Graphic Processing Unit by dynamically adjusting the drive to the liquid crystal display.
Abstract:
Disclosed is a method for driving pixels of an LCD device, wherein an overlapping area between a data line connected to a data driver and a gate line connected to a gate driver defines a pixel of an LCD device. A first gate driver is selected from the LCD device' at least two gate drivers based on a selection rule. Starting from a line A, the first gate driver displays a part of a picture image by sequentially displaying the image line by line up to a number of lines according to a pre-determined display range. Then a second gate driver based on the selection rule displays a part of an all black image by displaying, from a line B, a number of lines based on a pre-determined display range simultaneously. The line B is separated from the line A by a number of lines according to a pre-determined gap range.
Abstract:
A method of increasing image gray-scale response speed comprising the following steps: to divide plural driven gate lines of an LCD into plural areas; to divide the frame interval time relative to the plural areas into plural sub-intervals, and to sequentially activate each first gate line of these areas during a time period of synchronized signals, then to sequentially activate the next gate lines of these areas, the operation is repeated; to apply an advance voltage to at least a gate line to overdrive frames, and to apply an image data voltage to at least a gate line; to repeat the above steps until the end of the entire frame interval time and to enter the next frame interval. The LCD can be fast driven by dividing of time and space. The method suits for treatment of frames of displays of various LCD's and organic light emitting diodes (OLED's).
Abstract:
An apparatus for driving LEDs using high voltage includes two LED driving circuits and two switches that can be turned on or off by a universal controller so as to connect the two LED driving circuits in two different configurations. When the input voltage is in a range from rectified 90 volt AC to rectified 140 volt AC, the two switches are controlled in such a way that the two LED driving circuits are connected in parallel. When the input voltage VIN is in a range from rectified 180 volt AC to rectified 265 volt AC, the two switches are controlled to connect the LED segments of the LED unit in one LED driving circuit in series with the other LED driving circuit.