Abstract:
Power management in a light emitting diode (LED) system having a plurality of LED strings is disclosed. A voltage source provides an output voltage to drive the LED strings. An LED driver monitors the tail voltages of the active LED strings to identify the minimum, or lowest, tail voltage and adjusts the output voltage of the voltage source based on the lowest tail voltage. The LED driver can adjust the output voltage so as to maintain the lowest tail voltage at or near a predetermined threshold voltage so as to ensure that the output voltage is sufficient to properly drive each active LED string with a regulated current in view of pulse width modulation (PWM) performance requirements without excessive power consumption.
Abstract:
A circuit can provide an approximately constant resistance value that is virtually independent of process and temperature variations. A current control circuit may use a device that tracks the changes in a corresponding device over process and temperature variations. As a result, the behavior of device may be used to help determine the control information provided to device in order to maintain an approximately constant resistance Rm over process and temperature variations. The approximately constant resistance Rm may be used to provide an approximately constant current ILED. A wide variety of applications, not just LED drivers, may benefit from the use of an approximately constant resistance and/or current.
Abstract:
A voltage source provides an output voltage to drive a plurality of light emitting diode (LED) strings. A LED driver adjusts the level of the output voltage so as to maintain the lowest tail voltage of the LED strings at or near a predetermined threshold voltage so as provide sufficient headroom voltages for current regulators for the LED strings. The LED driver operates in an operational mode and a calibration mode, which can be implemented in parallel with, or part of, the operational mode. During the calibration mode, the LED driver determines, for each LED string, a code value representative of the level of the output voltage necessary to maintain the tail voltage of the corresponding LED string at or near the predetermined threshold voltage. In the operational mode, the code values from the calibration mode are used to control the voltage source to provide an appropriate level for the output voltage.
Abstract:
A battery latching device is using for accommodating a battery and includes a housing, two opposite latching portions, a resisting portion, and a stopping member. The housing has a bottom wall and configured for accommodating the battery therein. The latching portions are formed on the bottom wall of the housing, and are configured for limiting the two opposite sides of the battery. The resisting portion are formed on the bottom wall of the housing and aligned with one end of the latching portions. The stopping member is retained to the bottom wall of the housing and aligned with another end of the latching portions. The two opposite ends of the battery are hold between the resisting portion and the stopping portion. When detaching the battery from the housing, the stopping member is capable of being pressed toward the bottom wall to release the battery.
Abstract:
A surface treatment method for housings, comprising: providing a substrate made of damascus steel; and chemically etching the substrate using inorganic acid solution or inorganic salts solution to give the substrate a patterned appearance.
Abstract:
In one embodiment, a distributed environment for supporting on-line collaborative meetings among a plurality of users includes a plurality of applications executing on different client machines. A sequence of messages is transmitted from a first application of the distributed environment to a second application of the distributed environment, using a multicast form of delivery. A request for re-transmission is received from the second application specifying at least one message of the sequence that was not received by the second application. In response to the request, the specified at least one message of the sequence is retransmitted from the first application to the second application using a reliable unicast form of delivery.
Abstract:
According to one exemplary embodiment, a voltage up-conversion circuit includes a modulated voltage generator circuit, where the modulated voltage generator circuit is configured to receive an input voltage and generate a modulated voltage, and where the modulated voltage generator circuit includes at least one transistor. The voltage up-conversion circuit further includes a switching circuit coupled to the modulated voltage generator circuit, where the switching circuit is configured to couple the modulated voltage to a load capacitor when the modulated voltage is at a high level and decouple the modulated voltage to the load capacitor when the modulated voltage is at a low level. In the voltage up-conversion circuit, the load capacitor reaches a voltage greater a breakdown voltage of the at least one transistor in the modulated voltage generator circuit. The breakdown voltage can be a reliability breakdown voltage.
Abstract:
According to one exemplary embodiment, a voltage up-conversion circuit includes a modulated voltage generator circuit, where the modulated voltage generator circuit is configured to receive an input voltage and generate a modulated voltage, and where the modulated voltage generator circuit includes at least one transistor. The voltage up-conversion circuit further includes a switching circuit coupled to the modulated voltage generator circuit, where the switching circuit is configured to couple the modulated voltage to a load capacitor when the modulated voltage is at a high level and decouple the modulated voltage to the load capacitor when the modulated voltage is at a low level. In the voltage up-conversion circuit, the load capacitor reaches a voltage greater a breakdown voltage of the at least one transistor in the modulated voltage generator circuit. The breakdown voltage can be a reliability breakdown voltage.
Abstract:
A distributed collaborative computer system is provided that comprises a plurality of server computers interconnected via a high-speed link. Client computers can connect to any available server computer and start or join a conference hosted on either the server computer to which the client computer is connected or any other server in the system. As a result, the system and method of the present invention is easily scalable to support an arbitrary number of participants to a conference by merely adding the appropriate number of server computers to the system. In addition, by replicating the conference information on more than one server computer, the single point of failure limitation is eliminated. In fact, if a server hosting or participating in a conference malfunctions, the failure is detected by other server computers and the client computer is able to reconnect to the conference through a new server computer.
Abstract:
A graphical user interface for editing a video story includes a storyboard pane, a timeline pane, and a layer pane. The storyboard pane displays video clips of the video story and their transitions. The timeline pane displays tracks including a video track, a video overlay track, a text track, an effect track, and at least one audio track. The layer pane displays layers of a selected video clip from the video track. Each layer displays one layer clip. The layer clip can be a video layer clip, a text layer clip, or an audio layer clip. The layers in the layer pane show how the layer clips overlay each other (or not) in time to compose the selected video clip. A user uses the storyboard pane and the timeline pane to layout the video story, and the layer pane to layout the video clips in the video story.