公开(公告)号：US20140104910A1

公开(公告)日：2014-04-17

申请号：US13653016

申请日：2012-10-16

申请人： Kwok Kuen (David) KWONG ,  Kwai Chi CHAN ,  Yunlong LI ,  Lee L. YANG

发明人： Kwok Kuen (David) KWONG ,  Kwai Chi CHAN ,  Yunlong LI ,  Lee L. YANG

IPC分类号： H02M7/219

CPC分类号： H02M7/219 ,  H02M2007/2195 ,  Y02B70/1408

摘要： A transistor-based full-wave bridge rectifier is suitable for low A.C. input voltages such as received by a Radio-Frequency Identification (RFID) device. Voltage drops due to bridge diodes are avoided. Four p-channel transistors are arranged in a bridge across the A.C. inputs to produce an internal power voltage. A comparator receives the A.C. input and controls timing of voltage boost drivers that alternately drive gates of the four p-channel transistors with voltages boosted higher than the peak A.C. voltage. Four diode-connected transistors are connected in parallel with the four p-channel bridge transistors to conduct during initial start-up before the comparator and boost drivers operate. Substrates are connected to the power voltage on the power-voltage half of the bridge and to the A.C. inputs on the ground half of the bridge to fully shut off transistors, preventing reverse current flow. The transistor bridge can be integrated onto system chips.

摘要翻译： 基于晶体管的全波桥式整流器适用于诸如由射频识别（RFID）设备接收的低交流输入电压。 避免了由桥二极管引起的电压降。 四个p沟道晶体管布置在跨过交流输入的桥中以产生内部电源电压。 比较器接收交流输入并控制升压驱动器的定时，该电压升压驱动器交替地驱动四个p沟道晶体管的栅极，其电压升高高于峰值交流电压。 在比较器和升压驱动器运行之前，四个二极管连接的晶体管与四个p沟道桥式晶体管并联连接，以在初始启动期间导通。 基板连接到桥的电源电压一半的电源电压和桥接器的一半的交流输入，以完全关闭晶体管，防止反向电流流动。 晶体管桥可以集成到系统芯片上。

公开(公告)号：US20130049628A1

公开(公告)日：2013-02-28

申请号：US13218426

申请日：2011-08-25

申请人： Kwok Kuen (David) KWONG ,  Lee L. YANG ,  Yunlong LI ,  Weina ZHOU

发明人： Kwok Kuen (David) KWONG ,  Lee L. YANG ,  Yunlong LI ,  Weina ZHOU

IPC分类号： H05B37/02

CPC分类号： G09G3/3406 ,  H05B33/0818

摘要： A light-emitting diode (LED) driver provides faster rise and fall times for LED current to reduce image sticking and other interference. A standard DC-DC converter provides a sum current that is slowly ramped up and down by a bypass current digital-to-analog converter (DAC). A digital value to the bypass current DAC is ramped up or down before an LED current is turned on or off. When the LED current is turned on, current is shifted from a bypass path to a path through the LED, maintaining a constant sum current from the DC-DC converter. When a different LED is turned on, current is shifted from one LED's path to the other LED's path. Separate LED current DAC's in each LED path and in the bypass path can share the sum current with digital precision. Using a single DAC for the sum current and switches in each path reduces cost.

摘要翻译： 发光二极管（LED）驱动器为LED电流提供更快的上升和下降时间，以减少图像残留和其他干扰。 标准DC-DC转换器提供由旁路电流数模转换器（DAC）缓慢上升和下降的和电流。 在LED电流打开或关闭之前，旁路电流DAC的数字值上升或下降。 当LED电流接通时，电流从旁路路径移动到通过LED的路径，保持来自DC-DC转换器的恒定的和电流。 当不同的LED打开时，电流从一个LED的路径移动到另一个LED的路径。 每个LED路径和旁路路径中的独立LED电流DAC可以以数字精度共享和电流。 使用单个DAC作为每个路径的总和电流和开关可以降低成本。