Invention Grant
US08493003B2 Serial cascade of minimium tail voltages of subsets of LED strings for dynamic power control in LED displays
有权
用于LED显示屏中动态功率控制的LED灯串子串的最小尾电压串联级联
- Patent Title: Serial cascade of minimium tail voltages of subsets of LED strings for dynamic power control in LED displays
- Patent Title (中): 用于LED显示屏中动态功率控制的LED灯串子串的最小尾电压串联级联
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Application No.: US12690972Application Date: 2010-01-21
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Publication No.: US08493003B2Publication Date: 2013-07-23
- Inventor: Bin Zhao
- Applicant: Bin Zhao
- Applicant Address: US TX Austin
- Assignee: Freescale Semiconductor, Inc.
- Current Assignee: Freescale Semiconductor, Inc.
- Current Assignee Address: US TX Austin
- Main IPC: H05B37/02
- IPC: H05B37/02

Abstract:
A light emitting diode (LED) system implements a power management technique. The LED system includes a plurality of LED drivers connected in series, each LED driver configured to regulate the current flowing through a corresponding subset of a plurality of LED strings. Each LED driver determines the tail voltages of the one or more LED strings of the corresponding subset. Each LED driver, except for the first LED driver in the series, also receives a voltage representative of the minimum tail voltage of the other subsets regulated by the upstream LED drivers. Each LED driver then provides the lowest of the voltage received from the upstream LED driver and the one or more tail voltages of the corresponding subset to the downstream LED driver. In this manner a voltage representative of the minimum tail voltage of the plurality of LED strings is cascaded through the series. A feedback controller monitors the minimum tail voltage represented by this cascaded voltage and accordingly adjusts an output voltage provided to the head ends of the plurality of LED strings.
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