Integrated LED Driver for LCOS Panel Pin Reduction
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Solution Overview
Problem
Conventional LED current driving systems for LCOS displays lack integration, leading to increased pin count, area, and system cost, as well as poor current control, resulting in suboptimal color quality.
Innovation Solution
An integrated LED current driving system that includes a timing controller and an LED driver with multiple current sources and switches, controlled by duty cycle and current control signals, to provide precise and stable current output to LEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the LED driver is integrated on the LCOS panel, then the pin number, overall area, and system cost are reduced, but the manufacturing complexity increases
Solution Approach 1:
The patent integrates the LED driver circuit directly on the LCOS panel by merging the timing controller and LED driver functions into a single integrated structure. This combining of previously separate components (timing controller 111/121 and LED driving transistors 113/161-181) into one integrated unit reduces the overall pin count and area while achieving the desired functionality through unified circuit design.
2Measurement precision
If multiple current sources and switches are used in each LED driving unit, then the current control precision is improved, but the device complexity increases
Solution Approach 1:
The LED driver is divided into multiple independent LED driving units, with each unit containing multiple current sources (e.g., first current source 311, second current source 312, third current source 313) and corresponding switches (314, 315, 316). This segmentation allows each current source to be independently controlled by dedicated control signals (R0, R1, RN for red LED), enabling precise current control for each LED while managing complexity through modular organization.
Solution Approach 2:
The patent employs dynamic control of multiple current sources through PWM (pulse width modulation) signals and duty cycle control signals. The switches (314, 315, 316) are dynamically switched ON/OFF based on control signals to regulate the current flowing through each LED. This dynamic control mechanism enables precise current adjustment without requiring complex static circuitry, as the precision is achieved through temporal switching patterns rather than complex simultaneous circuit arrangements.
Data Source
AI summary
The invention relates to an LED current driving system. The LED current driving system comprises an LED driver. The LED driver comprises at least one LED driving unit for outputting a driving current to an LED. Each LED driving unit comprises a plurality of current sources and a plurality of switches. The switches are connected to the corresponding current source. Each switch controls the ON/OFF state of the corresponding current source in accordance with the duty cycle control signal and a current control signal. Therefore, by integrating the LED driver on the LCOS panel, the LED current driving system of the invention can decrease the pin number of the LCOS chip, the overall area and the system cost so as to improve the yield of the LED current driving system. Besides, the LED current driving system utilizes the current sources to form the driving current to stably and precisely control the driving current flowing through the corresponding LED so that the color quality of the image can be improved.