Distributed LED Driver Circuits with Shared Multi-Wire Interface
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Solution Overview
Problem
Current LED driver circuitry for displays requires significant external chip area, impacting the size of display devices due to the need for extensive driver circuitry to manage millions of individual LEDs.
Innovation Solution
A display device architecture with distributed driver circuits and a control circuit that uses a multi-wire shared command interface and readback line to efficiently manage driver currents and communicate control signals, allowing for reduced chip area usage by integrating driver circuits within the display area and enabling serial and parallel communication for high-speed data exchange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If driver circuitry is integrated externally to manage individual LEDs, then control precision and reliability are improved, but chip area and device size increase significantly
Solution Approach 1:
The display is divided into multiple LED zones with distributed driver circuits, where each driver circuit independently controls a specific zone. This segmentation allows precise control of individual zones while reducing the need for extensive external driver circuitry, thereby maintaining control precision without significantly increasing chip area.
Solution Approach 2:
Driver circuits are integrated within the display area rather than being placed externally, transitioning from a two-dimensional external arrangement to a distributed three-dimensional integration within the display structure. This reduces the external chip area required while maintaining control capabilities.
2Area of stationary object
If distributed driver circuits are integrated within the display area, then chip area is reduced, but communication complexity and control difficulty increase
Solution Approach 1:
A shared multi-wire command interface is implemented that can communicate with all driver circuits simultaneously, allowing a single communication bus to perform multiple functions (addressing, control, status reading) for multiple driver circuits. This reduces communication complexity compared to dedicated separate interfaces for each driver.
Solution Approach 2:
Driver circuits provide readback data through a shared readback line to the control circuit, enabling the control circuit to monitor and verify the state of each driver circuit. This feedback mechanism simplifies control by allowing the system to detect and correct communication issues automatically.
3Area of stationary object
If a shared multi-wire command interface is used for communication, then chip area and wiring complexity are reduced, but communication speed and data exchange capacity are limited
Solution Approach 1:
The communication system uses periodic clock cycles to serialize data transmission over the shared multi-wire interface. By organizing data exchange into periodic time slots and using clock-synchronized bit-banging communication, the system achieves reliable high-speed data transfer despite the shared nature of the interface.
Solution Approach 2:
The control circuit preliminarily addresses and selects specific driver circuits before data transmission begins. This preliminary addressing ensures that each driver circuit is properly configured and ready to receive commands or send data, optimizing the efficiency of subsequent high-speed communication over the shared interface.
Data Source
AI summary
Embodiments relate to a display device that includes a control circuit, an array of light emitting diode (LED) zones, and an array of driver circuits that are distributed in the display area. The driver circuits are arranged in groups that are coupled to each other and to the control circuit in a serial communication chain via serial communication lines. The group of driver circuits are also coupled in parallel to a shared multi-wire command line that provides a high-speed interface for providing the driver control signals from the control circuit. The control circuit may furthermore issue readback commands to the driver circuits via the shared multi-wire command line or the serial communication chain. In response to the commands, the driver circuits provide readback data via a readback line through the serial communication chain or via parallel connections from the driver circuits.