Compact PWM Generator for Micro-LED Displays
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Solution Overview
Problem
Existing display technologies face challenges in creating compact pixel driver circuits for small, high-resolution displays, particularly micro-LED displays, where the area occupied by PWM generator circuits is a concern due to the need for precise control of brightness at the pixel level without increasing the circuit's size.
Innovation Solution
A modified PWM generator circuit design that uses a simplified multiplexer structure with control bits as signal inputs and clock signals as select inputs, reducing the area requirement by eliminating the need for conflict resolution circuitry and utilizing pass gates instead of Boolean logic gates, allowing for a more compact implementation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional PWM generator circuit with conflict resolution circuitry is used, then reliable pulse width modulation control is achieved, but the circuit area and transistor count increase
Solution Approach 1:
The patent extracts and removes the conflict resolution circuitry from the PWM generator, keeping only the essential multiplexer functionality. By taking out the unnecessary conflict resolution components, the circuit area is reduced while maintaining reliable PWM control through the simplified pass gate-based multiplexer structure
Solution Approach 2:
The patent substitutes traditional Boolean logic gates with pass gates in the multiplexer structure. This replacement reduces the transistor count and circuit complexity while maintaining the same logical functionality for selecting clock signals based on control bits
2Adaptability or versatility
If Boolean logic gates are used in the multiplexer structure, then complete logic functionality is achieved, but the transistor count and area occupancy increase
Solution Approach 1:
The patent replaces Boolean logic gates with pass gates in the multiplexer structure. Pass gates provide the necessary logic functionality with fewer transistors, reducing device complexity while maintaining adaptability in controlling the PWM output through control bits
Solution Approach 2:
The patent changes the implementation parameter of the multiplexer from Boolean logic gates to pass gates. This parameter change reduces the transistor count and area occupancy while preserving the essential logic functionality needed for PWM generation
Data Source
AI summary
A micro-LED display has an array of separately controllable micro-LEDs and corresponding pixel drivers. The pixel drivers have pulse-width modulation (PWM) generator circuits for the LEDs. The PWM generator circuits include the following. N input nodes are coupled to receive N control bits that determine a brightness of the LEDs. An output node is coupled to output the drive signal to the LEDs. Each of N transistors are connected between one of the input nodes and the output node. Each transistor is controlled by a clock signal CKn and couples the input node to the output node as controlled by the clock signal CKn.