Current Mode DA Converter Circuit for OLED Data Line Driving
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Solution Overview
Problem
Conventional current mode DA converters for data line driving circuits in OLED electro-optical devices are complex due to the need for multiple current sources and additional voltage mode DA converters for pre-charge voltages, leading to increased circuit size and power consumption.
Innovation Solution
A current mode DA converter with a simple configuration using reference voltage generating means, voltage selecting means, and voltage-to-current converting means, where the reference is set by voltage, eliminating the need for multiple current sources and allowing for both voltage and current output, and incorporating compensating and gain adjusting mechanisms to improve precision and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current mode DA converters use multiple current sources corresponding to the number of bits, then conversion precision is improved, but device complexity increases
Solution Approach 1:
The patent changes the fundamental parameter from current-based representation to voltage-based representation. Instead of using multiple current sources with different current values, the invention uses a single current source with variable voltage control, fundamentally altering how the conversion is achieved while maintaining precision.
Solution Approach 2:
The patent uses a single current source that is controlled by voltage to replicate the function of multiple current sources. The voltage-controlled current source effectively 'copies' the functionality of multiple discrete current sources through a unified, controllable mechanism.
2Adaptability or versatility
If voltage mode DA converters are added for pre-charge voltage supply, then pre-charge functionality is improved, but device complexity increases
Solution Approach 1:
The patent makes the voltage-controlled current source universal by enabling it to perform multiple functions: it can supply pre-charge voltage and can supply drive current. This single circuit element replaces what would traditionally require separate voltage mode and current mode converters, achieving multi-functionality.
Solution Approach 2:
The patent merges the pre-charge function and the drive current function into a single voltage-controlled current source circuit. By combining these functions, the patent eliminates the need for separate voltage mode and current mode converters, reducing overall device complexity.
3Measurement precision
If multiple current sources are equipped for each current mode DA converter, then conversion precision is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent changes from using multiple current sources with different current values to using a single current source with variable voltage control. This parameter change eliminates the need for precise matching of multiple current sources, as only one current source needs to be maintained with stable characteristics.
4Use of energy by moving object
If current mode DA converters are used for data line driving, then power efficiency is improved, but device complexity increases due to multiple current sources
Solution Approach 1:
The patent merges the pre-charge function and drive current function into a single voltage-controlled current source, reducing the number of active components while maintaining current mode operation for power efficiency.
Solution Approach 2:
The voltage-controlled current source serves multiple functions (pre-charge and drive current supply), making the circuit more efficient by eliminating redundant components and reducing overall power consumption associated with multiple separate converters.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration simplifies the DA converter and data line driving circuit, reducing circuit size and power consumption while maintaining high precision and flexibility in output, enabling efficient gray-scale level representation and pre-charging of data lines.
Implementation Method 1
voltage selecting means for selecting one of the plurality of reference voltages, based on data inputted thereto, and outputting an analog voltage signal
Implementation Method 2
voltage to current converting means for converting the analog voltage signal into an analog current signal
Data Source
AI summary
To simplify s configuration of a current mode DA converter. A data line driving circuit includes DA converting units U1 to Un. Each DA converting unit U1 to Un a voltage DA converting circuit for generating an analog voltage signal Sv based on image data, a V/I converting circuit for converting the analog voltage signal Sv into an analog current signal Si, and a voltage current selector for selecting one of the analog voltage signal Sv and the analog current signal Si based on a pre-charge control signal CTL. In addition, the analog voltage signal Sv outputted from the voltage current selector serves as a pre-charge voltage, and the analog current signal Si serves as a driving current of an OLED element.