Capacitive DA Conversion Circuit for Multi-Bit Linearity
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Solution Overview
Problem
Existing DA conversion circuits for electro-optical devices, such as those using OLEDs, face accuracy and linearity issues when converting digital data into analog voltages, particularly when dealing with multiple bits, leading to deteriorated voltage conversion and worsened linearity.
Innovation Solution
A DA conversion circuit comprising a first DA conversion circuit unit for higher bits and a second DA conversion circuit unit for lower bits, with a coupling capacitance between them, where the switching elements supply specific potentials to the capacitance elements, ensuring distinct potentials for improved voltage conversion and linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional DA conversion circuit with capacitance elements and switching elements is used, then the circuit can convert digital data to analog voltage, but the accuracy and linearity of voltage conversion deteriorates with multi-bit input data
Solution Approach 1:
The DA conversion circuit is divided into multiple independent conversion units, each handling a specific bit position. Each unit includes its own capacitance element and switching element, allowing independent optimization of each bit's contribution to the final analog voltage, thereby maintaining accuracy and linearity across multi-bit input data
Solution Approach 2:
A coupling capacitance is introduced as an intermediary element between the first and second DA conversion circuit units. This coupling capacitance mediates the interaction between higher-bit and lower-bit conversion results, ensuring proper voltage level matching and maintaining linearity while enabling accurate multi-bit to analog voltage conversion
Data Source
AI summary
A DA conversion circuit includes a first DA conversion circuit unit corresponding to a higher bit, a second DA conversion circuit unit corresponding to a lower bit, a capacitance element provided between the first DA conversion circuit unit and the second DA conversion circuit unit, the first DA conversion circuit unit includes a capacitance element and a selection circuit, the second DA conversion circuit unit includes a capacitance element and a selection circuit, and the selection circuit supplies a potential VL or VPH to one end of the capacitance element, and the selection circuit supplies the potential VL or VPL to one end of the capacitance element. The potential VPL is different from the potential VPH, and for example, VPL>VPH.