Current Source Array Switching for DAC Gradient Error Reduction
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Solution Overview
Problem
Existing digital to analog converters face challenges in achieving high precision due to system errors, particularly linear and square gradient errors, which are not adequately addressed by current turn-on sequence control methods for unit current sources in current source arrays.
Innovation Solution
A digital to analog converter design that includes a decoding module, switch array, and current source array, where the decoding module generates temperature codes to control the working sequence of unit switches, specifically switching all unit switches on diagonals of a 2n×2n matrix, reducing system errors by controlling high-order and low-order unit switches differently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the area of unit current source is increased to reduce random error, then random error is reduced significantly, but system error deteriorates with the increase of circuit area
Solution Approach 1:
The patent segments the current source array into multiple groups and applies different turn-on sequences to different segments. By dividing the array into sub-arrays with independent control, the system can optimize the turn-on sequence for each segment to minimize system errors while maintaining smaller individual unit areas that reduce random errors.
Solution Approach 2:
The patent implements local quality by applying different turn-on sequence strategies to different regions of the current source array. Specifically, it uses sequential turn-on for some groups and random turn-on for others, allowing each region to be optimized for its specific error characteristics rather than applying a uniform approach.
2Ease of operation
If existing turn-on sequence control methods (sequential, symmetrical, layered symmetrical, random) are used, then the current source array can be controlled, but system errors (linear gradient error and square gradient error) are not adequately eliminated
Solution Approach 1:
The patent changes the control parameters by introducing a hybrid turn-on sequence that combines elements of sequential and random approaches. It dynamically adjusts the turn-on timing and sequence based on the specific group and element indices, using parameter variations to minimize both linear and square gradient errors that plague traditional fixed sequences.
Solution Approach 2:
The patent creates a composite control strategy by combining multiple turn-on sequence approaches (sequential and random) into a hybrid method. This composite approach leverages the advantages of both methods: the structured nature of sequential turn-on and the error-randomizing benefits of random turn-on, resulting in superior overall performance.
Data Source
AI summary
A digital to analog converter and a method for controlling a current source array in a digital to analog converter relate to the field of electronics technologies, and are used to reduce a system error. The digital to analog converter includes: a decoding module, a switch array, and a current source array, where the decoding module is configured to generate a 2n−1-bit first temperature code by using high n bits of an input 2n-bit binary digital signal, generate a 2n−1-bit second temperature code by using low n bits of the 2n-bit binary digital signal, and control, by using the 2n−1-bit first temperature code and the 2n−1-bit second temperature code, a working sequence of 2n×2n−1 unit switches.