Current Output DAC Circuit with Switched Voltage Holding
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Solution Overview
Problem
Existing current output DA conversion apparatuses face challenges in accurately setting current levels for each current source, leading to imprecise operation and increased circuit complexity due to the need for calibration with AD converters.
Innovation Solution
The apparatus includes a plurality of current sources, holding sections to store designated voltages, a setting DAC to generate these voltages, and a supply section to switch them among holding sections, allowing for precise current adjustment and simple configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a plurality of current sources are connected in parallel with switches to achieve high-speed response, then response speed is improved, but current setting accuracy deteriorates
Solution Approach 1:
The patent divides the current control system into separate functional blocks: current sources, holding sections (capacitors), switching section, and setting DAC. Each current source can be independently controlled through its dedicated holding section, enabling precise current setting while maintaining high-speed switching capability. The segmentation allows independent optimization of accuracy (through holding sections) and speed (through switching section).
Solution Approach 2:
The holding sections (capacitors) pre-store the designated voltages that correspond to the desired current values before switching occurs. The setting DAC sequentially generates these designated voltages and stores them in advance in the holding sections. This preliminary action ensures that when switching occurs, the current sources immediately receive the correct voltage without requiring real-time adjustment, thus achieving both accuracy and high-speed response.
2Manufacturing precision
If an AD converter is added to calibrate current sources, then current setting accuracy is improved, but device complexity increases
Solution Approach 1:
The system uses a setting DAC (digital-to-analog converter) that sequentially generates designated voltages for each current source without requiring external calibration equipment or AD converters. The DAC self-configures the current sources by directly providing the precise voltages needed, eliminating the need for separate calibration circuits. This self-service approach achieves accurate current setting while keeping the circuit relatively simple.
Solution Approach 2:
The setting DAC serves multiple functions: it generates designated voltages for calibration, stores calibration data, and provides ongoing current control for all current sources. By making the DAC multi-functional, the patent eliminates the need for separate AD converters and calibration circuits, reducing overall device complexity while maintaining accurate current setting capability.
3Manufacturing precision
If multiple current sources are controlled independently, then current precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the control functions for multiple current sources into a unified architecture: a single setting DAC generates all designated voltages, and a centralized switching section controls all current sources. Each current source has its own holding section for precision, but the control logic is consolidated. This merging approach achieves independent precision control for each current source while avoiding the complexity of completely separate control circuits for each source.
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 solution enables accurate and high-speed current output while maintaining a compact circuit design, with the ability to share components like the setting DAC, comparator, and control section across multiple current output DA conversion apparatuses.
Implementation Method 1
a plurality of holding sections that correspond respectively to the current sources and that each hold a designated voltage that designates a current flowing through the corresponding current source
Implementation Method 2
a setting DAC that sequentially generates the designated voltage to be held by each holding section
Implementation Method 3
a supply section that sequentially switches a supply of the designated voltage generated by the setting DAC among corresponding holding sections
Data Source
AI summary
Provided is an output apparatus comprising a plurality of current sources; a plurality of holding sections that correspond respectively to the current sources and that each hold a designated voltage that designates a current flowing through the corresponding current source; a setting DAC that sequentially generates the designated voltage to be held by each holding section; and a supply section that sequentially switches a supply of the designated voltage generated by the setting DAC among corresponding holding sections.