Programmable Delay Circuit Calibration for Linear Delay Control
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Solution Overview
Problem
Existing electronic retarders face challenges in ensuring a reliable relationship between the desired delay setting and the actual delay value, particularly in terms of resolution and linearity, due to factors like technological dispersions and aging effects.
Innovation Solution
A calibration method and circuit design that utilize digital-analog converters to control the current and voltage sources for a capacitive element, allowing for precise calibration of the delay generation circuit by iteratively adjusting digital control codes to achieve a desired delay range with linear variation, using a reference channel for calibration and redundancy to minimize errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional delay circuits are used without calibration, then the circuit structure is simple, but the relationship between setpoint and actual delay value is unreliable with poor resolution
Solution Approach 1:
The patent applies preliminary action by performing calibration before actual use. The calibration process pre-determines the relationship between digital control codes and actual delay values, storing calibration data that compensates for manufacturing variations. This preliminary calibration action ensures high precision delay values without requiring complex real-time adjustment mechanisms during operation.
Solution Approach 2:
The patent uses calibration data as an intermediary between the simple delay circuit structure and the desired high precision delay values. The calibration data, obtained through preliminary measurements and stored in lookup tables, mediates the relationship between digital control codes and actual delay times, enabling precise delay generation without complex circuitry.
2Reliability
If digital control codes are used to program delay values, then the delay is programmable, but technological dispersions and aging effects cause deviations from desired delay values
Solution Approach 1:
The patent implements feedback by measuring actual delay values during calibration and using these measurements to create correction data. The calibration process involves applying digital control codes, measuring the resulting delay times with high precision, and storing the relationship between control codes and actual delays. This feedback loop compensates for technological dispersions and aging effects, ensuring reliable delay values despite manufacturing variations.
3Manufacturing precision
If the delay circuit operates without calibration data, then the operation is fast and simple, but the linearity and resolution of delay values are poor
Solution Approach 1:
The patent applies preliminary action by performing comprehensive calibration during manufacturing or initialization. The calibration process pre-determines the relationship between digital control codes and actual delay values across the full range of operation, storing calibration data in lookup tables. This preliminary action ensures excellent linearity and resolution without adding complexity to the operational phase.
Solution Approach 2:
The patent uses periodic action by implementing calibration at specific intervals - during manufacturing, after aging periods, or when environmental conditions change significantly. The calibration process is performed periodically to maintain delay linearity and compensation accuracy, with calibration data updated as needed based on measured performance degradation or drift.
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
The solution provides a reliable and precise programmable delay generation circuit with improved linearity and resolution, capable of compensating for manufacturing dispersions and aging effects, ensuring consistent delay values across multiple channels.
Implementation Method 1
solutions based on a voltage ramp generator using a capacitor load. In these solutions, a voltage ramp is obtained by charging a capacitor at a constant current
Implementation Method 2
a capacitive integrating element for a first current supplied by a first current source, wherein the first current source comprises a first digital-to-analog converter controlled by a first digital control code
Implementation Method 3
a comparator for a first charging voltage of said capacitive element with respect to a second voltage, said second voltage being generated from a second digital-to-analog converter controlled by a second digital control code
Data Source
Figure 1~2C
Figure 3
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AI summary
This description relates to a calibration method for a delay generation circuit and the corresponding circuit.