Closed-Loop DAC Ripple Injection for Stable DC Outputs
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Solution Overview
Problem
Existing amplifier systems for introducing ripple or noise into DC outputs, such as those used in automatic test equipment, are bulky and inflexible, making them unsuitable for generating artifact signals effectively.
Innovation Solution
A closed-loop circuit supply system using digital means to generate and control ripple or noise signals without bulky transformer networks, employing primary and secondary control circuit paths with independent DAC channels and feedback loops to maintain a regulated DC output while adding non-DC artifact signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If transformer networks are used to generate ripple signals, then ripple generation capability is achieved, but device size becomes bulky
Solution Approach 1:
The patent replaces the mechanical transformer network with an electronic circuit implementation using operational amplifiers, resistors, capacitors, and switches. This substitution eliminates the need for bulky magnetic components while maintaining the ripple generation function through electronic signal processing.
Solution Approach 2:
The patent changes the operating parameters by using high-frequency switching (e.g., 1 MHz clock signal) to generate ripple at frequencies much higher than traditional transformer-based solutions. This allows for smaller component values (lower resistance, smaller capacitance) and eliminates the need for large magnetic cores.
2Adaptability or versatility
If transformer networks are used for artifact signal generation, then ripple signals can be coupled onto the supply, but flexibility regarding artifact signal types is limited
Solution Approach 1:
The patent implements dynamic control by using programmable switch timing and controllable current sources that can be programmed to generate different ripple waveforms (sinusoidal, triangular, square, or custom shapes). The circuit transitions from a fixed transformer-based approach to a dynamically reconfigurable electronic system.
Solution Approach 2:
The patent creates a universal artifact injection circuit that can generate multiple types of ripple signals (voltage ripple, current ripple, noise) using the same core circuitry. The operational amplifier-based design with programmable switching provides multi-functionality without requiring separate transformer networks for each signal type.
3Device complexity
If a single control loop is used for DC output regulation, then regulation simplicity is maintained, but artifact signal injection disrupts DC loop stability
Solution Approach 1:
The patent segments the control function by implementing a nested dual-loop architecture: an outer DC regulation loop that maintains the average DC output voltage, and an inner high-frequency ripple injection loop that adds artifact signals. The inner loop operates at a frequency much higher than the outer loop bandwidth, allowing independent control without destabilizing the DC regulation.
Solution Approach 2:
The patent introduces an intermediary operational amplifier stage that acts as a buffer between the DC control voltage and the ripple injection circuit. This intermediary allows the ripple signal to be superimposed on the DC output without directly affecting the DC feedback loop, maintaining stability while enabling artifact injection.
Data Source
AI summary
A circuit supply system includes a main digital to analog converter (DAC) circuit to produce a direct current (DC) output level at a system output; a feedback circuit path connected to the system output; a primary control circuit path connected to the feedback circuit path and configured to regulate the DC output level at the system output using the main DAC circuit and the feedback circuit path; and a secondary control circuit path connected to the feedback circuit path and configured to add a non-DC signal component to the DC output level and regulate the non-DC signal component using the feedback circuit path.