Multi-phase Switched Mode Programmable Load for Noise Cancellation
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Solution Overview
Problem
Current programmable load modules are large, heavy, and expensive due to the use of linear topologies with large MOSFETs, which limits their application in high-power density applications and makes them difficult to fit into compact form factors.
Innovation Solution
A programmable load circuit utilizing a switching topology with multiple phases of boost regulators in parallel, where each phase is out of phase with others to cancel ripple current, and a second sub-circuit with a switchable resistor to adjust load values, allowing for continuous programmability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If linear topology with large MOSFETs is used, then reliability is improved, but weight increases and device complexity increases
Solution Approach 1:
The patent replaces the mechanical/linear topology system with a switching topology system. Specifically, it uses a multi-phase switching regulator architecture where electronic switches (MOSFETs) operate in switching mode rather than linear mode, enabling weight reduction while maintaining reliability through controlled switching operations
Solution Approach 2:
The patent divides the single large MOSFET system into multiple smaller switching elements arranged in parallel phases. The multi-phase architecture segments the current handling across multiple smaller switches, reducing the size and weight of individual components while collectively handling the same total current
2Reliability
If linear topology with large MOSFETs is used, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent segments the device into multiple identical modular phases, each containing smaller switching elements. This modular segmentation reduces individual component complexity while the repetitive structure allows for simplified design and manufacturing processes
Solution Approach 2:
The patent changes the operational parameters from linear mode to switching mode, and from single-phase to multi-phase operation. This parameter change enables the use of smaller, less complex components while achieving the same or better performance through controlled switching and phase interleaving
3Weight of stationary object
If switching topology with multiple phases is used, then weight is reduced and device complexity is reduced, but input current noise increases
Solution Approach 1:
The patent segments the switching operation into multiple phases that are temporally distributed. By interleaving the switching events across phases, the individual current ripple contributions from each phase partially cancel each other, reducing the total input current noise despite the switching topology
Solution Approach 2:
The patent designs the phase shifts and timing of each phase to preemptively counteract the ripple current effects. The out-of-phase operation of multiple phases creates opposing current variations that cancel each other before they can accumulate, reducing input current noise
4Manufacturing precision
If fixed load values are used, then manufacturing precision is improved, but adaptability decreases
Solution Approach 1:
The patent implements a programmable control system that dynamically adjusts the duty cycle and switching parameters of each phase. This allows the load value to be continuously varied through software control rather than requiring physical reconfiguration, achieving high adaptability while maintaining manufacturing precision through controlled parameter changes
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 design results in a smaller, lighter, and more cost-effective programmable load module with reduced input current noise and the ability to achieve a continuous range of load values, suitable for high-power density applications.
Implementation Method 1
each first sub-circuit includes an inductor, a load, and a switch coupled to the inductor
Implementation Method 2
the load is a second sub-circuit including a capacitor connected in parallel to a switchable fixed resistor
Data Source
AI summary
Circuits and methods for operating a programmable load circuit that includes a plurality of sub-circuits connected in parallel between an input and an output. Each sub-circuit may include an inductor, a load, and a switch coupled to the inductor. Each switch may be configurable in a first state and a second state, wherein the inductor is either connected to the output through the load or connected to the output through a connection that bypasses the load. The switches of the plurality of first sub-circuits may be programmable to periodically switch between the first state and the second state according to a duty cycle, and the switches may be out of phase with each other by a predetermined amount. The duty cycle may be programmable to tune the load of the programmable load circuit.