Switching Regulator Ripple Cancellation Using Adaptive Coil Current
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Solution Overview
Problem
Switching regulators produce undesirable voltage ripples due to coil current charging and discharging, which lead to energy spikes at the switching frequency, particularly problematic in sensitive applications like RF systems.
Innovation Solution
A self-adaptive ripple attenuation method that senses the coil current, generates an artificial coil current of opposite phase, and injects it into the output node to cancel out the ripple, using a circuit with a current sensor, voltage generator, comparator, and converters to adjust and convert the artificial coil current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If switching regulators are used to convert input voltage to output voltage, then voltage conversion function is achieved, but output voltage ripple is generated
Solution Approach 1:
The patent generates an artificial coil current that mirrors the actual coil current waveform but with opposite phase, effectively converting the harmful ripple current into a beneficial canceling signal. This artificial current is injected into the output node to neutralize the voltage ripple caused by the actual coil current, transforming the problem of ripple generation into a solution through constructive interference of opposing signals.
Solution Approach 2:
The patent introduces an intermediary artificial coil current as a mediator between the switching regulator and the output load. This intermediary current signal serves as a buffer that absorbs and cancels the harmful effects of the actual coil current ripple, protecting the output voltage from ripple contamination while allowing the switching regulator to continue its normal operation.
2Object-generated harmful factors
If coil current ripple is canceled, then output voltage ripple is reduced, but switching frequency performance may be affected
Solution Approach 1:
The patent applies local quality by making the artificial coil current specifically targeted at canceling only the ripple component at the output node, while leaving the main power transfer function at the switching frequency untouched. The artificial current is designed to match only the AC ripple portion of the coil current, not the DC component or the fundamental switching frequency components, thus locally addressing the ripple problem without globally affecting switching performance.
Data Source
AI summary
Described herein is a spur-free technique for a switching regulator. The switching regulator may self-adaptively reduce the spur of the output voltage without affecting performance of the switching frequency, The switching regulator may track a coil current and may use an active feedback loop to adaptively generate an artificial coil current, which tracks an amplitude of the coil current but having opposite phase. The artificial coil current may then be injected into an output node to cancel the coil current ripple.