SIDO Buck Converter with Negative Current for Charge Recycling
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Solution Overview
Problem
Conventional single-inductor dual-output (SIDO) and multiple-output (SIMO) Buck converters can only supply output currents with the same polarity, limiting their ability to perform negative dynamic voltage control and reduce overshoots efficiently, leading to inefficiencies and increased PCB area and cost due to the need for additional components.
Innovation Solution
A SIDO/SIMO Buck converter design that includes additional switches to enable the supply of opposite polarity currents to outputs, allowing for charge recycling and improved power efficiency by discharging overshoots from one output to another, thereby enhancing power efficiency and output voltage ripple.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional SIDO Buck converter supplies positive current to one output, then it can maintain simple circuit topology, but it cannot perform negative dynamic voltage control or reduce overshoot at the other output
Solution Approach 1:
The patent segments the current path by introducing separate positive and negative current switches (SW_P and SW_N) that independently control current flow to different outputs. This allows the inductor current to be divided into positive and negative components, enabling independent control of current polarity at each output while maintaining the overall SIDO structure
Solution Approach 2:
The patent implements dynamic control of switch states to enable bidirectional current flow. The control circuit dynamically adjusts the switching states of SW_P and SW_N based on output voltage feedback, allowing the converter to adapt between supplying positive current, negative current, or recycling charge between outputs depending on real-time conditions
2Reliability
If a pull-down switch is used to discharge output capacitor during overshoot, then overshoot can be reduced, but significant efficiency loss occurs due to charge dissipation
Solution Approach 1:
Instead of discarding excess charge through dissipation (pull-down switch), the patent recycles it by redirecting the overshoot charge to the other output through the negative current path. The inductor acts as an energy transfer medium, moving charge from the high-voltage output to the low-voltage output, thereby recovering what would otherwise be wasted energy
Solution Approach 2:
The patent converts the harmful effect of overshoot (excess voltage/energy) into a beneficial resource by using it to charge the other output capacitor. The excess energy that would normally be dissipated as heat or wasted is instead utilized to supply the other output, turning a problem into an opportunity for charge recycling
3Adaptability or versatility
If additional components are added to enable opposite polarity current supply, then current polarity control is improved, but PCB area and cost increase
Solution Approach 1:
The patent makes the single inductor serve multiple functions: it acts as an energy storage element for positive current supply, as a discharge path for negative current supply, and as an energy transfer medium for charge recycling between outputs. This multi-functionality reduces the need for additional inductors or complex component arrangements
Solution Approach 2:
The patent merges the positive and negative current paths into a single integrated circuit topology that shares common components (inductor, control circuit, switching nodes). By combining the bidirectional current control functionality into the existing SIDO framework rather than adding separate circuits, the PCB area overhead is minimized
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 enables significant charge recycling and increased power efficiency by allowing both outputs to be supplied simultaneously, addressing the inefficiencies of prior art by enabling negative current supply and improving output voltage ripple.
Implementation Method 1
A single-inductor dual-output (SIDO), or single-inductor multiple-output (SIMO), Buck switching converter which can supply opposite polarity current to its outputs, through a single inductor
Implementation Method 2
A SIDO/SIMO Buck converter design that includes additional switches to enable the supply of opposite polarity currents to outputs, allowing for charge recycling and improved power efficiency by discharging overshoots from one output to another
Data Source
AI summary
It is an object of one or more embodiments of the present disclosure to provide a single-inductor dual-output (SIDO), or single-inductor multiple-output (SIMO), Buck switching converter which can supply opposite polarity current to its outputs, through an inductor. It is a further object of one or more embodiments, when one output has an overshoot and the other output is below a reference, to enable discharging the overshoot output to the other output, resulting in a significant charge recycling and considerable increase in power efficiency. Still further, it is an object of one or more embodiments to improve output voltage ripple, as both outputs are being supplied at the same time, compared to prior art SIDO operation, where only one output is supplied for a given phase.