SIMO Voltage Converter Auxiliary Switch Cross Regulation

Solution Overview

Problem

Single-inductor multiple-output (SIMO) DC-DC converters face challenges in regulating output voltages due to cross regulation issues, where a load transient on one output affects the voltage regulation of other outputs, particularly in continuous conduction mode (CCM) based designs.

Innovation Solution

Incorporating an auxiliary switch in the voltage converter, which alternates with the main output switches during a predetermined time period, allowing for non-overlapped duty cycles and independent control of each output switch to prevent cross regulation, with the auxiliary switch not being used for controlling output voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If CCM-based control scheme is used for SIMO converters, then efficiency is improved, but cross regulation between different regulated output voltages occurs

Engineering Contradiction:

ImproveefficiencyVSAvoidvoltage regulation stability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent segments the switching control by introducing an auxiliary switch that operates independently from the main output switches. This segmentation allows the main switches to control output voltages while the auxiliary switch compensates for cross-regulation effects, enabling CCM operation without voltage regulation instability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The auxiliary switch acts as an intermediary element that mediates between the main output switches and the inductor current. By controlling the auxiliary switch's on/off states based on the operating phase, the system compensates for cross-regulation effects and maintains stable voltage regulation in CCM mode.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If multiple main output switches are used for multiple outputs, then each output can be controlled, but cross regulation affects other outputs when one output experiences load transient

Engineering Contradiction:

Improvemultiple output controlVSAvoidvoltage regulation independence

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent segments the switching control by introducing an auxiliary switch that operates independently from the main output switches. This segmentation allows the main switches to control output voltages while the auxiliary switch compensates for cross-regulation effects, enabling CCM operation without voltage regulation instability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The control system uses feedback from the operating phase information to dynamically adjust the auxiliary switch's state. This feedback mechanism ensures that cross-regulation effects are compensated in real-time, maintaining voltage regulation independence across all outputs even during load transients.

Inventive Principle:

Principle #23Feedback

3Volume of moving object

If conventional SIMO converter design is used, then size reduction is achieved, but cross regulation problem persists and complicates control design

Engineering Contradiction:

Improveconverter sizeVSAvoidcontrol design complexity

Core Design Contradiction:

Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent segments the switching control by introducing an auxiliary switch that operates independently from the main output switches. This segmentation allows the main switches to control output voltages while the auxiliary switch compensates for cross-regulation effects, enabling CCM operation without voltage regulation instability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The auxiliary switch operates in a periodic manner based on the identified operating phases. By switching the auxiliary element on during specific phases and off during others, the system systematically compensates for cross-regulation effects without requiring complex continuous control mechanisms.

Inventive Principle:

Principle #19Periodic action

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 solution effectively regulates each output voltage to its target value, preventing cross regulation and ensuring stable voltage delivery across all outputs, even during load transients.

Implementation Method 1

The DC-DC power supply block has an input node and an output node, and is configured for storing energy through the input node coupled to the input terminal and discharging the stored energy through the output node

Methodology Applied

Scientific EffectEnergy storage and discharge: Inductor

Data Source

PatentUS9065334B2Voltage converter having auxiliary switch implemented therein and related voltage converting method thereof

Publication Date: 2015.06.23 MEDIATEK INC

AI summary

A voltage converter has an input terminal and only N output terminals, and includes a DC-DC power supply block having an input node and an output node, (N+1) switches including N main output switches and an auxiliary switch each having a first end and a second end, and a switch control circuit. The DC-DC power supply block includes an inductor, and a switch module configured for alternating between a first interconnection configuration and a second interconnection configuration during a predetermined time period. First ends of the (N+1) switches are coupled to the output node, and second ends of the N main output switches are coupled to the N output terminals, respectively. The switch control circuit is configured for controlling the switch module and the (N+1) switches, wherein the (N+1) switches are switched on alternately during the predetermined time period.