Time-Multiplexed Capacitor DC/DC Converter for Multiple Outputs

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Solution Overview

Problem

Conventional charge pumps are limited to producing a single-voltage, single-polarity output, which restricts their application and requires multiple charge pumps for systems needing multiple regulated voltages, increasing costs and component count.

Innovation Solution

A multiple output DC-to-DC voltage converter using a time-multiplexed-capacitor converter algorithm and circuit topologies that generate multiple voltage outputs of both positive and negative polarities from a single supply voltage, enabling dual-polarity, multiple-positive-output, multiple-negative-output, and reconfigurable multi-output converters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional charge pumps are used to produce a single voltage output, then the circuit is simple and cost-effective, but multiple charge pumps are required for systems needing multiple regulated voltages, increasing component count and cost

Engineering Contradiction:
Improvenumber of voltage outputsVSAvoidcomponent count
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a single charge pump circuit capable of generating multiple regulated voltage outputs (e.g., +5V, +3.3V, +1.8V, -5V, -3.3V) by time-multiplexing a single flying capacitor among multiple output nodes. This multi-functional approach eliminates the need for separate charge pumps for each voltage rail, directly resolving the contradiction between versatility and component count.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent employs dynamic switching of the flying capacitor connections through control logic that selectively connects the capacitor to different output nodes based on which voltage regulation is currently needed. This dynamic reconfiguration allows one capacitor to serve multiple functions sequentially, achieving multiple voltage outputs without proportionally increasing component count.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If multiple charge pumps are used to provide multiple voltage outputs, then each output can be regulated independently, but the cost and component count increase significantly

Engineering Contradiction:
Improvevoltage regulation capabilityVSAvoidcost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The invention makes a single charge pump circuit perform the work of multiple charge pumps by implementing time-multiplexed operation where the flying capacitor is sequentially connected to different output nodes. This universal design provides multiple regulated voltage outputs from a single circuit instance, directly reducing cost while maintaining regulation capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges multiple charge pump functions into a single integrated circuit by combining multiple voltage regulation paths that share common components (the flying capacitor, control logic, and switching network). This consolidation reduces the total component count and manufacturing cost while preserving the ability to regulate multiple voltages independently through time-multiplexed operation.

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If a single charge pump is used to generate multiple voltage outputs through time-multiplexing, then component count is reduced, but the charge pump must efficiently switch between multiple output nodes

Engineering Contradiction:
Improvecomponent countVSAvoidswitching control complexity
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The control logic automatically determines which output node requires charging based on voltage detection circuits that monitor each output voltage level. When an output voltage drops below its regulation threshold, the control logic autonomously routes the flying capacitor to that node for charging, eliminating the need for complex external control signals and simplifying operation.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent incorporates voltage detection and feedback mechanisms that continuously monitor the state of each output node and automatically control the switching of the flying capacitor accordingly. This feedback-based control simplifies operation by making the switching decision automatic rather than requiring manual or complex external control, directly addressing the ease of operation concern.

Inventive Principle:
Principle #23Feedback

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 allows for simultaneous production of multiple voltage outputs, including both positive and negative polarities, from a single charge pump, reducing component count and increasing flexibility, while maintaining efficiency and adaptability to varying input voltages.

Implementation Method 1

a first flying capacitor; a first output node; a second output node... the switching network being configured to provide first, second and third modes of circuit operation

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

a switching network including a first, second, third, fourth, fifth and sixth metal oxide semiconductor field effect transistors... the control circuit that is configured to drive the first, second, third, fourth, fifth and sixth metal oxide semiconductor field effect transistors

Methodology Applied
Scientific EffectField effect transistor operation:

Data Source

PatentEP2176953B1Time-multiplexed-capacitor DC/DC converter with multiple outputs
Publication Date: 2020.01.01 ADVANCED ANALOGIC TECHNOLOGIES INC
  • EP2176953B1 patent drawingFigure 1A~1B
  • EP2176953B1 patent drawingFigure 1C~2
  • EP2176953B1 patent drawingFigure 3~4B

AI summary

A multiple output DC-to-DC voltage converter using a new time- multiplexed-capacitor converter algorithm and related circuit topologies is herein disclosed. One embodiment of this invention includes a flying capacitor, a first output node, a second output node, and a switching network. The switching network configured to provide the following modes of circuit operation: 1 ) a first mode where the positive electrode of the flying capacitor is connected to an input voltage and the negative electrode of the flying capacitor is connected to ground; 2) a second mode where the negative electrode of the flying capacitor is connected to the input voltage and the positive electrode of the flying capacitor is connected to the first output node; and 3) a third mode where the positive electrode of the flying capacitor is connected to ground and the negative electrode of the flying capacitor is connected to the second output node.