Switched Capacitor Converter Mode Transition Control

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Solution Overview

Problem

Switched capacitor power converters face challenges in efficiently managing output voltage variations across a wide range of input voltages, requiring smooth mode transitions to maintain efficient power conversion in electronic devices.

Innovation Solution

A control mechanism is implemented for a switched capacitor power converter to operate in multiple modes, including switching, bypass, charging, and discharging modes, using switches and a charge pump capacitor to achieve smooth transitions by controlling the on/off times of switches S1-S4, allowing the converter to function as a voltage divider and ensuring efficient power conversion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the switched capacitor converter operates in a single mode, then the circuit structure remains simple, but the output voltage cannot adapt to wide input voltage variations

Engineering Contradiction:
Improveoutput voltage adaptation rangeVSAvoidcircuit structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements multiple operating modes (2:1 voltage division mode, 1:1 bypass mode, charging mode, discharging mode) that dynamically switch based on input voltage levels. The controller selectively activates different switch configurations to adapt the converter's voltage transformation ratio, enabling the system to maintain efficiency across wide input voltage ranges while keeping the physical circuit structure relatively simple through controlled operational diversity.

Inventive Principle:
Principle #15Dynamics

2Speed

If mode transitions are implemented abruptly, then the response speed is fast, but output voltage ripple and instability increase

Engineering Contradiction:
Improvemode transition speedVSAvoidoutput voltage stability
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The patent introduces intermediate charging and discharging modes that serve as transition buffers between the 2:1 voltage division mode and the 1:1 bypass mode. Before switching between extreme modes, the system first transitions through these intermediate states, allowing capacitors to gradually charge or discharge and reducing abrupt voltage changes. This preliminary action through intermediate states smooths the transition process while maintaining relatively fast response.

Inventive Principle:
Principle #10Preliminary action

3Loss of energy

If the charge pump capacitor is switched rapidly for high efficiency, then power conversion efficiency improves, but large discharge currents may damage the converter

Engineering Contradiction:
Improvepower conversion efficiencyVSAvoiddischarge current damage risk
Core Design Contradiction:
Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent implements soft-start circuitry that gradually increases the switching frequency and duty cycle during startup and mode transitions, preventing sudden large discharge currents. The controller monitors operating conditions and ramps up the charge pump operation incrementally, cushioning against current surges that could damage switches or capacitors while still achieving high efficiency once the converter is fully operational.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 smooth mode transitions and efficient power conversion, reducing output voltage variation, and protecting the converter from large discharge currents, thereby maintaining stable operation across varying input voltages.

Implementation Method 1

the switched-capacitor converters are formed by a plurality of switches and a charge pump capacitor

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

the switched-capacitor converters are formed by a plurality of switches and a charge pump capacitor

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentEP3921934B1Switched capacitor converter and control method
Publication Date: 2023.07.26 HUAWEI DIGITAL POWER TECH CO LTD
  • EP3921934B1 patent drawingFigure 1
  • EP3921934B1 patent drawingFigure 2
  • EP3921934B1 patent drawingFigure 3

AI summary

A method includes configuring a switched capacitor converter to operate in a switching mode and configuring the switched capacitor converter to enter into a bypass mode after applying a charging mode to the switched capacitor converter, wherein as a result of applying the charging mode, the switched capacitor converter has a smooth transition from the switching mode to the bypass mode.