Multi-LDO Regulating Circuit for Ripple Reduction Without Larger Capacitors

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Solution Overview

Problem

Existing regulating circuits face a trade-off between reducing ripple voltage and increasing the size of the load capacitor in low drop output (LDO) regulators, necessitating a solution that stabilizes output voltage without enlarging the capacitor.

Innovation Solution

The proposed solution involves a regulating circuit that includes a DC-DC converter and multiple LDO regulators, where a switching circuit connects the converter to different nodes based on mode settings, and a second LDO regulator provides auxiliary current to maintain voltage stability when the converter is disconnected from a node.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the size of the load capacitor is increased to reduce ripple voltage, then the ripple voltage is reduced, but the device size and complexity increase

Engineering Contradiction:

Improveripple voltageVSAvoidload capacitor size

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

A second LDO regulator is introduced as an intermediary component to provide auxiliary current to the first node. This mediator supplies additional current during transitions or high-demand periods, stabilizing the voltage at the first node and reducing ripple voltage without requiring an oversized load capacitor. The second LDO regulator acts as a supporting element that complements the primary regulation path.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system dynamically changes operational parameters by switching between different modes (first mode and second mode) depending on the connection state of the DC-DC converter. When the converter is disconnected, the second LDO regulator activates to provide auxiliary current, effectively changing the current supply parameters to maintain voltage stability without increasing capacitor size.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If multiple LDO regulators and switching circuits are added to reduce ripple voltage, then the ripple voltage is reduced, but the device complexity increases

Engineering Contradiction:

Improveripple voltageVSAvoidregulating circuit structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The second LDO regulator serves multiple functions: it provides auxiliary current to the first node, stabilizes voltage during converter transitions, and reduces ripple voltage. This multi-functional component addresses several problems simultaneously without requiring separate dedicated circuits for each function, thereby limiting the increase in overall device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The regulating circuit operates dynamically by switching between different operational modes based on the connection state of the DC-DC converter. The second LDO regulator is activated only when needed (in the second mode), allowing the system to adapt its complexity to the actual operational requirements rather than maintaining maximum complexity continuously.

Inventive Principle:

Principle #15Dynamics

3Adaptability or versatility

If the DC-DC converter is switched to different nodes based on mode settings, then the adaptability is improved, but the stability of voltage supply may be affected

Engineering Contradiction:

Improvemode switching capabilityVSAvoidvoltage stability

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The second LDO regulator is positioned as a pre-prepared supporting element that activates when the DC-DC converter switches nodes. It provides auxiliary current in advance during transition periods, cushioning the potential voltage instability that would occur during mode switching. This ensures that voltage stability is maintained throughout the transition process.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The system uses mode setting signals to control the switching circuit, creating a feedback mechanism that coordinates the operation of the DC-DC converter and the second LDO regulator. When the converter switches to a different node, the feedback signal triggers the second LDO regulator to provide auxiliary current, ensuring stable voltage supply throughout the transition.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11860658B2Regulating circuit including a plurality of low drop out regulators and method of operating the same

Publication Date: 2024.01.02 SAMSUNG ELECTRONICS CO LTD

AI summary

A regulating circuit including a first direct current (DC)-DC converter configured to apply a first supply voltage to a first node in a first mode and apply the first supply voltage to a second node in a second mode, a first low drop output (LDO) regulator connected to the first node, the first LDO regulator configured to provide an output voltage to an output node by regulating the first supply voltage of the first node, and a second LDO regulator connected to the first node, the second LDO regulator configured to provide an auxiliary current to the first node in the second mode may be provided.