Transformerless Floating Power Circuit for Multi-Supply Amplifiers

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The use of transformers to configure floating power sources in audio amplifiers increases production costs and limits the number of lead wires, especially when multiple floating power sources are required, leading to unnecessary cost escalation in small-power amplifiers.

Innovation Solution

A floating power source circuit is designed without using transformers, utilizing a constant-voltage source connected in series with first and second constant-current sources, which have high internal impedance, allowing the constant-voltage source to function as a floating power source.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a transformer is used to configure a floating power source, then the floating power source can be provided with isolation and stable voltage, but the production cost increases and the number of lead wires is limited

Engineering Contradiction:
Improvefloating power source stabilityVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts the essential function of the transformer (providing isolated floating voltage) and implements it through a simplified circuit topology using a single-winding transformer with tap points, removing the need for multiple secondary windings and associated rectifier circuits. This reduces device complexity while maintaining the core functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The single-winding transformer with multiple tap points serves multiple functions simultaneously: it provides multiple isolated voltage levels, enables multiple floating power sources from a single transformer, and maintains electrical isolation. This multi-functionality reduces the number of components needed while maintaining reliability.

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

2Quantity of substance

If multiple transformers are disposed to provide multiple floating power sources, then the required number of floating power sources can be satisfied, but the production cost increases needlessly

Engineering Contradiction:
Improvenumber of floating power sourcesVSAvoidproduction cost
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The invention merges multiple floating power source functions into a single transformer by utilizing multiple tap points on one winding. This allows multiple isolated voltage outputs to be generated from one transformer core, eliminating the need for multiple separate transformers and reducing overall production cost.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single transformer with multiple tap points performs multiple functions of providing several isolated floating voltage levels simultaneously, enabling the system to satisfy multiple floating power source requirements without proportionally increasing transformer quantity or cost.

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

3Quantity of substance

If a transformer with multiple secondary windings is used, then multiple floating power sources can be provided, but the number of lead wires increases and lead wire connections are limited

Engineering Contradiction:
Improvenumber of floating power sourcesVSAvoidlead wire connections
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The invention combines multiple secondary windings into a single winding with multiple tap points, significantly reducing the number of lead wires required. Instead of needing separate lead wires for each secondary winding, the tap points provide multiple voltage outputs from a single continuous winding, simplifying connections.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3343764B1Floating power source circuit and amplifier
Publication Date: 2026.02.11 YAMAHA CORP
  • EP3343764B1 patent drawingFigure 1~2
  • EP3343764B1 patent drawingFigure 3~4
  • EP3343764B1 patent drawingFigure 5

AI summary

A floating power source is configured without using an insulating unit such as a transformer. A floating power source circuit 1 includes a high-side constant-current source 1H which is connected to a high potential source +VB, a low-side constant-current source which is connected to a low potential source -VB, and a constant-voltage source 1M which is connected between the high-side constant-current source 1H and the ow-side constant-current source 1L. The high-side constant-current source 1H and the ow-side constant-current source 1L have a high internal impedance, and therefore the constant-voltage source 1M functions as a floating constant-voltage source.