Multi-Level Charge Pump Circuit for Audio Amplifier Power Supply
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Solution Overview
Problem
Existing Switched Mode Power Supply (SMPS) systems for portable devices, such as mobile phones, require dedicated and costly SMPS units and additional area on semiconductor substrates, limiting efficiency and increasing manufacturing costs, despite achieving high efficiency with dual output charge pumps generating two voltage levels.
Innovation Solution
A multi-level charge pump circuit using a dual output charge pump with positive and negative outputs, coupled to tank capacitors and fly capacitors, and controlled by switches to generate four distinct positive and negative voltage levels, leveraging existing SMPS units to reduce costs and enhance efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a dedicated SMPS unit is used to provide positive voltage for audio amplification, then high efficiency is achieved, but device complexity and manufacturing cost increase due to dedicated coils and additional semiconductor substrate area
Solution Approach 1:
The patent combines the functions of dedicated SMPS and negative charge pump into a single integrated charge pump circuit that generates both positive and negative voltage levels. This merging eliminates the need for separate dedicated SMPS units and their associated coils, reducing device complexity while maintaining high efficiency through unified voltage generation architecture
Solution Approach 2:
The charge pump circuit is designed to provide multiple voltage levels (±VDD and ±VDD/2) that can serve different audio signal amplitude requirements. This multi-functional capability allows a single circuit to replace multiple dedicated power supply units, reducing both complexity and manufacturing cost while maintaining the efficiency benefits of switched-mode operation
2Ease of manufacture
If a dual output charge pump is used to generate two voltage levels, then manufacturing cost is reduced by eliminating dedicated SMPS, but voltage levels are insufficient for optimal H-class amplifier performance across all audio signal amplitudes
Solution Approach 1:
The patent segments the voltage generation into multiple discrete levels (±VDD and ±VDD/2) that can be selectively activated based on audio signal amplitude. This segmentation allows the system to provide fine-grained voltage control for H-class amplifier operation, enhancing adaptability while maintaining the cost benefits of using a single charge pump circuit rather than dedicated SMPS units
3Loss of energy
If additional area is allocated on semiconductor substrate for dedicated SMPS components, then high efficiency power supply is achieved, but manufacturing cost and device complexity increase
Solution Approach 1:
The patent merges the functions of multiple power supply circuits into a single charge pump implementation, eliminating the need for separate dedicated SMPS units and their associated coils and capacitors. This consolidation significantly reduces the semiconductor substrate area required while maintaining the high efficiency benefits of switched-mode operation through unified voltage generation architecture
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 achieves high efficiency and versatility in powering H-class audio amplifiers, reducing manufacturing costs by eliminating the need for specific SMPS circuits and minimizing power consumption, while maintaining high performance across various audio signal amplitudes.
Implementation Method 1
A first fly capacitor is arranged to transfer a charge into the first tank capacitor, and a second fly capacitor is arranged to transfer a charge into the second tank capacitor
Data Source
AI summary
A multi level charge pump circuit may be associated with at least two power supplies, and may provide at least four levels of positive and negative voltage. The multi level charge pump may include first and second fly capacitors, and first and second tank capacitors. A plurality of PMOS transistors and NMOS transistors may allow generation of two high voltage levels and two low voltage levels for the multi level charge pump, the low voltage levels being derived from a charging of the two fly capacitors in series. This multi level charge pump may be embodied in an audio device within a platform without a dedicated SMPS circuit.