Class-D Amplifier Power Conversion Using Shared Inductors
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Solution Overview
Problem
Conventional class-D amplifying systems face high power consumption and increased manufacturing costs due to large power supply differences and the need for extra power devices like inductors and switches.
Innovation Solution
A class-D amplifying system with a power converter circuit that uses a class-D amplifier circuit to generate complementary output signals, employing inductors and switches, and a power converter circuit to generate a DC power supply using selected output signals, reducing the need for external devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a low drop-out power converter is used to convert power supply PVDD to AVDD, then power supply is provided, but power consumption increases when there is a large difference between PVDD and AVDD
Solution Approach 1:
The power supply conversion is divided into two stages: first, a switching regulator converts PVDD to an intermediate power supply AVPP; second, a low drop-out power converter converts AVPP to AVDD. This segmentation allows the switching regulator to handle the large voltage difference efficiently, reducing overall power consumption.
Solution Approach 2:
An intermediate power supply AVPP is introduced as a mediator between PVDD and AVDD. The switching regulator converts PVDD to AVPP, and then the low drop-out power converter converts AVPP to AVDD. This intermediary approach enables efficient power conversion by breaking down the large voltage difference into manageable steps.
2Loss of energy
If a switching regulator is used to convert PVDD to AVPP and then AVPP to AVDD, then power conversion efficiency improves, but manufacturing cost and circuitry size increase due to extra power devices
Solution Approach 1:
The class-D amplifier circuit's power stage components (inductors and switches) are made to serve dual functions: they generate the complementary output signals for audio amplification and simultaneously generate the intermediate power supply for the low drop-out power converter. This multi-functionality eliminates the need for separate dedicated power conversion components.
Solution Approach 2:
The power conversion function is merged with the audio amplification function. The same inductors and switches used for generating complementary output signals are also utilized to generate the intermediate power supply, combining two functions into a single integrated system and reducing overall component count.
3Loss of energy
If extra power devices such as inductor and switches are added for switching conversion, then power conversion efficiency improves, but manufacturing cost increases
Solution Approach 1:
The inductors and switches in the class-D amplifier power stage are designed to perform multiple functions: generating complementary output signals and generating the intermediate power supply. This eliminates the need for additional dedicated power conversion components, reducing manufacturing cost while maintaining efficiency.
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
Improves power conversion efficiency and reduces power consumption without additional external devices, maintaining a compact circuit size and low manufacturing costs.
Implementation Method 1
operate a first inductor and a second inductor to convert an input power to respectively generate a positive output signal and a negative output signal
Implementation Method 2
a power converter circuit, which is configured to operably generate a direct current (DC) power supply according to at least one of the positive output signal and the negative output signal
Data Source
AI summary
A class-D amplifying system includes: a class-D amplifier circuit configured to convert an input signal to a switch control signal in pulse width modulation fashion, wherein the switch control signal controls switches to operate a first inductor and a second inductor, thus converting an input power to a positive output signal and a negative output signal which are complementary to each other, to thereby drive a load; and a power converter circuit, which generates a direct current (DC) power supply according to at least one of the positive output signal and the negative output signal, wherein the DC power supply supplies at least a portion of power to the class-D amplifier circuit.