Capacitive Voltage-Boosting Stage for Class D Amplifiers
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Solution Overview
Problem
Existing voltage-boosting technologies for Class D amplifiers, such as inductive DC/DC converters, are inefficient due to the use of expensive and bulky inductors, and capacitive solutions like charge-pump circuits face issues with output voltage stability and component count.
Innovation Solution
A voltage-boosting stage utilizing two capacitive circuits with strategically placed switches to achieve a two- or three-level boosted power stage, reducing the number of components and eliminating inductors, while maintaining circuit performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If an inductive DC/DC converter is used to boost the supply voltage, then the power delivery capability is improved, but the device size and cost increase due to the use of inductors
Solution Approach 1:
The patent replaces the inductive DC/DC converter (which uses magnetic fields and inductors) with a capacitive voltage-doubler circuit that uses only capacitors and switches. This substitution eliminates the need for bulky inductors while achieving the same voltage boosting function, thereby reducing device footprint and cost while maintaining improved power delivery capability.
Solution Approach 2:
The patent changes the fundamental operating principle from inductive to capacitive voltage boosting. By using capacitors charged to different voltage levels and switching them in series/parallel configurations, the circuit achieves voltage multiplication without requiring magnetic components, thus reducing size while maintaining power delivery capability.
2Area of stationary object
If a capacitive voltage-doubler circuit is used to boost the supply voltage, then the device footprint is reduced, but the output voltage stability deteriorates due to varying slopes in different states
Solution Approach 1:
The patent divides the voltage-doubler circuit into two separate capacitive circuits (first and second capacitive circuits) with distinct functions. The first capacitive circuit charges a first capacitor to the supply voltage, while the second capacitive circuit charges a second capacitor to twice the supply voltage. This segmentation allows each capacitor to be optimized for its specific voltage level, improving overall output voltage stability.
Solution Approach 2:
The patent implements dynamic switching between different capacitor configurations based on the required output voltage level. The switching circuitry dynamically connects capacitors in series or parallel configurations, allowing the output voltage to be adjusted between multiple discrete levels (e.g., Vs, 2Vs, 3Vs). This dynamic operation maintains voltage stability by selecting the appropriate configuration for the current load conditions.
3Power
If the number of capacitive circuits is increased to improve voltage boosting capability, then the power delivery is enhanced, but the device complexity increases
Solution Approach 1:
The patent merges the functions of multiple capacitive voltage-doubler circuits into a unified multi-level voltage generator. By sharing common components (such as the supply voltage source, switching elements, and capacitor arrays) between different voltage boosting functions, the circuit achieves enhanced power delivery capability without proportionally increasing complexity. The first and second capacitive circuits work together in a coordinated manner to generate multiple output voltage levels.
Solution Approach 2:
The patent designs the capacitive circuits to serve multiple functions simultaneously. The same capacitors and switches are used to generate different voltage levels (Vs, 2Vs, 3Vs) depending on the switching configuration. This multi-functionality allows the circuit to adapt to different power delivery requirements without requiring separate dedicated circuits for each voltage level, thereby controlling overall complexity.
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
This solution effectively doubles or triples the supply voltage without inductors, reducing component count and maintaining performance, thus enhancing power delivery to loudspeaker loads without the drawbacks of traditional capacitive voltage-doubler circuits.
Implementation Method 1
A first capacitive circuit (101, 102) coupled to a power supply (103) and providing an output voltage (104) at an output terminal (105)
Data Source
AI summary
The invention relates to a voltage-boosting stage (100) comprising a first capacitive voltage circuit (S1, S2, S3, S4, C0, Cb) coupled to a power supply (Vs) and providing an output voltage at an output terminal. The voltage-boosting stage further comprises a second capacitive voltage circuit (S5, S6, S7, S8, C1, Cb) coupled to a power supply (Vs) and providing another output voltage at another output terminal the output terminal and the other terminals being coupled together and further coupled to a supply terminal of a power stage (S9, S10) for implementing a two-level boosted power stage.