Single Inductor Differential Boost Converter for Piezo Drivers
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Solution Overview
Problem
Existing boost converters for capacitive loads require two inductors, leading to a non-compact design that compromises fidelity and efficacy, especially when driving piezo ceramic speakers with continuous time-varying signals.
Innovation Solution
A fully integrated differential boost converter and amplifier circuit that uses a single inductor and employs a full bridge driver configuration with controlled switches and non-overlapping driver circuits to achieve efficient voltage stepping without shorting issues, allowing for compact design while maintaining high fidelity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a typical boost converter circuit is used to generate high voltage for capacitive loads, then the output voltage can be stepped up, but the circuit requires two inductors which increases device complexity and reduces compactness
Solution Approach 1:
The patent combines the boost converter function and amplifier function into a single integrated circuit that shares one inductor. The full-bridge configuration allows the same inductor to serve both the voltage stepping function and the capacitive load driving function, eliminating the need for separate inductors while maintaining both functionalities.
Solution Approach 2:
The single inductor in the circuit performs multiple functions: it acts as the energy storage element for voltage conversion in the boost converter mode, and simultaneously serves as the output inductor for the amplifier driving the capacitive load. This multi-functionality reduces component count and increases design compactness.
2Device complexity
If a compact design with single inductor is used, then device complexity is reduced, but it may compromise fidelity and efficacy when driving capacitive loads
Solution Approach 1:
The circuit dynamically switches between different operating modes using controlled switches in a full-bridge configuration. The ability to rapidly switch between modes allows the single inductor to effectively perform both boost conversion and amplifier functions, maintaining high fidelity and efficacy despite the reduced component count.
Solution Approach 2:
The circuit changes operating parameters (switching states, current directions, voltage polarities) to enable the single inductor to serve multiple purposes. By dynamically adjusting parameters through controlled switching, the circuit achieves both compactness and high performance for driving capacitive loads.
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 enables a compact and efficient boost converter that effectively steps up input voltage for capacitive loads, providing high fidelity and eliminating the need for two inductors, thus improving the overall performance and design efficiency.
Implementation Method 1
an inductor 114 coupled between a third node 126 and a fourth node 136
Implementation Method 2
a capacitive load 212 coupled between a first output node 125 and a second output node 135
Data Source
AI summary
A circuit and method for providing a fully integrated differential boost converter and amplifier. A first half bridge circuit has a first output node and a first switching node. A second half bridge circuit has a second output node and a second switching node. A capacitive load is coupled between the first output node and the second output node. An inductor is coupled between the first switching node and the second switching node. Control modes are provided to couple the first output node to a supply voltage and the first switching node to ground; to couple the first output node to the supply voltage and the second switching node to ground; to couple the second output node to the supply voltage and the first switching node to ground; and to couple the second output node to the supply voltage and the second switching node to ground.