Bidirectional Synchronous Driver for Piezo Actuators
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Solution Overview
Problem
Existing actuator drivers for high voltage capacitive loads, such as piezoelectric actuators, face challenges including high power consumption, large size, and high distortion levels, particularly in ultrathin devices like tablets and laptops, due to inefficient energy use and noise issues in current driver technologies.
Innovation Solution
A bidirectional synchronous power converter with a boost-buck converter topology is used to generate an analog voltage waveform with a peak amplitude at least twice the input voltage, incorporating a controller to manage switching nodes and reduce distortion, enabling efficient energy transfer and low power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a prior art voltage source inverter topology is used for high voltage capacitive loads, then the device can drive piezoelectric actuators, but the distortion level exceeds 5% and power efficiency is low
Solution Approach 1:
The patent changes the fundamental operating parameters of the power converter by implementing a bidirectional synchronous architecture with optimized switching control. This enables the system to achieve less than 1% distortion level while maintaining high power efficiency through synchronized switching of both high-side and low-side MOSFETs, fundamentally improving upon the prior art's asymmetric topology
Solution Approach 2:
The patent incorporates feedback mechanisms through the controller that monitor switching node voltages and adjust switching timing accordingly. This feedback control enables precise waveform generation with minimal distortion by dynamically compensating for voltage drops and timing variations during the bidirectional energy transfer process
2Power
If discrete parts are used to implement the power converter, then high power processing is achievable, but the device size becomes large and cost increases
Solution Approach 1:
The patent merges multiple discrete power processing functions into a single integrated bidirectional synchronous power converter chip. By combining the boost and buck converter functionalities, along with control circuitry, into one monolithic device, the system achieves high power processing capability while dramatically reducing device area and cost compared to discrete implementations
Solution Approach 2:
The bidirectional synchronous power converter is designed with universal functionality that enables it to operate in both forward-boost mode and reverse-buck mode, accommodating a wide voltage range single-ended analog inputs from various sensors. This multi-functionality eliminates the need for separate circuits for different operating conditions, reducing overall device size while maintaining high power capability
3Adaptability or versatility
If ADC is incorporated in actuator driver for sensor processing, then autonomous flight control is enabled, but power consumption increases and electrical noise is generated
Solution Approach 1:
The patent introduces an intermediary bidirectional synchronous power converter stage between the voltage source and the capacitive load that actively manages electrical noise through synchronized switching. This intermediary circuit isolates noise from sensitive ADC operations while maintaining power efficiency, enabling sensor processing without the full power penalty of traditional ADC implementations
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 a distortion level lower than 1% and high power efficiency at low power output, suitable for applications like high-definition haptic feedback in mobile devices and piezo cooling fans, with a voltage ratio boost exceeding 10:1, while being compact and cost-effective.
Implementation Method 1
A bidirectional synchronous power converter with a first switch, a second switch, and an inductive device connected to the first and/or second switch
Data Source
AI summary
A driver for a circuit with a capacitive load is configured for coupling to a voltage source which provides a DC input voltage, and is configured to generate an output voltage at an output. The driver includes a bidirectional synchronous power converter with a first switch, a second switch, and an inductive device connected to the first and/or second switch. A controller is configured to control the first switch and the second switch. The bidirectional synchronous power converter generates a switching voltage from the input voltage at a switching node and generates the output voltage having an analog voltage waveform with a peak amplitude of at least twice the input voltage. The bidirectional synchronous power converter includes a boost-buck converter configured to generate the analog voltage waveform from the input voltage by transferring increments of energy to the capacitive load in a forward-boost mode and from the load in a reverse-buck mode.