On-Chip High-Voltage Driver Circuit for Ultrasonic Transducers
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Solution Overview
Problem
Ultrasonic transducers require high voltage drive levels, which are inefficiently generated and result in high power dissipation due to the large capacitive load they present, making it impractical to integrate high voltage generation and associated level shifters at the system level.
Innovation Solution
An integrated circuit with a charge pump and multi-level inverter is used to generate high voltage, where the charge pumps are active only when required, optimizing efficiency and eliminating the need for off-chip components, and the multi-level inverter produces an output voltage that drives the transducer with lower power consumption by using auxiliary voltages for gate drive.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high voltage is generated using conventional inverters at the system level, then the ultrasonic transducer receives sufficient drive levels, but the power dissipation increases and efficiency decreases
Solution Approach 1:
The charge pump circuit and multi-level inverter are merged into a single integrated circuit, allowing the charge pump to generate high voltage only when needed and eliminating the need for separate system-level high voltage generation. This integration reduces power dissipation by eliminating unnecessary power conversion stages and improving overall system efficiency.
Solution Approach 2:
The charge pump operates in a periodic manner, being activated only during the transmit phase when high voltage is required to drive the ultrasonic transducer, and remaining inactive during receive and idle phases. This periodic operation significantly reduces average power dissipation compared to continuous operation of conventional inverters.
2Power
If conventional inverters are used to drive the ultrasonic transducer, then the transducer receives the necessary high voltage, but off-chip components are required increasing system complexity
Solution Approach 1:
The charge pump circuit and multi-level inverter are merged into a single integrated circuit, consolidating multiple functions (high voltage generation, voltage level shifting, and transducer driving) into one chip. This eliminates the need for separate off-chip high voltage generation components and reduces overall system complexity.
Solution Approach 2:
The integrated circuit performs multiple functions: the charge pump generates high voltage, the multi-level inverter provides voltage level shifting and driving capability, and the circuit interfaces with both the ultrasonic transducer and imaging system. This multi-functionality eliminates the need for separate dedicated components for each function.
3Speed
If charge pumps are continuously active to ensure high voltage availability, then the transducer can be driven immediately, but power consumption increases
Solution Approach 1:
The charge pump is activated periodically only during the transmit phase when high voltage is actually needed to drive the ultrasonic transducer, and is turned off during receive and idle phases. This periodic operation maintains the ability to drive the transducer when needed while significantly reducing average power consumption compared to continuous operation.
Solution Approach 2:
The charge pump is activated slightly before the actual transmit signal is needed, allowing the high voltage to be ready in advance. This preliminary action ensures immediate transducer drive capability while limiting the active period to only what is necessary, optimizing both response time and power consumption.
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 reduces power consumption and minimizes the need for off-chip components, achieving efficient high voltage generation and transmission to the ultrasonic transducer while reducing unnecessary power dissipation.
Implementation Method 1
The charge pumps may be configured such that they are active only when required to supply the high voltage transmit waveform applied to the ultrasound transducer
Implementation Method 2
Ultrasonic transducers typically require high voltage drive levels in order to produce sufficient output power
Data Source
AI summary
An ultrasound transducer may be driven by a driver circuit having one or more charge pumps and a multi-level inverter. The one or more charge pumps are configured to drive the ultrasound transducer only during output transitions of the inverter.