MST Driver Circuit with Programmable Slew Rate Control
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Solution Overview
Problem
Current magnetic secure transmission (MST) systems face challenges with high power consumption due to varying battery voltages, lack of control over coil current slew rate, and inadequate overvoltage protection, leading to inefficient energy use and reduced battery life.
Innovation Solution
The implementation of a system that includes a buck converter to regulate voltage, a full bridge driver to control current polarity, and an overvoltage protection circuit, along with a programmable slew rate control, to optimize power usage and stability in MST systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If traditional MST systems use a simple driver circuit without voltage regulation, then the device structure remains simple, but power consumption increases and battery life decreases
Solution Approach 1:
A buck converter is introduced as an intermediary component between the battery and the full bridge driver. The buck converter regulates voltage from varying battery levels to a stable output, enabling efficient power delivery to the coil while protecting the driver circuit. This intermediary solution resolves the contradiction by adding controlled complexity to achieve significant power savings.
Solution Approach 2:
The system dynamically adjusts operating parameters including voltage conversion ratio in the buck converter, current slew rate in the full bridge driver, and switching frequencies based on battery voltage levels and transmission requirements. These parameter changes optimize power consumption across different battery states while maintaining transmission effectiveness.
2Use of energy by moving object
If the MST system operates without slew rate control, then the circuit design is simpler, but energy efficiency decreases and battery life is reduced
Solution Approach 1:
The full bridge driver incorporates dynamic slew rate control that adjusts the rate of current change through the coil based on transmission requirements and power constraints. This dynamic adjustment optimizes energy efficiency by preventing excessive current transitions while maintaining effective magnetic signal generation, resolving the contradiction between simplicity and efficiency.
3Reliability
If traditional MST systems lack overvoltage protection, then the device complexity is lower, but reliability decreases under varying battery conditions
Solution Approach 1:
The buck converter and full bridge driver are designed with built-in overvoltage protection mechanisms that prevent voltage spikes and transient damage before they can harm the circuit. The buck converter's inherent voltage regulation and the driver's protection circuits provide beforehand cushioning against varying battery voltages, enhancing reliability without requiring complex external protection circuits.
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 by allowing MST systems to operate efficiently across a range of battery voltages, improves current slew rate control, and enhances reliability through effective overvoltage protection, resulting in lower energy expenditure and extended battery life.
Implementation Method 1
A MST driver sends a signal to an inductive coil that causes the inductive coil to send a magnetic signal from the device
Data Source
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AI summary
According to another embodiment, a system includes a driver circuit that drives a first output and a second output; a coil coupled between the first output and the second output such that the driver circuit drives current through the coil in response to control signals; and a programmable slew circuit coupled to the driver circuit. In some embodiments, a switch is coupled between the first output and the coil. In some embodiments an over-voltage protection circuit is coupled to protect the driver circuit.