Power Converter Slew Rate Control for Noise Reduction
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Solution Overview
Problem
Conventional power converters generate high noise when high-side and low-side switches operate at high frequencies, affecting signal transmission and device operations.
Innovation Solution
A power converter with a slew rate controlling mechanism, including a high-side switch, low-side switch, capacitors, an inductor, buffers, and a current controlling device that adjusts resistance to regulate the slew rate of voltage waveforms, reducing noise and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-side and low-side switches are operated at high frequency for power conversion, then power conversion efficiency is improved, but noise is generated that affects signal transmission and device operations
Solution Approach 1:
The patent applies dynamics by making the slew rate of the high-side switch controllable and adjustable. The slew rate, which determines the rate of change of the gate voltage, is dynamically adjusted based on operating conditions through a current controlling device that regulates the charging/discharging current of the gate capacitor. This dynamic control allows the system to optimize between fast switching (for efficiency) and controlled transitions (for noise reduction).
Solution Approach 2:
The patent changes the electrical parameters of the switching operation by controlling the slew rate parameter. By adjusting the gate voltage transition rate through the current controlling device, the system modifies the switching characteristics to reduce noise generation while maintaining acceptable conversion efficiency. The resistance of the current controlling device is varied to achieve different slew rates appropriate for different operating modes.
2Speed
If the slew rate of the high-side switch is increased to improve switching speed, then power conversion efficiency is improved, but noise generation is increased
Solution Approach 1:
The patent makes the slew rate dynamic rather than fixed. The current controlling device adjusts the gate charging/discharging current in real-time based on operating conditions, allowing the switching speed to be optimized for each phase of operation while controlling noise during critical signal transmission periods.
Solution Approach 2:
The patent implements periodic control of the slew rate through different resistance values in the current controlling device during different switching phases. The system alternates between faster slew rates (when noise is less critical) and slower, more controlled slew rates (when noise reduction is prioritized), creating a periodic pattern of switching behavior that balances efficiency and noise reduction.
3Object-generated harmful factors
If a current controlling device is added to regulate slew rate, then noise is reduced, but device complexity is increased
Solution Approach 1:
The patent introduces a current controlling device as an intermediary component between the high-side switch and the gate driver. This intermediary regulates the gate charging/discharging current, thereby controlling the slew rate and reducing noise. The current controlling device acts as a mediator that decouples the direct connection, allowing independent optimization of switching performance and noise reduction.
Solution Approach 2:
The current controlling device changes the electrical parameters of the gate drive circuit by varying the resistance value to control the slew rate. This parameter adjustment approach allows noise reduction without fundamentally changing the circuit topology, thereby limiting the increase in complexity to a single controllable resistance element rather than a complex control system.
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 mechanism effectively reduces noise to a desired level and enhances the power converter's operational efficiency by adjusting the slew rate of voltage waveforms, optimizing performance for various device operations.
Implementation Method 1
The first capacitor has a first terminal and a second terminal. The second terminal of the first capacitor is connected to a node between the second terminal of the high-side switch and the first terminal of the low-side switch
Implementation Method 2
A first terminal of the inductor is connected to the second terminal of the first capacitor
Implementation Method 3
A signal output terminal of the high-side buffer is connected to a control terminal of the high-side switch. An input terminal of the current controlling device is connected to a power output terminal of the high-side buffer
Data Source
AI summary
A power converter having a slew rate controlling mechanism is provided. A first terminal of a high-side switch is coupled to an input voltage. A first terminal of a low-side switch is connected to a second terminal of the high-side switch. A second terminal of a first capacitor is connected to a node between the second terminal of the high-side switch and the first terminal of the low-side switch. A first terminal of an inductor is connected to the second terminal of the first capacitor and to the node. A first terminal of a second capacitor is connected to a second terminal of the inductor. A second terminal of the second capacitor is grounded. An input terminal of a current controlling device is connected to a power output terminal of a high-side buffer. An output terminal of the current controlling device is connected to the node.