PWM Control Circuit for Non-Simultaneous Switching Noise Reduction
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Solution Overview
Problem
Conventional pulse signal amplification using switching amplifiers often results in noise due to simultaneous switching of switching elements, which requires additional circuitry to phase-shift pulse signals, increasing circuit complexity and cost.
Innovation Solution
A control circuit with a data replacement section that modifies control data to ensure pulse signals have different edge timings, preventing simultaneous switching, comprising a control data output section, a data replacement section, a pulse width modulation circuit, and a pair of switching amplifiers, which modulate and amplify the pulse signals to achieve approximately the same pulse width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If pulse signals with different phases are used to avoid simultaneous switching, then noise is reduced, but circuit scale and costs increase due to additional phase-shifting circuits
Solution Approach 1:
The patent extracts the phase-differentiation function from separate hardware circuits and implements it through data processing in the PWM circuit. By removing the need for physical phase-shifting circuits and using control data manipulation instead, the invention reduces circuit scale while maintaining the noise-reduction effect of differential switching.
Solution Approach 2:
The patent replaces the mechanical/analog approach of using physical phase-shifting circuits with a digital/data-based approach. The PWM circuit uses control data processing to achieve phase differentiation, substituting hardware complexity with software/algorithmic solutions.
2Object-affected harmful factors
If pulse signals with different phases are used to avoid simultaneous switching, then noise is reduced, but costs increase due to additional circuits
Solution Approach 1:
The patent removes the need for expensive additional phase-shifting circuits by extracting the phase-differentiation function and implementing it through data processing. This eliminates the need to manufacture and assemble extra hardware components, directly reducing production costs.
Solution Approach 2:
The patent uses inexpensive control data manipulation instead of expensive physical circuits. The data-based phase differentiation approach is cheaper to implement and manufacture compared to additional analog phase-shifting hardware.
3Object-affected harmful factors
If control data is modified to prevent simultaneous switching, then noise is reduced, but pulse width modulation precision may be affected
Solution Approach 1:
The patent employs feedback mechanisms within the PWM circuit to monitor and adjust control data modifications. By using feedback control, the system can detect when control data modification affects pulse width precision and make real-time corrections, maintaining both noise reduction and modulation precision.
Solution Approach 2:
The patent carefully manages parameter changes in control data to achieve phase differentiation while minimizing impact on pulse width precision. By controlling the magnitude and nature of data modifications, the system maintains adequate modulation precision while still preventing simultaneous switching.
Data Source
AI summary
Noise caused by switching is reduced using a simple configuration in a circuit amplifying a pulse signal using a switching amplifier. A control data output section outputs control data that instructs that a pulse width of each of a pair of pulse signals be modulated. A data replacement section replaces the control data with data for replacement different from the control data in the case where the control data is output that instructs that the modulation leading to approximately a same pulse width for the pair of pulse signals be performed. A pulse width modulation circuit performs the modulation on each of the pair of pulse signals in accordance with the data for replacement. A pair of switching amplifiers amplify the pair of pulse signals that have been subjected to the modulation.