Wireless Module Noise Suppression via Frequency Filter
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Solution Overview
Problem
Existing wireless communication modules suffer from noise interference from DC-DC converters, which degrade communication quality due to noise leakage through the ground, especially in compact devices like wireless earphones and IoT devices, where securing a large ground is difficult.
Innovation Solution
A wireless communication module design that includes a DC-DC converter with a switching element, a smoothing capacitor, a bypass capacitor, and a frequency filter inserted in series in specific current paths, sharing the ground with the antenna element, to reduce noise flowing into the antenna via the ground.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a smoothing capacitor is coupled to the output section of a DC-DC converter to reduce noise, then noise over a wide frequency range is reduced, but noise components still flow into the ground and affect the antenna
Solution Approach 1:
The patent extracts the harmful noise components from the ground path by inserting a frequency filter that selectively removes noise in the antenna's operating frequency band. The filter takes out the problematic frequency components before they can reach the antenna through the ground connection.
Solution Approach 2:
The frequency filter acts as an intermediary element inserted in the current path between the switching element and the smoothing capacitor. This mediator selectively blocks noise frequencies while allowing the DC component to pass through to the antenna.
2Area of stationary object
If the ground area is reduced to accommodate compact device design, then device size is reduced, but noise from the DC-DC converter more easily affects the antenna
Solution Approach 1:
The frequency filter serves as an intermediary that protects the antenna from ground-borne noise. By placing the filter in the current path, it creates a selective barrier that blocks noise frequencies regardless of the ground area size, enabling compact designs without sacrificing noise performance.
Solution Approach 2:
The patent applies local quality by introducing a frequency-selective filter at a specific location in the circuit (between the switching element and smoothing capacitor). This localized intervention targets only the problematic frequency components in the ground path without affecting the overall ground structure.
3Object-affected harmful factors
If a frequency filter is inserted in the current path between the switching element and smoothing capacitor, then noise in the antenna operating frequency band is reduced, but device complexity increases
Solution Approach 1:
The frequency filter is introduced as a minimal intermediary element in the current path. Rather than redesigning the entire DC-DC converter or ground structure, a single filter component is inserted to achieve noise attenuation, minimizing the increase in device complexity.
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 frequency filter effectively attenuates noise in the operating frequency band of the antenna, improving communication quality by reducing noise transferred to the antenna element, as demonstrated by evaluation experiments showing lower noise levels when using a ferrite bead as the frequency filter.
Implementation Method 1
a frequency filter inserted in series in at least either a current path between the switching element and the smoothing capacitor or a current path between the bypass capacitor and the switching element and having a stop band that is an operating frequency band of the antenna element
Implementation Method 2
as demonstrated by evaluation experiments showing lower noise levels when using a ferrite bead as the frequency filter
Data Source
AI summary
A power supply circuit includes a switching element coupled in a current path between an input terminal and an output terminal and includes a smoothing capacitor coupled between the output terminal and a ground. A bypass capacitor is coupled between the input terminal and the ground. An antenna element shares the ground with the power supply circuit. A frequency filter having a stop band that is an operating frequency band of the antenna element is inserted in series in at least either a current path between the switching element and the smoothing capacitor or a current path between the bypass capacitor and the switching element. It is possible to suppress deterioration of wireless communication quality due to noise caused in a DC-DC converter.