Murata Electronics Noise Suppression for Rapid Charging

The noise generated from rapid charging emits patterns and cables on the substrate into the air, interfering with the wireless reception antenna and reducing reception sensitivity, range, and speed, reducing device performance.

1. Noise is transmitted through the DC-DC converter output line
2. Noise is transmitted to the substrate ground from the power supply line through the smoothing capacitor
3. Noise transmitted to the substrate ground radiates from the pattern and reduces reception sensitivity

Proposal for Noise Suppression

Ferrites with a high rated current can be inserted into the output and input section of the DC-DC converter. The recommended filter is the BLE18PS series that supports up to 8A and achieves high impedance up to the GHz band, while the BLE18PK series supports rated currents from 5A to 6A.

The effect of noise suppression by ferrite beads has been confirmed using an actual device. Ferrite bead BLE18PS080SN1 was inserted before the smoothing capacitor.

The comparison of the sensitivity during rapid charging before and after the insertion of a filter shows an improvement in the reception sensitivity at the 700MHz to 900MHz range of the LTE low band. 

A noise visualization tool was used to check that the noise level distributed on the substrate has been reduced. 

Due to concern about the impact on the efficiency of the DC-DC converters, the possibility of the impact was checked. According to the results, there was no change in efficiency before and after the insertion of a filter, ensuring no negative effect on efficiency and performance.

Noise Filter Introduction

The BLE18Px noise filter features a compact design, supports large currents from 5A to 8A, and is capable of handling noise in the GHz band. This filter has a high self-resonant frequency due to the construction of the internal structure.

COMMUNITY FORUM

Murata Community Forum provides searchable content with various discussion topics, popular blogs, and articles. The Murata broad market support team holds regular reviews to discuss open issues, allowing inquiries to be answered in a timely manner. The forum content is freely accessible to the public. However, users must log in to post questions or answers. Registration is free of charge.