Explosion-proof flashlight power switch is a component that many people tend to ignore. Most explosion-proof flashlight users will not pay special attention to the power switch when purchasing. As an explosion-proof flashlight manufacturer, it is impossible not to ignore flashlight power switches, because the seemingly inconspicuous power switches actually have a lot of mystery. Electromagnetic interference is a headache for many flashlight manufacturers. So let’s see how the TANK007 explosion-proof and strong light flashlight manufacturer solves the electromagnetic interference of LED explosion-proof flashlight power switch.
TANK007 explosion-proof flashlight engineers have summarized three methods to solve electromagnetic interference of power switches after years of exploration: 1) Reduce interference signal sources; 2) Cut off the interference signal propagation channels; 3) Improve anti-interference ability. For this purpose, the corresponding explosion-proof and strong light flashlight switch power supply electromagnetic interference control technology covers circuits, EMI filtering, components, shielding and printed circuit board anti-interference design.
① Reduce interference signal source
to increase inductance and capacitance components. In the existing circuit, the inductor and capacitor are added, and the resonance of the inductor and capacitor are used to reduce du/dt and di/dt during the switching process. The purpose is to make the current rise slower than the voltage of the switching device, thereby eliminating the overlap between voltage and current.
reduces the EMI amplitude. Using the modulation switching frequency fc, the concentrated energy on fc and its harmonics 2fc, 3fc... are dispersed on the surrounding frequency bands, thereby reducing the EMI amplitude at each frequency point. Although reducing the EMI amplitude cannot reduce the total amount of interference, the energy on the FC is dispersed on the baseband of each frequency point, so that each frequency point is within the limit specified by the EMI.
chooses more ideal components: try to choose components with low noise, less conduction and less radiant noise. This is especially true for core components such as diodes and transformers. For diodes with small reverse recovery current and fast recovery time, switches are the most ideal components.
suppress common mode interference: the main idea is to extract the switching voltage waveform of electromagnetic interference from the main circuit and compensate the EMI noise voltage in a completely inverted manner. This compensation voltage is used to balance the original switching voltage.
② Use power line filter to cut off the interference signal
A reasonable and effective switching power supply EMI filter can have a very effective suppression of differential and common mode interference on the power line. This is because the power line filter can filter out the power line interference signal.
③Enhance anti-interference ability
solves electromagnetic interference of power switches on explosion-proof and strong light flashlights mainly by shielding.
