At present, the design of module power supply is becoming more standardized, the control circuit tends to adopt digital control mode, and the non-isolated DC-DC converter (including VRM) grows faster than the isolated one. With the improvement of semiconductor technology and packaging technology, a large number of applications of high-frequency soft-switching technology, the higher the power density of the module power supply, the higher the power conversion efficiency of the module power supply, the smaller the volume, the chip appears. Level module power supply. Module power supplies are commonly used in communication equipment, access equipment, mobile communications, microwave communications, optical communications, routers and other communications, automotive electronics, aerospace and so on. It features power for application specific integrated circuits (ASICs), digital signal processors (DSPs), microprocessors, memories, field programmable gate arrays (FPGAs), and other digital or analog loads. The noise test of the module power supply is mainly divided into three points, as follows: 1. Test conditions: module power supply AC input voltage 220V, output full load (for multiple output, each channel is fully loaded) (The AC input voltage can be set to 90V, 220V, 265V, as required, and tested under full load output conditions). 2, test method: When testing, the oscilloscope TIME/DIV file is set to 10uS/div, the bandwidth is set to 20MHz, and the peak-to-peak value of the output voltage displayed by the oscilloscope is the output ripple voltage (the peak-to-peak value including the glitch is ripple) + noise). 1) The input voltage of the module power supply is adjusted to the nominal voltage, and the output current is adjusted to the rated current. 2) Module power supply ripple is usually expressed in peak-to-peak. The main test method. Module power supply ripple and noise are AC components superimposed on the DC output voltage. Ripple and noise are measured at rated load and ambient temperature. For a switched AC/DC module power supply, the output ripple voltage is a small pulse of a system with high frequency components, so the peak-to-peak value is usually measured instead of the effective value (RMS). Its measured value is expressed in millivolt peak-to-peak (mVp-p). For example, when the ripple peak-to-peak value of an AC/DC module power supply is 50mV, the RMS value is very low, only 5mV, but whether it can be used in a certain system must be further considered. Because of the high frequency components contained in the measured ripple, special measurement techniques must be used to obtain the correct measurement results. To measure all high frequency harmonics in the ripple spike, an oscilloscope with a 20MHz bandwidth is typically used. Secondly, when performing ripple measurements, great care must be taken to prevent false signals from being introduced into the test equipment. The probe ground clamp must be removed during measurement because in a high frequency radiation field, the ground clamp will accept noise like an antenna and interfere with the measurement. Use a measurement method with a probe with a grounding ring to eliminate interference. A method of measuring the ripple output voltage of a module's power supply using a 50Ω coaxial cable. The coaxial cable is directly connected to the oscilloscope. To reduce noise, an aluminum or copper grounding plate should be used for the measurement. The measured value is 1/2 of the actual value. It is another measurement method using double lines. Place the module power supply at a location 25 mm above the ground plane. The ground plane consists of aluminum or copper. The output common terminal of the module power supply and the AC input ground are directly connected to the grounding plate. The grounding wire should be thick and not longer than 50mm. Use a 16AWG copper wire to make a 300mm long twisted pair, one end connected to the power supply output, the other end connected in parallel with a 47μF tantalum capacitor, and then connected to the oscilloscope. The leads of the capacitor should be as short as possible, and the polarity should not be reversed. The “ground†of the oscilloscope probe should be connected to the ground loop as much as possible. The oscilloscope bandwidth should be no less than 50MHz, and the oscilloscope itself should be grounded. 3, output noise test (select the test content, divided into peak-to-peak noise, telephone weight noise, broadband noise, discrete noise). At present, the main suppliers of module power supply in the domestic market are VICOR, ASTEC, LAMBDA, ERICCSON and POWER-ONE. Since the types, series and specifications of module power supplies produced by various companies are difficult to count, their functional characteristics and physical characteristics are not The same is true, so there are also differences in installation, use and maintenance. With the extensive use of semiconductor technology, packaging technology and high-frequency soft switching, the module power supply density is getting larger and larger, the conversion efficiency is getting higher and higher, and the application is also It's getting simpler. Led Photo Clip Remote String Lights, 100 LEDs Fairy Twinkle String Lights, Wedding Party Home Decor Lights for Hanging Photos, Cards and Artwork (44 Feet, Warm White) DECORATE ANYWHERE - Portable string lights with infinite possibilities. It can be used outdoors, just be sure to protect the USB cord/port from rain/snow/etc. if you choose to put the lights outdoors. This is a SIMPLE AND ELEGANT way to take your room to the next level. 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