Prekidač način rada napajanje napajanje mjerenje metoda s digitalni osciloskop
U redoslijedu točno mjerenje napajanje napajanje prebacivanje uređaji, to je potrebno za prvo izmjeriti isključeno i uključeno napone. Međutim, dinamički raspon od a tipično 8-bit digitalno osciloskop nije ne dovoljno za točno hvatanje oboje milivolt razina signali tijekom uključivanje razdoblje i visoki naponi tijekom skretanje isključivanje period u u istom akviziciji ciklusu. Za hvatanje ovo signal, vertikalno raspon osciloskopa treba biti postavljeno na 100 volti po podjeli. Is ovo postavka, osciloskop može prihvatiti naponi do do 1000V, dopuštajući za akviziciju od 700V signali bez preopterećenja osciloskop. Problem s korištenje ove postavke je to to maksimalna osjetljivost ( minimum signal amplituda to može biti riješeno) je postao 1000/256, koji je približno 4V.
To use a digital oscilloscope for power measurement, it is necessary to measure the voltage and current between the drain and source of MOSFET switching devices (as shown in Figure 2), or the voltage between the collector and emitter of IGBT. This task requires two different probes: a high-voltage differential probe and a current probe. The latter is usually a non insertable Hall effect probe. These two probes each have their own unique transmission delay. The difference between these two delays (known as time deviation) can result in inaccurate amplitude measurements and time related measurements. It is important to understand the impact of probe transmission delay on the measurement of maximum peak power and area. After all, power is the product of voltage and current. If two multiplied variables are not properly corrected, the result will be incorrect. When the probe is not correctly calibrated for time deviation, the accuracy of measurements such as switch losses will be affected.
Actual oscilloscope screen diagram showing the impact of probe delay. It uses differential probes and current probes connected to the DUT. Voltage and current signals are provided through calibration fixtures. Figure 6 illustrates the time delay between the voltage probe and the current probe, while Figure 7 shows the measurement results obtained without correcting the time delay of both probes (6.059mW). Figure 8 shows the effect of correcting probe delay. The overlap of two reference curves indicates that the delay has been compensated for. The measurement results in Figure 9 indicate the importance of correctly correcting time delays. This example demonstrates that time delay introduces a measurement error of 6%. Accurately correcting the time delay reduces the measurement error of peak to peak power loss.
Neki snaga mjerenje softver mogu automatski ispraviti vrijeme odstupanje odabrana sonda kombinacija. Softver kontrole osciloskop i podešava kašnjenje između napona i struje kanala kroz stvarno vrijeme struja i napon signali za eliminaciju razlike u prijenosu kašnjenje između napona i struje sonde.
A statička korekcija vrijeme odstupanje funkcija može također biti korištena, pod uvjetom da specifična napon i struja sonde imaju konstantno i ponovljivo prijenos kašnjenja. Funkcija statička korekcija vrijeme odstupanje automatski podešava kašnjenje između odabrani napon i struja kanali za odabrana sonda temeljena na a ugrađena prijenos raspored. Ova tehnologija pruža brza i praktična metoda za minimiziranje vrijeme odstupanja.
