AN3152

Measurements on the BOOST stage

Doc ID 17056 Rev 1

9/17

3

Measurements on the BOOST stage

Although MDmesh™ power MOSFETs and SiC diodes are used on every stage of the

inverter, the following results derive from the inverter front-end stage called the BOOST

stage. This stage is used as a case study to validate the performance of the fastest power

MOSFETs and diodes available on the market. The basic BOOST configuration is very

similar to other applications like a traditional single switch PFC, as shown in

Figure 2, but in

this case, the input voltage is continuous rather than pulsed. Efficiency is measured in the

worst conditions, which means at the lowest input voltage, so that at full load the input

current is the highest possible. Note that higher-speed commutation leads to higher

efficiency, but at the same time spike voltage and current stimulus on the main switch are

higher also. Therefore finding a good trade-off is recommended. In any case, a 650 V

breakdown voltage keeps the MDmesh™ V within a safe working zone. An STW42N65M5

and an STPSC1006 are used for this stage.

Figure 6 shows the efficiency versus output

With 8.2

Ω, we achieved a di/dt of 1400 A/µs during turn-on, which provides good noise

immunity and low EMI irradiation.

Figure 6.

di/dt = 1400 W

Figure 7 shows the BOOST signals during normal operation at V