Explore the use cases and end application benefits offered by ON Semiconductor’s expanded range of wide bandgap (WBG) devices, the 1200 V and 900 V N-channel Sic MOSFETs, in this article by Brandon Becker, ON Semiconductor’s Product Line Manager of Wide Band Gap.
ON Semiconductor has expanded their range of wide bandgap (WBG) devices with the introduction of two new families: 1200 V and 900 V N-channel SiC MOSFETs. Let’s take a closer look at the use cases and the end applications that benefit the most from these new SiC solutions with a question and answer session with ON Semiconductor’s experts.
Q: What is the major characteristic of the NTHL020N120SC1, SiC Carbide MOSFET, N‐Channel, 1200 V, 20 mΩ?
A: The NTHL020N120SC1 was designed to provide extremely low conduction losses with a blocking voltage (VDSS) of 1200V. In addition, it was designed to drive fast with low internal gate resistance (Rg = 1.81Ω) and low output capacitance (Coss = 260pF).Q: Compared to existing ON Semiconductor SiC MOSFETs (prior to releasing the NTHL020N120SC1), what characteristics were improved in the NTHL020N120SC1?
A: This is ON Semiconductor’s first generation of SiC MOSFETs so it can’t be compared to previous devices. However, these devices have some advantages over other devices on the market – strong oxide performance (VGS rating +25V/-15V), no Vth drift, no body diode drift, high switching speed, smooth gate drive with dv/dt control and strong body diode for hard switching.Q: What are competitive specs the NTHL020N120SC1 offers?
A: The 1200V SiC MOSFET devices are very competitive in the market, meeting or beating most customer specs. Each application cares about different parameters, but in general, it was designed to operate quickly, reducing switching and conduction losses. This was done by achieving a low RDSon, as well as choosing a low internal gate resistor for fast switching. The devices are designed to be rugged with fast transient immunity capable of over 100V/ns.
Q: What are the advantages of SiC?
A: The advantage of SiC starts in the material itself having a 10x higher dielectric breakdown field strength, 2x higher electron saturation velocity, 3x higher energy bad gap and 3x higher thermal conductivity than Silicon. System benefits offer the highest efficiency by lowering power loss, greater power density, higher operating frequency, increased temperature operation, reduced EMI and most importantly, reduced system size and cost.
End Applications
Q: What is an end application that will fully utilize the major characteristic of the NTHL020N120SC1?
A: A wide variety of end applications will benefit significantly by reducing BOM content as well as increasing power density. Two specific applications where this is evident is in solar power inverters as well as electric vehicle (EV) charging stations.
Q: Why does the SiC MOSFET product especially benefit solar power inverters and electric vehicle charging stations? Do those applications have strong requirements of size/form factor? If so, could you please tell us the background or needs?
A: Traditionally most PFC stages are complex, have limited frequency and have never achieved more than 98% efficiency. Using SiC allows fewer components (less complex), smaller passives, better cooling, as well as greater than 98% efficiency.
Q: Is there a great demand for smaller solar power inverters and charging stations? And if so, what are the reason?
A: Yes.
Solar Inverters
There are currently two trends in the solar inverters market space. ON Semiconductor has an estimated 30% share of the market TAM.
1) Multiple small inverters < 20kW for each row of panels that convert the DC to AC and then feed into a big megawatt inverter
1. The small < 20kW inverters typically are moving to discrete SiC for the PCF stage. For LLC it is a mix of SJ and SiC depending on the timeline, cost and efficiency targets.
2. If the customer moves to SiC, there are many advantages but the gate drive voltage is higher so that is a drawback the circuit has to be re-designed.
2) A few larger inverters > 20kW that take multiple rows of panels and don’t feed into a bigger one
1. The bigger inverters > 20kW are typically using power modules.
2. Previously these were IGBT modules, then it moved to hybrid modules the last 5 years (IGBT + SiC Diode), now we are seeing SiC MOSFET modules being used.
Charging Stations
Charging stations have four levels of power. Levels 1 and 2 are 1/3 phase AC chargers. These chargers do not use SiC and use a car’s OBC to charge the battery. Levels 3 and 4 are higher power and use AC/DC on the charging pole, so when you connect to a car it charges the battery directly.
In addition, these 3 “market” segments within charging stations are classified as the following:
1) Residential – level 1 or 2 charger
2) Commercial – level 2 or 3 (mall, work, somewhere the car is parked for a bit)
3) Highway – level 3 or 4 (this is where SiC will be used)
In general, the charging market in especially high power is still developing. Here we see a majority of it being power modules due to the high power, but there are some discrete on the LLC or secondary rectification stage.