In high power motor control applications requiring the use of MOSFETs connected in parallel, there is a common request for MOSFETs with matched VGS threshold voltage. However, even with very tightly controlled production facilities there is an inevitable spread in the threshold voltage across the wafer and any effort to provide matched Vt may require special screening and sorting that could result in yield loss, thus affecting the cost of the products supplied. Nexperia have been developing MOSFETs to have improved current sharing capability and when used in parallel removes the need for matching threshold voltages.
Early indications that the parts developed for improved current sharing provide benefit when used in hotswap, linear mode and in motor drive applications. Further optimisations have been identified and will be implemented over the coming months leading to new parts being released with this benefit.
When tested in a parallel motor drive application (Figure 1), beginning with standard design and then optimised parts (3 parts each from the 90th percentile and 1 from the 10th percentile) the findings were very encouraging. The optimised parts achieved close to ideal current sharing (Figure 4) and much better thermal performance (Figure 5) than the standard parts (Figures 2 and 3).
The optimisations for improved current sharing compliments the Superjunction trench technology which gives industry leading linear mode performance. This leads us onto the next innovation in this industry segment.
The 100 V, 120 A Rated PSMN3R7-100BSE is an ideal choice when choosing a MOSFET for use in high current battery powered applications, where there is a requirement to isolate the battery voltage under certain fault conditions. The battery protection MOSFET sometimes has to operate in linear mode until the battery voltage is isolated.
Nexperia has developed parts in several package options which give far superior (up to 6 times better than leading competitors) linear mode performance and high current capability up to 380A, including parts to meet the increased spacing required by the UL2595 standard.
The 100 V portfolio gives low Qrr figure of merit and provides improved EMC performance in motor drive applications. Other parts being developed are the 40V, 425 A rated LFPAK88, half bridge and dual MOSFETs in several voltage ranges.