45-V MOSFET, latest MOSFET, low RDS(ON), low Qoss, power supply development
Voltage surge transients exceeded the available margin.
There seemed no alternative but to place an order for a MOSFET with custom specifications...
45-V devices in the U-MOSIX-H series that meet your requirements for “a little more voltage margin”
U-MOSIX-H series available with five VDSS points: 30 V, 40 V, 45 V, 60 V and 100 V
*1 As of November 2017 for MOSEFTs with equivalent ratings (as surveyed by Toshiba)
*2 QOSS: Output charge
Company F was developing a new power supply product, applying a 20% derating factor to the in-house specification requirements. At first, its design team used typical 40-V MOSFETs for the power supply unit with a 12-V output. The 20% derating means that the maximum allowable voltage for the 40-V MOSFETs is 32 V . An evaluation indicated, however, that the power supply unit could generate voltage surge transients as high as 34 V, i.e., 2 V higher than the maximum allowable voltage.
The design could not be modified in such a manner as to keep surge voltage below 32 V because doing so caused the circuit’s switching speed to become too slow. In contrast, using 60-V MOSFETs, for example, was inconceivable because of high on-resistance. Another alternative was to place an order for a customized MOSFET rated at 43 V, but it was unjustifiable in terms of cost.
Company F faced a tough decision of whether to use standard MOSFETs or order customized MOSFETs.
It was just at that time when F’s engineer heard about Toshiba’s MOSFET from an agent. In addition to 30-V and 40-V MOSFETs, 45-V MOSFETs are available in Toshiba’ latest U-MOSIX-H series.
Toshiba’s 45-V MOSFETs of the U-MOSIX-H series, which have the same size and footprint as 40-V MOSFETs, serve as an easy replacement for 40-V MOSFETs. In addition, the 45-V MOSFETs have an on-resistance, RDS(ON), close to that of the 40-V MOSFETs. Therefore, when derated by 20%, the 45-V MOSFETs tolerate surge transients of up to 36 V.
By using Toshiba’s 45-V MOSFETs of the U-MOSIX-H series, Company F met the customer requirements and managed to deliver a power supply unit to the customer.
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