Contact us

A new window will open A new window will open

Case 1: Selection of a MOSFET to meet power supply specifications: DC-DC converter
Low-voltage MOSFET, Qoss reduction, low on-resistance, double-sided-cooling package, reducing the size of a DC-DC converter


A new power supply unit with reduced size failed the final test.
Its design was so complicated, finding a solution seemed a hopeless task. And time ticked away...
U-MOSIX-H low-voltage MOSFET series with the industry’s best-in-class trade-off between on-resistance and capacitance*1

Product Overview


Toshiba offers a high-efficiency, low-voltage MOSFET series for DC-DC converter applications with improved Qoss characteristics. Fabricated with the latest Gen-9 process, this MOSFET series helps improve the power supply efficiency.


  • Industry’s best-in-class trade-off between on-resistance and capacitance*1
  • Low on-resistance due to the use of a new process
  • Extensive product lineup, including MOSFETs in thermally enhanced packages

*1 As of November 2017 for MOSFETs with equivalent ratings (as surveyed by Toshiba)

Problem-Solving Examples

Solution for Company B, a power supply unit manufacturer (Employee population: 2,000)


Company B started to develop a new power supply unit, aiming to reduce the size and improve the efficiency of a DC-DC converter. However, the final pre-production test of the new power supply unit revealed that it did not meet the target specifications.
The design team tried to identify the causes, but was having difficulty due to the complexity of its design. Since the power supply unit consists of many parts from different sources, the design team only managed to acquire information about individual parts from their manufacturers. Therefore, the design team did not have the slightest clue as to the matching between devices. After production was put on hold, time just passed away as the design team was unable to find a solution.

Solving the problem using MOSFETs of the low-voltage U-MOSIX-H series


One day, an engineer of Company B asked a distributor for advice. The distributor referred him to an engineer of Toshiba Electronic Devices & Storage Corporation, saying, “Toshiba is good at finding solutions for problems concerning power supply circuits.” Toshiba’s engineer visited Company B to analyze the circuit board in question. As a result, it was found that characteristic matching between devices from different manufacturers and heat dissipation were not working well, causing a decrease in conversion efficiency.
In order to improve conversion efficiency, Toshiba’s engineer recommended using the U-MOSIX-H low-voltage MOSFET series. Designed specifically to improve the Qoss characteristics, the U-MOSIX-H series provides the industry’s best-in-class trade-off between on-resistance and capacitance and therefore delivers high conversion efficiency.
The U-MOSVIII-H and U-MOSIX-H series are available with a wide range of VDSS from 30 V to 250 V. They are also available in double-sided-cooling packages to aid in heat dissipation. Because of their extensive product lineups, there was a device in the U-MOSIX-H series that provides optimal matching with the converter circuit concerned.
Consequently, a prototype of a new power supply unit met the specifications, enabling Company B to proceed with its production.

List of Problem-Solving Examples

Case 2: Selection of a MOSFET to increase the withstand voltage margin: Power supply product

45-V MOSFET, latest MOSFET, development of a low-RDS(ON) and low-Qoss power supply product 

Case 3: Selection of a MOSFET to improve the efficiency of a server power supply

High-voltage MOSFET, super-junction MOSFET, standard switching speed, high switching speed, high-speed diode

Case 4: EMI noise solutions based on the results of simulation

EMI noise problem, documents on the resolution of EMI problems, causes of gate oscillation, maintaining high efficiency, development of a new product

Case 5: Using a photocoupler to solve a problem of an industrial robot caused by overcurrent

Photocoupler for IGBT/MOSFET drive, optical isolation, alleviating an overcurrent problem, design support by specialized engineers

Case 6: Using a solid-state relay to reduce the size and prolong the service life of power supply units for Programmable Logic Controller

Reducing the size of a control relay unit, semiconductor, long service life, board size reduction, countermeasure for the effects of magnetic fields 


If you have any questions, click one of these links:

Technical queries
Questions about purchasing, sampling and IC reliability
To Top
·Before creating and producing designs and using, customers must also refer to and comply with the latest versions of all relevant TOSHIBA information and the instructions for the application that Product will be used with or for.