A Method for Selection of Power MOSFETs to Minimize Power Dissipation

Abstract

A balance between static and dynamic losses of a power MOSFET is always desirable for accomplishing the maximum efficiency for a specific power converter. The standard semiconductor theory suggests that a minimum power dissipation in a MOSFET can be achieved by selecting a specific device active area. However, for power circuit designers, the active device area is unknown given that only datasheet parameters are available. Hence, in this paper, we propose a simple method, based on semiconductor theory, to select optimum power MOSFET from a family of MOSFETs using only datasheet parameters. By applying this optimization method to the specific power supply circuit under development, power engineers can select the best transistors to yield lowest power losses for the systems under development.

Circuit-Specific and Technology-Independent Criterion for Selection of Power MOSFETs That Minimize Energy Dissipation

“…Regarding the power dissipation due to charging and discharging of the input capacitance, 𝑃 𝑆𝑊−𝐼𝑆𝑆 , we have shown in a recently published paper [2] that this power is independent of the channel width. It should be noted that the external gate resistance and the maximum output current of the driver IC limit the charging and discharging current of 𝐶 𝐼𝑆𝑆 .…”

“…Therefore, the selection of a MOSFET with the optimum channel width depends on specific circuit parameters and switching frequency. Because the circuit designers do not have information about channel width, we have developed and published an approach that selects the most suitable MOSFETs, determined by their on resistance alone [2]. We have also published a figure of merit for the selection of the best family of SiC MOSFETs in terms of device reliability [3].…”

A Comparative Study of Switching Performances and Efficiency of Gan, Sic and Si Based Dc-Dc Converters

“…Balancing these two power losses is crucial in order to achieve higher overall efficiency of the specific power converter. In [12] a method for selecting the optimal power switch for a given dc-dc converter application is presented. The method uses datasheet information for the on-resistance (Ron) and the effective output capacitance (Cо(er)) and is demonstrated using a family of commercial Si and SiC-MOSFETs.…”

A Figure of Merit for Selection of the Best Family of SiC Power MOSFETs

“…The width of the channel (W) is a critical parameter that is not available in the power MOSFET datasheets. It is a well known fact that the R DS(on) of the power MOSFET is inversely proportional to W [16,17,19]. Accordingly, MOSFETs with different R DS(on) values that are in a single family have different W values, whereas all other technological parameters are the same.…”