Transistors|Basic
Confirmation of Suitability in Actual Operation and Preparations
2017.10.12
Points of this article
・In prototyping, it is essential to determine whether a selected transistor can be used in actual operation.
・For purposes of confirmation, the voltages and currents handled by the transistor are measured.

Confirmation of Suitability in Actual Operation
The flowchart shown on the right is an example of judgment to determine whether or not a selected transistor poses problems in actual operation. In the explanation, a switching circuit is assumed, and so in ⑤, “Continuous pulses” is selected.
- ① Measurement of the actual currentand voltage waveforms
- ② Confirmation that absolutemaximum ratings are satisfied
- ③ Confirmation that operation is withinthe SOA (safe operating area)
- ④ Confirmation that operation is withinthe SOA derated at the ambientoperating temperature
- ⑤ Continuous pulses (switching operation)
- ⑥ Confirmation that average powerconsumption is within the rated power
- ⑦ Confirmation of the chip temperature
Although not shown in the chart, as an addition final measure, ⑦, confirmation of the transistor chip temperature, is added.
①Measurement of the actual current and voltage waveforms
When confirming the various parameters described above, first it is necessary to check how the transistor handles voltages and currents in the circuit operation. Here, an example of a switching circuit is used. The transistor is the R6020ENZ, a low-noise super-junction MOSFET in the EN series (600 V, 20 A, 0.17 Ω, TO-3PF).
Specifically, waveform data is captured using an oscilloscope. The following waveform is the overall image of switching operation of the R6020EZN.

In addition to this, enlarged waveform data during on-off transitions is also captured in order to calculate power losses during switching, explained below. Here, we have also captured the waveforms for ID, VDS, VGS, and the power, shown in the waveform graphs. Waveforms during the on and off states, and during transitions between these states, are needed.

Next time, these waveforms will be used to check whether operations is within the maximum rated values.
【Download Documents】 Basics of Si Power Devices
In this handbook, although there are so many types of power devices using Si semiconductors, the basic points are explained, focusing mainly on diodes and transistors for power supply applications. It also introduces the procedure and decision method for transistor selection when designing circuits, as well as application examples that utilize each characteristic and feature.
Transistors
Basic
-
Basics of Transistors
- Transistor Fundamentals: Structure, Types, and Operating Principles
- Bipolar Junction Transistor (BJT) Basics: Operation and Applications (NPN & PNP)
- NPN Transistor: Low-Side Switch Fundamentals
- PNP Transistor: High-Side Switch Fundamentals
- What is a Digital Transistor?
- Digital Transistor Selection
- ON Resistance
- Total Gate Charge
- How to select<Selecting Transistors to Ensure Safe Operation>
- Junction Temperature <Calculating Transistor Chip Temperature>
- What is a Load Switch?
-
Basics of MOSFETs
- What are MOSFETs? – MOSFET Parasitic Capacitance and Its Temperature Characteristic
- What are MOSFETs? – MOSFET Switching Characteristics and Temperature Characteristics
- What are MOSFETs? – MOSFET Threshold Values, ID-VGS Characteristics, and Temperature Characteristics
- What are MOSFETs? – Super-junction MOSFET
- What are MOSFETs? – Types and Features of High Voltage Super-Junction MOSFET
- What are MOSFETs? – Fast trr SJ-MOSFET:PrestoMOS™
- MOSFET Thermal Resistance and Power Dissipation: Packages Capable of Back-Surface Heat Dissipation
- Introduction
-
Confirming the Suitability of a Transistor in Actual Operation – Introduction
- Confirmation of the Chip Temperature
- Confirmation of Suitability in Actual Operation and Preparations
- Confirmation that Absolute Maximum Ratings are Satisfied
- Confirmation that Operation is within the SOA (Safe Operating Area)
- Confirmation that Operation is within the SOA Derated at the Actual Operating Temperature
- Confirmation that Average Power Consumption is within the Rated Power
- Summary
- Summary
Evaluation
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The Importance of the Recovery Characteristics of Primary-side Switching Elements in LLC Converters -Introduction-
- Basic Configuration of an LLC Converter
- Features of LLC Converter Operation
- Basic Operation of LLC Converters
- Importance of MOSFET Recovery Characteristics for Off-Resonance of LLC Converters
- The Importance of the Recovery Characteristics of Primary-side Switching Elements in LLC Converters ーSummaryー
-
The Importance of the Reverse Recovery Characteristics of Switching Elements in Inverter Circuits -Introduction-
- Types of Inverter Circuits and Energization Methods
- Basic Operation of 3-Phase Modulation Inverter Circuits
- Comparison of Losses in a PrestoMOS™ MOSFET and a Standard SJ MOSFET Using Double-Pulse Tests (Actual Measurement Results)
- Comparison of Efficiency of a PrestoMOS™ MOSFET and a Standard SJ MOSFET in a 3-Phase Modulation Inverter Circuit (Simulations)
- The Importance of the Reverse Recovery Characteristics of Switching Elements in Inverter Circuits -Summary-
- Mechanisms of MOSFET Destruction
- About Double-Pulse Tests
-
Improving the Power Conversion Efficiency of Phase Shift Full Bridge Circuits – Introduction
- Basic Configuration of a PSFB Circuit
- Basic Operation of PSFB Circuits
- Guidelines Relating to Operation of Switching Elements Under Light Loading
- Guidelines Relating to Operation of Switching Elements Under Heavy Loading
- Evaluation of Efficiency
- Improving the Power Conversion Efficiency of Phase Shift Full Bridge Circuit – Summary –