Rohm Co., Ltd.

Tatsuya Yanagi

Hirotaka Otake

Hiroyuki Sakairi

Yusuke Nakakohara

Naotaka Kuroda

Takashi Sawada

Seiya Kitagawa

Yohei Nakamura

A power conversion circuit in which a switching transistor and a synchronous rectifier transistor are connected in series, and a source inductance of the switching transistor is smaller than a source inductance of the synchronous rectifier transistor.

Power conversion circuit, power module, converter, and inverter

A method for measuring a current-voltage characteristic (Id-Vds characteristic) representing the relationship between the drain current Id (or collector current) and the drain-source voltage Vds (or collector-emitter voltage) of a transistor Mincludes setting the drain current Id (or collector current) and the drain-source voltage Vds (or collector-emitter voltage), measuring the gate-source voltage Vgs (or gate-emitter voltage) and the gate current Ig of the transistor Min a switching transient state, and acquiring the current-voltage characteristic (Id-Vds characteristic) of the transistor Mbased on the measurement results of the gate-source voltage Vgs (or gate-emitter voltage) and the gate current Ig.

Method for measuring current-voltage characteristic

For example, a method of measuring a device parameter includes: a step of repeatedly measuring the gate-source voltage (or gate-emitter voltage) of a switching element in its switching transient state while switching the external gate resistance for the switching element among m resistance values (where m is an integer of three or more); and a step of, while representing the internal gate resistance and the plateau voltage of the switching element by Rgin and Vp respectively and using the m resistance values of the external gate resistance and corresponding m voltage values of the gate-source voltage (or gate-emitter voltage) as Rg(k) and Vgs(k) respectively (where k=1, 2 . . . m), performing the fitting of the equation Vgs(k)=Rg(k)/(Rg(k)+Rgin)×Vp, thereby to derive the internal gate resistance Rgin or the plateau voltage Vp of the switching element.

Method of measuring a device parameter

A method for measuring current-voltage characteristics representing the relationship between the drain current and the drain-source voltage of a first transistor includes: a first step of setting the drain current and the drain-source voltage using a voltage source and a current source connected in series with the first transistor and a rectifying element connected in parallel with, with the reverse polarity to, an inductive load as the current source; a second step of measuring the gate-source voltage and the gate current in the switching transient state of the first transistor; and a third step of calculating the voltage applied to the gate oxide film of the first transistor using the results of the measurement of the gate-source voltage and the gate current and acquiring the current-voltage characteristics of the first transistor using the result of the calculation. In the first step, during an excitation period in which an excitation current is passed through the inductive load, part of the excitation current is bypassed through a path that does not pass through the first transistor.

Method for measurement of current-voltage characteristics

A gate drive circuit has a capacitor and a gate drive voltage source connected in series with a gate terminal of a voltage-driven switching device. The gate drive source voltage feeds, as a gate drive voltage, a voltage higher than the sum of the voltage applied to a gate-source parasitic capacitance of the switching device when the switching device is in a steady ON state and the voltage applied to, of any circuit component interposed between the gate drive voltage source and the gate terminal of the switching device, a circuit component other than the capacitor (such as an upper transistor forming the output stage of the driver). No other circuit component (such as a resistor connected in parallel with the capacitor) is essential but the capacitor as the sole circuit component to be directly connected to the gate terminal of the switching device.

Gate drive circuit

A method for measuring a current-voltage characteristic (Id&#x2212;Vds characteristic) representing the relationship between the drain current Id (or collector current) and the drain-source voltage Vds (or collector-emitter voltage) of a transistor Mincludes setting the drain current Id (or collector current) and the drain-source voltage Vds (or collector-emitter voltage), measuring the gate-source voltage Vgs (or gate-emitter voltage) and the gate current Ig of the transistor Min a switching transient state, and acquiring the current-voltage characteristic (Id&#x2212;Vds characteristic) of the transistor Mbased on the measurement results of the gate-source voltage Vgs (or gate-emitter voltage) and the gate current Ig.

The power circuit includes: a main substrate; a first electrode pattern disposed on the main substrate and connected to a positive-side power terminal P; a second electrode pattern disposed on a main substrate and connected to a negative-side power terminal N; a third electrode pattern disposed on the main substrate and connected to an output terminal O; a first MISFET Qof which a first drain is disposed on the first electrode pattern; a second MISFET Qof which a second drain is disposed on the third electrode pattern; a first control circuit (DG) connected between a first gate Gand a first source Sof the first MISFET, and configured to control a current path conducted from the first source towards the first gate.

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Kyoto, Japan

Tatsuya Yanagi