Sumitomo Electric Industries, Limited

Toyohashi University of Technology

Tuya Wuren

Nobuo Shiga

Kazuhiro Fujikawa

Takashi Ohira

Kazuyuki Wada

Satoshi Hatsukawa

Takashi Tsuno

Kazuya Ishioka

Kazushi Sawada

Kotaro Tanimura

Provided is a transistor protection circuit capable of appropriately protecting a transistor even when a switching frequency is high. A transistor protection circuit according to an embodiment of the present invention is a transistor protection circuit for protecting a voltage-driven transistor that is switch-controlled by the application of a high-potential-side voltage or low-potential-side voltage of a power supply to a gate terminal of the transistor by a drive circuit. The transistor protection circuit has a power supply controller that gradually lowers the high-potential-side voltage of the power supply upon receiving a protection command for executing protection of the transistor.

Transistor protection circuit

A switching circuitcomprises a connection circuit cascade-connecting control terminals for controlling switching of n number of transistors M-Mn via n&#x2212;1 number of coils Lrespectively (n is an integer equal to or more than 2; and coils Lrespectively connected between one end of each of the transistors M-Mn and other end of a coil L, one end of the coil Lbeing electrically connected to a DC power source. The transistors M-Mn is sequentially switched with PWM signals inputted to an input terminal of the connection circuit. The switching circuitfurther comprises a transistor Minserted at the one end or the other end of the coil Lin cascade-connection.

Switching circuit and envelope signal amplifier

A switching circuit according to one embodiment includes: a switching element that has a first terminal and a second terminal, and is driven by a pulse signal to switch a conduction state between the first and second terminals; a power source section that supplies a voltage to the first terminal; a load circuit that is connected in parallel with the power source section; a passive circuit section that is connected between a connection point between the power source section and the load circuit, and the first terminal, and suppresses a current flowing from the connection point to the switching element at a frequency N times (N is an integer of 1 or more) as high as a clock frequency of the pulse signal; and a resonant circuit section that is connected between the passive circuit section and the connection point, and resonates at the frequency of N times.

Switching circuit

Growing community of inventors

Toyohashi, Japan

Tuya Wuren