Fuji Electric Co., Ltd.

Fuji Electric Device Technology Co., Ltd.

Fuji Electric Systems Co. Ltd.

Shin Kiuchi

Kazuhiko Yoshida

Shoichi Furuhata

Takeshi Ichimura

Naoki Yaezawa

Tatsuhiko Fujihira

Yuichi Harada

Yukio Yano

Kazunori Oyabe

Yoshiaki Minoya

Tetsuhiro Morimoto

Hiroshi Tobisaka

Ryu Saitou

Shouichi Furuhata

A composite integrated semiconductor device. In one embodiment, an input surge/noise absorbing circuit absorbs surge from an input signal, an attenuating circuit attenuates the input signal, and an electrical signal converting circuit converts the input signal to an output signal. The input surge/noise absorbing circuit, the attenuating circuit, and the electrical signal converting circuit together form a unit, and a plurality of these units are arranged in parallel in one semiconductor substrate to form the composite integrated semiconductor device, resulting in a reduction in the number of discrete components mounted on a printed circuit board.

Composite integrated semiconductor device

A semiconductor device in includes a transistor and a surge absorption element such as Zener diode, that are formed on the same substrate and connected in parallel. The surge absorption element has a resistance during breakdown operation that is smaller than the resistance of the surge absorption element during breakdown operation of the transistor. In addition, the secondary breakdown current of the surge absorption element is larger than the secondary breakdown current of the transistor. Upon application of a high ESD voltage and high surge voltage, the energy of the ESD and surge is absorbed by operation of the surge absorption element and is limited to a voltage equal to or less than the breakdown voltage of the transistor, which would otherwise be destroyed.

Semiconductor device having transistor with high electro-static discharge capability and high noise capability

A composite integrated semiconductor device. In one embodiment, an input surge/noise absorbing circuit absorbs surge from an input signal, an attenuating/level-shifting circuit attenuates or level-shifts the input signal, and an electrical signal converting circuit converts the input signal to an output signal. The input surge/noise absorbing circuit, the attenuating or level-shifting circuit, and the electrical signal converting circuit together form a unit, and a plurality of these units are arranged in parallel in one semiconductor substrate to form the composite integrated semiconductor device, resulting in a reduction in the number of discrete components mounted on a printed circuit board.

The disclosed invention is designed to prevent the oscillation which often occurs in an over-current protection apparatus for an insulated gate controlled transistor. The apparatus improves the response in current detection, to prevent oscillation, and improves protection speed against over-current. This is accomplished by separating the gates of the main transistor and the current detector transistor; by setting a shorter time constant for the gate circuit of the current detector transistor than that of the gate circuit of the main transistor; by feeding the detection signal obtained from the current detecting means which detects the current i of the current detector transistor proportional to the current I flowing through the main transistor, to the control means; and by controlling the gate potentials of both transistors to protect the main transistor from the over-current by feeding the comparison output Sd from the comparator circuit, which compares the voltage of the signal Vd with the reference voltage Vr, to the control circuit.

Over-current protection apparatus for transistor

A current detecting device of the invention has a temperature compensating function used for a current limiting device. A sensing resistance and a reference voltage source are connected to a comparison device. A compensating device, such as semiconductor element, is inserted in series into the reference voltage source in a voltage source circuit for supplying a reference voltage to compensate a temperature dependency of the sensing resistance. Temperature dependency of the reference voltage is a negative temperature dependency in the forward voltage drop. The manufacturing process of the current detecting device becomes simple.

Current detecting device with temperature compensating device

Growing community of inventors

Nagano, Japan

Shin Kiuchi