Fuji Electric Co., Ltd.

Shigeyuki Takeuchi

Tatsuhiko Fujihira

Shoichi Furuhata

Morio Iwamizu

Kazuhiko Yoshida

Motoi Kudoh

Takashi Kobayashi

Yoshiki Kondo

Provided is a semiconductor device capable of reducing a mounting area. A semiconductor device () includes a semiconductor element () and a control element () arranged on a front surface () of the semiconductor element (). The semiconductor element () includes a semiconductor substrate (SB) including a first region ARand a second region ARadjacent to each other, a first MOS transistor (Tr) provided is the first region (AR), and a second MOS transistor (Tr) provided in the second region (AR). A first drain region () of the first MOS transistor (Tr) is connected to a second drain region () of the second MOS transistor (Tr). The control element () turns on and off the first MOS transistor (Tr) and the second MOS transistor (Tr).

Semiconductor device

A semiconductor device, including a main transistor configured to supply power from a power source to a load, and a current limiting device including a control transistor. The current limiting device is configured to detect that the current flowing from the main transistor is an overcurrent, and to limit the current upon determining that the current is equal to or greater than a current limit value, and an operating voltage of the control transistor is equal to or greater than a current limiting activation voltage. The current limit value is a threshold for determining whether the current is greater than an operating current of the main transistor for the load to operate in a steady state. The current limiting activation voltage is a sum of a correction voltage and a predetermined threshold voltage at the gate of the control transistor when the current rises to the current limit value.

Semiconductor device and current limiting method

A semiconductor apparatus according to aspects of the invention includes a power MOSFET including a main MOSFET and sensing MOSFET's. The main MOSFET and the sensing MOSFET's are formed on a semiconductor substrate, and a sensing MOSFET is selected for changing the sensing ratio and further for confining the sensing ratio variations within a certain narrow range stably from a low main current range to a high main current range. A semiconductor apparatus according to aspects of the invention facilitates reducing the manufacturing costs thereof, obviating the cumbersomeness caused in the use thereof, and confining the sensing ratio variations within a certain narrow range stably.

Semiconductor apparatus

A MOS type semiconductor apparatus is provided which includes a main MOS type semiconductor device, an internal control circuit connected between a control input terminal (G) and a control input port (g) of the main MOS type semiconductor device, and a protecting device connected between the control input terminal (G) and one of output terminals (S) of the apparatus, for protecting the semiconductor device or internal control circuit against overvoltage. The protecting device includes a first branch including a Zener diode (Z ) consisting of a polysilicon layer deposited on an insulating film over the semiconductor substrate, and a second branch including a Zener diode (Z ) formed in a surface layer of the semiconductor substrate, and a diode (Z ) that consists of a polysilicon layer deposited on an insulating film over the semiconductor substrate, and is connected in series with the Zener diode (Z ) in a reverse direction. The first and second branches are connected in parallel with each other.

MOS type semiconductor apparatus

A MOS type semiconductor apparatus is provided which includes a main MOS type semiconductor device, an internal control circuit connected between a control input terminal (G) and a control input port (g) of the main MOS type semiconductor device, and a protecting device connected between the control input terminal (G) and one of output terminals (S) of the apparatus, for protecting the semiconductor device or internal control circuit against overvoltage. The protecting device includes a first branch including a Zener diode (Z,) consisting of a polysilicon layer deposited on an insulating film over the semiconductor substrate, and a second branch including a Zener diode (Z,) formed in a surface layer of the semiconductor substrate, and a diode (Z,) that consists of a polysilicon layer deposited on an insulating film over the semiconductor substrate, and is connected in series with the Zener diode (Z,) in a reverse direction. The first and second branches are connected in parallel with each other.

A circuit is provided in which a voltage due to a minute current is applied to a gate terminal from a collector terminal when a collector voltage is higher than a gate voltage in an operation of current limitation. Thus, an increase in the collector voltage immediately after the operation of current limitation starts serves to boost the gate voltage. The boosted voltage suppress an abrupt increase in the collector voltage. When the collector voltage is reduced by oscillation, the action of boosting the gate voltage is lowered to suppress the reduction of the collector voltage.

Circuit device for igniting internal combustion engine and semiconductor

A MOS type semiconductor device is provided which includes a series Zener diode array for overvoltage protection, which is provided between source regions and an electrode having substantially the same potential as a drain electrode, and a field insulating film on which the series Zener diode array is provided. The thickness T (.mu.m) of the field insulating film is determined as a function of the clamp voltage V.sub.CE (V) of the series Zener diode array, such that the thickness T is held in the range as represented by: T.gtoreq.2.0.times.10.sup.-3 .times.V.sub.CE. The width W.sub.1 (.mu.m) of a portion of a second-conductivity-type isolation well that is close to the field insulating film on which the series Zener diode array is provided, and the width W.sub.2 (.mu.m) of a portion of the second-conductivity-type isolation well that is close to the field insulating film on which the series Zener diode array is not provided, are determined as a function of the clamp voltage V.sub.CE of the series Zener diode array, such that the widths W.sub.1, W.sub.2 are held in respective ranges as represented by: W.sub.1 .gtoreq.0.15 V.sub.CE, and W.sub.2 .gtoreq.0.05 V.sub.CE. By controlling the widths W.sub.1, W.sub.2 to these ranges, respectively, the concentration of current into an end portion of the cell portion of the device can be prevented upon cut-off of current from an inductive load.

Growing community of inventors

Matsumoto, Japan

Shigeyuki Takeuchi