Abstract: The object of the invention is to protect a power MOS transistor using a transistor having trench structure from overcurrent and to enhance the reliability. To achieve the object, a power MOS transistor, a transistor for detecting current for detecting the current of the power MOS transistor and generating a detection signal supplied to an external control circuit and devices configuring a protection circuit for detecting the current of the power MOS transistor and inhibiting current by forcedly dropping the gate voltage of the power MOS transistor when current equal to or exceeding a predetermined value flows are provided in the same semiconductor chip.

Abstract: This semiconductor integrated circuit is constituted by any one of a p-channel MOS transistor and an n-channel MOS transistor, and is connected between the control terminal and the common terminal so as to produce predetermined voltage. The comparing circuit is operated in response to a control voltage applied between the control terminal and the common terminal so as to compare the predetermined reference voltage with the current-detected voltage which is obtained from the current detecting circuit. The gate controlling MOS transistor controls a gate voltage of the power MOS transistor based upon the comparison output of the comparing circuit. Then, all of these structural members are formed on the same semiconductor substrate.

Abstract: This semiconductor integrated circuit is constituted by any one of a p-channel MOS transistor and an n-channel MOS transistors and is connected between the control terminal and the common terminal so as to produce predetermined voltage. The comparing circuit is operated in response to a control voltage applied between the control terminal and the common terminal so as to compare the predetermined reference voltage with the current-detected voltage which is obtained from the current detecting circuit. The gate controlling MOS transistor controls a gate voltage of the power MOS transistor based upon the comparison output of the comparing circuit. Then, all of these structural members are formed on the same semiconductor substrate.

Abstract: A power transistor device is provided which has a function of clamping the collector voltage to a stable level for a wide range of temperature variations. In the power transistor device, a plurality of pn junctions are formed to fabricate Zener diodes in the polycrystalline silicon film in the form of rings. The ring configuration of the Zener diodes eliminates an end at the pn junction and prevents the junction surface from being exposed, making it possible to use as a stable Zener voltage the dielectric strength characteristic of the pn junction having a very small temperature coefficient.

Abstract: In a transistor where collector is connected to an inductive load and switching current flows, a Zener diode comprising structure of plural pn-junctions constituted in series form to a polysilicon is provided between collector and base. Further MOSFET is switch-controlled by control voltage formed based on Zener current flowing through the Zener diode, and current path in parallel form to the Zener diode is constituted. Since temperature characteristic coefficient of a Zener diode formed in a polysilicon film is very small, the reverse voltage generated in the inductive load can be set to stable voltage in spite of the temperature variation. Further the MOSFET is provided in parallel form, thereby relatively large ON-resistance value of the Zener diode can be decreased.