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Two-terminal semiconductor overcurrent limiter

Imported: 23 Feb '17 | Published: 22 Oct '02

Kunihito Ohshima, Masaya Shirota, Toshikazu Tezuka

USPTO - Utility Patents

Abstract

A semiconductor overcurrent limiter having input and output terminals includes a depletion type vertical MOSFET, a depletion type lateral MOSFET, and a zener diode. A back gate of the lateral MOSFET is formed in common with a drain electrode of the vertical MOSFET to provide the input terminal, and a gate of the vertical MOSFET is connected to an anode of the zener diode to provide the output terminal. Further, a source electrode of the vertical MOSFET is connected to source and gate electrodes of the lateral MOSFET and a cathode electrode of the zener diode.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate presently preferred embodiments of the invention, and together with the general description given above and the detailed description of the preferred embodiments given below, serve to explain the principles of the invention.

FIG. 1 is a cross-sectional view showing a two-terminal semiconductor overcurrent limiter according to an embodiment of the present invention;

FIG. 2 is an equivalent circuit of the semiconductor overcurrent limiter shown in FIG. 1;

FIG. 3 shows a voltage V

AK-current I

AK characteristic of the semiconductor overcurrent limiter;

FIG. 4 shows a voltage V

AK-current I

AK characteristic of a conventional semiconductor overcurrent limiter; and

FIG. 5 is an equivalent circuit of the conventional semiconductor overcurrent limiter.

Claims

1. A semiconductor overcurrent limiter having first and second terminals comprising

2. The semiconductor overcurrent limiter according to claim 1, wherein said vertical and lateral MOSFETs have a depletion mode.

3. The semiconductor overcurrent limiter according to claim 1, wherein said lateral MOSFET has an on-resistance enough to obtain a voltage drop there across.

4. The semiconductor overcurrent limiter according to claim 1, wherein said vertical MOSFET has a first conductivity type while said lateral MOSFET has a second conductivity type opposite to said first conductivity type.

5. The semiconductor overcurrent limiter according to claim 1, wherein said zener diode has a breakdown voltage lower than that between gate and source regions of said lateral MOSFET.

6. The semiconductor overcurrent limiter according to claim 3, wherein an overcurrent is controlled by a voltage applied to said back gate electrode of said lateral MOSFET.

7. The semiconductor overcurrent limiter according to claim 1, wherein said vertical and lateral MOSFETs are provided in said first surface of said semiconductor substrate, while provided on said second surface thereof is a common electrode including said drain electrode of said vertical MOSFET and said back gate electrode of said lateral MOSFET.

8. A semiconductor overcurrent limiter having first and second terminals consisting essentially of: