PROTECTIVE CIRCUITRY FOR ELECTRONIC DEVICE

• US 20090168272A1
• Filed: 08/15/2008
• Published: 07/02/2009
• Est. Priority Date: 12/27/2007
• Status: Active Grant

• Current Assignee: Chi Mei Communication Systems Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Chi Mei Communication Systems Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: CHEN, CHIEN-CHIH
• Granted Patent: US 7,990,670 B2
• Time in Patent Office: Days
• US Class Current: 361/1
• CPC Class Codes: H02H 5/083 responsive to the entry or leakage of a liquid into an electrical appliance moisture alarm G08B21/20
• CPC Class Codes: Y10T 137/189 Soil moisture sensing

Abstract

A protective circuitry (20) is connected between a power input port (11) and an electronic component (12) of an electronic device. The protective circuitry includes a field effect transistor (21) and a detection unit (25). The field effect transistor has a gate and a drain both electrically connected to an anode of the power input port, and a source electrically connected to a cathode of the power input port via the electronic component. The detection unit has two conductive pads spaced to each other. One pad is electrically connected to the gate and the other pad is electrically connected to the cathode of the power input port.

Claims

1. A protective circuitry connected between a power input port and an electronic component of an electronic device, the protective circuitry comprising:

a field effect transistor, the field effect transistor having a gate and a drain both electrically connected to an anode of the power input port, and a source electrically connected to a cathode of the power input port via the electronic component; and

a detection unit, the detection unit having two spaced apart conductive pads, and one pad is electrically connected to the gate and the other pad is electrically connected to the cathode of the power input port.

2. The protective circuitry as claimed in claim 1, further comprising an adjustable resistor, and the adjustable resistor is electrically connected in series between the gate and the anode of the power input port.

3. The protective circuitry as claimed in claim 1, wherein the pads of the detection unit are bar shaped.

4. The protective circuitry as claimed in claim 1, wherein a first pad of the detection unit has a circular portion and a plurality of leaves protruding radially outward from the circular portion, and a second pad has a hole defined therein to receive the first pad.

5. The protective circuitry as claimed in claim 1, wherein a first pad of the detection unit is a toothed strip having a plurality of leaves protruding outwardly from opposite sides thereof, and a second pad has a hole defined therein to receive the first pad.

6. The protective circuitry as claimed in claim 1, wherein the field effect transistor is a metal oxide semiconductor field effect transistor.