Disarm circuit using semiconductor switch device

Details Disarm circuit using semiconductor switch device Disarm circuit using semiconductor switch device

2001-05-15

2003-09-30

Nguyen, Matthew V. (Department: 2836)

Electricity: electrical systems and devices

Safety and protection of systems and devices

With specific current responsive fault sensor

C361S232000

Reexamination Certificate

active

06628492

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a disarm circuit using a semiconductor switch device, particularly relates to a disarm circuit using a semiconductor switch device used for an electrotherapy apparatus for defibrillation.
2. Related Art
An arrhythmia, particularly ventricular fibrillation in the heart of a patient having cardiac disease suddenly kills the patient. To terminate the fibrillation, an electrotherapy apparatus for terminating the fibrillation by applying a shock by an electric pulse to the heart of the patient (also called a defibrillator) is generally used.
Such an electrotherapy apparatus is provided with an electric energy storage section that generates a high-voltage electric pulse such as a capacitor. A method of forcedly discharging high-voltage electric energy left inside the electrotherapy apparatus (the electric energy storage section) after the electrotherapy apparatus is used to secure safety has been considered.
For one method, there is a method of providing a disarm circuit using a semiconductor switch device.
Referring to the drawings, a method of discharging by a disarm circuit using a semiconductor switch in a conventional type electrotherapy apparatus will be described below.
FIG. 7
is a schematic drawing for explaining a method of disarming by the disarm circuit using the semiconductor switch in the conventional type electrotherapy apparatus.
As shown in
FIG. 7
, the on-off control of the semiconductor switch
201
is performed by a semiconductor switch driving section
203
controlled according to a control signal
206
from a microprocessor
202
.
A resistor for disarming
205
is inserted between an electric energy storage section (a capacitor)
204
for storing high-voltage electric energy and the semiconductor switch
201
, current flows to a ground terminal
208
via the resistor for disarming
205
by turning on the semiconductor switch
201
and electric energy is disarmed.
However, the method of discharging by the disarm circuit using the semiconductor switch in the conventional type electrotherapy apparatus has the following problems.
The semiconductor switch
201
is controlled by the semiconductor switch driving section
203
controlled according to a control signal from the microprocessor
202
and therefore, when the control of the semiconductor switch
201
is disabled due to the unexpected cutoff of power supply by the disconnection of a battery and others and some failure of the apparatus such as the single fault of a control circuit, the semiconductor switch
201
is turned off and energy stored in the electric energy storage section
204
is not disarmed.
Therefore, the method of disarming by the disarm circuit using the semiconductor switch in the conventional type electrotherapy apparatus has a problem of safety that in case the control of the switch is disabled because of some cause, high-voltage electric energy remains in the circuit undischarged and when the electrotherapy apparatus is operated or repaired, an operator or a repairman may get electric shock.
SUMMARY OF THE INVENTION
The invention is made to solve the problem of the related art and the object is to provide a disarm circuit using a semiconductor switch device wherein the safety of an electrotherapy apparatus can be secured by disarming even if the control of a semiconductor switch is disabled because of some cause.
To achieve the object, a disarm circuit using a semiconductor switch device according to a first aspect is based upon A disarm circuit comprising a semiconductor switch device discharging electric energy stored in an electric energy storage section by turning on the semiconductor switch device according to a control signal from a control circuit via a first resistor for disarming provided between one terminal of the electric energy storage section and a first terminal of the semiconductor switch device; and
a second resistor for limiting current which flows from one terminal of the electric energy storage section and for transmitting the current to a control terminal of the semiconductor switch device, the second resistor being provided between one terminal of the electric energy storage section and the control terminal of the semiconductor switch device, electric energy stored in the electric energy storage section automatically turns on the semiconductor switch device and is discharged via the resistor for disarming in case the control of the semiconductor switch is disabled because of some cause when the electric energy storage section is disarmed.
As a disarm circuit using a semiconductor switch device according to a second aspect is formed so that a transformer is at least provided, a primary side area controlling current on the primary side of the transformer according to a control signal for controlling the semiconductor switch device, the primary area being provided on the primary side of the transformer;
a secondary side area directly driving the semiconductor switch device, the secondary side area being provided on the secondary side of the transformer,
wherein the primary side area receives a control signal, transmits power for controlling the semiconductor switch device to the secondary side area and inhibits back electromotive force caused when current that flows on a primary winding of the transformer is cut off, back electromotive force caused when current flowing in the transformer is cut off is inhibited.
As the secondary side area in a disarm circuit using a semiconductor switch device according to a third aspect is formed so that the secondary side area receives power supplied from the primary side area, transmits power for controlling the semiconductor switch device to the semiconductor switch and cuts off voltage caused by back electromotive force caused when current that flows on a primary winding of the transformer is cut off so that impedance is lower, compared with the second resistor, the control according to a control signal of the semiconductor switch device is also preceded in a state in which electric energy is stored in an electric energy storage section.
As in the secondary side area in a disarm circuit using a semiconductor switch device according to a fourth aspect, a terminal at one end of a secondary winding of the transformer is connected to a first Zener diode, a second Zener diode such that the same kind terminals of the first and second Zener diodes are connected with the same terminals face to face is connected to a control terminal of the semiconductor switch device via a resistor, a terminal at the other end of the secondary winding of the transformer is connected to a second terminal of the semiconductor switch device and a capacitor is connected between the second Zener diode and the second terminal of the semiconductor switch device, the secondary side area receives power supplied from the primary side area and transmits power for control to the semiconductor switch device.
As in a disarm circuit according to a fifth aspect the plural semiconductor switch devices are provided, the withstand voltage against the application of high voltage has a value acquired by adding the withstand voltage of the switch device of each stage.
As in a disarm circuit according to a sixth aspect, each second resistor for limiting current is connected between one terminal of the electric energy storage section and the control terminal of each semiconductor switch device.
As in a disarm circuit according to a seventh aspect, each third resistor for equalizing the characteristic of each semiconductor switch devices is connected between a first terminal and a second terminal of each semiconductor switch device.
As in a disarm circuit according to an eighth aspect, the second resistor for limiting current for a first stage is connected between one terminal of the electric energy storage section and a control terminal of a semiconductor switch device of the first stage and the second resistor for limiting current for a second or the subsequent stage is connected between a sec

Affiliated with

Also associated with

Rating

Disarm circuit using semiconductor switch device does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Disarm circuit using semiconductor switch device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Disarm circuit using semiconductor switch device will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3058300