CN216819697U - Circuit for reducing residual voltage and medical equipment - Google Patents

Abstract

The utility model discloses a circuit for reducing residual voltage and medical equipment. It is including setting up the step-down circuit between wave filter and switching power supply, the step-down circuit includes first resistance, second resistance and third resistance, the live wire output and the zero line output of wave filter are connected respectively to first resistance both ends, ground wire is connected to the live wire output of wave filter, the other end of second resistance one end connection, ground wire is connected to the zero line output of wave filter, the other end of third resistance one end connection. The utility model respectively arranges the resistor structures between the lines between the equipment plug and the power supply network, when the equipment plug and the power supply network are disconnected, a path is formed between the lines through the three resistor structures to consume the residual current of the energy storage element in the circuit, so that the current is reduced, the voltage is rapidly reduced, the purpose of reducing the residual voltage is achieved, and the abnormal influence of the residual voltage on the electrical safety items of the medical equipment can be effectively avoided.

Description

Circuit for reducing residual voltage and medical equipment

Technical Field

The utility model belongs to the technical field of electrical safety, and particularly relates to a circuit for reducing residual voltage and medical equipment.

Background

Medical device electrical safety code standard GB9706.01-2007/IEC 60601-1: 1988, the equipment connected to the mains supply by the plug within the limits of voltage and/or energy should be designed so that the voltage between the power pins and between each power pin and the housing does not exceed 60V 1s after the plug has been disconnected.

At present, the residual voltage of medical equipment with a switching power supply exceeds the standard, and finally, the medical equipment is sent to various large medical instruments to be detected, so that the problems occur, and if a circuit is added, the previous detected items can be rechecked, so that the problems are not paid.

Since the medical equipment is a life-related equipment for the patient and the user, if the residual voltage is too high, the user may get an electric shock if the user touches the pins of the plug after pulling the plug, because the operator may get an electric shock inadvertently.

The medical equipment and equipment is forced to implement GB9706.01-2007/IEC 60601-1: 1988 standard, that is to say that the medical instrument device must reduce the residual voltage to not more than 60V before detection.

The residual voltage in the voltage and/or energy limitation is not more than 60V, namely the voltage between each power supply plug-in and between each power supply pin and the metal grounding shell is not more than 60V, L and N, L and ground, N and ground, L and the metal grounding shell, N and the metal grounding shell respectively, and the 5 groups of residual voltages are not more than 60V.

To ensure that the medical device meets the electrical safety code standard, a circuit for reducing the residual voltage is needed to reduce the residual voltage without having an abnormal effect on other electrical safety items of the medical device.

Therefore, it is an urgent technical problem to be solved by those skilled in the art to design a small-sized modular circuit for reducing the residual voltage without causing abnormal influence on other electrical safety of the device, or to embed in a switching power supply, or to embed in a filter.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the defects of the background technology, and provides the circuit medical equipment for reducing the residual voltage, which can quickly and effectively reduce the residual voltage and avoid the influence on the electrical safety of the medical equipment.

The technical scheme adopted by the utility model is as follows: the utility model provides a reduce residual voltage's circuit, is including setting up the step-down circuit between wave filter and switching power supply, the step-down circuit includes first resistance, second resistance and third resistance, the live wire output and the zero line output of wave filter are connected respectively to first resistance both ends, the ground wire is connected to the live wire output of wave filter, the other end of second resistance one end connection, the ground wire is connected to the zero line output of wave filter, the other end of third resistance one end connection.

Further, the first resistor comprises a plurality of shunt resistors connected in parallel.

Further, the resistance values of the plurality of partial resistors are the same.

Furthermore, the resistance value of the first resistor is 300k omega-1000 k omega, and the power is 4.5W-10W.

Furthermore, the resistance value of the second resistor is 2.2-20M omega, and the power is 0.15-3W.

Furthermore, the third resistor has the resistance value of 2.2M omega-20M omega and the power of 0.15W-3W.

Further, the filter is an EMC filter circuit.

Furthermore, the switch power supply is an AC/DC power supply module.

A medical device apparatus comprising an apparatus plug, characterized in that: one end of the equipment plug connected with a power supply network is provided with the circuit for reducing the residual voltage.

The resistance structure is arranged between the equipment plug and the line between the power supply network, when the equipment plug is disconnected with the power supply network, the three resistance structures form a path between the lines to consume the residual current of the energy storage element in the circuit, so that the current is reduced, the voltage is rapidly reduced, and the purpose of reducing the residual voltage is achieved. The scheme is simple, convenient to realize and capable of effectively avoiding the influence of abnormal residual voltage on the electrical safety items of the medical apparatus.

Drawings

FIG. 1 is a schematic diagram of a circuit for reducing remnant voltage according to the present invention.

FIG. 2 is a schematic diagram of a voltage drop of a circuit without applying a reduced remnant voltage.

FIG. 3 is a voltage drop diagram of the circuit with the addition of the remnant voltage reduction of the present invention.

Detailed Description

The following further describes embodiments of the present invention with reference to the drawings. It should be noted that the description of the embodiments is provided to help understanding of the present invention, but the present invention is not limited thereto. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

When the equipment plug is disconnected with a power supply network, due to the fact that a large number of energy storage elements such as capacitors and inductors exist in a switching power supply, a main board, a driving board and a display screen in a circuit, the equipment plug is not changed from 220V alternating current commercial power to 0V alternating current immediately after power failure, and a linear change process exists, and for medical equipment, the linear change process is that the voltage between power pins and the voltage between each power pin and a shell does not exceed 60V when the equipment plug is disconnected with the power supply network for 1S. In order to achieve the purpose, the present invention provides a circuit for reducing residual voltage, as shown in fig. 1, including a voltage-reducing circuit arranged between a filter and a switching power supply, where the voltage-reducing circuit includes a first resistor, a second resistor R4 and a third resistor R5, two ends of the first resistor are respectively connected to a live wire output end and a null wire output end of the filter, one end of the second resistor R4 is connected to a live wire output end (i.e., L ') of the filter, the other end is connected to a ground wire, one end of the third resistor R5 is connected to a null wire output end (i.e., N') of the filter, the other end is connected to the ground wire, and the filter is used for blocking input interference signals of the live wire L, the null wire N and the ground wire outside the input end to form an anti-interference circuit; the switching power supply is used for converting the filtered alternating current into direct current for the use of a subsequent direct current load.

In the above scheme, the first resistor includes a plurality of shunt resistors, the resistances of the shunt resistors are the same, and specifically includes three shunt resistors, namely a resistor R1, a resistor R2, and a resistor R3. The filter is an EMC filter circuit, the switching power supply is an AC/DC power supply module, and the EMC filter circuit and the AC/DC power supply module are both conventional circuits.

The utility model also provides medical equipment and equipment, which comprises an equipment plug, wherein the circuit for reducing the residual voltage is arranged at one end of the equipment plug, which is connected with a power supply network.

When the equipment plug and the power supply network are disconnected, the resistor R1, the resistor R2 and the resistor R3 can form a path between L 'and N' to consume the current of an energy storage element in the circuit, and the voltage is reduced due to the reduction of the current, so that the voltage between L, N is rapidly reduced; the resistances of the resistor R1, the resistor R2 and the resistor R3 are selected, and in a parallel circuit, according to the formula, R1R 2R 3/R1+ R2+ R3, P1+ P2+ P3 are determined according to the medical instrument standard GB9706.01-2007/IEC 60601-1: in 1988, dielectric strength A-f, 1500V applied between the mains supply and the opposite polarity is not broken down, i.e. the current is large, i.e. typically 3 mA; parallel total resistance: r is always not less than

1500V/3mA equals 500k omega ", total power of parallel resistance: the total P is more than or equal to 1500V and 3mA and more than or equal to 4.5W; for the overview, the resistor R1, the resistor R2 and the resistor R3 are connected in parallel between L 'and N', the total resistance R is more than or equal to 300k Ω, the total resistance P is more than or equal to 4.5W, the upper limit values of the resistances of the resistor R1, the resistor R2 and the resistor R3 are determined according to actual needs, and the upper limit value of the resistance of the resistor R1, the resistance of the resistor R2 and the resistance of the resistor R3 is preferably 1000k Ω/2W.

When the equipment plug and the power supply network are disconnected, the resistor R4 is arranged between L 'and the ground wire, the resistor R5 forms a path between N' and the ground wire to consume the current of an energy storage element in the circuit, the voltage is reduced due to the reduction of the current, and the voltage between L and the ground (or a metal grounding shell) and between N and the ground (or a metal grounding shell) is rapidly reduced; the resistances of the resistor R4 and the resistor R5 are selected, and the resistance is determined according to the medical instrument standard GB9706.01-2007/IEC 60601-1: in 1988, the minimum value of the shell leakage current requirement in the leakage current is less than 0.1mA, and the resistance value required when the shell leakage current is measured is as follows: r > 220V/0.1mA ═ 2.2M omega, due to medical device standards

GB9706.01-2007/IEC 60601-1: 1988 dielectric strength A-a1, 1500V applied between the live part and the accessible metal part protected to ground, without breaking down, i.e. current is greater, i.e. typically 3 mA; therefore, the required resistance value when measuring the dielectric strength is as follows: r is more than or equal to 1500V/3mA and is 500k omega, and R is more than or equal to 2.2M omega if the leakage current and the dielectric strength of the integrated shell are both heavy; the power of the resistor is: p is more than or equal to 1500V by 0.1mA and is 0.15W, R4 is reviewed between L 'and the ground, R5 is reviewed between N' and the ground, R3 is more than or equal to 2.2M omega, P3 is more than or equal to 0.15W, R4 is more than or equal to 2.2M omega, P4 is more than or equal to 0.15W, the upper limit value of the resistance values of the resistor R4 and the resistor R5 is determined according to actual needs, and the embodiment is preferably 20M omega/2W.

In summary, a path can be formed between L 'and N' through the resistor R1, the resistor R2, and the resistor R3 to consume the current of the energy storage element in the circuit, and the voltage is reduced due to the reduction of the current, so that the voltage between L, N is rapidly reduced; the resistor R4 can be between L 'and the ground, the resistor R5 can form a path between N' and the ground to consume the current of the energy storage element in the circuit, and the voltage is reduced due to the reduction of the current, so that the voltage between L to the ground (or a metal grounding shell) and the voltage between N to the ground (or a metal grounding shell) are rapidly reduced; tests show that when the circuit for reducing the residual voltage is not added, as shown in fig. 2, after the equipment plug is powered off, the voltage is reduced slowly, and the residual voltage after 1S still exceeds 60V; after the circuit for reducing the residual voltage of the utility model is adopted, as shown in fig. 3, the residual voltage can be below 25V within 1S. The circuit of the utility model is a linear circuit, and the electromagnetic compatibility of the whole medical apparatus and instrument is not affected basically because a high-frequency circuit is not added.

The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Those not described in detail in this specification are within the skill of the art.

Claims (9)

1. A circuit for reducing remnant voltage, comprising: the voltage reduction circuit comprises a first resistor, a second resistor and a third resistor, wherein the two ends of the first resistor are respectively connected with the live wire output end and the zero wire output end of the filter, one end of the second resistor is connected with the live wire output end and the other end of the filter and is connected with the ground wire, and one end of the third resistor is connected with the zero wire output end and the other end of the filter and is connected with the ground wire.

2. The circuit for reducing remnant voltage of claim 1, wherein: the first resistor comprises a plurality of shunt resistors.

3. The circuit for reducing remnant voltage of claim 2, wherein: the resistances of the plurality of partial resistors are the same.

4. The circuit for reducing remnant voltage of claim 1, wherein: the first resistor is 300k omega-1000 k omega in resistance.

5. The circuit for reducing remnant voltage of claim 1, wherein: the resistance value of the second resistor is 2.2M omega-20M omega.

6. The circuit for reducing remnant voltage of claim 1, wherein: the third resistor is 2.2-20M omega in resistance.

7. The circuit for reducing remnant voltage of claim 1, wherein: the filter is an EMC filter circuit.

8. The circuit for reducing remnant voltage of claim 1, wherein: the switching power supply is an AC/DC power supply module.

9. A medical device apparatus comprising an apparatus plug, characterized in that: the device plug-in connection to the supply network is provided at one end with a circuit for reducing residual voltage according to any one of claims 1 to 8.

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