RU108889U1 - DEVICE FOR PROTECTING RADIO ELECTRONIC EQUIPMENT FROM OVER VOLTAGE - Google Patents

Abstract

 An overvoltage protection device for electronic equipment comprises: a common bus; serially connected input bus, key with control input and output bus; a control element with two voltage comparison inputs, the output of which is connected to the control input of the switch, and the first input is connected to the input bus; a threshold element connected between the second input of the control element and the common bus.

Description

The overvoltage protection device for electronic equipment (REA) is designed to protect special-purpose equipment from the effects of transient operation of the primary source +27 V, provided for by the requirements of GOST 19705-89: limit values - 65 V for up to 0.5 sec of voltage supplied from the generator to the moment of its launch; short-term excesses during operation up to 50 V, duration up to 50 ms, as well as to protect electronic equipment from the effects of transient modes of operation of other primary DC power supply systems.

A device is known for protecting the load from overvoltage [1] (Patent 1840216 A device for protecting communication means from surge overvoltage), comprising a delay unit, a threshold element, a control pulse shaper, regulating and controlling transistors, a threshold zener diode resistor circuit, current-setting and limiting resistors, diode matrix. The device is connected between the voltage source and the load. The device allows you to limit the amplitude of the transition process.

The disadvantages of the device for protecting the load from overvoltage [1], is the presence of a linear mode of operation of the regulating transistor, which limits its use at elevated levels of transmitted power, as well as the certain complexity of the circuit design.

The purpose of the creation of the claimed device is to protect the CEA from the effects of transient voltage in the power supply network with parameters according to GOST 19705-89 or similar, which can lead to equipment failure.

This is achieved by the fact that the load is automatically disconnected from the power supply with a minimum time delay at the moment of exceeding the voltage limit for the equipment during the transient process.

An overvoltage protection device for electronic equipment comprises: a common bus; serially connected input bus, key with control input and output bus; a control element with two voltage comparison inputs, the output of which is connected to the control input of the switch, and the first input is connected to the input bus; a threshold element connected between the second input of the control element and the common bus.

In the drawing (figure 1) shows a diagram of a protection device CEA from overvoltage.

The device for protecting electronic equipment from overvoltage (Fig. 1) contains: a common bus (1); input bus (2), key (3) with control input, output bus (4); a control element (5) and a threshold element (6). Figure 1 also shows the voltage source 7 and the protected equipment 8.

The device for protecting electronic equipment from over-voltage in the normal mode ensures the connection of the voltage source (7) to the load (8) through the key (3), which is in the closed state under the action of the signal from the output of the control element (5), which performs the function of a comparing device of two voltages : voltage on the input bus 2 with voltage on the threshold element (6), the level of which corresponds to the maximum allowable voltage for load 8.

When the voltage on the input bus 2 exceeds the threshold voltage level specified by the threshold element (6), the control element (5) generates a signal to disconnect the load, opening the key (3) for the duration of the transition mode.

Figure 2 shows a diagram of the practical implementation of the protective device. The designations 1, 2, 3, 4, 5, and 6 correspond to the designations in Fig. 1. The key 3 consists of a field-effect transistor and a zener diode protecting the gate, the control element 5 includes p -pr-transistor, limiting resistors and the delay time of the device from interference overvoltage, the threshold device 6 is made on a zener diode, as well as the input diode matrix 9 from the reverse polarity of the input voltage.

In the circuit of FIG. 2, an IRF5210 field effect transistor with a protective zener diode BZX84C 15, a threshold zener diode BZX55C33, a 2T208 transistor with limit resistors Rl, R2, R3 of type C2-33 and a capacitance C of type K10-17, and a diode array are used - CPQ40 \ 80,

In the design of the protective device made according to the scheme of figure 1, the following functional structures are used:

control element 5 - compares the voltage of the input bus 2 and the threshold element 6 and when the emergency threshold is exceeded, discharges the shutter capacity of the key 3, locking it. When removing excess voltage, the key 3 is opened by the voltage at the gate from the input voltage source.

Tests of the patented device for protecting electronic equipment from overvoltage corresponding to the functional diagram of FIG. 1 and manufactured according to the circuit diagram of FIG. 2 were carried out as part of a product prepared for serial production with positive results.

Information sources

1. Patent 1840216 A device for protecting communications from surge surges.

2. Patent 2069436 Device for protecting the load from overvoltage.

Claims (1)

An overvoltage protection device for electronic equipment comprises: a common bus; serially connected input bus, key with control input and output bus; a control element with two voltage comparison inputs, the output of which is connected to the control input of the switch, and the first input is connected to the input bus; a threshold element connected between the second input of the control element and the common bus.