SU1262467A1 - Device for protection of power sources - Google Patents

Description

The invention relates to electrical engineering and can be applied to protective secondary power sources, in particular with voltage converters, and consumers from emergency operation.

The purpose of the invention is to expand the functionality of the device to protect power sources.

The device contains a differential comparison unit 1, the first input of which is connected to the source 2 of the reference voltage, and its second input - to the tap of a resistor divider 3 voltage, connected by its first input to the common bus, and the second input - to the outlet for connecting the controlled voltage . The output of the comparator unit 1 is connected to the control input of the actuator 4 through an amplifier (5,: consisting of a composite transistor, and a matching unit 6, made in the form of an inverting stage on the transistor 7, the emitter of which is connected to the common power supply bus. 5, the collectors of the transistors 8 and 9 of the switching-on node 10 are connected. The emitter of the transistor 8 is connected to the common power line, and the emitter of the transistor 9 is connected to the tap of an additional resistor voltage divider 11 connected to the source 2 of the reference voltage. transistor 7 is connected to the output of the amplifier 5 via the resistor 12, and its collector is coupled through a resistor 13 to the base of transistor circuit 8. The common bus power is turned on resistor 14, performing the role of the current sensor. Between the base and the emitter circuit of the transistor 8 is turned on the capacitor 15.

The device works as follows.

In the absence of a voltage, from the output of the monitored voltage, the second input of the comparison unit 1 receives a voltage that is less than the reference voltage, the noatoMy transistor of the comparison unit 1, to the collector of which the input of the amplifier 5 is connected, is closed. The composite transistor amplifier 5 is open. The transistor 7 is open and shunts the input of the actuator 4. The actuator 4 is turned off.

In normal mode, the current transistor 9 is closed and does not have

influence on the amplifier 5. This is provided by appropriately setting the reference voltage at the output of the voltage divider 11, locking the transistor 9, so that it compensates with a certain margin, depending on the maximum allowable load current. As the transistor 7 is open, that voltage on; the base of the transistor 8 is insufficient to open it. The transistor 8 is closed and does not affect the amplifier 5.

When the voltage on the protected circuit of the higher level, determined by voltage divider 3, increases, a voltage higher than the reference voltage is applied to the second input of the comparison unit 1. The transistors of the comparison unit 1 change their state to the opposite. In this case, the composite transistor of the amplifier 5 and, accordingly, the transistor 7 are closed. From the collector of transistor 7, a signal is supplied to the control input of the actuator 4 and through a resistor 13 to the base circuit of the transistor 3. The actuator 4 turns on and limits the voltage across the protected circuit. At the same time, the capacitor 15 starts charging through the resistor 13. off. With a longer voltage, the transistor 8 opens and, shunt the control circuit of the amplifier 5, maintains it in the closed state, thus providing a blocking protection circuit, and accordingly disconnecting the power source.

Claims (2)

When an overcurrent occurs, the voltage drop across the current sensor 14 reaches the opening threshold of transistor 9. Transistor 9 opens and bridges the control circuit of the component transistor of amplifier 5. The component transistor closes and at the same time closes transistor 7. Actuator 4 is turned on. Simultaneously, through the resistor 13, the capacitor 15 begins to charge, providing a blocking delay for the protection to operate, as when an overvoltage occurs. Claim 1. A device for protection of power sources, containing an amplifier, an input connected to an input terminal, a control input to the output of a differential comparison unit, the first input of the Kotbpoi-connected to the output of a voltage source connected between the input output and a common bus, and the second input - to the output of the resistive voltage divider connected between the common bus and the output for connecting the monitored voltage block, the output of the amplifier is connected to the input of the matching node, the output of which is connected to the pack the driving input of the actuator connected between the output terminal and the common bus, the amplifier turn-off node on two transistors, the collectors of which are combined and connected to the control input of the amplifier, the emitter of the first transistor connected to the common bus, capabilities, two resistors and an additional resistive divider are inserted into it, and the matching cell is made in the form of an inverting amplifier on at least one transistor, the emitter of which is connected to to the bus, the base is to the base of the second transistor of the amplifier turn-off node, and the collector is through the first resistor to the base depy of the first transistor of the switch-off node, the second resistor is connected to the common bus, and an additional resistive voltage divider is connected between the output of the reference voltage source and the common bus, its output is connected to the emitter of the second transistor of the node switching off the amplifier. 2. The device according to claim 1, wherein the capacitor is connected to it between the base circuit and the emitter of the first transistor of the amplifier turn-off node.