SU1617525A1 - Device for overvoltage protection of transistor gate - Google Patents

Abstract

The invention relates to electrical engineering and can be used to protect against overvoltages arising from the operation of transistor inverters on inductive loads. The purpose of the invention is to expand the scope of application while improving the weight and size parameters. The goal is achieved by connecting between the collector and the base of the transistor switch 1 of a chain of a series-connected capacitor 2, shunted by a resistor 3, a diode 4 and a threshold element 5. 1 Il.

Description

9

SP

is made equivalent to the value of the capacitor capacitance, equal to:

С „to С (р + 1),

J where p is the current gain of the transistor.

After transferring the energy stored in the load inductance, to the charge of the capacitor 2 and to heat; Receiving Invention is electrical engineering and can be used to protect against overvoltages that occur when transistor inverters operate on inductive loads.

The aim of the invention is to expand the field of application while simultaneously improving the mass and size parameters. 0, my threshold element 5, the transistor on the drawing is shown by the principle 1 and the active component of the device's circuit.

The overvoltage protection device of transistor switch 1 contains an interconnected capacitor 2 connected between its collector and its base, a series of capacitors 2 connected in series, shunted by a resistor 3, a diode 4 and a threshold element 5. The magnitude of the threshold

power supply, lead wires, etc., the current through the transistor is interrupted, and the capacitor 2 is discharged 5 through the resistor 3. Moreover, if in the interval of its discharge the resistor 1 is opened by the voltage from the control signal source la .; then this will not affect the discharge mode of the condensate voltage of the element 5 is chosen equal to 20 PZ 2, since diode 4 will be the fault of the working voltage of transistor 1, capacitor 2 is used low voltage, the required value of its capacitance 1, which in the most likely 25 cases of using a composite transistor will be 100-1000. The choice of the value of the resistor 3 is determined by considerations, which are to be devoted to the closure of the circuit through the transistor 1, the source of the control signal, the threshold element 5.

Thus, the reduction in overvoltages on the transistor in the proposed device is ensured by using small components economically, reliably and independently of the switching circuit of the transistors in inverted time should be approximate, which expands the range of application

but 3 times less than the switching period of transistor 1. Diode 4 can be selected as low-voltage and low-voltage.

The device works as follows.

Claims (1)

When the transistor 1 is turned on, the emf of the inductance in its load circuit changes sign, trying to maintain the current at a level corresponding to the precommand device while simultaneously improving the weight and size parameters. Claims An overvoltage protection device for a transistor switch, comprising a chain for connecting a transistor switch to a collector of a series-connected capacitor and a diode, a common point tactile spacing. However, at the time of DO that is connected to the first conclusion resistor, characterized in that, in order to expand the scope of application while improving the weight and size parameters, it when the voltage across the collector of the transistor 1 reaches the threshold value of the element 5, the latter opens and the current through the pre-discharged capacitor 2 and the open diode 4, is pro-45, is equipped with a threshold element, one of which is connected to the free transistor 1 through a control junction, translates its in active mode. As a result, a portion of the load current is branched into the collector circuit of transistor 1. The voltage increment on the capacitor, in this case, is the component V.Zmurko Tehred M. Didyk 50 the output of the diode, and the other output is designed to connect to the base of the transistor switch, while the second. The output of the resistor is designed to connect to the collector of the transistor switch Editor 0.Speedyh Proofreader L. Beskid is made equivalent to the value of the capacitor capacitance, equal to: С „to С (р + 1), where p is the current gain of the transistor. After transferring the energy stored in the load inductance, to the charge of the capacitor 2 and to heat; reversible by the threshold element 5, the transistor 1 and the active component power supply, lead wires, etc., the current through the transistor is interrupted, and the capacitor 2 is discharged through the resistor 3. Moreover, if in the interval of its discharge the resistor 1 is opened by the voltage from the control signal source la .; This will not affect the discharge mode to condense the closure of the circuit through transistor 1, the source of the control signal, the threshold element 5. Thus, the reduction of the overvoltages on the transistor in the proposed device is achieved by using small components economically, reliably and independently of the transistor incorporation scheme into the inverters, while at the same time improving the weight and size parameters. Claims An overvoltage protection device for a transistor switch, comprising a chain for connecting a transistor switch to a collector switch of a series-connected capacitor and a diode, a common point resistor, characterized in that, in order to expand the scope of application while improving the weight and size parameters, it equipped with a threshold element, one output of which is connected to the free equipped with a threshold element, one output of which is connected to the free the output of the diode, and the other output is designed to connect to the base of the transistor switch, while the second. The output of the resistor is designed to connect to the collector of the transistor switch, Proofreader L. Beskid