Control circuit for eliminating a voltage and current spike

A control circuit for eliminating a voltage and current spike in a DC circuit, the control circuit being connected to control a solid state switch (T2), such as a transistor or a FET transistor, serially connected to a load, in such a way that when a current through the load (L) is turned on, the switching current increases in a controlled manner without a detrimental voltage and current spike, the control circuit including at least one operational amplifier (O1, O2), or other combination of an amplifier (U1A) and a comparator (U2A, U2B, U3B), which has a first and second control input (+, −) and a control output (1, 7), which has an effects on the base control of the solid state switch (T2), and a matching network (T1, R1, C1, R2 or U2A, T4, R8) which is connected to the control circuit between the input terminal (input;

• ON/OFF) of the control signal and the base of the switching transistor (T2) in order to delay the ascending speed of the control signal (input/ON), and correspondingly that of the load current and voltage, during turn-on of the load current, characterised in that the voltage of the DRAIN pin, or collector, of the solid state switch (T2), which is after the load (L) in direction of current flow from the positive terminal (VCC, VPP) of the power supply of the DC circuit, is connected to control the said operational amplifier (O1, O2) or the circuit means (U3B, T1) connected to the said matching network in such a way that in connection with the turn-off control (input/OFF) of the solid state switch (T2), the operational amplifier (O1, O2) and/or the matching network (T1, R1, C1, R2 or U3B, T1, T4) switches the control voltage to the base of the solid state switch (T2) in order to open the solid state switch (T2) at least partly if its DRAIN, or collector, voltage exceeds the voltage (VCC, VPP) of the power supply of the control circuit, or other higher predetermined voltage.