| NPN composite tube circuit can improve the amplification ability of single-tube circuit.In the industrial control field such as DC motor,solenoid valve,etc.,which need large drive capability,the most commonly used is to use two transistors to form the composite tube to increase the current amplification in the circuit.In order to improve the ability of the circuit to load the rear stage load.Moreover,due to the limitations of the application environment,such circuits are often exposed to a complex electromagnetic environment and are easily affected by strong electromagnetic pulses.Therefore,the damage effect of the EMP injection on the composite tube circuit and the related theories have been studied to improve the performance of the composite tube circuit in the industrial control field.The reliability of the application is of great significance.In this paper,a two-dimensional numerical model of a typical bipolar transistor of a typical semiconductor device NPN bipolar transistor is established by the simulation software Sentaurus.By calling this transistor model,a composite tube amplifier consisting of two double-click transistors was constructed.Adjust the DC operating point of the amplifier.Based on this model,the effects of external resistance,power supply voltage,EMP signal mode,injection position and other parameters on the anti-EMP effect of the circuit structure were studied.The control variables are used to change the above-mentioned variables that may affect the anti-EMP effect of the structure on by one.Compare the burned degree of the circuit structure before and after change.Obtain the burning rule of the circuit structure under the EMP action.Combining the burnout mechanism and the vulnerable parts of the device,the reinforcement measures against the EMP effect of the structure are preliminarily given.Based on the established two-dimensional electro-thermal model of silicon-based NPN transistor and the simulation model of the hybrid tube amplifier circuit,the influence of the variation trend of the internal temperature peak value of the semiconductor device with time and the variation of the internal temperature peak value of the device was analyzed.The main failure mechanism of bipolar devices and ICs is secondary breakdown of PN junctions.In the case of a failed bipolar transistor device,the percentage of transistor failure due to junction breakdown is around 90%.Studies have shown that the increase in the quiescent operating point of the amplifying circuit caused by the increase in the power supply voltage will cause the transistor to burn more easily.Different methods of providing DC bias to the composite tube in the composite tube amplifier circuit also affect the damage threshold of the transistor in the circuit structure.In addition,due to the different doping concentrations of the emitter,base,and collector regions of the transistors,the voltage amplitudes of the transistors that cause thermal damage due to injection of electromagnetic pulse signals from different positions are different.Also,the order of the burned transistors is different for different injection positions.The collector junction of the transistor is more prone to avalanche breakdown,and the current generated by the avalanche double effect causes the collector junction to burn out.The effects of different factors,such as the amplifier circuit structure,the DC bias resistance of the amplifier circuit,the power supply voltage,signal strength of the EMP injection signal,and the signal injection position,on the resistance of the amplifier circuit to the EMP injection effect are studied.The composite tube amplifier circuit structure has strong resistance to the base EMP injection with respect to the Darlington amplifier circuit structure because the bias resistor providing DC bias to the transistor in the composite tube structure forms an input port to the power supply ground.Between the energy release paths,the energy of the EMP signal injected from the input port can be discharged directly through the bias resistor without going through the transistor.The effect of the power supply voltage on the EMP injection effect is mainly due to the change of the power supply voltage will change the position of the DC operating point of the amplifier circuit.Under the condition of a higher amplitude power supply voltage,the avalanche multiplication effect of the space charge region of the transistor collector junction will follow.As the power supply voltage increases,the current density of the collector junction and the increase in the strength of the reverse electric field will cause the transistor to generate more heat,making the transistor easier to burn.The results of injection studies on different signal types for the two amplifier circuit structures show that the response of different structures to different injected signals is different.Under the condition of the same amplitude and the same frequency,the Darlington structure is more injected under the step signal.The capacitance is burned,and the composite tube amplifier circuit structure is mainly affected by the triangular wave.With the injection of the three EMP signals,the temperature of the structure first reaches the melting point of the silicon material when the triangular wave is injected,and the heat burns out.The zener diode,limiting resistor and other protective devices are connected to the input and output ports of the circuit to limit the maximum current within the microelectronic device or limit the input voltage of the input port so as to protect the microelectronic device from electromagnetic pulse and other signals.The simulation of the two kinds of composite tube amplifier circuits proposed in Chapter 4 from different ports loading protection devices,compared with the device before and after the application of the protection circuit temperature rise trend and the length of burn time,can be clearly seen in Darling In the structure,a resistor with a small value in series between the emitter and the base of the two transistors can significantly increase the base guarding capability of the Darlington structure,and the resistance ratio of the composite pipe structure is increased proportionally to increase the bias resistance.It can effectively enhance the resistance of composite pipes to EMP effect. |
