SU420969A1 - DEVICE FOR MEASURING THE RELATIONSHIPS OF STATIC TRANSFER COEFFICIENTS OF TOKATRISTRANTS - Google Patents

Description

one

The invention relates to the field of electronics and can be used to control semiconductor devices in their manufacture.

A device is known for measuring the ratio of static current transfer coefficients of transistors, comprising emitter current pulse sources, a collector voltage source, a zero indicator, and a variable resistance for performing a division operation.

However, in this device, the division of the static current transfer coefficients of the transistors is carried out manually using a potentiometer, which reduces the measurement speed.

Low measurement accuracy due to the error introduced by the dividing device.

The aim of the invention is to automate the measurement process and increase accuracy.

The device contains a reversible counter, the input of which is connected to the input of the "OR and" AND circuits and the output of the first control trigger, the counting input of the reversible counter through the inhibiting circuit is connected to the output of the counting pulse generator, the summing input through the OR circuit is connected to the output of the counting pulse generator , the summing input through the OR circuit is connected to the inhibition circuit input and to one of the outputs of the second control trigger, the output of the reversible counter through the third control trigger is connected to the second input The AND outputs, whose output is connected to a cycle counter and a delay circuit, the second outputs of the first and second control flip-flops are connected to the inputs of the respective linearly varying base current generators, the outputs of which through the OR circuit are connected to my terminal for connecting the base of the tested transistor, the inputs control triggers are connected to a threshold device, the output of the delay circuit through the circuit

"OR connected to the input of the second control trigger."

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The drawing shows a block diagram of the proposed device. It contains a prohibition circuit 1, a reversible counter 2, a trigger 3, an AND 4 circuit, a counting pulse generator 5, an OR 6 circuit, a threshold device 7, a cycle counter 8, triggers 9 and 10, a transistor 11 under test, a delay circuit 12, generators linearly varying currents of base 13 and 14, the circuit OR 15 and 16. In addition, the circuit includes collector resistances Ri and Rz and sources of reference voltage and supply voltage of the collector of the tested transistor.

The device works as follows. Contact Ki is closed and the base current is measured at a collector current / KJ. The "Start - 1" signal overturns trigger 10, and the voltage drop from the left output of trigger 10 converts reversible counter 2 into the summing mode, and through the OR 6 circuit removes the prohibition on the arrival of counting pulses from generator 5 through the prohibition circuit 1 to the output of the reversible counter 2

At the same time, the voltage drop from the right output of the trigger 10 starts the generator of the linearly varying current of base 14 and the base current of the tested transistor I begins to grow linearly. As the base current increases, the collector current starts to rise when they reach the value of / k, the voltage drop across the collector of the tested transistor reaches the value at which the threshold device 7. The signal from the output of the threshold device 7 will return the trigger 10 to its initial state. This will stop the flow of counting pulses into the reversible counter 2 and stop the process of increasing the base current. Since the amplitude of the base current increment is proportional to the transition of the counting pulses, the number of pulses in the reversible counter 2 is proportional to the base current at a given collector current / k, and the output of counter 2 shows a voltage indicating that the counter .

To measure the base current at a given collector current / k, the contact / KI opens, then the start-and-through signal OR 16 tilts trigger 9, and the voltage drop from its left output switches the reversible counter 2 into subtraction mode, and through “OR 6 removes the ban on the arrival of the counting pulses from generator 5 through the prohibition circuit 1 to the input of the reversible counter 2.

At the same time, the voltage drop from the right output of the trigger 9 starts the generator of the linearly varying current of the base 13, and the base current of the tested transistor 11 starts to grow linearly. The growth of the base current causes an increase in the collector current, which in turn leads to the triggering of the threshold device 7 when it reaches the value of / k. . The signal from the output of the threshold device

7 will return trigger 9 to its original state. This will stop the arrival of counting pulses in reversible counter 2 and stop the process of increasing the base current of the tested transistor 11. Since the amplitude of the base current increment is proportional to the period of the counting pulses, the number of pulses proportional to the base current when collector current collector / k is subtracted from the reverse counter. .

When trigger 9 returns to its initial state, voltage is not reversed from the left output through circuit 4 and 4 is counted in loop counter 8 and through delay circuit 12 and

5, the OR 16 circuit again trips the trigger 9, and the cycle for measuring the base current (/ e,) is repeated.

During K-Cycle, the number accumulated in the reversible counter when measuring the base current

0 (1b,) will be written off. The voltage drop from the output of the reversible counter 2 will overturn the trigger 3, which closes the & 4 circuit, and the counting process for measuring the base current (/ bg) will stop. So as when cheating

the number accumulated in the reversible counter is equal to / b, - k / b, 0, then / C

b,

- and so in the loop counter

(g

8, the ratio of static current transfer ratios of the transistor under test is fixed.

Subject invention

A device for measuring the ratio of current transfer coefficients of transistors, containing a source of collector voltage, characterized in that, in order to automate the measurement process and improve accuracy, the device contains a reversible counter, the input subtraction of which is connected to the input of the AND and OR circuits and the first control output the trigger input, the counting input of the reversible counter is connected to the output of the generator of counting pulses through the inhibiting circuit, the input of the summing through the OR circuit is connected to the input of the inhibiting circuit and to one of the one second control trigger, the output of the reversible counter through the third control trigger is connected to the second input of the AND circuit, the output of which is connected to the cycle counter and the delay circuit, the second outputs of the first and second control triggers are connected to the inputs of the respective linear-variable current generators the bases, the outputs of which through the OR circuit are connected to the terminal for connecting the base of the tested transistor, the inputs of the control triggers are connected to the threshold device, the output of the delay circuit via the OR circuit Inonii with the control input of the second flip-flop.