SU881631A1 - Device for measuring value of charge - Google Patents

Description

(54) DEVICE FOR MEASURING THE VALUE The device is a nuclear radio electronics and is designed to measure the amount of charge generated by a popuproduct detector under the influence of a pulsed x-ray radiation. It can also be used in all industries of the national economy and scientific research where semiconductor detectors are used. for measuring pulsed radiation fluxes over a wide range of intensities, as well as for measuring electrical pulsed magnitudes of current and voltage with automatic They select the measurement range. A device for measuring the magnitude of a charge generated by a semiconductor detector under the action of ionizing radiation, consisting of an input electronic key, an input trigger key, an integrator, an analog-digital converter, and an analog-digital converter control trigger, is known. This device is designed to convert the charge to a voltage into a voltage and then convert the voltage to a digital code using various circuit solutions: a device with a balanced discharge, a device for parallel weighting, a device for comparing voltages. The start integration signal triggers the control of the input dongle. In this case, the integrator input through the input electronic key is connected to the input of the device. There is an integration of the magnitude of the charge, i.e. conversion of charge to voltage. The End of Integration signal turns off the input key dongle control and turns on the A / D converter trigger. The input dongle is closed, a voltage proportional to the charge value is fixed at the integrator output, and an analog-to-digital converter is turned on. The voltage from the integrator output is converted to a digital code. The end of the conversion is fixed to turn off the control trigger of the analog-to-digital converter. In this case, the analog-to-digital converter is turned off. With the arrival of the next pair of signals, the start of integration and the end of integration, the measurement cycle is repeated 1. The disadvantages of this device are a small range of measured values of charge and low accuracy. The closest to the technical essence of the invention is a device for measuring the magnitude of the charge, which contains an input electronic switch, the first input of which is the measuring input of the device, a current stabilizer of the discharge, the output of which is connected to the second input of the electronic switch, to the output of the electronic switch, the lower level comparison circuit, the input of which is connected to the output of the integrator, the control trigger of the electronic switch and the control trigger input logic, the first inputs of which are connected to the output of the low-level comparison circuit, and the same generator and the first AND-series register connected in series, and the output counter of the register, with the output of the electronic switch control trigger connected to the third (control) input of the electronic switch and one of the inputs of the first circuit And, the other entrance is under the key to the output of the generator. The start of integration signal triggers the control of the input, electronic switch. In this case, the integrator input is connected via the input electronic nei switch to the input of the device. Integration occurs — the charge values, i.e. conversion of the .zar value to voltage. The End of Integration signal turns off the input key dongle control and includes three germs controlling the output counter-register. The integrator input is switched by the input electronic key to the output of the discharge current regulator, the AND circuit opens, and the signals of the quartz oscillator are fed to the input of the output register chip. There is a simultaneous integration of a stable current, the polarity of which is inverse to the input current, and the filling of the output counter of the register with a crystal oscillator signal. As soon as the voltage at the output of the integrator becomes zero, the comparison circuit operates. The signal of the comparison circuit turns off the control trigger. no output counter; -registrom. Scheme And closes. The number recorded in the output counter-register is proportional to the voltage at the integrator output, therefore, proportional to the charge at input 2. However, in this device, the range of measured values of the charge is limited from below to the value of the leakage current at the input of the integrator. rarator, and above — the maximum voltage value at the integrator output without saturating the latter. In addition, with this method of measuring the magnitude of the charge, the absolute measurement error remains constant over the entire range of measured values of charge. The relative error in this case increases with a decrease in the measured value and, at a sufficiently small value of the measured charge, can completely distort the value of the latter. The aim of the invention is to expand the range of measurable charge values and increase the accuracy of the reference. This goal is achieved by the fact that in a device for measuring the magnitude of a charge that contains an input electronic switch, the first input of which is the measuring input of the device, a discharge current regulator whose output is connected to the second input of an electronic switch, an integrator whose input is connected to the output of a switch, a lower level comparison circuit, the input of which is connected to the integrator output, an electronic switch control trigger and input logic control trigger, the first inputs Which are connected to the output of the lower level comparison circuit, as well as the generator and the first AND circuit and the output counter register connected in series, the output of the control trigger of the electronic switch is connected to the third (control) input of the electronic switch and from the inputs of the first, AND circuit , the other input of which is connected to the generator output, the integration-memory control trigger has been introduced, three AND schemes, a comparing all-level circuit, an input clock counter for the target healing, and the upper level is connected to the integrator output, and its output is connected to the second input of the control logic of the input logic, the first output of which is connected to the first input of the second AND circuit, and the second to the first inputs of the third and fourth IC circuits. (connected to the second control input of the device, and their outputs, respectively, to the second control trigger input of the electronic switch and the first input of the integration control-memory trigger, the second input of the fourth AND circuit connected to the first control to the input of the device, and its output to the input of the integration clock counter and to the second input of the integration-memory control trigger, the output of which is connected to the second (control) input of the integrator, the output of the integration clock counter to the second input which is connected to the output of the output register counter.

The drawing shows a block diagram of a charge measurement device.

The device contains an input electronic switch 1, a control tripper for the input electronic switch 2, a discharge current regulator 3, an integrator 4 a lower level comparison circuit 5, trier. control logic of the input logic 6, cxe.Niy high level comparison 7, second circuit 8, third circuit 9, fourth circuit 10, trigger integration control trigger 11, first circuit 12, quartz generator 13, output counter-register 14, counter integration cycles 15, dividing circuit 16, measuring input 17, first control input 18, second control input 19, device output 20.

The device for measuring the magnitude of the charge operates as follows.

The measuring input 17 through the input electronic switch 1, which is controlled by the control trigger of the input electronic switch 2 is connected to the integrator 4. Signal The start of integration from control input 18 through the open with: -, and AND 10 turns on the integration control-trigger 11. The input charge The signal of the end of integration from the control input of the open circuit AND 9 turns off the integrating-storing control trigger 11 and the integrator 4 switches to the storage mode of the voltage value at its output. Then the process repeats until the voltage at the 1st output of the integrator 4 exceeds the threshold of the high comparison circuit 7. At this moment, the input control trigger 6 is activated. At the same time, the circuit AND 9 and circuit AND 1O are closed, and circuit 8 is opened

vyatsya. Signal The end of integration from control input 19 through open circuit AND 8 turns on the control trigger of input electronic switch 2, which switches input electronic key 1 in such a way that current regulator of discharge 3 is connected to input of integrator 4. As integrator 4 is in integrated mode then the integration of the direct current takes place until the moment when the voltage at the output of the integrator 4 becomes equal to the response voltage of the lower level comparison circuit B, the signal of which turns off the control trigger neither the input electronic switch 2 and the trigger control input logic 6, which indicates the end. ) 1: -kla device operation. Simultaneously with the conversion of the magnitude of the charge into the voltage, the integrator 4 counts clock cycles with a clock counter, i.e. the number of signals counts. Start of integration in the measurement cycle. In addition, the control trigger signal by the input electronic switch 2 opens the AND 12 circuit and the signals of the crystal oscillator 1 3 are recalculated by the output counter-registers 14. As a result, the output counter-register 14 contains the recorded number of pulses proportional to the output voltage of the integrator 4 or proportional to the total input charge for such a number of integration cycles that is recorded in the clock counter 15. These {values in digital form come on the division circuit 16, the output of which is the output devices. The magnitude of the input air of claim 1 is calculated by the formula

dcf,

 1 — measured charge; i - constant k1; s: device; & - the value of integrating efficiency; N - -. Number in the output counter register 14; C - the number in the counter clock.

The integrator 4 consists of an operational amplifier, analog, storage capacitor, source rlovtop: body and integrator capacitance. The analog CLK is switched on between the interrupt of the operating device and the input of the source follower to the gate of which the evtKocTb memory is connected. The output of the SOURCE repeater through the integrating capacitor is connected to the inverse gathering of the operational amplifier.

Thus, for any large or small input charge, the device operates a very small output voltage range. Therefore, the absolute measurement error of the voltage at the integrator output remains constant regardless of the number of integration cycles in one cycle. The absolute measurement error of the charge decreases by a factor of K, where k is the number of integration cycles. In this case, the relative measurement error does not depend on the magnitude of the measured charge, which is especially important when measuring small charges. In addition, the dynamic range of the device at the input can be significantly expanded by increasing the difference between the response voltages of the comparison circuits to the maximum possible.

Claims (2)

1.Connell J. Analog integrated circuits. M., Mir, 1977, p. 349357. 2. Cruise; Bipinghurst. Microprocessor and software for universal voltmeter. M., Electronics, No. 12, 1978, p. 52 (prototype). I ID r N C4J ten P vr