KR20170050021A - Bias-voltage controller for Geiger-mode avalanche photodiode of particle detection system - Google Patents

Abstract

The present invention relates to a bias voltage controller of a geiger-mode avalanche photodiode for detecting a particle. An electrical charge is recharged to reduce time for recovering a state before avalanche. Therefore, when operating a laser diode and an avalanche photodiode applied to a fluorescent sensor for detecting a biological particle which calculates the number of rapidly moving biological particles, the bias voltage controller of the present invention is able to minimize the recovery time consumed when an electrical charge is recharged to recover a state before avalanche. The bias voltage controller comprises: a bias voltage control part which rapidly increases an electrical current, which flows in a driving circuit operating a pulse laser diode (LD) or an avalanche photodiode (APD) to reduce a time constant and rapidly amplifies an output of power, and controls an input direct current voltage not to make a change in an ambient temperature or a power voltage delivered to the bias voltage; and a time constant reduction power driving part which includes a photodiode driving part having a transistor in which an output terminal and an input terminal are respectively connected to an input terminal of a voltage control oscillator and an output terminal of the driving circuit.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a Bias-voltage controller for a Geiger-mode avalanche photodiode for particle detection,

The present invention relates to a particle sensor fluorescent sensor for measuring the number of rapidly moving particles by shortening the time taken for recovery to a pre-avalanche state by charge recharging in a bias voltage control circuit for an avalanche photodiode of a particle sensor fluorescent sensor A Geiger-mode avalanche photodiode for particle detection, which attempts to minimize the recovery time, which is the time taken for the charge to be recharged and recovered to the pre-avalanche state, when driving the applied laser diode and Avalanche Photodiode And a bias voltage control device.

Ultraviolet light in the mid-ultraviolet region (200 to 300 nm) can be applied to technologies such as detection and identification of harmful biomolecules and pathogens. This principle is based on the fact that amino acids and biomolecule substances (300 to 400 nm) and visible light (380 to 750 nm) in comparison with the quantum efficiency in the near-ultraviolet region (300 to 400 nm) In particular, in the real-time biological particle measurement using the fluorescence sensor for detecting bio-particles as described above, in-air suspended particles are sucked and sorted, and the particles are irradiated with light It is possible to distinguish between bacterium particles and general particles by measuring the intensity of scattering light and the intensity of fluorescent light generated by the light source. Recently, Ultraviolet ray-induced fluorescence technology using ultraviolet LEDs capable of miniaturization and using only a desired wavelength without additional optical filter is under development.

The avalanche photodiode (APD), which is used for weak signal detection, is operated by the magnitude of the reverse voltage applied to each cell of the semiconductor chip in the avalanche photodiode used in the fluorescent sensor for detecting the biological particle , A linear mode (LM) and a geiger mode (GM).

As shown in FIG. 1, the GM-APD detects a signal by repeatedly reciprocating the VOFF point immediately before the breakdown voltage (V breakdown) and the VON point immediately after the breakdown voltage for a very short time.

A photodiode using an avalanche photodiode absorbs photons and absorbs photons. When a photocurrent is generated, a current flows, a voltage drop occurs in a series connected resistor Rs, a quench phenomenon is quenched, and a charge is recharged to SPAD, It takes a recovery time, which is the time required for recovery to the state before the launch, so that it is difficult to grasp the quantity of the measurement target biomolecules that move rapidly.

In addition, even if there is a variation in the ambient temperature or a change in the power supply voltage, the influence of the bias voltage is not given to the bias voltage of the APD, so that the bias voltage can be controlled at the optimum multiplication factor in the APD, A bias voltage control circuit for a diode and an adjustment method thereof are required to be realized.

Japanese Patent Publication No. 3839574 (Aug. 11, 2006)

SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide a method of shortening the time constant of a driving circuit of a novel LD or APD capable of rapidly amplifying the output of a power source for driving a pulsed LD (Laser Diode) or APD (Avalanche photodiode) .

A bias voltage control circuit for an avalanche photodiode according to the present invention is a method for shortening the time constant of a drive circuit of a novel type LD or APD capable of rapidly amplifying a supply voltage supplied to an avalanche photodiode (APD) And a circuit and method for providing a circuit configuration accordingly.

The bias voltage control circuit for an avalanche photodiode according to the present invention includes a voltage varying means for controlling and outputting an input DC voltage by a voltage control signal and controlling the output voltage as a bias voltage to be applied to the APD, And,

Corresponding voltage output means corresponding to a temperature change for outputting a voltage at a temperature gradient of a reverse breakdown voltage of the APD and set voltage output means for outputting a set voltage for setting a voltage of the output terminal to a predetermined voltage;

The reference voltage is extracted from the voltage corresponding to the slope of the temperature corresponding voltage output means and the set voltage, and the voltage control signal is generated so that the reference voltage and the voltage supplied from the output terminal through the resistor become equal, Wherein the voltage changing means includes a digital variable resistance means capable of digitally changing a resistance value by a digital voltage control signal and converting the voltage control signal into a digital voltage control signal, A bias voltage control unit for setting the resistance value of the digital variable resistance means by the digital voltage control signal and controlling the input DC voltage;

A capacitor connected in parallel to the DC power supplied from the bias voltage control unit;

An induction unit connected to the direct current power source and connected to a drive circuit output terminal for supplying power to the laser diode or the avalanche photodiode;

A field effect transistor having an output terminal connected between the inductor and the output terminal of the driving circuit; A voltage controlled oscillator coupled to an input terminal of the field effect transistor; And

And a photodiode driver configured to include an input terminal of the voltage control oscillator and a transistor having an output terminal and an input terminal connected to an output terminal of the driving circuit. And a bias voltage control device for the diode.

According to the present invention, it is possible to rapidly increase the current flowing through a driving circuit for driving a pulse laser diode (LD) or an APD (Avalanche photodiode) to shorten the time constant and amplify the output of the power supply quickly, A bias of a Geiger mode Avalanche photodiode for particle detection that can control the bias voltage at the optimum multiplication factor in the APD so as to reduce the circuit size, A voltage control device is provided.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing the concept of the principle and structure of the detection of particle detection value using an avalanche photodiode of a detection fluorescent sensor. Fig.
2 is a diagram showing a VOFF point immediately before the breakdown voltage (Vbreakdown) of the avalanche photodiode and a VON immediately after the breakdown voltage.
3 is a bias voltage control circuit according to the present invention.
4 is a time-constant short-circuit power source driving unit according to the present invention.
5 is a bias voltage control device of a Geiger mode Avalanche photodiode for particle detection.

Preferred embodiments of the present invention will be described with reference to the drawings. 3 is a schematic circuit diagram of an embodiment of a bias voltage control circuit 100 for an avalanche photodiode (APD) of the present invention. 3, the high voltage generating circuit 10 outputs a high direct current voltage (for example, several tens V) 10a to the input terminal 12. In this case, The voltage variable circuit 20 variably controls the DC voltage 10a applied to the input terminal 12 to the corresponding DC voltage 20a by the voltage control signal 30a output from the voltage comparator 30, 28).

The reference voltage generating circuit 40 generates the reference voltage based on the setting of the voltage for obtaining the optimum amplification factor for the terminal 28 and the temperature gradient of the breakdown voltage of the APD 70, Providing a reference voltage 43a for the input 31. The output voltage setting circuit 41 outputs a predetermined voltage 41a for setting the voltage of the terminal 28 to a voltage at which the optimum amplification factor can be obtained with respect to the APD 70 (shown in Fig. 5 to be described later) And supplies it to the circuit 43. The temperature compensation circuit 42 outputs a voltage 42a corresponding to the temperature slope A (V / 占 폚) of the breakdown voltage of the APD 70 and supplies it to the addition circuit 43. This temperature gradient indicates how much the breakdown voltage changes with respect to the temperature change. The adding circuit 43 adds the predetermined voltage 41a and the voltage 42a corresponding to the temperature gradient A (V / ° C) and outputs the reference voltage 43a to the input 31 of the voltage comparator 30, .

The attenuator 50 is composed of a resistor 51 connected in series to the terminal 28 and a resistor 52 connected in series to the resistor 51 so that the other end of the resistor 52 is connected to the lowest potential terminal 53 to supply the divided voltage 50a of the connection point 54 between the resistor 51 and the resistor 52 to the input 32 of the voltage comparator 30. [ The voltage comparator 30 obtains the voltage difference between the voltage 50a and the reference voltage 43a and supplies the voltage difference to the voltage variable circuit 20 as the voltage control signal 30a.

Pass filter circuit 60 is constituted by a resistor 61 serially connected to the terminal 28 and a capacitor 62 connected to the resistor 61 so that the other end of the capacitor 62 is connected to the lowest potential terminal 63 So that the filter output voltage from the connection point 64 between the resistor 61 and the capacitor 62 passes the low frequency component as the bias voltage 60a and the noise signal of the high frequency component is removed, .

The bias voltage 60a is supplied to the APD 70 shown in FIG. 5 through the time constant short axis power source driving unit 200 described later. The bias voltage 60a is applied to the APD 70 through the single axis power source driving unit 200 and the operation current 70a is outputted to the current voltage conversion amplification circuit 80 when the optical signal is applied. The current-to-voltage conversion amplifying circuit 80 amplifies the operating current 70a of the APD 70 at the same time as voltage conversion and outputs a detection voltage signal 80a.

4 is a circuit of the time constant power supply driving unit according to the present invention. In supplying the bias voltage 60a, which is the output of FIG. 3, to the APD 70, the current is rapidly increased to shorten the time constant, And is a time constant shortening power source driving unit which enables rapid amplification.

The bias voltage 60a (referred to as VCC in FIG. 4) includes a first inductor 201, a second inductor 202, and a first capacitor 208 having a bias voltage for charging or removing noise, And the output terminals of the second inductor 202 are connected to the drain terminals of the field effect transistor 1 (FET1) and the field effect transistor 2 (FET2), respectively, and the output terminals of the first and second inductors Respectively, to the anode terminals of the first diode 203 and the second diode 204, respectively. The first diode 203 and the second diode 204 are connected to each other through a second capacitor 205 and a resistor 207 which supplies a control voltage of the VCO 206 through the chassis ground or the voltage- And the output of the VCO 206 whose output frequency is changed in accordance with the output of the TR 207 is connected to the gate terminal of the field effect transistor 1 (FET1) and the field effect transistor 2 (FET2) Axis power supply.

When the APD is operated in a state where the bias voltage is supplied, the current flowing in the APD rapidly increases, thereby reducing the voltage applied to the voltage-dividing resistors R1 and R2. When the voltage applied to the base decreases, the voltage of the base terminal of the transistor Tr becomes lower, the voltage of the emitter terminal of the transistor Tr, which is the control terminal of the VCO, is lowered and the output switching frequency of the VCO becomes lower. Lt; / RTI > Therefore, the impedance of the induction unit is lowered, and the current flowing in the induction unit is increased. By operating in this way, the current is quickly charged in the capacitor of the second high-voltage condenser 205, so that the time constant can be reduced.

Claims (1)

The bias voltage control circuit for the avalanche photodiode includes a voltage varying means for controlling the input DC voltage by a voltage control signal and outputting the voltage. The bias voltage control circuit controls the bias voltage to apply the output voltage to the APD, As a circuit,
Corresponding voltage output means corresponding to a temperature change for outputting a voltage at a temperature gradient of a reverse breakdown voltage of the APD and set voltage output means for outputting a set voltage for setting a voltage of the output terminal to a predetermined voltage;
The reference voltage is extracted from the voltage corresponding to the slope of the temperature corresponding voltage output means and the set voltage and a voltage control signal is generated so that the reference voltage and the voltage supplied through the resistor from the output terminal become equal, And the voltage changing means includes a variable resistance means capable of changing the resistance value by a control signal to convert the voltage control signal into a voltage control signal, A bias voltage control unit for setting a resistance value of the variable resistance means and controlling an input DC voltage;
A capacitor connected in parallel to the DC power supplied from the bias voltage control unit;
An induction unit connected to the direct current power source and connected to a drive circuit output terminal for supplying power to the laser diode or the avalanche photodiode;
A field effect transistor having an output terminal connected between the inductor and the output terminal of the driving circuit; A voltage controlled oscillator coupled to an input terminal of the field effect transistor;
And a photodiode driver configured by an input terminal of the voltage control oscillator and a transistor having an output terminal and an input terminal connected to an output terminal of the driving circuit, respectively, and a time constant single axis power source driver for detecting a particle, An apparatus for controlling a bias voltage of a photodiode.

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