Ion implanter arcing power supply circuit and feedback control method thereof

Abstract

The invention relates to the technical field of control circuits, and discloses a feedback control method for an arcing power supply circuit of an ion implanter, and the power supply circuit comprises an input circuit, an output circuit, a control circuit and a display circuit. The input circuit comprises a master control IC chip and three groups of transformer coils for supplying power to the master control IC chip, the three groups of transformer coils comprise a group of primary coils and two groups of secondary coils, one group of secondary coils is + 20V and supplies power to the master control IC chip, and the other group of secondary coils generate three direct current power supplies. According to the arcing power supply circuit of the ion implanter and the feedback control method of the arcing power supply circuit, when the content input by a user is set voltage, the voltage feedback circuit operates, when the content input by the user is set current, the current feedback circuit operates, and the voltage and the current in the circuit are controlled in a feedback control mode, so that feedback regulation of the circuit is realized; the existence of environment variables in the circuit can be adaptively adjusted, and the power supply circuit is effectively protected.

Description

Technical Field

[0001] The invention relates to the technical field of arc starting power supply, in particular to an arc starting power supply circuit of an ion implanter and a feedback control method thereof. Background Art

[0002] Traditional AD-DC power supplies usually adopt a linear power supply working mode. First, a power frequency transformer is used to convert high-voltage AC into low-voltage AC, and then low-voltage and high-current DC is output through diode rectification, filtering and other circuits. The output power change is adjusted by adjusting the load size of the adjustment tube. This causes the adjustment tube working in a linear state to generate a lot of heat, resulting in a large amount of power loss and very low efficiency. In addition, the huge power frequency transformer also makes the power supply very bulky.

[0003] Switching power supplies can solve the shortcomings of linear power supplies, such as low efficiency, large size, and bulky body. By increasing the frequency, the switching power supply greatly reduces the size of the transformer and capacitor. At the same time, the PWM wave generated by the integrated PWM switch chip can adjust the output power by controlling the PWM frequency or duty cycle to achieve the purpose of improving efficiency and reducing the heat of the power supply. The input voltage range of the switching power supply can also be made very wide, and when the input voltage fluctuates, the output can also be very stable. In different countries and regions, the AC input voltage is different, and the voltage fluctuates by about 10%. The wide voltage input of the switching power supply also makes it more widely applicable.

[0004] In the prior art, the power supply circuit will experience different voltages and currents during use, and in the process of feedback control, it is impossible to quickly and effectively adjust the data feedback of the power supply circuit, resulting in a very small feedback range of the power supply circuit in the actual working process, and it cannot be used normally in larger dynamic data; in view of this, we propose an arc starting power supply circuit for an ion implanter and a feedback control method thereof. Summary of the invention

[0005] The object of the present invention is to provide an arc starting power supply circuit of an ion implanter and a feedback control method thereof, so as to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions: an arc starting power supply circuit for an ion implanter, the power supply circuit comprising an input circuit, an output circuit, a control circuit and a display circuit, the input circuit comprising a main control IC chip, three groups of transformer coils for supplying power to the main control IC chip, the three groups of transformer coils comprising a group of primary coils and two groups of secondary coils, one group of the secondary coils being +20V and supplying power to the main control IC chip, and the other group of the secondary coils generating three DC power supplies, the output voltages of the DC power supplies being +15V, -15V and +5V, respectively, supplying power to the control circuit and the cooling fan, respectively;

[0007] The output circuit includes a circuit conversion circuit, a rectification and filtering anti-reverse circuit and a current and voltage feedback circuit.

[0008] The circuit conversion circuit includes four groups of MOS tubes;

[0009] The rectifier, filter and anti-reverse circuit includes an inductor L8, one end of the inductor L8 is electrically connected to the positive electrode of the capacitor CD1, the negative electrode of the capacitor CD1 is electrically connected to the second end of the inductor L8, and the capacitor CD1 is connected in parallel with the capacitor CD6, the resistor R11 and the resistor R12.

[0010] Optionally, the current-voltage feedback circuit includes an operational amplifier OPA, wherein terminal 2 of the operational amplifier OPA is electrically connected to one end of a resistor R29, the other end of the resistor R29 is electrically connected to terminal 6 of the operational amplifier OPA, and terminal 4 of the operational amplifier OPA is electrically connected to a -15V terminal.

[0011] Optionally, the control circuit includes three groups of CD4051B analog multiplexers, and the three groups of CD4051B analog multiplexers respectively select the set voltage signal, the current signal and the overvoltage protection signal, and the 9th, 10th and 11th pins of the CD4051B analog multiplexer are selection pins.

[0012] The present invention also proposes a feedback control method for an arc starting power supply circuit of an ion implanter, wherein the control system method comprises the following steps:

[0013] S1, current partial feedback, set the current signal range, corresponding to the actual output current 0-7A, the sampling resistor will sample back the actual output current signal; amplify the signal to 0-5V and give it to the inverting input of the operational amplifier; given the set current signal range, after processing, give it to the non-inverting input of the operational amplifier;

[0014] S2, voltage part feedback, set the voltage signal range, corresponding to the actual output voltage 0-150V, the sampling circuit samples the actual output voltage signal, and then amplifies the signal to 0-5V and gives it to the inverting input of the operational amplifier; given the set voltage signal range, it is processed and given to the non-inverting input of the operational amplifier;

[0015] S3, when the user inputs a set voltage, the voltage feedback circuit operates; when the user inputs a set current, the current feedback circuit operates;

[0016] S4, feedback protection processing, if the content input by the user does not belong to the set current signal range and the given voltage signal range, feedback error processing is performed and the power supply circuit is shut down to protect the circuit from being burned.

[0017] Optionally, a type 3 compensator is used in S1, which increases the phase to 180°, where Z f is the equivalent impedance on the operational amplifier, Z i is the equivalent impedance of the input terminal, where Z f The expression is:

[0018]

[0019] Compensator transfer function

[0020] Optionally, the S1 further comprises:

[0021] If the actual output current at the set instant is greater than the set current, the voltage at the inverting input of the operational amplifier is higher than that at the non-inverting input, the output of the operational amplifier decreases, the level of pin 2 of UC3524ADWTR also decreases, and the output pulse width waveform also becomes narrower, further reducing the output current until the actual output current is equal to the set current, and the output current is stabilized through the feedback loop;

[0022] On the contrary, if the actual output current is less than the set current, the voltage at the inverting input of the operational amplifier is lower than that at the non-inverting input, the output of the operational amplifier increases, the level of pin 2 of UC3524ADWTR also increases, and the output pulse width waveform also becomes wider, further increasing the output current until the actual output current is equal to the set current, and the output current reaches stability through the feedback loop.

[0023] Optionally, the S2 comprises: a voltage feedback loop:

[0024]

[0025]

[0026] The zero poles are configured according to the attenuation and phase improvement at the crossover frequency required by the current loop compensator; the calculation results are: R 8 =2.7KΩ, C NC18 =0, C 2 =22nF, R 19 =1KΩ, R 20 =2.2KΩ, C 12 =220nF.

[0027] Optionally, the S2 further includes:

[0028] For the current feedback loop:

[0029]

[0030] Configure the zero poles according to the attenuation and phase improvement at the crossover frequency required by the voltage loop compensator; calculate: R 9 =470KΩ, C NC6 =0, C 13 =22nF, R 10 =1KΩ, R 18 =15KΩ, C 3 =220nF;

[0031] If the actual output voltage at the set instant is higher than the set voltage, the voltage at the inverting input of the operational amplifier will be higher than that at the non-inverting input, the output of the operational amplifier will decrease, the level of pin 2 of UC3524ADWTR will also decrease, and the output pulse width waveform will also become narrower, further reducing the output voltage until the actual output voltage is equal to the set voltage, and the output voltage will be stable through the feedback loop;

[0032] On the contrary, if the actual output voltage is lower than the set voltage, the voltage at the inverting input of the operational amplifier is lower than the non-inverting input, the output of the operational amplifier increases, the level of pin 2 of UC3524ADWTR also increases, and the output pulse width waveform also becomes wider, further increasing the output voltage until the actual output voltage is equal to the set voltage, and the output voltage is stabilized through the feedback loop.

[0033] Optionally, the current signal range is set to 0-10V in S1.

[0034] Optionally, the voltage signal range is set to 0-10V in S2.

[0035] Compared with the prior art, the present invention provides an arc starting power supply circuit for an ion implanter and a feedback control method thereof, which has the following beneficial effects:

[0036] The arc starting power supply circuit of the ion implanter and the feedback control method thereof operate the voltage feedback circuit when the user inputs a set voltage, and operate the current feedback circuit when the user inputs a set current. The voltage and current in the circuit are controlled by feedback control, thereby realizing feedback regulation of the circuit, being able to adaptively adjust the existence of environmental variables in the circuit, and effectively protecting the power supply circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the input circuit part of the present invention;

[0038] Figure 2 It is a schematic diagram of the input circuit part of the present invention;

[0039] Figure 3 It is a schematic diagram of the power conversion circuit of the present invention;

[0040] Figure 4 This is a schematic diagram of the rectifier, filter and anti-reverse circuit of the present invention;

[0041] Figure 5 This is a schematic diagram of a voltage and current feedback circuit of the present invention;

[0042] Figure 6 is a schematic diagram of the control circuit part of the present invention;

[0043] Figure 7 is a schematic diagram of the control circuit part of the present invention;

[0044] Figure 8 is a schematic diagram of the control circuit part of the present invention;

[0045] Fig. 9 is a schematic diagram of the control circuit part of the present invention;

[0046] Fig.10 A circuit diagram showing the present invention. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] like Figure 1-Figure 10 As shown, the present invention provides a technical solution: an arc starting power supply circuit of an ion implanter and a feedback control method thereof, wherein the power supply circuit includes an input circuit, an output circuit, a control circuit and a display circuit.

[0049] The input circuit includes a main control IC chip, three sets of transformer coils for powering the main control IC chip, the three sets of transformer coils include a set of primary coils and two sets of secondary coils, one set of secondary coils is +20V and powers the main control IC chip, and the other set of secondary coils generates three DC power supplies, the output voltages of the DC power supplies are +15V, -15V and +5V, respectively, to power the control circuit and the cooling fan;

[0050] Among them, the AC power enters the EMC circuit through the AC input socket, including input fuse, X capacitor, Y capacitor and common mode inductor; then the subsequent rectification and filtering circuit is pre-charged through the series power resistor, and the two ends of the power resistor are connected in parallel with the relay. After the pre-charging is completed, the relay is turned on, the power resistor is short-circuited, and the circuit starts to work normally; the circuit after rectification and filtering is sent to the full bridge behind. At the same time, the wire is connected in the middle of the filter capacitor to make the 230VAC and 115AC switchable design.

[0051] The output circuit includes a circuit conversion circuit, a rectifier filter anti-reverse circuit and a current and voltage feedback circuit. The circuit conversion circuit includes four groups of MOS tubes; the rectifier filter anti-reverse circuit includes an inductor L8, one end of the inductor L8 is electrically connected to the positive electrode of the capacitor CD1, the negative electrode of the capacitor CD1 is electrically connected to the two ends of the inductor L8, and the capacitor CD1 is connected in parallel with the capacitor CD6, the resistor R11 and the resistor R12. The current and voltage feedback circuit includes an operational amplifier OPA, the two ends of the operational amplifier OPA are electrically connected to one end of the resistor R29, the other end of the resistor R29 is electrically connected to the six ends of the operational amplifier OPA, and the four ends of the operational amplifier OPA are electrically connected to the -15V end.

[0052] Before the output circuit of the current and voltage feedback circuit reaches the output, a 5mΩ sampling resistor is connected in series. The output current signal is monitored by monitoring the voltage across the sampling resistor. Since the voltage across the sampling resistor is very small, it is necessary to amplify the small voltage signal through an amplifier circuit for further processing. This design uses a differential amplifier circuit built with OPA177GP to amplify the voltage signal across the sampling resistor by 20 times. The potentiometer VR1 can adjust the bias of the amplifier to compensate for the impact of temperature changes. The output current feedback signal is divided by two sets of resistors and given to the subsequent control circuit and display circuit. The two feedback signals can be adjusted independently by two potentiometers, which is convenient for correcting subsequent current parameters. Voltage sampling: Voltage sampling directly collects the voltage signal at both ends of the output, and gives it to the subsequent control circuit and display circuit in the form of two sets of resistor dividers with a suitable voltage value. At the same time, an independent potentiometer is also designed to facilitate the correction of subsequent voltage-related parameters.

[0053] The control circuit includes three groups of CD4051B analog multiplexers, which respectively select the set voltage signal, current signal and overvoltage protection signal. Pins 9, 10 and 11 of the CD4051B analog multiplexer are selection pins. Eight combinations are generated through the different high and low levels of the three pins to select different channel switch setting working modes, so that the local set voltage signal or the remote set voltage signal passes through the CD4051B;

[0054] The control circuit is built around TI's PWM pulse width modulation chip - UC3524ADWTR. The chip is highly integrated and contains a 5V reference source. The maximum output current can reach 20mA. The UC3524 chip integrates an error amplifier. The in-phase input terminal of the error amplifier is pin 2, the inverting input terminal is pin 1, and the output terminal is pin 9. The output signal obtained by the feedback comparison part enters the UC3524ADWTR through the in-phase input terminal pin 2; Pin 10 is the control shutdown terminal SD (Shutdown). By using an external circuit to control the conduction and cutoff of the transistor inside the chip, the output pulse can be controlled to work and shut down, thereby realizing various protection functions of the power supply; At the same time, the chip also includes current limiting circuits, triggers, comparators, output transistors and other parts. The phase-shifted full-bridge pulse width modulation signal controlled by the input signal is output through the CA and CB pins and given to the optocoupler of the aforementioned MOS drive circuit;

[0055] Power-off protection and remote switch circuits, etc. This part of the circuit is mainly built around the BU4051BCFV chip. The BU4051BCFV is an eight-channel analog multiplexer switch with the ability to select mixed analog signals and digital signals. The digital signal of the control terminal turns on the corresponding switch of each channel. The remote control switch signal is added to the control terminal of one of the BU4051BCFV to remotely control the output of the power supply. After the over-temperature signal and the power-off protection signal are processed by the 358 amplifier, they are added to the control terminal of another BU4051BCFV. The output control signal of the BU4051BCFV is finally given to the 10-pin SD terminal of the UC3524ADWTR through the optical coupler, so that the master control UC3524ADWTR turns off the output and the power supply is protected.

[0056] The display circuit includes a display control chip TC7107CKW, which converts analog signals into digital signals and displays the analog quantities through a 3-digit digital tube.

[0057] Directly convert analog signals into digital signals and display the analog quantities through 3-digit digital tubes, which is very convenient and flexible to build ammeters and voltmeters. This design also uses TC74HC4052A as a multiplexer. The key switch is used to select the real-time output voltage and current or the set voltage and current. The analog signals of voltage and current are divided by resistors and added to INHI and INLO of TC7107CKW. The potentiometer can be adjusted to correct the display values ​​of the ammeter and voltmeter. This part of the circuit also includes LED power supply + delayed start circuit and negative power generation circuit.

[0058] This embodiment also proposes a feedback control method for an arc starting power supply circuit of an ion implanter. The control system method includes the following steps:

[0059] S1, current partial feedback, set the current signal range, corresponding to the actual output current 0-7A, the sampling resistor will sample back the actual output current signal; amplify the signal to 0-5V and give it to the inverting input of the operational amplifier; given the set current signal range, after processing, give it to the non-inverting input of the operational amplifier, and set the current signal range to 0-10V;

[0060] S2, voltage part feedback, set voltage signal range, corresponding to the actual output voltage 0-150V, the sampling circuit samples the actual output voltage signal, and then amplifies the signal to 0-5V, and gives it to the inverting input terminal of the operational amplifier; given the set voltage signal range, it is processed and given to the non-inverting input terminal of the operational amplifier, and the voltage signal range is set to 0-10V;

[0061] S3. When the content input by the user is to set the voltage, the voltage feedback circuit operates; when the content input by the user is to set the current, the current feedback circuit operates.

[0062] S1 uses a type 3 compensator, which increases the phase to 180°, where Z f is the equivalent impedance on the operational amplifier, Z i is the equivalent impedance of the input terminal, where Z f The expression is:

[0063]

[0064] Compensator transfer function

[0065] For the voltage feedback loop:

[0066]

[0067] Configure the zero poles according to the attenuation and phase improvement at the crossover frequency required by the voltage loop compensator; calculate: R9 =470KΩ, C NC6 =0, C 13 =22nF, R 10 =1KΩ, R 18 =15KΩ, C 3 =220nF;

[0068] If the actual output voltage at the set instant is higher than the set voltage, the voltage at the inverting input of the operational amplifier will be higher than that at the non-inverting input, the output of the operational amplifier will decrease, the level of pin 2 of UC3524ADWTR will also decrease, and the output pulse width waveform will also become narrower, further reducing the output voltage until the actual output voltage is equal to the set voltage, and the output voltage will be stable through the feedback loop;

[0069] On the contrary, if the actual output voltage is lower than the set voltage, the voltage at the inverting input of the operational amplifier is lower than the non-inverting input, the output of the operational amplifier increases, the level of pin 2 of UC3524ADWTR also increases, and the output pulse width waveform also becomes wider, further increasing the output voltage until the actual output voltage is equal to the set voltage, and the output voltage is stabilized through the feedback loop.

[0070] The current feedback loop in S2 is:

[0071]

[0072]

[0073] The zero poles are configured according to the attenuation and phase improvement at the crossover frequency required by the current loop compensator; the calculation results are: R 8 =2.7KΩ, C NC18 =0, C 2 =22nF, R 19 =1KΩ, R 20 =2.2KΩ, C 12 =220nF.

[0074] If the actual output current at the set instant is greater than the set current, the voltage at the inverting input of the operational amplifier is higher than that at the non-inverting input, the output of the operational amplifier decreases, the level of pin 2 of UC3524ADWTR also decreases, and the output pulse width waveform also becomes narrower, further reducing the output current until the actual output current is equal to the set current, and the output current is stabilized through the feedback loop;

[0075] On the contrary, if the actual output current is less than the set current, the voltage of the inverting input terminal of the operational amplifier is lower than that of the non-inverting input terminal, the output of the operational amplifier increases, the level of pin 2 of UC3524ADWTR also increases, and the output pulse width waveform also becomes wider, further increasing the output current until the actual output current is equal to the set current, and the output current reaches stability through the feedback loop;

[0076] S4, feedback protection processing, if the content input by the user does not belong to the set current signal range and the given voltage signal range, feedback error processing is performed and the power supply circuit is shut down to protect the circuit from being burned.

[0077] The above generally describes the present invention in detail, but it is obvious to a person skilled in the art that some modifications or improvements can be made to the present invention. Therefore, modifications or improvements that do not depart from the spirit of the present invention are within the scope of protection of the present invention.

Claims

1. A feedback control method for an arc starting power supply circuit of an ion implanter, characterized in that: The control system method comprises the following steps: S1, current partial feedback, set the current signal range, corresponding to the actual output current 0-7A, the sampling resistor will sample back the actual output current signal; amplify the signal to 0-5V and give it to the inverting input of the operational amplifier; given the set current signal range, after processing, give it to the non-inverting input of the operational amplifier; S2, voltage part feedback, set the voltage signal range, corresponding to the actual output voltage 0-150V, the sampling circuit samples the actual output voltage signal, and then amplifies the signal to 0-5V and gives it to the inverting input of the operational amplifier; given the set voltage signal range, it is processed and given to the non-inverting input of the operational amplifier; S3, when the user inputs a set voltage, the voltage feedback circuit operates; when the user inputs a set current, the current feedback circuit operates; S4, feedback protection processing, if the content input by the user does not belong to the set current signal range and the given voltage signal range, feedback error processing is performed and the power supply circuit is shut down.

2. The feedback control method of the arc starting power supply circuit of an ion implanter according to claim 1, characterized in that: The S1 uses a type 3 compensator, which increases the phase to 180°, where Z f is the equivalent impedance on the operational amplifier, Z i is the equivalent impedance of the input terminal, where Z f The expression is: Compensator transfer function 3. The feedback control method of the arc starting power supply circuit of an ion implanter according to claim 2, characterized in that: Said S1 further comprises: If the actual output current at the set instant is greater than the set current, the voltage at the inverting input of the operational amplifier is higher than that at the non-inverting input, the output of the operational amplifier decreases, the level of pin 2 of UC3524ADWTR also decreases, and the output pulse width waveform also becomes narrower, further reducing the output current until the actual output current is equal to the set current, and the output current is stabilized through the feedback loop; On the contrary, if the actual output current is less than the set current, the voltage at the inverting input of the operational amplifier is lower than that at the non-inverting input, the output of the operational amplifier increases, the level of pin 2 of UC3524ADWTR also increases, and the output pulse width waveform also becomes wider, further increasing the output current until the actual output current is equal to the set current, and the output current reaches stability through the feedback loop.

4. The feedback control method of the arc starting power supply circuit of an ion implanter according to claim 1, characterized in that: The S2 includes: the voltage feedback loop: The zero poles are configured according to the attenuation and phase improvement at the crossover frequency required by the current loop compensator; the calculation results are: R8 = 2.7KΩ, C NC18 =0, C2 = 22nF, R 19 =1KΩ, R 20 =2.2KΩ, C 12 =220nF.

5. The feedback control method of the arc starting power supply circuit of an ion implanter according to claim 4, characterized in that: Said S2 further comprises: For the current feedback loop: The zero poles are configured according to the attenuation and phase enhancement at the crossover frequency required by the voltage loop compensator; the calculation results are: R9 = 470KΩ, C NC6 =0, C 13 =22nF, R 10 =1KΩ, R 18 =15KΩ, C3=220nF; If the actual output voltage at the set instant is higher than the set voltage, the voltage at the inverting input of the operational amplifier will be higher than that at the non-inverting input, the output of the operational amplifier will decrease, the level of pin 2 of UC3524ADWTR will also decrease, and the output pulse width waveform will also become narrower, further reducing the output voltage until the actual output voltage is equal to the set voltage, and the output voltage will be stable through the feedback loop; On the contrary, if the actual output voltage is lower than the set voltage, the voltage at the inverting input of the operational amplifier is lower than the non-inverting input, the output of the operational amplifier increases, the level of pin 2 of UC3524ADWTR also increases, and the output pulse width waveform also becomes wider, further increasing the output voltage until the actual output voltage is equal to the set voltage, and the output voltage is stabilized through the feedback loop.

6. The feedback control method of the arc starting power supply circuit of an ion implanter according to claim 1, characterized in that: The current signal range is set to 0-10V in S1.

7. The feedback control method of the arc starting power supply circuit of an ion implanter according to claim 1, characterized in that: The voltage signal range is set to 0-10V in S2.

8. An arc starting power supply circuit for an ion implanter as claimed in any one of claims 1 to 7, characterized in that: The power supply circuit includes an input circuit, an output circuit, a control circuit and a display circuit. The input circuit includes a main control IC chip and three groups of transformer coils for powering the main control IC chip. The three groups of transformer coils include a group of primary coils and two groups of secondary coils. One group of secondary coils is +20V and powers the main control IC chip. The other group of secondary coils generates three DC power supplies. The output voltages of the DC power supplies are +15V, -15V and +5V, respectively, which power the control circuit and the cooling fan. The output circuit includes a circuit conversion circuit, a rectifier filter anti-reverse circuit and a current and voltage feedback circuit; The circuit conversion circuit includes four groups of MOS tubes; The rectifier, filter and anti-reverse circuit includes an inductor L8, one end of the inductor L8 is electrically connected to the positive electrode of the capacitor CD1, the negative electrode of the capacitor CD1 is electrically connected to the second end of the inductor L8, and the capacitor CD1 is connected in parallel with the capacitor CD6, the resistor R11 and the resistor R12.

9. The arc starting power supply circuit of an ion implanter according to claim 8, characterized in that: The current-voltage feedback circuit includes an operational amplifier OPA, wherein terminal 2 of the operational amplifier OPA is electrically connected to one end of a resistor R29, the other end of the resistor R29 is electrically connected to terminal 6 of the operational amplifier OPA, and terminal 4 of the operational amplifier OPA is electrically connected to a -15V terminal.

10. The arc starting power supply circuit of an ion implanter according to claim 8, characterized in that: The control circuit includes three groups of CD4051B analog multiplexers, and the three groups of CD4051B analog multiplexers respectively select and set voltage signals, current signals and overvoltage protection signals. Pins 9, 10 and 11 of the CD4051B analog multiplexers are selection pins.

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