CN215641868U

CN215641868U - PCB coil control system

Info

Publication number: CN215641868U
Application number: CN202121401550.6U
Authority: CN
Inventors: 周礼
Original assignee: Changsha Jingheng Electronic Technology Co ltd
Current assignee: Changsha Jingheng Electronic Technology Co ltd
Priority date: 2021-06-23
Filing date: 2021-06-23
Publication date: 2022-01-25
Anticipated expiration: 2031-06-23

Abstract

A PCB coil control system comprises a PCB coil and a control circuit, wherein the PCB coil comprises a main coil and a plurality of secondary coils; the control circuit comprises a microprocessor, a main coil driving unit and a secondary coil sampling unit; the output end of the microprocessor is connected with the main coil driving unit; the secondary coil is connected with the input end of the microprocessor through the secondary coil sampling unit; the secondary coil sampling unit comprises a signal amplifying circuit, and the output end of the main coil driving unit is connected with the main coil through a capacitor and is connected with the trigger end of the signal amplifying circuit through another capacitor. The utility model can obtain more enhanced and stable signal quality.

Description

PCB coil control system

Technical Field

The utility model relates to a PCB coil, in particular to a control system for the PCB coil.

Background

There are many methods for detecting the number of turns and direction of rotation of a metal object (e.g. a metal sheet) at a certain distance, such as a non-metal object rotating device and detecting system disclosed in CN 208736342U, which adopts a PCB coil structure in the form of one main coil and four secondary coils, or one main coil winding and three secondary coil windings. In either way, a problem is solved, that is, both the number of rotations of the metal object and the direction of rotation of the metal object are detected. The detection system comprises a Microprocessor (MCU), a pulse output circuit, a main coil driving circuit and an induction coil detection circuit, wherein the output end of the microprocessor is connected with a main coil through the main coil driving circuit, and each induction coil in a secondary coil is connected with the input end of the microprocessor through the induction coil detection circuit; the output end of the microprocessor is also connected with a pulse output circuit. The document does not provide specific structures of a main coil driving circuit and an induction coil detection circuit, and an output signal of the main coil driving circuit is only used as a driving signal of the main coil and is irrelevant to the induction coil detection circuit, so that the circuit structure is complex and the signal stability is poor.

SUMMERY OF THE UTILITY MODEL

The utility model aims to overcome the defects in the prior art and provide a PCB coil control system with simple circuit structure and high signal stability.

The technical scheme of the utility model is as follows: a PCB coil control system comprises a PCB coil and a control circuit, wherein the PCB coil comprises a main coil and a plurality of secondary coils; the control circuit comprises a microprocessor, a main coil driving unit and a secondary coil sampling unit; the output end of the microprocessor is connected with the main coil driving unit; the secondary coil is connected with the input end of the microprocessor through the secondary coil sampling unit; the secondary coil sampling unit comprises a signal amplifying circuit, and the output end of the main coil driving unit is connected with the main coil through a capacitor and is connected with the trigger end of the signal amplifying circuit through another capacitor.

Further, the main coil driving unit is a nand gate driving circuit or a nor gate driving circuit.

Further, the NAND gate driving circuit comprises a NAND gate chip, and a pin B of the NAND gate chip is connected with an IO output end of the microprocessor through a capacitor; pin A of the NAND gate chip is connected with a power supply, pin Y of the NAND gate chip is used as an output end, is connected with the main coil through a capacitor and is used as a high-frequency excitation signal, and is connected with a trigger end of the signal amplifying circuit through another capacitor and a resistor and is used as a trigger signal of the signal amplifying circuit.

Further, the NOT gate driving circuit comprises a NOT gate chip, and a pin 2A of the NOT gate chip is connected with an IO output end of the microprocessor through a capacitor; the pin VCC is connected with a power supply, the pin 1A and the pin 2Y are used as first output ends, and are connected with a trigger end of the signal amplification circuit through a capacitor and a resistor to be used as a trigger signal of the signal amplification circuit; and the pin 1Y is used as a second output end and is connected with the main coil through a capacitor to be used as a high-frequency excitation signal.

Further, the signal amplification circuit comprises a plurality of high-frequency triodes, and the number of the high-frequency triodes corresponds to the number of the secondary coils; the base electrode of the high-frequency triode is connected with the induction coil, the emitter electrode is used as a trigger end, the collector electrode is grounded through the capacitor, the collector electrode is also connected with the analog-to-digital conversion unit, and then the analog-to-digital conversion unit is connected with the microprocessor.

Further, the output end of the main coil driving unit is connected with the trigger end of the signal amplifying circuit through another capacitor and a resistor, and the capacitor is grounded through another resistor to form a charging and discharging circuit.

Further, the number of the secondary coils is four, each induction coil is distributed in two layers of the PCB, two induction coils and the main coil are distributed in one layer, the secondary coils are located in the main coil, the other two induction coils are distributed in the other layer, the two induction coils in each layer are connected in series, and the induction coils in the two adjacent layers are arranged at an angle of 90 degrees.

Further, the four induction coils are connected to a common terminal, i.e. a node between two induction coils is connected to a node between two other induction coils.

Furthermore, the secondary coil sampling unit is a single-path sampling or multi-path sampling circuit.

The utility model has the beneficial effects that: on one hand, the main coil driving unit uses high-speed logic devices such as a NAND gate or a NOT gate to carry out waveform shaping, the signal can be used as a driving signal of the main coil and also can be used as a trigger signal of a signal amplifying circuit of the secondary coil sampling unit, and in order to ensure the signal strength and the signal quality, the driving unit can be continuously triggered for multiple times to obtain more enhanced and stable signal quality; on the other hand, the secondary coil sampling unit circuit is simple and reliable, the stability is high, the sampling unit and the main coil driving unit can be synchronously triggered, the triggering time is short, the power consumption is low, and the anti-interference performance is strong.

Drawings

Fig. 1 is a schematic circuit connection diagram of a main coil driving unit according to embodiment 1 of the present invention;

FIG. 2 is a schematic diagram of the circuit connection of the output terminal of the NAND gate chip U1 according to embodiment 1 of the present invention;

FIG. 3 is a schematic circuit diagram of a secondary coil sampling unit according to embodiment 1 of the present invention;

fig. 4 is a schematic circuit connection diagram of a PCB coil of embodiment 1 of the present invention;

FIG. 5 is a schematic circuit diagram of a main coil driving unit according to embodiment 2 of the present invention;

FIG. 6 is a schematic circuit diagram of the output terminal of the NOT gate chip U4 according to embodiment 2 of the present invention;

FIG. 7 is a schematic circuit diagram of a secondary coil sampling unit according to embodiment 2 of the present invention;

fig. 8 is a schematic circuit connection diagram of the PCB coil of embodiment 2 of the present invention.

Detailed Description

The utility model will be described in further detail below with reference to the drawings and specific examples.

Example 1

As shown in FIGS. 1-4: a PCB coil control system comprises a PCB coil and a control circuit, wherein the PCB coil comprises a main coil L1 and a secondary coil, and the secondary coil comprises four induction coils L2-L5. Preferably, each of the induction coils is distributed in at least two layers of the multilayer PCB, for example, two induction coils L2 and L3 and the main coil L1 are distributed in one layer, and L2 and L3 are located in the main coil, while the other two induction coils L4 and L5 are distributed in the other layer, and the two induction coils in each layer are connected in series, and the induction coils in two adjacent layers are arranged at 90 °. The primary coil is used for sending out pulse oscillation signals, and the secondary coil is used for receiving the oscillation signals. The secondary coil in the embodiment has large area and high signal sensitivity, effectively improves the induction distance, increases the signal-to-noise ratio and improves the anti-interference capability.

The control circuit comprises a Microprocessor (MCU), a main coil driving unit and a secondary coil sampling unit; the output end of the microprocessor is connected with the main coil driving unit; the secondary coil is connected with the input end of the microprocessor through the secondary coil sampling unit; the secondary coil sampling unit comprises a signal amplifying circuit, and the output end of the main coil driving unit is connected with the main coil through a capacitor and is connected with the trigger end of the signal amplifying circuit through another capacitor.

As shown in fig. 1 and 2: in this embodiment, the main coil driving unit is implemented by using a nand gate chip. The NAND gate comprises a NAND gate chip U1, wherein a pin 2B of a U1 is connected with an INPUT port PULSE _ INPUT through a capacitor C2, and the PULSE _ INPUT port is connected with an IO output end of a microprocessor; the 1 pin a and the 5 pin VCC of the U1 are both connected between the power source VCC and the capacitor C1, and the 4 pin Y of the U1 is used as an OUTPUT terminal, i.e., PULSE _ OUTPUT, and is OUTPUT to the main coil L1 through the capacitor C3 as a high-frequency excitation signal.

The working principle of the main coil in this embodiment is as follows: when the IO output port of the MCU outputs a high-level effective TTL level PULSE signal to the PULSE _ INPUT port of the nand gate chip U1, after waveform shaping of U1, that is, nand processing between pin 2B and pin 1a, a low-level effective narrow PULSE signal can be output from the output pin Y of the nand gate U1, and this signal is output to the main coil L1 through the capacitor C3 as a high-frequency excitation signal.

As shown in fig. 3: in this embodiment, the secondary coil sampling unit includes two signal amplification chips U2 and U3; two high frequency triodes are respectively arranged in the U2 and the U3. The induction coils L2 and L3 are connected in series, and the induction coils L4 and L5 are connected in series, wherein two ends of the induction coils L2 and L3 are connected to GND through resistors R4 and R5 respectively to form a loop, two ends of the induction coils L4 and L5 are connected to GND through resistors R6 and R7 respectively to form a loop, and the induction coils L2 and L3 are also connected with bases of two high-frequency triodes, namely a pin 2 and a pin 3, of the signal amplification chip U2 respectively; similarly, the induction coils L4 and L5 are also respectively connected to the bases of two triacs of the signal amplification chip U3. The collectors of the U2 and U3 are grounded through capacitors C5, C6, C7 and C8, respectively, and the collector ends are connected with an analog-to-digital conversion unit (ADC) and then connected with the IO input end of the MCU through the ADC; the PULSE _ OUTPUT end of the main coil driving unit is connected with the emitting electrodes of the U2 and the U3 of the high-frequency triodes through a capacitor C4 and a resistor R2, and the capacitor C4 and the resistor R3 are connected in series to form a charging and discharging circuit. Wherein, the capacitors C3 and C4 are arranged in parallel.

The working principle of the secondary coil sampling unit in the embodiment is as follows: the induction coils L2 and L3 are connected in series, and the induction coils L4 and L5 are connected in series, and are connected to GND through resistors R4, R5, R6 and R7 to form a loop, and the connection points between the resistors R4, R5, R6 and R7 and the induction coils are in a low level state at ordinary times; when a high-frequency excitation signal appears in the main coil L1, the four induction coils L2, L3, L4 and L5 receive electromagnetic wave induction signals to generate induction current, and after the current flows through the resistors R4, R5, R6 and R7, terminal voltages are formed between the resistors R4, R5, R6 and R7 and the induction coils, and the voltage points are directly connected to the bases of the high-frequency triodes of the two signal amplification chips U2 and U3, so that the voltage is weak and can be used after being amplified by the high-frequency triodes of the U2 and U3. However, the transistor amplification condition needs to make the BE junction conductive to form a bias voltage, and the transistor can BE amplified only when entering the amplification region of the transistor, so that the capacitor C4 and the resistors R2 and R3 can play the auxiliary role. The capacitor C4 and the resistor R3 are connected in series to form a charging and discharging circuit. The OUTPUT of the PULSE _ OUTPUT pin is high level at ordinary times, and the voltage on the capacitor C4 is charged into a left positive and right negative level state; when a PULSE _ OUTPUT pin OUTPUTs a high-frequency PULSE signal with effective low level, the left side of a capacitor C4 is instantly converted into low level, because the voltage at two ends of the capacitor can not generate sudden change, the right end of the capacitor C4 has negative level of PULSE, the capacitor C4 is coupled to the emitter of a triode of a signal amplification chip U2 and U3 through a resistor R2, so that the triodes of U2 and U3 are in an amplification state in a short time, at the moment, a sensed weak electric signal is amplified and then OUTPUT from the collector of the triode to discharge to the capacitors C5, C6, C7 and C8, the voltage on the capacitors is reduced, the signal intensity can be judged by detecting the voltage on the capacitors through an ADC, and the MCU acquires the level value through the ADC to acquire the intensity of the signal to sense the position of a metal object, so that the rotation direction, the rotation position and the number of the metal object are detected.

The working principle of the embodiment is as follows: the main coil L1 receives a high-frequency pulse electrical signal sent by the main coil driving unit, a trace amount of high-frequency electromagnetic wave signals are induced from the secondary coil, a stable and balanced induced oscillating wave is formed after shaping and amplification of the sampling unit, when the four induction coils L2, L3, L4 and L5 are influenced by the external metal object 4 in different degrees, the balance of the oscillating wave can be influenced, different signal levels are output, and the metal object position is sensed through the change of the ADC detection level, so that the rotating direction, the rotating position and the number of turns of the metal object are detected.

Example 2

As shown in fig. 5 to 8: the difference from embodiment 1 is that the induction coils L2 are connected in series with L3, L4 is connected in series with L5, and the induction coils L2, L3, L4 and L5 are connected to a common end, that is, a node between the induction coils L2 and L3 is connected to a node between the induction coils L4 and L5, and the connection to the common end can enable the four induction coils to mutually influence and drag each other, so that a pinning effect is formed, and the induction of the metal sheet is more sensitive and effective.

The main coil driving unit is realized by adopting a NOT gate chip. The circuit specifically comprises a NOT gate chip U4, wherein a pin 3A 2 of a U4 is connected with an INPUT port PULSE _ INPUT through a capacitor C2, and the PULSE _ INPUT port is connected with an IO output end of a microprocessor; pin 5 VCC of U4 is connected between the power source VCC and the capacitor C1, pin 1A and pin 4 2Y of U4 serve as the first OUTPUT terminal, i.e., PULSE _ OUTPUT, and pin 6 1Y of U4 serves as the second OUTPUT terminal, i.e., PULSE _ OUTPUT _ 2. The end of PULSE _ OUTPUT _2 is connected to the main coil L1 through a capacitor C3.

In this embodiment, the secondary winding sampling unit is different from embodiment 1 in that the PULSE _ OUTPUT terminal is connected to four resistors R2, R8, R9 and R10 connected in parallel through a capacitor C4; the other ends of the resistors R2, R8, R9 and R10 are a NET _1 terminal, a NET _2 terminal, a NET _3 terminal and a NET _4 terminal, respectively.

The emitters of the triacs of the signal amplification chips U2 and U3 are separately connected, that is: a pin 5 of a high-frequency triode of the signal amplification chip U2 is connected with a NET _1 end, a pin 1 of the other high-frequency triode is connected with a NET _2 end, a pin 5 of a high-frequency triode of the signal amplification chip U3 is connected with a NET _3 end, and a pin 1 of the other high-frequency triode is connected with a NET _4 end.

The working principle of the circuit is similar to that of the embodiment, namely, the not gate has the function of performing waveform shaping by using the schmitt effect of the not gate so as to obtain a high-frequency PULSE signal, namely, an IO output port of the MCU outputs a low-level effective TTL level PULSE signal to a PULSE _ INPUT port of the not gate chip U4, after the "not" processing is performed between the 4-pin 2Y and the 3-pin 2A, a high-level effective narrow PULSE signal can be output, and the 4-pin 2Y is connected with the 1-pin 1A, so that after the "not" processing is performed at the 6-pin 1Y end, a low-level effective PULSE signal can be output, and after passing through the capacitor C3, the low-level effective PULSE signal can be output to the main coil L1 to serve as a high-frequency excitation signal. When the output of the 4-pin 2Y is a high-level effective high-frequency pulse signal, the voltage on the capacitor C4 is charged into a left positive and right negative level state; when the 4-pin 2Y outputs a high-frequency pulse signal with effective low level, the left side of the capacitor C4 is instantaneously converted into low level, because the voltage at two ends of the capacitor cannot generate sudden change, the negative level of the pulse appears at the right end of the capacitor C4, and the negative level is respectively coupled to the emitters of the high-frequency triodes of the signal amplification chips U2 and U3 through the resistors R2, R8, R9 and R10, so that the high-frequency triodes of the U2 and U3 are in an amplification state in a short time.

In summary, in the aspect of the present invention, the main coil driving unit uses a nand gate or a not gate or other high-speed logic device to perform waveform shaping, and the signal can be used as a driving signal of the main coil L1 and also as a trigger signal of a signal amplifying circuit of the secondary coil sampling unit, so that the driving unit can be continuously triggered for multiple times to ensure signal strength and signal quality, thereby obtaining more enhanced and stable signal quality; on the other hand, the secondary coil sampling unit can be designed into single-path sampling or multi-path sampling, the sampling mode can use a multi-pulse capacitor charging and discharging method to collect the change of the signal level, and the MCU acquires the level value through the ADC unit; or the MCU acquires a signal value by detecting the charge-discharge time of the capacitor; and the circuit is simple and effective, small in size, low in cost and high in reliability.

Claims

1. A PCB coil control system comprises a PCB coil and a control circuit, wherein the PCB coil comprises a main coil and a plurality of secondary coils; the control circuit is characterized by comprising a microprocessor, a main coil driving unit and a secondary coil sampling unit; the output end of the microprocessor is connected with the main coil driving unit; the secondary coil is connected with the input end of the microprocessor through the secondary coil sampling unit; the secondary coil sampling unit comprises a signal amplifying circuit, and the output end of the main coil driving unit is connected with the main coil through a capacitor and is connected with the trigger end of the signal amplifying circuit through another capacitor.

2. The PCB coil control system of claim 1, wherein the main coil driving unit is a nand gate driving circuit or a nor gate driving circuit.

3. The PCB coil control system of claim 2, wherein the NAND gate driving circuit comprises a NAND gate chip, and a pin B of the NAND gate chip is connected with an IO output end of the microprocessor through a capacitor; pin A of the NAND gate chip is connected with a power supply, pin Y of the NAND gate chip is used as an output end, is connected with the main coil through a capacitor and is used as a high-frequency excitation signal, and is connected with a trigger end of the signal amplifying circuit through another capacitor and a resistor and is used as a trigger signal of the signal amplifying circuit.

4. The PCB coil control system of claim 2, wherein the NOT gate driving circuit comprises a NOT gate chip, and a pin 2A of the NOT gate chip is connected with an IO output end of the microprocessor through a capacitor; the pin VCC is connected with a power supply, the pin 1A and the pin 2Y are used as first output ends, and are connected with a trigger end of the signal amplification circuit through a capacitor and a resistor to be used as a trigger signal of the signal amplification circuit; and the pin 1Y is used as a second output end and is connected with the main coil through a capacitor to be used as a high-frequency excitation signal.

5. The PCB coil control system according to any one of claims 1 to 4, wherein the signal amplification circuit comprises a number of triacs corresponding to the number of secondary coils; the base electrode of the high-frequency triode is connected with the induction coil, the emitter electrode is used as a trigger end, the collector electrode is grounded through the capacitor, the collector electrode is also connected with the analog-to-digital conversion unit, and then the analog-to-digital conversion unit is connected with the microprocessor.

6. The PCB coil control system of any one of claims 1 to 4, wherein the output end of the main coil driving unit is connected to a trigger end of the signal amplifying circuit through another capacitor and a resistor, and the capacitor is grounded through another resistor to form a charging and discharging circuit.

7. The PCB coil control system of any one of claims 1 to 4, wherein the number of the secondary coils is four, each induction coil is distributed in two layers of the PCB, two induction coils and the main coil are distributed in one layer, the secondary coil is located in the main coil, the other two induction coils are distributed in the other layer, two induction coils of each layer are connected in series, and the induction coils of two adjacent layers are arranged at 90 degrees.

8. The PCB coil control system of claim 7, wherein the four induction coils are connected to a common terminal, i.e. a node between two induction coils is connected to a node between two other induction coils.

9. The PCB coil control system of any one of claims 1 to 4, wherein the secondary coil sampling unit is a single-path sampling or multi-path sampling circuit.