CN205230179U

CN205230179U - Utilize inductance digital converter to realize bank note thickness check's circuit

Info

Publication number: CN205230179U
Application number: CN201520986421.6U
Authority: CN
Inventors: 刘立明
Original assignee: Shenzhen Yihua Computer Co Ltd; Shenzhen Yihua Time Technology Co Ltd; Shenzhen Yihua Financial Intelligent Research Institute
Current assignee: Shenzhen Yihua Computer Co Ltd; Shenzhen Yihua Time Technology Co Ltd; Shenzhen Yihua Financial Intelligent Research Institute
Priority date: 2015-12-02
Filing date: 2015-12-02
Publication date: 2016-05-11
Anticipated expiration: 2025-12-02

Abstract

The utility model provides an utilize inductance digital converter to realize bank note thickness check's circuit, including FPGA controller, inductance digital converter LDC1000Q1, LC oscillation circuit, power module, the FPGA controller carries out the communication with inductance digital converter LDC1000Q1 to the stable work of control LDC1000Q1, FPGA controller are sent control signal and are given LDC1000Q1, and LDC1000Q1 gives the FPGA controller with the data transmission who records, inductance digital converter drive LC oscillation circuit produces the electromagnetic field of reversal, and the inductance is the planar coil board, and power module is FPGA controller, inductance digital converter LDC1000Q1 and LC oscillation circuit power supply. The utility model provides a non -contact sensing technology, the dependable performance, it is smaller influenced by external environment, avoids receiving the influence of media such as dust, greasy dirt, can prolong the life of equipment.

Description

A kind of circuit utilizing inductance digital quantizer to realize stiff thickness detection

Technical field

The utility model relates to electronic circuit field, particularly relates to a kind of circuit utilizing inductance digital quantizer LDC1000Q1 to realize stiff thickness detection.

Background technology

In automatic teller machine, be a very the key link to the detection of stiff thickness, by the detection to stiff thickness, to judge the true and false of banknote.Traditional detection method is generally utilize ultrasound wave or hall principle to detect, but ultrasound wave is stable not, and precision is also short of to some extent, and easily by the impact of external environment; When hall principle detects, signal output nonlinear, and the impact being also subject to environment, as temperature etc.

Utility model content

Utilize the detection of eddy current principle realization to stiff thickness, it is a kind of very reliable, stable and implementation method that precision is high, this kind of method not only sensitivity resolution is high, and fast response time, measurement range are wide, interference resistance is strong, structure simply, not by the impact of the media such as greasy dirt.

The application is intended to utilize eddy current principle, realizes the accurate detection to stiff thickness by high performance integrated chip LDC1000Q1 and simple hardware circuit; When using this electric circuit inspection stiff thickness, hardware configuration is simple, requires lower, and with low cost, realizes than being easier to.

In order to solve problem in prior art, the utility model provides a kind of circuit utilizing inductance digital quantizer to realize stiff thickness detection, comprise FPGA controller, inductance digital quantizer LDC1000Q1, LC oscillatory circuit, power module, FPGA controller and inductance digital quantizer LDC1000Q1 carry out communication, and control LDC1000Q1 steady operation, FPGA controller transmits control signal, to LDC1000Q1, LDC1000Q1, the data recorded is transferred to FPGA controller; Inductance digital quantizer drives LC oscillatory circuit to produce the electromagnetic field of alternation, and inductance is planar line girth sheets, and power module is FPGA controller, inductance digital quantizer LDC1000Q1 and LC oscillatory circuit are powered.

As further improvement of the utility model, described FPGA controller carries out communication by SPI interface and inductance digital quantizer LDC1000Q1.

As further improvement of the utility model, inductance digital quantizer LDC1000Q1 is provided with 10 sense channels, and during control, passage gating carries out data acquisition respectively one by one.

As further improvement of the utility model, the 7V voltage of input is converted to the stable voltage of 5V, 3.3V and 1.2V by LDO power conversion chip by power module.

As further improvement of the utility model, in LC oscillatory circuit, coil plate is six layers, wherein has five layers of high-density coils through direct-connected.

As further improvement of the utility model, the oscillating capacitance C241 in LC oscillatory circuit is more than 470pF.

As further improvement of the utility model, C283, C284 two filter capacitors are provided with between LC oscillatory circuit and power supply, one end of C283, C284 two filter capacitors connects the two ends of the oscillating capacitance C241 in LC oscillatory circuit respectively, and the other end of C283, C284 two filter capacitors connects power supply.

As further improvement of the utility model, also comprise external crystal-controlled oscillation, described external crystal-controlled oscillation is connected with inductance digital quantizer LDC1000Q1, and described external crystal-controlled oscillation is 16 or 24M.

The beneficial effects of the utility model are:

The utility model provides contactless sensing technology, dependable performance, is affected by the external environment smaller, avoids the impact by the medium such as dust, greasy dirt, can serviceable life of extension device.

This LDC1000Q1 numeral inductance converter, can be used as sensor by the coil of low cost and spring, compared with existing sensor, can realize submicron resolution, high reliability and dirigibility under more low system cost.

Measuring accuracy is high, and when the distance of metallic conductor and inductive coil changes and causes induced impedance to change, the precision of the inductive coil eddy current resistance that LDC1000Q1 can detect is 16; LDC1000Q1 coordinates with inductance and produces LC oscillatory circuit, and oscillation frequency is relevant to inductance value, can measure the variable quantity of inductance value and inductance, and the precision of this inductance converter is 24, and the resonant frequency range that can detect is very wide, 5KHz ~ 5MHz.

In circuit, FPGA controller directly controls the work of inductance digital quantizer, and pilot process is simple, and integrated components and parts used are less, do not have too much signaling conversion circuit, and little by ectocine in transmitting procedure, antijamming capability is strong, and measuring accuracy is improved further.

Utilize the principle of eddy current effect, coil and spring can be used as inductance sensor by inductance digital quantizer LDC1000Q1, the relative position of Measurement accuracy measured body (metallic conductor) and probe end face, the change calculations stiff thickness of the alternating electromagnetic field induced impedance relying on the slight change of distance to cause is a kind of non-contacting linearization metering outfit.

Circuit hardware realizing circuit structure is simple, and system power dissipation is lower, and LDC1000Q1 standard operation power consumption is less than 8.5mW, and under standby mode, power consumption is less than 1.25mW.

Accompanying drawing explanation

Fig. 1 is the utility model principle framework structural representation;

Fig. 2 is a kind of circuit diagram utilizing inductance digital quantizer to realize stiff thickness detection of the utility model;

Fig. 3 is that the utility model plane inductive coil and planar metal plate form current vortex sensor.

In figure, each component names is as follows:

Inductive coil 100, metallic conductor 200.

Embodiment

Below in conjunction with accompanying drawing, the utility model is described further.

As shown in Figure 1, FPGA (field programmable gate array) controller, by SPI interface, carries out communication with inductance digital quantizer LDC1000Q1, and control LDC1000Q1 steady operation; Inductance digital quantizer drives LC oscillatory circuit to produce the electromagnetic field of alternation, and wherein inductance is planar line girth sheets; This realizing circuit has 10 sense channels, and during control, passage gating carries out data acquisition respectively one by one.The 7V voltage of input is converted to the stable voltage supply corresponding module of 5V, 3.3V and 1.2V by LDO (low pressure difference linear voltage regulator) power conversion chip by power module.FPGA supply voltage needs 3.3V and 1.2V; LDC1000Q1 supply voltage needs 3.3V and 5V (as Fig. 2); LC oscillatory circuit is connected directly between on LDC1000Q1, is powered by LDC1000Q1, does not need independent power supply.In addition, also have other chip modules to need power supply in complete circuit design, as MAX3232 level switch module need be powered 3.3V, outside Flash memory chip need be powered 3.3V etc.

As Fig. 2, inductance digital conversion chip LDC1000Q1, pin 1,2,3,5 is SPI (Serial Peripheral Interface (SPI)) interface of itself and FPGA communication, and FPGA controller transmits control signal, to LDC1000Q1, LDC1000Q1, the data recorded is transferred to FPGA controller.

Coil plate is six layers, being wherein has five layers of high-density coils through direct-connected (L4), and oscillating capacitance (C241) is more than 470pF, and namely now the inductance L of LC oscillatory circuit, electric capacity C are larger.Be provided with C283, C284 two filter capacitors, oscillator signal is obviously stable a lot.

Increase vibration inductance and electric capacity, resonance frequency during now oscillatory circuit work is smaller, can be low to moderate hundreds of K, obviously can be subject to outside and the electromagnetic interference (EMI) to outside in reduction work like this; The sensitivity of Coil Detector significantly improves; Measured data shows simultaneously, and under inductance, electric capacity increase rational condition, monotonicity and the stability of sensor detecting distance image data all have clear improvement.

Fig. 2 lower left corner, be 16 or 24M external crystal-controlled oscillation, chip clock frequency obviously increases a lot.Actual effect shows, increases chip operation clock frequency, and during test banknote under the change of identical measuring distance, the data difference gathered before and after test obviously increases, and the sensitivity namely detecting stiff thickness is obviously increased.

Timing strobe controls: directly by FPGA controller, exports A, B two-way SPI signal and controls front 5 passages and rear 6 channels operation respectively.When working on power, FPGA controller selects the work of pin control chip by the CSB sheet controlling each road LDC1000Q1 chip, and its course of work is as follows:

1, power on stable after, controller simultaneously gating 1,6 passage LDC1000Q1 works simultaneously, and the LC oscillatory circuit work of 1,6 passages, exports the electromagnetic field of alternation.

2, LDC1000Q1 is by responding to the variable quantity of sheet metal and coil distance, is converted into digital signal and sends controller FPGA to, and this signal detected is resonant frequency value.

3, controller judges stiff thickness, with or without adhesive tape etc. according to the variable quantity of numerical value.

4, carry out the switching of passage, repeat the data acquisition of 1 ~ 4.

In the whole course of work, passage bridge order is 1,5,2,7,3,8,4,9,5,10, and totally 5 groups are carried out work respectively, then circulation gating work.

This kind 1,5,2,7,3,8,4,9,5,10, the gated fashion of points 5 groups, two passages simultaneously worked at a distance of distant, work at the same time the electromagnetic field producing high-frequency alternating time, do not have mutual electromagnetic interference (EMI) between it; For the passage of each work, be just equivalent to only have one in work, now the job stability of whole sensor and antijamming capability obviously strengthen.

L4 in Fig. 2 is plane inductive coil, and its effect forms current vortex sensor with planar metal plate, as shown in Figure 3.When producing the electromagnetic field of alternation in coil, induce corresponding alternating electromagnetic field on a metal plate; When detecting banknote, the distance X between sheet metal and coil plate changes, and corresponding change can occur for the induced impedance of coil alternating magnetic field and resonance frequency; The data of change are given FPGA controller through conversion by SPI oral instructions by inductance digital quantizer LDC1000Q1; FPGA draws the variable quantity of distance by corresponding computing formula, i.e. the thickness of banknote, reaches the object of detection.

Above content is in conjunction with concrete preferred implementation further detailed description of the utility model, can not assert that concrete enforcement of the present utility model is confined to these explanations.For the utility model person of an ordinary skill in the technical field, without departing from the concept of the premise utility, some simple deduction or replace can also be made, all should be considered as belonging to protection domain of the present utility model.

Claims

1. the circuit utilizing inductance digital quantizer to realize stiff thickness detection, it is characterized in that: comprise FPGA controller, inductance digital quantizer LDC1000Q1, LC oscillatory circuit, power module, FPGA controller and inductance digital quantizer LDC1000Q1 carry out communication, and control LDC1000Q1 steady operation, FPGA controller transmits control signal, to LDC1000Q1, LDC1000Q1, the data recorded is transferred to FPGA controller; Inductance digital quantizer drives LC oscillatory circuit to produce the electromagnetic field of alternation, and inductance is planar line girth sheets, and power module is FPGA controller, inductance digital quantizer LDC1000Q1 and LC oscillatory circuit are powered.

2. a kind of circuit utilizing inductance digital quantizer to realize stiff thickness detection according to claim 1, is characterized in that: described FPGA controller carries out communication by SPI interface and inductance digital quantizer LDC1000Q1.

3. a kind of circuit utilizing inductance digital quantizer to realize stiff thickness detection according to claim 1, is characterized in that: inductance digital quantizer LDC1000Q1 is provided with 10 sense channels, and during control, passage gating carries out data acquisition respectively one by one.

4. a kind of circuit utilizing inductance digital quantizer to realize stiff thickness detection according to claim 1, is characterized in that: the 7V voltage of input is converted to the stable voltage of 5V, 3.3V and 1.2V by LDO power conversion chip by power module.

5. a kind of circuit utilizing inductance digital quantizer to realize stiff thickness detection according to claim 1, it is characterized in that: in LC oscillatory circuit, coil plate is six layers, wherein has five layers of high-density coils through direct-connected.

6. a kind of circuit utilizing inductance digital quantizer to realize stiff thickness detection according to claim 1, is characterized in that: the oscillating capacitance C241 in LC oscillatory circuit is more than 470pF.

7. a kind of circuit utilizing inductance digital quantizer to realize stiff thickness detection according to claim 1, it is characterized in that: between LC oscillatory circuit and power supply, be provided with C283, C284 two filter capacitors, one end of C283, C284 two filter capacitors connects the two ends of the oscillating capacitance C241 in LC oscillatory circuit respectively, and the other end of C283, C284 two filter capacitors connects power supply.

8. a kind of circuit utilizing inductance digital quantizer to realize stiff thickness to detect according to claim 1, it is characterized in that: also comprise external crystal-controlled oscillation, described external crystal-controlled oscillation is connected with inductance digital quantizer LDC1000Q1, and described external crystal-controlled oscillation is 16 or 24M.