CN217404501U - Medical operation shadowless lamp multichannel LED automatic checkout circuit - Google Patents

Abstract

The utility model discloses a medical operation shadowless lamp multichannel LED automatic detection circuit, which comprises an auxiliary single chip microcomputer, a current sampling circuit, a chip selection circuit, an auxiliary enabling circuit and a driving chip, wherein the current sampling circuit is used for sending lamp string sampling current to the auxiliary single chip microcomputer; the input end of the driving chip is connected with an enabling driving circuit and a DA chip, and the chip selection circuit and the auxiliary enabling circuit are both connected to the input end of the enabling driving circuit and used for enabling the DA chip. The utility model discloses can the short-term test trouble, reduce test time, improve work efficiency, replace artifical the detection, improve the rate of accuracy, method is simple, the strong operability.

Description

Multi-path LED automatic detection circuit for medical operation shadowless lamp

Technical Field

The utility model relates to a medical operation shadowless lamp specifically is a medical operation shadowless lamp multichannel LED automatic check out circuit.

Background

The detection technology commonly used in the market at present is to light the whole lamp and visually observe the LED lamp beads before leaving a factory and observe the change value of input current and nominal current.

The detection method is not suitable for application with a large number of lamp beads, only a small part of the whole current is changed when the current of a certain string of lamp beads is changed, and whether the lamp beads are damaged or not can not be accurately judged by observing current value detection;

the shadowless lamp has the advantages that the minimum lighting current of a lamp bead in a single group is 12mA, the maximum current is 250mA, and the current change cannot be accurately tested by common power supply testing equipment.

The shadowless lamp beads adopt a cross mode (2 x 2 matrix), 4 lamp beads are tightly pasted together to form a light-emitting unit, and if a certain lamp bead is not bright, the lamp bead is difficult to identify by naked eyes.

276 LED lamp pearl quantity are total, 2 kinds of lamp pearls, 2 kinds of specification lens, 2 kinds of aluminium base boards, and every group corresponds lamp pearl quantity different, total 8 compound mode:

the outer frame lenticule warms up the lamp pearl: 16 are connected in series;

frame lenticule cold light pearl: 16 are connected in series;

frame small lens warm lamp pearl: 8 are connected in series;

the outer frame small lens cold lamp bead: 8 are connected in series;

inner frame large lens warm lamp pearl: 10 are connected in series;

inner frame large lens cold lamp pearl: 10 are connected in series;

inside casing small lens warm lamp pearl: 12 are connected in series;

inner frame little lens cold lamp pearl: 12 are connected in series;

each set of lamps uses 3 sets, namely 3 × 8, 24 paths;

the detection equipment in the current market cannot quickly detect which specific path fails, cannot quickly cooperate with inspection and test, has long test time and cannot ensure the performance of the product.

SUMMERY OF THE UTILITY MODEL

For solving the defect of above-mentioned prior art, the utility model provides a medical operation shadowless lamp multichannel LED automatic check out circuit, the utility model discloses can the short-term test trouble, reduce test time, improve work efficiency, replace artifical the detecting, improve the rate of accuracy, the method is simple, the strong operability.

In order to achieve the technical purpose, the utility model adopts the following technical scheme: a medical operation shadowless lamp multi-path LED automatic detection circuit comprises an auxiliary single chip microcomputer, a current sampling circuit, a chip selection circuit, an auxiliary enabling circuit and a driving chip, wherein the current sampling circuit is used for sending lamp string sampling current to the auxiliary single chip microcomputer; the input end of the driving chip is connected with an enabling driving circuit and a DA chip, and the auxiliary enabling circuit is connected to the input end of the enabling driving circuit and used for enabling signals.

Further, the chip selection circuit comprises an outer frame plug connector P11 and an inner frame plug connector P12, the chip selection circuit comprises a left chip selection circuit and a right chip selection circuit, the input end of the left chip selection circuit is connected to the 13 pins of the auxiliary single chip microcomputer, and the output end of the left chip selection circuit is connected to the 5 pins of the outer frame plug connector P11 and the 5 pins of the inner frame plug connector P12; the input end of the right chip selection circuit is connected to the 12 pins of the auxiliary single chip microcomputer, and the output end of the right chip selection circuit is connected to the 7 pins of the outer frame plug connector P11 and the 7 pins of the inner frame plug connector P12; and the 2 pins of the outer frame plug connector P11 and the 2 pins of the inner frame plug connector P12 are connected to the input end of the enabling drive circuit.

Furthermore, the left chip selection circuit adopts a triode Q24, a collector of the triode Q24 is connected to the 5 pins of the outer frame plug connector P11 and the 5 pins of the inner frame plug connector P12, an emitter is grounded, and a base is connected to the 13 pins of the auxiliary single chip microcomputer; the right side chip selection circuit adopts a triode Q25, the collector of the triode Q25 is connected to the 7 pins of the outer frame plug connector P11 and the 7 pins of the inner frame plug connector P12, the emitter is grounded, and the base is connected to the 12 pins of the auxiliary single chip microcomputer.

Further, supplementary enabling circuit includes triode Q26, triode Q26's base is connected to the 11 feet of supplementary singlechip, emitter ground, the collecting electrode is connected to through resistance R77 all the way the 3 feet of inside casing plug connector P12, another way is connected to through resistance R121 the 3 feet of outside frame plug connector P11.

Further, the enable driving circuit comprises a triode Q2, the base of the triode Q2 receives EN signals from the 2 pins of the outer frame plug-in unit P11 and the 2 pins of the inner frame plug-in unit P12 through a resistor R27, and the collector is connected to the 7 pins of each driving chip through a resistor R10.

Further, the DA chip is connected to the 3 pins of the driving chip.

To sum up, the utility model discloses following technological effect has been gained:

1. the utility model utilizes the chip selection circuit to select which path to work, utilizes the auxiliary enabling circuit to assist the driving chip to perform the function, controls which path of driving chip to perform what operation according to the EN signal of the chip selection circuit and the auxiliary enabling circuit, and realizes the automatic detection of the multi-path circuit;

2. the utility model utilizes the clock signal to control the working sequence of the multi-path auxiliary single chip microcomputer, and ensures the stable operation of the detection circuit;

3. the utility model has no stroboscopic phenomenon under low current, can work under 8mA ultralow current, and has high precision of driving current (2mA precision error);

4. the utility model utilizes the analog signal input circuit to receive different analog signals for controlling the MOS tube switch and adjusting the output duty ratio, thereby controlling the output current of the lamp string, and matching with the control of the main singlechip and the auxiliary singlechip, all the lamp strings work in the same state, the consistency of the driving current is good, thereby the optical performance of the shadowless lamp is better, and no stroboflash is realized;

5. the utility model discloses utilize the sampling resistance to sample the electric current of lamp cluster, give the singlechip after operational amplifier enlargies, the singlechip compares the current value that detects with internal program default, gives corresponding adjustment signal according to the comparison, changes the analog signal parameter for the output current value changes, thereby carries out the current calibration, realizes high accuracy, little error;

6. The utility model discloses single chip microcomputer control drive chip enables, receives the analog signal who comes from the DA chip, compares with internal voltage, drives MOS pipe break-make, changes output current, and output current gives the singlechip again through the fortune processing of putting; the current value of the lamp bead is determined by sampling the current value through the sampling resistor, a signal is transmitted back to the single chip microcomputer, the single chip microcomputer transmits a command to the DA chip according to corresponding data, and the DA chip outputs an analog signal to the driving chip to perform current fine adjustment calibration;

7. the utility model can rapidly detect the fault, reduce the testing time and improve the working efficiency; manual detection is replaced, and the accuracy is improved; the method is simple and strong in operability; the complex design is converted into a simple picture interface for display, so that the display is clear; designing special program to drive 276 lamp beads; and controls 24 loads.

Drawings

Fig. 1 is a schematic diagram of a shadowless lamp control circuit provided by an embodiment of the present invention;

FIG. 2 is a schematic diagram of a current sensing circuit;

FIG. 3 is a schematic diagram of an aluminum substrate conversion circuit;

FIG. 4 is a schematic diagram of an auxiliary single-chip microcomputer;

FIG. 5 is a schematic diagram showing the connection relationship between the chip select circuit, the auxiliary enable circuit and the connector;

FIG. 6 is a schematic diagram showing the connection relationship between the driving chip, the enable driving circuit, the analog signal input circuit and the MOS transistor driving circuit;

FIG. 7 is a schematic diagram of an enable driver circuit;

FIG. 8 is a schematic diagram of a conversion circuit;

FIG. 9 is a schematic diagram of a signal assist circuit;

FIG. 10 is a schematic diagram of a DA chip;

FIG. 11 is a schematic diagram of an analog signal input circuit;

FIG. 12 is a schematic diagram of a MOS transistor driving circuit.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

The specific embodiments are only for explaining the present invention, and it is not a limitation to the present invention, and those skilled in the art can make modifications to the embodiments without inventive contribution as required after reading the present specification, but all the embodiments are protected by patent law within the scope of the claims of the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically limited otherwise.

In the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly, e.g., as being fixedly connected, detachably connected, or integrated; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood according to specific situations by those of ordinary skill in the art.

In the present application, unless expressly stated or limited otherwise, the first feature may be directly on or directly under the second feature or indirectly via intermediate members. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

Example (b):

the utility model provides a medical operation shadowless lamp detects control circuit, including a main singlechip (not shown in the figure), 3 supplementary singlechip IC3, 12 drive plates, 24 drive chip U5, wherein, 3 supplementary singlechips of main singlechip control, 4 drive plates of 1 supplementary singlechip control, 2 drive chip of 1 drive plate control, set up three illumination zone on the shadowless lamp, each illumination zone is controlled by a supplementary singlechip, each illumination zone all sets up an frame and an inside casing, set up 2 drive chip on the frame, set up 2 drive chip on the inside casing. The main single chip microcomputer is used for controlling the main chip of the whole shadowless lamp to work and controlling the work of the auxiliary single chips, the auxiliary single chips are module single chips for controlling the subareas of the shadowless lamp, one main single chip microcomputer is used for controlling the auxiliary single chips, and the auxiliary single chips respectively control the light strings in charge, so that all the light strings work in the same state, and the accuracy is further improved. In the embodiment, a main single chip microcomputer and 3 auxiliary single chip microcomputers are used for controlling, so that automatic detection of multiple paths of LEDs can be realized, all lamp strings are controlled to work under the same frequency, the consistency of driving current is good, the optical performance of the shadowless lamp is good, and stroboflash is avoided.

As shown in fig. 1, the lighting system comprises an auxiliary single chip microcomputer, a current sampling circuit 1 for sending light string sampling current to the auxiliary single chip microcomputer, a chip selection circuit 3 connected to the output end of the auxiliary single chip microcomputer, an auxiliary enabling circuit 4 connected to the output end of the auxiliary single chip microcomputer, and a driving chip; the input end of the driving chip is connected with an enable driving circuit 5 and a DA chip 8, an auxiliary enabling circuit 4 is connected to the input end of the enable driving circuit 5 for transmitting an enabling signal, and a chip selection circuit 3 is connected to a signal auxiliary circuit 7 for selecting the DA chip 8 to work. The auxiliary single-chip microcomputer, the chip selection circuit 3, the auxiliary enabling circuit 4, the driving chips and the DA chip 8 form an LED automatic detection circuit, wherein only 1 auxiliary single-chip microcomputer and 1 driving chip are shown in fig. 1, and the connection mode of the rest of the driving chips is the same as that in fig. 1, and is not described again. Since one auxiliary single chip microcomputer controls 8 driving chips, the auxiliary single chip microcomputer selects and controls which DA chip 8 on which driving chip works by using the chip selection circuit 3, and the auxiliary enabling circuit 4 is used for assisting the driving chips and the DA chips to enable.

Meanwhile, the circuit also comprises a current sampling circuit 1 for sampling the current resistance of the lamp string, an aluminum substrate switching circuit 2, a conversion circuit 6, a signal auxiliary circuit 7, a DA chip 8 for converting signals, an analog signal input circuit 9 for transmitting current signals to the driving chip, and an MOS tube driving circuit 10 for controlling the work of the shadowless lamp, wherein the current sampling circuit 1 is connected to the aluminum substrate switching circuit 2, the aluminum substrate switching circuit 2 is connected to an auxiliary single chip microcomputer, the auxiliary single chip microcomputer is connected to the conversion circuit 6, the analog signals are transmitted to the DA chip 8 through the signal auxiliary circuit 7, the auxiliary single chip microcomputer selects which path of DA chip works and enables, the selected DA chip 8 sends the analog signals to the analog signal input circuit 9 and then to the driving chip, and the driving chip sends instructions to the MOS tube driving circuit 10 to change the output duty ratio, the output current is controlled, so that the light strings are in the same current state, and no stroboflash is realized.

Fig. 2 is a schematic diagram of a current sampling circuit 1, wherein the current sampling circuit 1 includes an operational amplifier U2A, the 3 pins of the operational amplifier U2A are divided into three paths, the first path is connected to one group of strings through a resistor R51 and the resistor R51 is grounded through a resistor R54, the second path is connected to the other group of strings through a resistor R35 and the resistor R35 is grounded through a resistor R40, and the third path is grounded through a capacitor C21; the pin 2 is grounded through a resistor R43, the pin 1 is divided into two paths, the first path is grounded after being connected to the resistor R43 through a resistor R44, and the second path outputs VC signals to the aluminum substrate switching circuit 2. The LED lamp string detection circuit comprises a resistor R54 and a resistor R40, wherein the resistor R54 and the resistor R40 are used as two sampling resistors to respectively collect currents of lamp strings, LEDB (lead finger) -shown in figure 1 is a group of lamp strings controlled by a driving chip, LEDA (lead finger) -is a group of lamp strings controlled by another driving chip, the circuit is used for collecting currents of the lamp strings controlled by the driving chip, centralized management is carried out through a single chip microcomputer, all lamp beads with the same functions of the inner frame and the outer frame work under the same instruction, and then calibration is carried out by utilizing preset values inside the single chip microcomputer, so that all the lamp beads of the inner frame and the outer frame work under the same current state, unified detection can be realized, and the condition that the working currents are the same and no stroboflash can be realized.

As shown in fig. 3, the aluminum substrate switching circuit 2 includes a capacitor C40 and a resistor R74 connected in parallel, one end of the parallel circuit is grounded, the other end of the parallel circuit receives the VC signal of the current sampling circuit 1 through the resistor R70, and the parallel circuit outputs a signal to the 10 pins of the auxiliary single chip microcomputer, so as to send the acquired current signal to the auxiliary single chip microcomputer.

As shown in fig. 4, the diagram of the auxiliary single-chip microcomputer is that 10 pins of the auxiliary single-chip microcomputer receive the current, then compare the current with the internal program preset value, and send a corresponding adjusting instruction to the DA chip for conversion.

Since each driver chip has a DA chip output, and the auxiliary single-chip microcomputer controls 8 driver chips, the auxiliary single-chip microcomputer determines which DA chip is activated and enabled first, i.e., the chip selection circuit 3 is used to select the DA chip.

As shown in fig. 5, the apparatus further includes an outer frame plug connector P11 and an inner frame plug connector P12, and the chip selection circuit 3 includes a right chip selection circuit 32 for selectively controlling the inner/outer frame right side driving board and controlling 2 sets of light strings and a left chip selection circuit 31 for selectively controlling the inner/outer frame left side driving board and controlling the other two sets of light strings. The input end of the left chip selection circuit 31 is connected to the 13 pins of the auxiliary single chip microcomputer, and the output end of the left chip selection circuit is connected to the 5 pins of the outer frame plug connector P11 and the 5 pins of the inner frame plug connector P12; the input end of the right chip selection circuit 32 is connected to the 12 pins of the auxiliary single chip microcomputer, and the output end of the right chip selection circuit is connected to the 7 pins of the outer frame plug connector P11 and the 7 pins of the inner frame plug connector P12; the 3-pin of the outer frame plug P11 and the 3-pin of the inner frame plug P12 output enable signals EN connected to the input terminal of the enable driving circuit 5.

As shown in fig. 5, the left chip selection circuit 31 adopts a triode Q24, the collector of the triode Q24 is connected to the 5-pin of the outer frame plug connector P11 and the 5-pin of the inner frame plug connector P12, the emitter is grounded, and the base is connected to the 13-pin of the auxiliary single chip microcomputer; the right chip selection circuit 32 adopts a triode Q25, the collector of the triode Q25 is connected to the 7 pins of the outer frame plug connector P11 and the 7 pins of the inner frame plug connector P12, the emitter is grounded, and the base is connected to the 12 pins of the auxiliary single chip microcomputer.

Meanwhile, the auxiliary enabling circuit 4 comprises a triode Q26, the base of the triode Q26 is connected to the 11 pins of the auxiliary single chip microcomputer, the emitting electrode is grounded, one path of the collecting electrode is connected to the 3 pins of the inner frame plug connector P12 through a resistor R77, and the other path of the collecting electrode is connected to the 3 pins of the outer frame plug connector P11 through a resistor R121.

The device utilizes the left chip selection circuit 31 and the right chip selection circuit 32 to gather the chip selection instructions and then uniformly send the chip selection instructions to the drive chip, the instructions of the auxiliary single chip microcomputer are sent to the enabling end of the corresponding drive chip, namely, the 7 pins of the drive chip, the 7 pins are connected with the enabling drive circuit 5, meanwhile, as shown in fig. 5, CS signals of the 5 pins and the 7 pins of the outer frame plug-in unit P11 and the 5 pins and the 7 pins of the inner frame plug-in unit P12 are connected onto the drive board through wiring harnesses and then are sent to the CS _ CD end of the signal auxiliary circuit 7 through an aluminum substrate, and the CS signals are sent to the DA chip through a resistor R50 to select whether to work, therefore, the auxiliary single chip microcomputer utilizes the chip selection circuit 3 and the auxiliary enabling circuit 4 to select which DA chip to work, and sends the instructions to the enabling drive circuit 5 to control the corresponding DA chip to work. The device utilizes the chip selection function to assist in selecting which path to work, and realizes respective detection and current regulation of the multi-path circuit. When the auxiliary single chip microcomputer finds that the current collected by a certain path of current detection circuit 1 is too large or too small, the current needs to be reversely adjusted, then the DA chip of the path is selected to work, and the current is adjusted through the driving chip.

As shown in fig. 6 and 7, the enable driving circuit 5 includes a transistor Q2, a base of the transistor Q2 receives EN signals from the 2-pin of the outer frame plug P11 and the 2-pin of the inner frame plug P12 through a resistor R27, and a collector is connected to the 7-pin of each driving chip through a resistor R10, and is configured to send an enable signal EN to the driving chip U5, so as to control the operation of the driving chip according to an instruction of the enable signal EN, where the enable signal EN is an operation signal sent by the auxiliary single chip microcomputer and is sent to the driving boards on the inner frame and the outer frame at the same time.

When it is determined that a certain DA chip is working, the current sampling circuit 1 sends the sampled current to the auxiliary single chip microcomputer through the aluminum substrate switching circuit 2, and then sends the sampled current to the DA chip through the conversion circuit 6 and the signal auxiliary circuit 7 for conversion, as shown in fig. 8 (fig. 8 is an enlarged schematic diagram of the conversion circuit 6 at the upper left corner of fig. 1), the conversion circuit 6 includes a sub-circuit for sending a clock signal and a sub-circuit for sending a data signal, wherein the sub-circuit for sending the clock signal includes a transistor Q23, an emitter of the transistor Q23 is connected with a power supply, a base receives the clock signal from a pin 32 of the auxiliary single chip microcomputer, a collector outputs a clock signal to the signal auxiliary circuit 7 through a resistor R67 and a resistor R68 for controlling the detection and feedback sequence of all DA chips, the sub-circuit for sending the data signal includes the transistor Q22, and an emitter of the transistor Q22 is connected with the power supply, the base receives the data signal from the pin 33 of the auxiliary single chip microcomputer, and the collector outputs a data signal to the signal auxiliary circuit 7 through the resistor R65 and the resistor R66 for transmitting data.

Taking the sub-circuit for sending the clock signal as an example, when the auxiliary single-chip microcomputer sends a signal, Q23 is turned on/off, and the clock signal SDO _ OUT3 is output to the signal auxiliary circuit 7. Similarly, when the transistor Q22 on the sub-circuit sending the data signal receives the signal from the auxiliary single-chip microcomputer, the transistor Q22 turns on/off to output a set of data signals, and then outputs the data signal SCK _ OUT3 to the signal auxiliary circuit 7.

As shown in fig. 9 (fig. 9 is an enlarged schematic diagram of the signal auxiliary circuit 7 at the lowermost position in fig. 1), the signal auxiliary circuit 7 includes a resistor R34 and a resistor 46 for receiving a clock signal and transmits the clock signal to the 2 pins of the DA chip, the signal auxiliary circuit 7 further includes a resistor R36 and a resistor R47 for receiving a data signal and transmits the data signal to the 1 pin of the DA chip, and the signal auxiliary circuit 7 further includes a resistor 37 and a resistor R5 for receiving a selection signal and transmits the selection signal to the 3 pins of the DA chip for determining whether the DA chip is operated.

As shown in fig. 10 (fig. 10 is an enlarged schematic diagram of the DA chip 8 at the lowest position in fig. 1), the DA chip receives data signals and clock signals of the auxiliary single chip microcomputer by using pins 1 and 2, and outputs 2 analog signals VE _ a and VE _ B through the internal control logic of the DA chip, and VE _ B is used for being transmitted to a resistor R7 of the analog signal input circuit 9 to participate in fine adjustment of the current of the string, and is used for comparing with the internal voltage of the driving chip to control whether the driving chip outputs a high level or a low level. The analog signals VE _ B and VE _ a are analog inputs of different driver chips.

As shown in fig. 11 (fig. 11 is an enlarged schematic diagram of the analog signal input circuit 9 at the middle right position in fig. 1), the analog signal input circuit 9 includes a resistor R7, a resistor R8, and a resistor R9, one end of the resistor R7 receives a current signal, and the other end is divided into two paths, one path is connected to the 3 pins of the driver chip through the resistor R8, and the other end is grounded through the resistor R9. In the embodiment, the analog signal input circuit 9 receives an analog signal VE _ B sent by the DA chip, and is used for performing fine adjustment on the current values of the light strings, so as to uniformly adjust the current values of the whole group of light strings, thereby solving the problems that the driving currents of different driving groups are poor in consistency and influence the optical effect of the shadowless lamp; and (3) analog modulation is carried out, so that the internal parameter output of the driving chip is changed, and the stroboscopic condition is avoided.

As shown in fig. 12 (fig. 12 is an enlarged schematic diagram of the MOS transistor driving circuit 10 at the right side position in fig. 1), the MOS transistor driving circuit 10 includes a MOS transistor Q3, one path of the gate of the MOS transistor Q3 is connected to the pin 10 of the driving chip through a resistor R13, the other path is grounded through a resistor R32, the source of the MOS transistor Q3 is grounded through a resistor R12, and a resistor R68 and a capacitor C29 are connected in series between the drain of the MOS transistor Q3 and the source of the MOS transistor Q3. Specifically, the input end of the MOS transistor driving circuit 10 is connected to a pin 10 of the driving chip, and is configured to receive an instruction of the driving chip, and the driving chip compares the received analog signal with an internal preset voltage to output a corresponding waveform, so that the MOS transistor performs a corresponding on-off action according to the waveform, changes an output duty ratio, and adjusts the magnitude of the output current. When the analog signal received by the analog signal input circuit 2 changes, the signal output by the pin 10 of the driving chip changes, so that the output duty cycle of the MOS transistor driving circuit 10 changes, and the change of the duty cycle can adjust the working current of the string light, ensure that the string light can work normally under a small current, adjust the output current value in a closed loop, and ensure the accuracy and stability of the current of the string light under the small current.

The DA chip is used for converting the instruction of the auxiliary single chip microcomputer into an analog signal, sending the analog signal to a resistor R7 of an analog signal input circuit 9, then sending the analog signal to a pin 3 of a driving chip for internal processing, and in the driving chip, the driving chip compares the received analog signal with an internal preset voltage and outputs a high/low level to the MOS tube driving circuit 10 by combining an internal logic circuit, so that the high/low level is used for controlling the on/off of the MOS tube Q3, the duty ratio of output current is changed, and the current of the light string is controlled.

The working principle is as follows:

the main single chip microcomputer controls 3 auxiliary single chip microcomputers, the auxiliary single chip microcomputers are instructed to send signals in sequence, the auxiliary single chip microcomputers send the signals to each path of LED group string after being processed through operational amplifier, then each path of LED signals are returned to the auxiliary single chip microcomputers, the auxiliary single chip microcomputers return to the main single chip microcomputer in sequence, the main single chip microcomputer processes the signals and sends the signals to the liquid crystal display screen, the LED states of each path are displayed, and the automatic detection of the LED states is achieved.

The current sampling circuit 1 is connected to the auxiliary single chip microcomputer after passing through the inner and outer frame aluminum substrate switching circuit 2, and is used for comparing the current sampled by the lamp string with the preset value of the internal program of the auxiliary single chip microcomputer, then sending a corresponding adjusting instruction, sending an analog signal to the driving chip for processing through the conversion of the DA chip, changing the output duty ratio of 10 pins of the driving chip, and further controlling the output current. In this embodiment, the resistor R54 and the resistor R40 are sampling resistors, and adopt a small resistance of 1 ohm, taking the resistor R54 as an example, the resistor R54 is connected to a string of lights on an aluminum substrate of a shadowless lamp, the aluminum substrate is used for mounting the string of lights, and the string of lights is composed of a plurality of light beads, so that when mounting, the light beads are electrically connected by a flat cable, and simultaneously, the light beads are electrically connected to the resistor R54 for current sampling. The current of lamp cluster is sampled to resistance R54, export for supplementary singlechip after operational amplification, send corresponding regulation instruction after with supplementary singlechip internal program default comparison, through the conversion of DA chip, send analog signal for analog signal input circuit 9 and finally act on driver chip's 10 feet, adjust MOS pipe output duty cycle of MOS pipe driver circuit 10, and then the output of control load, adjust load output current, make load current error less, work that can be stable, singlechip and DA chip closed-loop control, adopt the analog modulation mode, change driver chip internal parameter output, carry out current regulation, realize no stroboscopic work. If the voltage of the sampling resistor R54 becomes large, the current value needs to be reversely adjusted at the moment, namely, the current value of the lamp string needs to be reduced, VC output becomes large after operation and amplification, after the VC output becomes large and is transmitted to the auxiliary single chip microcomputer, the auxiliary single chip microcomputer outputs an instruction to the DA chip through internal operation and comparison, so that an analog signal of the DA chip becomes large, namely, the input of 3 pins of the driving chip is changed into a new analog signal from a VE _ B signal at the moment, the output duty of 10 pins of the driving chip becomes small at the moment, and finally the output current of the lamp string becomes small, thereby realizing current closed-loop control. The current flowing through the resistor R54 is reduced compared to before, so that the sampled voltage value of the resistor R54 is reduced, and reverse regulation is realized. After continuous adjustment, the differential pressure falls into a normal differential pressure range, thereby solving the problem of stability under low current.

The duty ratio is adjusted by adopting a simulation debugging mode, the stroboscopic problem is solved, in addition, the performance of the shadowless lamp requires small current to work, the minimum is 12ma, and the control is also determined by the closed-loop control of analog modulation controlled by a single chip microcomputer. In the circuit described by said device, the minimum current can be reduced to 8ma, and its accuracy can be raised. When the working is 12ma, no large error occurs to ensure the normal working. If the error is large, for example, the normal operating current is 12ma originally, but the detected current is only 5ma, the detected current is not in the normal range of the actual output of the DA chip, and the brightness of the lamp is not correct, and the consistency is not good. At this time, the current needs to be regulated by using the auxiliary single chip microcomputer and the driving chip.

In this device, single chip microcomputer control DA chip and control MOS pipe realize closed-loop control, and then realized not having the stroboscopic, and the voltage variation on the sampling resistor who detects adjusts and just adjusts the electric current, can improve the degree of accuracy, and real-time control output guarantees the no stroboscopic condition, stability under the undercurrent.

In this embodiment, the driver chip U5 adopts an LM3429 high-voltage constant-current driver chip, and is matched with a 10-bit digital DA chip TLC5617, a reference voltage regulator ADR5040, and an industrial-grade single-chip microcomputer PIC16F 1824. The ADR5040 voltage stabilization chip outputs a 2.048V high-precision voltage reference, a supply DA chip TLC5617 is provided, current closed loop control is formed by LM3429 and TLC5617, and PIC16F1824 controls TLC5617 to generate 1024-gear voltage gears. Meanwhile, the PIC16F1824 accurately samples and monitors the current.

The utility model adopts a cross-shaped mode (2 matrix 2) 4 lamp beads as a unit to be tightly pasted together to form a large light-emitting unit to be pasted on an aluminum substrate, 1 lens (big/small lens) is arranged on the 4 lamp beads, and the diagonal line is the same color temperature; the cold and warm lamp pearl during operation is supporting to have 2 kinds of lens, big lens and little lens, and the compound mode that corresponds has 4: big lens cold lamp pearl, big lens warm lamp pearl, little lens cold lamp pearl, little lens warm lamp pearl. 2 aluminum substrates, an inner frame aluminum substrate and an outer frame aluminum substrate are matched, the inner frame aluminum substrate and the outer frame aluminum substrate are respectively provided with a large lens cold lamp bead, a large lens warm lamp bead, a small lens cold lamp bead and a small lens warm lamp bead, and the corresponding control panel and the driving panel are only one, so that software and hardware need to drive 8 lamp strings with different combinations, and control the illumination, color temperature and light spots of the operation shadowless lamp; every whole lamp uses 3 sets of circuits, 24 street lamp strings altogether, minimum current 12mA when lighting of every group lamp cluster, because this kind of electricity and structural design mode, 24 kinds of LED lamp strings are if there is trouble all the way, and whole lamp is difficult for discovering, consequently in order to verify whether normal work of every cluster of lamp pearl, the utility model discloses an MCU control output specific LED electric current, then the electric current of output is enlarged through detecting filtering, gives MCUAD detection current size, and MCUAD detection lamp pearl current drive voltage size simultaneously judges this way drive current whether at the within range, sends the result code that detects for LED LCD screen through MCU, and this way of red representation is unusual, and this way of green representation is normal. By the method, specific lamp beads can be screened out and do not work, and the problems of open circuit of the lamp beads, disconnection of circuits, poor connection of wiring terminals and the like are solved.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and all the modifications and equivalents of the technical spirit of the present invention to any simple modifications of the above embodiments are within the scope of the technical solution of the present invention.

Claims (6)

1. The utility model provides a medical operation shadowless lamp multichannel LED automatic checkout circuit which characterized in that: the LED lamp string sampling circuit comprises an auxiliary single chip microcomputer, a current sampling circuit (1) used for sending lamp string sampling current to the auxiliary single chip microcomputer, a chip selection circuit (3) connected to the output end of the auxiliary single chip microcomputer, an auxiliary enabling circuit (4) connected to the output end of the auxiliary single chip microcomputer and a driving chip; the input end of the driving chip is connected with an enabling driving circuit (5) and a DA chip (8), and the auxiliary enabling circuit (4) is connected to the input end of the enabling driving circuit (5) and used for transmitting enabling signals.

2. The multi-path LED automatic detection circuit of the medical operation shadowless lamp according to claim 1, characterized in that: the single-chip microcomputer control circuit further comprises an outer frame plug connector P11 and an inner frame plug connector P12, the chip selection circuit (3) comprises a left chip selection circuit (31) and a right chip selection circuit (32), the input end of the left chip selection circuit (31) is connected to 13 pins of the auxiliary single-chip microcomputer, and the output end of the left chip selection circuit is connected to 5 pins of the outer frame plug connector P11 and 5 pins of the inner frame plug connector P12; the input end of the right chip selection circuit (32) is connected to the 12 pins of the auxiliary single chip microcomputer, and the output end of the right chip selection circuit is connected to the 7 pins of the outer frame plug connector P11 and the 7 pins of the inner frame plug connector P12.

3. The multi-path LED automatic detection circuit of the medical operation shadowless lamp according to claim 2, characterized in that: the left chip selection circuit (31) adopts a triode Q24, a collector of the triode Q24 is connected to the 5 pins of the outer frame plug connector P11 and the 5 pins of the inner frame plug connector P12, an emitter is grounded, and a base is connected to the 13 pins of the auxiliary single chip microcomputer; the right side chip selection circuit (32) adopts a triode Q25, the collector of the triode Q25 is connected to the 7 pins of the outer frame plug connector P11 and the 7 pins of the inner frame plug connector P12, the emitter is grounded, and the base is connected to the 12 pins of the auxiliary single chip microcomputer.

4. The multi-path LED automatic detection circuit of the medical operation shadowless lamp according to claim 3, characterized in that: supplementary enabling circuit (4) include triode Q26, triode Q26's base is connected to the 11 feet of supplementary singlechip, projecting pole ground connection, collecting electrode are connected to through resistance R77 all the way the 3 feet of inside casing plug connector P12, another way is connected to through resistance R121 the 3 feet of outside frame plug connector P11.

5. The multi-path LED automatic detection circuit of the medical operation shadowless lamp according to claim 4, characterized in that: the enabling drive circuit (5) comprises a triode Q2, the base of the triode Q2 is received through a resistor R27 and comes from the 2 pins of the outer frame plug connector P11 and the EN signal of the 2 pins of the inner frame plug connector P12, and the collector is connected to the 7 pins of each drive chip through a resistor R10.

6. The multi-path LED automatic detection circuit of the medical operation shadowless lamp according to claim 5, characterized in that: the DA chip (8) is connected to the 3 pins of the driving chip.

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