CN212969660U - Infrared receiving circuit and device with gain control - Google Patents
Infrared receiving circuit and device with gain control Download PDFInfo
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- CN212969660U CN212969660U CN202021197219.2U CN202021197219U CN212969660U CN 212969660 U CN212969660 U CN 212969660U CN 202021197219 U CN202021197219 U CN 202021197219U CN 212969660 U CN212969660 U CN 212969660U
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Abstract
The utility model discloses an infrared receiving circuit with gain control and a device, wherein the infrared receiving circuit comprises a variable gain amplifying module, a control module and a gain setting module; the control module is used for receiving a gain setting mode instruction or a signal amplification mode instruction sent by the upper computer, determining a gain setting value if the gain setting mode instruction is the gain setting mode instruction, and transmitting the gain setting value to the gain setting module; the gain setting module is connected with the control module and used for receiving the gain setting value transmitted by the control module and setting the gain of the variable gain amplification module when the gain setting module is in a gain setting mode; when in a signal amplification mode, maintaining the gain of the determined variable gain amplification module unchanged; the variable gain amplifying module is connected with the gain setting module and used for receiving the current signal output by the photosensitive diode, converting the current signal into a voltage signal according to the gain set by the gain setting module and amplifying and outputting the voltage signal.
Description
Technical Field
The utility model relates to an infrared detection technology field especially relates to a take gain control's infrared receiving circuit, device.
Background
The infrared photosensitive diode is widely used as an infrared detection unit due to the characteristics of large receiving angle, high response speed and the like; meanwhile, the dynamic range of photocurrent signals generated by the photodiode is large, and the photocurrent signals can be from pA level to mA level, and an amplifier with adjustable gain is often required to meet the signal amplification requirement.
The gain adjusting method of the adjustable gain amplifier is different in different application occasions, for example, the adjustable gain amplifier in the infrared detection unit of the infrared touch screen needs to define the working condition in advance and measure the required gain value, and the corresponding gain value which is measured in advance is called according to the working condition to set the gain of the adjustable gain amplifier when in use.
The infrared detection system of the infrared touch screen comprises a plurality of paths of infrared transmitting units consisting of infrared transmitting tubes and driving circuits thereof and infrared receiving units consisting of infrared photosensitive diodes and amplifying circuits thereof, wherein the infrared transmitting units and the infrared receiving units are arranged around the touch screen to form an infrared transmitting-receiving pair consisting of one path of infrared transmitting units and one path of infrared receiving units which form transmitting-receiving relation; each path of infrared receiving unit receives the optical signals transmitted by the corresponding multiple paths of infrared transmitting units in a time-sharing manner, namely, the optical signals and the multiple paths of infrared transmitting units form a plurality of infrared transmitting-receiving pairs, and the infrared transmitting-receiving pairs work in a certain sequence. The infrared touch screen system needs the output amplitude of the infrared receiving unit of each infrared transmitting-receiving pair to be consistent, but the distance, angle and the like from the infrared transmitting tube of different infrared transmitting-receiving pairs to the infrared photosensitive diode are different, so the photocurrent obtained on the infrared photosensitive diode is also different, and the gain of the amplifying circuit of the infrared receiving unit needs to be adjusted; meanwhile, the distance, angle and the like between the infrared transmitting tube and the infrared photosensitive diode in each infrared transmitting-receiving pair are fixed, namely the infrared photosensitive diode receives an optical signal with preset light intensity, so that a required gain value of a set amplitude value output by an amplifying circuit of each infrared transmitting-receiving pair can be measured in advance and stored, the gain value stored in advance is called to set the gain of the amplifying circuit when the infrared transmitting-receiving pair works, the output of the amplifying circuit can reach the set amplitude value, and the response speed of each infrared transmitting-receiving pair is greatly accelerated.
The existing scheme of the infrared detection system of the infrared touch screen comprises an infrared transmitting tube, a driving circuit, an infrared photosensitive diode, a triode, a voltage amplifier, a digital potentiometer, a resistor, a capacitor, a memory and an upper computer MCU (microprogrammed control Unit), wherein the infrared photosensitive diode and the triode form a transimpedance amplifier, and the gain of the voltage amplifier is adjustable. The upper computer MCU pre-measures the gain value needed by the output of the amplifying circuit of a certain infrared transmitting-receiving pair to be the set amplitude value, and stores the gain value in the memory, when the voltage amplifier works normally, the pre-stored gain value is called to set the high-speed digital potentiometer serving as the feedback resistance of the voltage amplifier to complete the gain setting of the voltage amplifier, and the output of the amplifying circuit can reach the set amplitude value.
The existing scheme has more components and parts and higher control complexity and cost; the trans-impedance amplifier composed of the infrared photosensitive diode and the triode has the advantages that the amplitude of an output voltage signal is small, and the voltage amplifier is provided with longer wiring, so that the problem of low signal-to-noise ratio is caused.
For example, patent publication No. CN203984363U discloses a control gain adjustment amplifier and an infrared true multi-touch device, the control gain adjustment amplifier includes: the infrared receiving module, the amplifying module, the gain control module, the gain adjusting module and the secondary amplifying module are sequentially connected, and the gain adjusting module is connected with the primary amplifying module and the secondary amplifying module. The utility model replaces the related module for realizing the infrared true multi-point touch function in the existing infrared true multi-point touch screen with the control gain adjusting amplifier, and performs amplification gain adjustment on the infrared touch screen according to the input infrared signal so as to keep the consistency of the infrared signal and be beneficial to the signal transmission of the whole circuit; the infrared true multi-point touch module has the advantages that the application field and market competitiveness of the infrared true multi-point touch module are greatly promoted, the modern intelligent control is realized, the cost is reduced, and the cost performance is high. Although the gain can be adjusted according to the input infrared signal, the gain value can not be measured in advance, and the problem of calling in use exists, so that the whole response is slow, and great limitation is brought to application.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a take gain control's infrared receiving circuit, device to prior art's defect.
In order to realize the above purpose, the utility model adopts the following technical scheme:
an infrared receiving circuit with gain control comprises a variable gain amplification module, a control module and a gain setting module;
the control module is used for receiving a gain setting mode instruction or a signal amplification mode instruction sent by the upper computer, determining a gain setting value if the gain setting mode instruction is the gain setting mode instruction, and transmitting the gain setting value to the gain setting module;
the gain setting module is connected with the control module and used for receiving the gain setting value transmitted by the control module and setting the gain of the variable gain amplification module when the gain setting module is in a gain setting mode; when in a signal amplification mode, maintaining the gain of the determined variable gain amplification module unchanged;
the variable gain amplifying module is connected with the gain setting module and used for receiving the current signal output by the photosensitive diode, converting the current signal into a voltage signal according to the gain set by the gain setting module and amplifying and outputting the voltage signal.
Further, the control module further comprises a comparator, an input end of the comparator is connected with an output end of the variable gain amplification module, and the comparator is used for receiving the signal output by the variable gain amplification module and comparing the received signal with a preset reference potential or a preset reference voltage range to obtain a comparison result; and the control module generates a gain setting value after performing signal processing according to the comparison result.
Furthermore, the control module further comprises a communication interface and a circuit corresponding to the communication interface, and the circuit is used for communicating with the upper computer and receiving the gain setting value set by the upper computer.
The device further comprises a storage module, a control module and a control module, wherein the storage module is used for storing one or more gain setting values determined by the control module; the storage mode of the storage module is to store one or more gain setting values according to a certain addressing mode.
Furthermore, the control module is further configured to call the gain setting value stored in the storage module according to a certain addressing mode.
Further, the digital-to-analog converter further comprises an analog-to-digital conversion module, which is used for converting the analog output signal of the variable gain amplification module into a digital output signal.
And the infrared receiving circuit is used for receiving control information of the upper computer and outputting a high-resistance state or an output signal of the variable gain amplification module.
Further, the variable gain amplification module is a first-stage transimpedance variable gain amplifier or a variable gain amplifier formed by cascading a first-stage transimpedance amplifier and a first-stage/multi-stage voltage amplifier.
Correspondingly, an infrared receiving device with gain control is also provided, and comprises an infrared receiving circuit with gain control.
Compared with the prior art, the beneficial effects of the utility model are that:
1. the utility model integrates the main components of the infrared receiving unit in the infrared detection system into a special integrated circuit, in particular to a variable gain amplifying circuit; the utility model can be matched with the upper computer to complete the gain setting of the special integrated circuit, thereby reducing the control difficulty, reducing the wiring length of small signals and being beneficial to improving the signal-to-noise ratio;
2. the utility model can store one or more gain setting values, the storage and calling of the gain setting values and the gain setting of the variable gain amplifier are carried out in the chip of the utility model, the dependence on an upper computer is reduced, the complexity of the system design is effectively reduced, and the system cost is reduced;
3. the utility model can automatically generate and store one or more gain setting values, complete the pre-measurement, storage, calling of the gain setting values and the gain setting of the variable gain amplifier, further reduce the dependence on the upper computer, reduce the complexity of the system design and reduce the system cost;
4. the utility model comprises an adjustable gain amplifier which can pre-measure the gain value and call the gain value in advance when in use, and the gain value is output by taking a fixed amplitude value as an output target when being pre-measured; the utility model has the application field of the amplifier which needs to adjust the gain to keep the output as the fixed amplitude value;
5. the utility model discloses the gain setting value that control module confirmed comes from the host computer setting or the storage module that control module self-tested or called, through setting up the mode of three kinds of differences so that this circuit is more nimble to the definite determination of gain setting value.
Drawings
FIG. 1 is a schematic block diagram of a prior art mid-infrared touch screen provided in the first embodiment;
FIG. 2 is a schematic block diagram of an infrared receiving dedicated circuit with gain control according to an embodiment;
FIG. 3 is a schematic block diagram of a variable gain amplifier and gain setting module according to one embodiment;
FIG. 4 is a schematic block diagram of a variable gain amplifier and a gain setting module according to a second embodiment;
fig. 5 is a schematic block diagram of an infrared receiving dedicated circuit with gain control according to a third embodiment;
FIG. 6 is a flowchart illustrating the operation of a gain setting value generation process according to the third embodiment;
fig. 7 is a schematic block diagram of an infrared receiving dedicated circuit with gain control according to a fourth embodiment;
fig. 8 is a schematic block diagram of an infrared receiving dedicated circuit with gain control according to the fifth embodiment;
fig. 9 is a schematic block diagram of an infrared touch screen according to a sixth embodiment;
fig. 10 is a schematic block diagram of an infrared receiving dedicated circuit with gain control according to a seventh embodiment;
11, a first voltage amplifier; 12. a second voltage amplifier; 13. a third voltage amplifier; 51. a photodiode; 52. a variable gain amplification module; 53. a control module; 54. a gain setting module; 55. a comparator; 56. a storage module; 57. an enabling module; 58. an analog-to-digital converter; 71. a first operational amplifier; 72. a first voltage controlled amplifier; 73. a second voltage controlled amplifier; a kbit register; 75. a decoder; 76. a digital-to-analog converter; 80. a micro control unit; 81. a first decoder; 82. and a second decoder.
Detailed Description
The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will be readily apparent to those skilled in the art from the disclosure herein. The present invention can also be implemented or applied through other different specific embodiments, and various details in the present specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict.
The utility model aims at providing a take gain control's infrared receiving circuit, device to prior art's defect.
It should be noted that the present embodiment is an improvement of the circuit structure, and how to receive signals, output signals, set signals, process signals, control signals, and the like according to the present invention is not what the present invention intends to protect, and all of them can be realized by the existing technology.
Example one
The embodiment provides an infrared receiving circuit with gain control, which comprises a variable gain amplification module, a control module and a gain setting module;
the control module is used for receiving a gain setting mode instruction or a signal amplification mode instruction sent by the upper computer, determining a gain setting value if the gain setting mode instruction is the gain setting mode instruction, and transmitting the gain setting value to the gain setting module;
the gain setting module is connected with the control module and used for receiving the gain setting value transmitted by the control module and setting the gain of the variable gain amplification module when the gain setting module is in a gain setting mode; when in a signal amplification mode, maintaining the gain of the determined variable gain amplification module unchanged;
the variable gain amplifying module is connected with the gain setting module and used for receiving the current signal output by the photosensitive diode, converting the current signal into a voltage signal according to the gain set by the gain setting module and amplifying and outputting the voltage signal.
It should be noted that the variable gain amplification module of this embodiment keeps operating in both the gain setting mode and the signal amplification mode, and only in the gain setting mode, the output may be unstable, and the upper computer MCU does not read the output.
Fig. 1 is a schematic block diagram of an infrared touch screen in the prior art, which generates a primary voltage signal V1 … … of a first infrared receiving and amplifying circuit through a photodiode PD1, an NPN tube TR1, and a resistor R1, and generates a primary voltage signal Vn of an nth infrared receiving and amplifying circuit through a photodiode PDn, an NPN tube TRn, and a resistor Rn; the three-stage voltage amplifier is composed of three general operational amplifiers, a resistor, a capacitor and other discrete devices, and sequentially comprises a first voltage amplifier 11, a second voltage amplifier 12 and a third voltage amplifier 13. The high-speed analog switches K1 to Kn are sequentially turned on, and the high-speed analog switches V1 to Vn are sequentially sent to the three-level voltage amplifier for amplification, so that the output amplitude of the signal is increased. The infrared pair tube detection system shown in fig. 1 has many components and complex system lines, which also results in high system cost, especially long routing path of small signals, resulting in low signal-to-noise ratio and reduced system performance.
As shown in fig. 2, an infrared receiving circuit with gain control of this embodiment includes: a variable gain amplification module 52, a control module 53, and a gain setting module 54.
It should be noted that the dedicated circuit described in this embodiment is an infrared receiving circuit with gain control.
The variable gain amplification module 52 receives a current signal generated by receiving the light signal by the photodiode 51, converts the current signal into a voltage signal, and finally amplifies the voltage signal according to a set gain; the variable gain amplifier module 52 may be a first-stage variable gain amplifier or a variable gain amplifier composed of a first-stage transimpedance amplifier and a first-stage/multi-stage voltage amplifier in cascade connection;
the gain setting module 54 receives the gain setting value set by the control module and sets the gain of the variable gain amplification module 52.
When the control module 53 receives the upper computer passing I2After the termination signal sent by the C bus, the dedicated circuit of this embodiment enters a signal amplification mode, at this time, the gain of the variable gain amplification module 52 does not change any more, and receives the current signal output by the photodiode 51, converts the current signal into a voltage signal, and amplifies and outputs the voltage signal according to the set gain.
Fig. 3 is a schematic block diagram of an embodiment of the variable gain amplification module 52 and the gain setting module 54 in the ir receiving dedicated circuit according to this embodiment. In this embodiment, the photodiode 51 is connected to the negative input terminal of the operational amplifier OP and to one end of the resistor R01, the resistor R01 to the resistor R (2)k) 2k resistors are connected in series in sequence, and the resistor R (2)k) The other end of the second switch is connected with the output end of the OP; the drain of an NMOS tube is connected between every two adjacent resistors from N1 to N (2)k-1) The NMOS transistors are 2k-1 in total, the source ends of all the NMOS transistors are connected to the output end of the operational amplifier OP, and the positive input end of the operational amplifier OP is connected to an internal reference potential Vref. The gain setting module 54 comprises a decoder 75 and a kbit register 74, and the kbit register 74 receives the gain setting value transmitted by the control module; decoder 75Read the data of kbit register 74 and control N1 through N (2)k-1) All off or have 1 of them on. When all NMOS transistors are turned off, the transimpedance gain of the variable gain amplification module 52 is maximum, which is about Gv ═ R01+ R02+ … + R (2)k) (ii) a When N1 is turned on, the transimpedance gain of the variable gain amplification module 52 is minimum, which is approximately Gv — R01; as can be seen from the above, the variable gain amplification module 52 has 2k gain stages for setting.
In the embodiment, main components of an infrared receiving unit in an infrared detection system are integrated in a special integrated circuit, in particular to a variable gain amplifying circuit; the embodiment can be matched with an upper computer to complete the gain setting of the special integrated circuit, thereby reducing the control difficulty, reducing the wiring length of small signals, being beneficial to improving the signal-to-noise ratio and reducing the cost. The utility model obtains the gain setting value from the upper computer to complete the gain setting process; after the setting is finished, the amplifier is used as a normal amplifier, and in practical application, the gain setting and the amplification are processed in two stages.
Example two
The difference between the infrared receiving circuit with gain control provided in this embodiment and the first embodiment is that:
fig. 4 is a schematic block diagram of another specific embodiment of the variable gain amplifier 52 and the gain setting module 54 in the ir receiving dedicated circuit according to this embodiment. In the present embodiment, the variable gain amplifier 52 is composed of a one-stage transimpedance amplifier stage and a two-stage voltage-controlled amplifier cascade, where the one-stage transimpedance amplifier stage is a fixed-gain transimpedance amplifier composed of the first operational amplifier 71 and the resistor R61; the two-stage voltage controlled amplifier cascade is a two-stage variable gain voltage amplifier consisting of a first voltage controlled amplifier 72 and a second voltage controlled amplifier 73. The gains of the first voltage controlled amplifier 72 and the second voltage controlled amplifier 73 are controlled by the voltage generated by the digital to analog converter 76. The gain setting module 54 comprises a kbit digital-to-analog converter 76 and a kbit register 74, and the kbit register 74 receives the gain setting value transmitted by the control module; the digital-to-analog converter 76 reads the data of the kbit register 74 and can generate 2k voltages; thereby causing the variable gain amplification module 52 to generate 2k gain steps.
EXAMPLE III
The difference between the infrared receiving circuit with gain control provided by this embodiment and the first embodiment is that:
fig. 5 shows a circuit dedicated for infrared reception with gain control according to this embodiment, which includes a variable gain amplification module 52, a control module 53, a gain setting module 54, and a comparator 55.
Compared with the dedicated infrared receiving circuit shown in fig. 2 in the first embodiment, the variable gain amplifying module 52 and the gain setting module 54 are the same, and are not described herein again.
The control module 53 further includes a mode pin, and the upper computer inputs a high level or a low level through the mode pin to enable the integrated circuit of this embodiment to be in a gain setting mode or in a signal amplification mode.
The control module 53 also includes a comparator 55; when in the gain setting mode, the comparator 55 receives the output of the variable gain amplifying block 52, compares it with a reference potential Vt and outputs a comparison value of high level or low level, and the control block 53 receives the output comparison value, generates a gain setting value after signal processing, and writes it into the gain setting block 54. The present embodiment sets the reference potential Vt appropriately, that is, satisfies the requirement that the output amplitude of the variable gain amplifier is the set amplitude.
The gain setting module comprises a kbit register 74 for receiving a gain setting value; the generation manner of the gain setting value is shown in fig. 6, and specifically includes:
1. the infrared emission source emits a signal that is,
2. the control module 53 writes the first bit, namely the most significant bit, of the kbit register 74 into 1, and writes the rest bits into 0; the gain setting module 54 sets the gain for the variable gain amplification module 52; the variable gain amplification module 52 amplifies the signal according to the set gain and outputs the signal;
3. the comparator 55 performs a first comparison, and if the output amplitude of the variable gain amplification module 52 is greater than the reference potential Vt, the control module 53 writes the first bit of the kbit register 74 into 0; if the output amplitude of the variable gain amplification module 52 is smaller than the reference potential Vt, the control module 53 writes the first bit of the kbit register 74 into 1; thereby completing the setting of the head;
4. the control module 53 writes the second bit of the kbit register 74 into 1, the gain setting module 54 sets the reset gain for the variable gain amplifying module 52, and the variable gain amplifying module 52 amplifies the signal again according to the set gain and outputs the signal;
5. the comparator 55 performs a second comparison, and if the output amplitude of the variable gain amplifying module 52 is greater than the reference potential Vt, the control module 53 writes the second bit of the kbit register 74 into 0; if the output amplitude of the variable gain amplification module 52 is smaller than the reference potential Vt, the control module 53 writes the first bit of the kbit register 74 into 1; thereby completing the setting of the second bit;
6. by analogy, after the kth comparison, the kth bit setting of the kbit register 74 is completed, resulting in a final gain setting value.
The gain setting values for this example were from an autonomous assay, set after the assay; the method can reduce the workload of the upper computer.
Example four
The difference between the infrared receiving circuit with gain control provided in this embodiment and the first embodiment is that:
as shown in fig. 7, the circuit with gain control dedicated to infrared reception of this embodiment includes: a variable gain amplification module 52, a control module 53, a gain setting module 54, and a storage module 56; wherein the storage module 56 may store one or more gain setting values;
compared with the dedicated infrared receiving circuit with gain control shown in fig. 2, the variable gain amplifier 52 and the gain setting module 54 of the present embodiment are the same, and are not described herein again.
The control module 53 includes I2C bus interface and corresponding circuit for receiving upper computer passing I2C bus issues command and gain setting value of I2Each dedicated circuit of this embodiment on the C bus sets a different address. The embodiment further comprises a counter for recording the stored incrementsA value of the benefit setting value; the embodiment also comprises a timing pin for setting whether the gain setting mode or the signal amplification mode is adopted; the control module 53 is controlled by the upper computer, obtains a gain setting value and then transmits the gain setting value to the storage module 56 according to a certain sequence; or in turn, call the gain setting values stored in the memory block 56 to the gain setting block 54.
When the control module 53 responds to the upper computer passing I2After the addressing signal sent by the C bus, the control module passes through I2The C bus receives the gain setting values, which are transmitted to the memory module 56 in sequence from the first memory location; until receiving the upper computer passing I2C termination signal from bus.
The counter starts at 0 and counts up by 1 each time a gain setting is stored until a termination signal is received, thereby recording the number of gain settings stored.
After receiving the termination signal, the control module 53 enters a gain setting mode, and the control module 53 controls the storage module 56 to write the gain setting value of the first address location into the gain setting module 54; when the timing pin receives the rising edge of a pulse, the signal amplification mode is entered, the gain of the variable gain amplifier 52 is unchangeable, and the current signal output by the photodiode 51 is received, converted into a voltage signal and amplified and output according to the set gain; when the timing pin receives the falling edge of the pulse, the gain setting mode is re-entered, and the control module 53 controls the storage module 56 to write the gain setting value of the second position into the gain setting module 54; and analogizing in turn, when the timing pin receives the rising edge and the falling edge of one pulse, the control module 53 controls to respectively enter a signal amplification mode and a gain setting mode; each time the gain setting mode is entered, the gain setting value of the next address position in the storage module 56 is sequentially called to the gain setting module 54; and calling from the first address position after the number of the gain setting values is reached.
In the embodiment, the storage module is arranged to improve the capability of processing the gain setting value, and multiple groups of gain setting values are stored simultaneously and called step by step. The method specifically comprises two conditions, wherein one condition is that a plurality of groups of gain setting values are directly obtained from an upper computer and stored locally and are controlled and called by the upper computer; a local post-assay storage.
EXAMPLE five
The difference between the infrared receiving circuit with gain control provided in this embodiment and the first embodiment is that:
as shown in fig. 8, the infrared receiving dedicated circuit with gain control of this embodiment includes: the variable gain amplifier comprises a variable gain amplifying module 52, a control module 53, a gain setting module 54, a storage module 56 and a switch module 57.
Compared with the dedicated infrared receiving circuit with gain control shown in fig. 2, the variable gain amplifier 52 and the gain setting module 54 of the present embodiment are the same, and are not described herein again.
The control module 53 includes a comparator 55 for receiving the output of the variable gain amplifier 52, comparing it with a reference potential Vt and outputting a comparison value of high level or low level, and the control module 53 receives the output comparison value and generates a gain setting value after signal processing (as shown in fig. 6); after obtaining the gain setting value, the control module 53 sequentially transmits the gain setting value to the storage module 56 according to the instruction; or in turn, call the gain setting values stored in the memory block 56 to the gain setting block 54. The present embodiment further comprises a counter for recording the stored values of the gain setting values; the embodiment further comprises a timing pin for setting a gain setting mode or a signal amplification mode.
The control module 53 further includes a control pin, when the input of the control pin is low level, the upper computer controls the infrared emission units corresponding to the dedicated circuit of this embodiment to sequentially emit light, the control module 53 executes the generation manner of the gain setting values as shown in fig. 6 for each infrared emission unit, and writes the gain setting values into the storage module 56 in sequence from the first storage location; until the input to the control pin is high.
The counter counts up by 1 each time a gain setting is stored, starting with 0, until the input to the control pin is high, thereby recording the number of gain settings stored.
When the input of the control pin is high level, the gain setting mode is entered, and the control module 53 controls the storage module 56 to write the gain setting value of the first position into the gain setting module 54; the following operation is the same as that of the circuit with gain control dedicated for infrared reception shown in fig. 7, and will not be described herein.
In addition, the integrated circuit of this embodiment further includes a switch module 57 including an EN pin, and the upper computer enables the special circuit of this embodiment to be in an enable mode or a high impedance mode by inputting a high level or a low level at the EN pin; when the circuit is in the enable mode, the output pin of the special circuit of the embodiment outputs the output signal of the variable gain amplification module; when in the high impedance mode, the output pin of the dedicated circuit of this embodiment outputs a high impedance state, and the control module 53 does not respond to the input signals of the control pin and the timing pin.
EXAMPLE six
The difference between the infrared receiving circuit with gain control provided in this embodiment and the first embodiment is that:
fig. 9 is a schematic block diagram of an infrared touch screen using the infrared receiving and amplifying circuit of the present embodiment.
W1 to Wn are n infrared receiving modules formed by connecting the photodiode 51 and the infrared receiving dedicated circuit according to the embodiment of fig. 8; LEDs 1 to LEDm are m infrared emitting tubes; the control pins of each infrared receiving module are connected together and respectively connected to the micro control unit 80; the timing pins of each infrared receiving module are connected together and respectively connected to the micro control unit 80; the EN pin of each infrared receiving module is respectively connected to the second decoder 82, and the second decoder 82 is connected to the micro control unit 80; LEDs 1 to LEDm are m infrared emitting tubes; whether each infrared emission tube emits light or not is controlled by a first decoder 81.
When the micro control unit 80 sets the control line to be at a low level, and the micro control unit 80 controls the infrared receiving module W1 to be in the enabling mode through the second decoder 82, and meanwhile, the other infrared receiving modules are in the high impedance mode; the micro control unit 80 controls the corresponding infrared transmitting tubes to sequentially transmit optical signals through the first decoder 81; the infrared receiving module W1 generates a gain setting value for each corresponding infrared transmitting tube in turn and stores the gain in turn; the micro control unit 80 controls the infrared receiving module to be in the high impedance mode through the second decoder 82, and enables the next infrared receiving module to be in the enabling mode; repeating the process, each infrared receiving module enters and exits the enabling mode in sequence, and setting and storing the gain setting value for each corresponding infrared emitting source in sequence.
The micro control unit 80 sets the control line to be at a high level, and after the micro control unit 80 controls the infrared receiving module W1 to be in the enabling mode through the second decoder 82, the other infrared receiving modules are in the high impedance mode at the same time; the micro control unit 80 controls the corresponding infrared emission tubes to emit light signals in sequence through the first decoder 81, and the emission sequence is the same as that of the infrared emission tubes in the gain setting mode; while the infrared transmitting tube transmits the optical signal, the micro control unit 80 generates a pulse on the timing line, wherein the width of the pulse is the same as the time of the infrared transmitting tube transmitting the optical signal; under the control of the timing line, the infrared receiving module W1 sequentially reads the gain setting value stored in the storage module for each transmitting unit, sets the gain for the variable gain amplifier in the module, receives the current signal generated by the photodiode, amplifies the current signal, and outputs the amplified current signal to the micro control unit 80 for signal processing;
at any one time, under the control of the second decoder 82, at most one infrared receiving module is in the enabling mode, while other infrared receiving modules are in the high-impedance mode, and the output pins are in the high-impedance state, so that although all the output pins of the infrared receiving modules are connected together and connected to the micro control unit 80, the output signals of the infrared receiving modules are not influenced to be read by the micro control unit 80; meanwhile, in the high-impedance mode, the infrared receiving module does not generate correspondence to signals of the control line and the time sequence line, so that the storage and the calling of the gain setting value of the storage module of the infrared receiving module are not influenced.
EXAMPLE seven
The difference between the infrared receiving circuit with gain control provided in this embodiment and the first embodiment is that:
as shown in fig. 10, the infrared receiving dedicated circuit with gain control provided in this embodiment includes: a variable gain amplifier 52, a control module 53, a gain control module 54, and an analog-to-digital converter 58.
The analog-to-digital converter 58 is used to convert the analog output signal of the variable gain amplifier 52 into a digital output signal, and output the digital output signal according to a certain data transmission mode.
Compared with the embodiment shown in fig. 3, the embodiment adds the analog-to-digital converter 58 to implement the function of digital output, and other working modes are basically the same, which is not described herein.
The embodiment can effectively reduce the number of components used by the infrared receiving and amplifying circuit applied to the infrared geminate transistor detection system, reduce the design difficulty of an application system and reduce the cost.
Example eight
The present embodiment provides an infrared receiving device with gain control, including an infrared receiving circuit with gain control according to any one of the first to seventh embodiments, where the infrared receiving circuit and the PD are packaged in a same product to form the infrared receiving device.
It should be noted that how the circuit and the PD are packaged in the same product in this embodiment is not the protection of the present invention, and it can be implemented according to the prior art.
It should be noted that the foregoing is only a preferred embodiment of the present invention and the technical principles applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail with reference to the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the scope of the present invention.
Claims (9)
1. An infrared receiving circuit with gain control is characterized by comprising a variable gain amplification module, a control module and a gain setting module; the gain setting module is connected with the control module, and the variable gain amplification module is connected with the gain setting module;
the control module receives a gain setting mode instruction or a signal amplification mode instruction sent by an upper computer;
if the command is a gain setting mode command, the control module determines a gain setting value and transmits the gain setting value to the gain setting module; the gain setting module receives the gain setting value transmitted by the control module and sets the gain of the variable gain amplification module;
if the signal amplification mode instruction is received, the gain setting module maintains the determined gain of the variable gain amplification module unchanged; the variable gain amplification module receives a current signal output by the photosensitive diode, converts the current signal into a voltage signal according to the gain set by the gain setting module, and amplifies and outputs the voltage signal.
2. The infrared receiving circuit with gain control of claim 1, wherein the control module further comprises a comparator, an input end of the comparator is connected to an output end of the variable gain amplification module, and the comparator is configured to receive the signal output by the variable gain amplification module and compare the received signal with a preset reference potential or a preset reference voltage range to obtain a comparison result; and the control module generates a gain setting value after performing signal processing according to the comparison result.
3. The infrared receiving circuit with gain control as claimed in claim 1, wherein the control module further comprises a communication interface and a circuit corresponding to the communication interface, for communicating with the upper computer and receiving the gain setting value set by the upper computer.
4. The infrared receiving circuit with gain control as set forth in claim 1, further comprising a storage module for storing the one or more gain setting values determined by the control module; the storage module stores one or more gain setting values according to an addressing mode.
5. The infrared receiving circuit with gain control as set forth in claim 4, wherein said control module is further configured to invoke the gain setting value stored in the storage module in an addressing manner.
6. The infrared receiving circuit with gain control as claimed in claim 1, further comprising an analog-to-digital conversion module for converting an analog output signal of said variable gain amplification module into a digital output signal.
7. The infrared receiving circuit with gain control of claim 1, further comprising a switch module for receiving control information of an upper computer to enable the infrared receiving circuit to output a high impedance state or output an output signal of the variable gain amplification module.
8. The infrared receiving circuit with gain control of claim 1, wherein the variable gain amplifying module is a one-stage transimpedance variable gain amplifier or a variable gain amplifier composed of a one-stage transimpedance amplifier and a one-stage/multi-stage voltage amplifier in cascade connection.
9. An infrared receiving apparatus with gain control, comprising the infrared receiving circuit with gain control of any one of claims 1 to 8.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021197219.2U CN212969660U (en) | 2020-06-24 | 2020-06-24 | Infrared receiving circuit and device with gain control |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021197219.2U CN212969660U (en) | 2020-06-24 | 2020-06-24 | Infrared receiving circuit and device with gain control |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111654329A (en) * | 2020-06-24 | 2020-09-11 | 杭州敏和光电子技术有限公司 | Infrared receiving circuit with gain control, device and receiving method |
| CN116719438A (en) * | 2022-09-13 | 2023-09-08 | 广州众远智慧科技有限公司 | Infrared touch device and electronic device |
-
2020
- 2020-06-24 CN CN202021197219.2U patent/CN212969660U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111654329A (en) * | 2020-06-24 | 2020-09-11 | 杭州敏和光电子技术有限公司 | Infrared receiving circuit with gain control, device and receiving method |
| CN116719438A (en) * | 2022-09-13 | 2023-09-08 | 广州众远智慧科技有限公司 | Infrared touch device and electronic device |
| CN116719438B (en) * | 2022-09-13 | 2024-06-11 | 广州众远智慧科技有限公司 | Infrared touch device and electronic device |
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