Multi-channel temperature sampling circuit

Abstract

The utility model discloses a multi-channel temperature sampling circuit, which comprises a multi-channel temperature sampling unit of at least two-channel temperature sampling modules, and the multi-channel temperature sampling unit is used for carrying out temperature sampling on a measured object; the cyclic gating unit comprises a counter and a multiplexing analog switch, one side of the multiplexing analog switch is connected with the multi-channel temperature sampling unit, and the other side of the multiplexing analog switch is connected with one side of the counter; one side of the signal conversion unit is connected with one side of the multiplexing analog switch, and the signal conversion unit is used for converting the analog quantity signal into a frequency signal; and the signal transmission unit is connected with the other side of the signal conversion unit. Gating is carried out through the multiplexing analog switch unit, and the analog quantity temperature signals are output in sequence. Therefore, multi-path signals are changed into single-path signals to be circularly output, and ADC channel resources occupied by a system main control chip are reduced during multi-path temperature sampling.

Description

Technical Field

[0001] The utility model belongs to the technical field of temperature detection, and in particular relates to a multi-channel temperature sampling circuit. Background Art

[0002] Usually, when collecting temperature of motors, power semiconductor modules, radiators, etc., a large number of temperature signals of the same type need to be collected, which occupies a lot of ADC channel resources of the system main control chip. At the same time, the temperature sampling signal, this analog signal, will be subject to strong signal interference when it is transmitted over medium or long distances in power electronic system products, affecting the signal quality and causing inaccurate temperature results. The traditional method is to increase the low-pass filter, but it will cause the signal delay to increase, and it cannot reflect the temperature of the measured object in time, affecting the speed of control response.

[0003] Therefore, how to reduce the occupied ADC channel resources of the system main control chip during multi-channel temperature sampling while enhancing signal quality and reducing signal delay is a technical problem to be solved by those skilled in the art. Utility Model Content

[0004] The purpose of the utility model is to solve the technical problem that the ADC channel resources of the system main control chip are occupied too much in the prior art. To this end, the utility model provides a multi-channel temperature sampling circuit, which includes:

[0005] A multi-channel temperature sampling unit of at least two temperature sampling modules, used for performing temperature sampling on the object to be measured;

[0006] A cyclic gating unit, comprising a counter and a multiplexing analog switch, wherein one side of the multiplexing analog switch is connected to the multi-channel temperature sampling unit, and the other side of the multiplexing analog switch is connected to one side of the counter;

[0007] A signal conversion unit, one side of which is connected to one side of the multiplexing analog switch, and is used to convert the analog quantity signal into a frequency signal;

[0008] The signal transmission unit is connected to the other side of the signal conversion unit.

[0009] Furthermore, each temperature sampling module in the multi-channel temperature sampling unit has the same structure, and the temperature sampling module specifically includes: one end of the thermistor is grounded, the other end of the thermistor is respectively connected to one end of a voltage divider resistor and one end of a low-pass filter, the other end of the voltage divider resistor is connected to a working power supply, and the other end of the low-pass filter is connected to the multiplexed analog switch.

[0010] Further, the counter is specifically a 4-bit binary counter, and the multiplexed analog switch is specifically a 16-channel multiplexed analog switch, wherein the I0 to I15 ports of the multiplexed analog switch are connected to the multi-channel temperature sampling unit, the OUT interface of the multiplexed analog switch is connected to the signal conversion unit, the ENB port of the multiplexed analog switch is grounded, the S0 port of the multiplexed analog switch is connected to the QA port of the counter, the S1 port of the multiplexed analog switch is connected to the QB port of the counter, the S2 port of the multiplexed analog switch is connected to the QC port of the counter, the S3 port of the multiplexed analog switch is connected to the QD port of the counter, the A to D ports of the counter are all grounded, and the QA port, QB port, QC port and QD port are all connected to the NAND gate.

[0011] Furthermore, the counter further comprises a CLK port, which is connected to the frequency-adjustable clock unit.

[0012] Furthermore, the signal conversion unit specifically includes:

[0013] The COMPIN port of the voltage-frequency conversion chip is connected to the multiplexed analog switch through a low-pass filter, the THRESH port of the voltage-frequency conversion chip is connected to the threshold voltage of the voltage-frequency conversion chip through an adaptation resistor, the IREF port of the voltage-frequency conversion chip is grounded through a current-limiting resistor, the FOUT port of the voltage-frequency conversion chip is connected to a signal transmission unit, the RC port of the voltage-frequency conversion chip is respectively connected to one end of the frequency adjustment resistor and one end of the frequency adjustment capacitor, the other end of the frequency adjustment resistor is connected to a working power supply, and the other end of the frequency adjustment capacitor is grounded.

[0014] Furthermore, the signal transmission unit includes an optical coupler isolation transmission module and an optical fiber isolation transmission module, the optical coupler isolation transmission module includes a first driving unit and a high-speed optical coupler, the optical fiber isolation transmission module includes a second driving unit and an optical fiber terminal, one end of the first driving unit and one end of the second driving unit are both connected to the other side of the signal conversion unit, the other end of the first driving unit is connected to the high-speed optical coupler, and the other end of the second driving unit is connected to the optical fiber terminal.

[0015] Compared with the prior art, the beneficial effects of the utility model are:

[0016] The utility model provides a multi-channel temperature sampling circuit. Compared with the prior art, the circuit includes: a multi-channel temperature sampling unit of at least two temperature sampling modules, which is used to perform temperature sampling on the object to be measured; a cyclic gating unit, including a counter and a multiplexed analog switch, one side of the multiplexed analog switch is connected to the multi-channel temperature sampling unit, and the other side of the multiplexed analog switch is connected to one side of the counter; a signal conversion unit, one side of which is connected to one side of the multiplexed analog switch, and is used to convert the analog signal into a frequency signal; a signal transmission unit, which is connected to the other side of the signal conversion unit. The analog temperature signals of each channel are sequentially outputted by gating through the multiplexed analog switch unit. In this way, the multi-channel signal is converted into a single-channel signal cyclic output, which reduces the occupied ADC channel resources of the system main control chip when multi-channel temperature sampling is performed. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of this specification, the drawings required for use in the embodiments will be briefly introduced below. The drawings described below are only some embodiments recorded in this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 The figure shows the overall structure diagram of the multi-channel temperature sampling circuit provided in the embodiment of this specification;

[0019] Figure 2 The figure shows a schematic diagram of the structure of a multi-channel temperature sampling unit in an embodiment of this specification;

[0020] Figure 3 The figure shows a schematic diagram of the structure of the cyclic gating unit in the embodiment of this specification;

[0021] Figure 4 The figure shows a schematic diagram of the structure of the signal conversion unit in the embodiment of this specification;

[0022] Figure 5 Shown is a schematic diagram of the structure of a signal transmission unit in an embodiment of this specification. DETAILED DESCRIPTION

[0023] In order to enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below in conjunction with the drawings in the embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this specification.

[0024] like Figure 1The structure diagram of the multi-channel temperature sampling circuit provided by the embodiment of this specification is shown. Although this specification provides the structure shown in the following embodiment or the accompanying drawings, more or fewer structures can be included in the structure based on routine or no creative work, and these structures are not limited to the structures shown in the embodiments or the accompanying drawings of this specification. When the structure is applied in an actual device or terminal product, it can be executed sequentially or in parallel according to the embodiment or module structure.

[0025] like Figure 1 As shown, the multi-channel temperature sampling circuit provided in the embodiment of this specification includes:

[0026] A multi-channel temperature sampling unit of at least two temperature sampling modules, used for performing temperature sampling on the object to be measured;

[0027] A cyclic gating unit, comprising a counter and a multiplexing analog switch, wherein one side of the multiplexing analog switch is connected to the multi-channel temperature sampling unit, and the other side of the multiplexing analog switch is connected to one side of the counter;

[0028] A signal conversion unit, one side of which is connected to one side of the multiplexing analog switch, and is used to convert the analog quantity signal into a frequency signal;

[0029] The signal transmission unit is connected to the other side of the signal conversion unit.

[0030] Specifically, the multi-channel temperature signals processed by the multi-channel temperature sampling unit can be T1 to T16 in this specific embodiment. They are gated by multiplexing analog switches, and the speed of gate switching is adjusted by an adjustable frequency clock unit, so that the analog temperature signals of T1 to T16 are output in sequence. In this way, the multi-channel signals are converted into single-channel signals for cyclic output, and then the CLK clock signal can be produced by a 555 timer, that is, an adjustable frequency clock unit is formed, and the frequency of the CLK clock is adjusted by adjusting the RC oscillation parameters. The CLK frequency determines the speed of channel switching, that is, the sampling frequency of each temperature channel, that is, fewer channels can be used to achieve the temperature acquisition of the original number of channels.

[0031] In the embodiments of the present application, Figure 2 The figure shows a schematic diagram of the structure of a multi-channel temperature sampling unit. Each temperature sampling module in the multi-channel temperature sampling unit has the same structure. The temperature sampling module specifically includes: one end of the thermistor is grounded, the other end of the thermistor is respectively connected to one end of a voltage divider resistor, i.e., the Rf resistor in the figure, and one end of a low-pass filter, the other end of the voltage divider resistor is connected to a working power supply, and the other end of the low-pass filter is connected to the multiplexed analog switch.

[0032] Specifically, the temperature of the object being measured is reacted by its built-in or external thermistor. This unit performs preliminary sampling through the Rf1~Rfn resistors, that is, each voltage-dividing resistor and each thermistor in series voltage division, and then filters the S1~Sn signals through an RC low-pass filter, and transmits the conditioned T1~Tn signals, that is, multi-channel signals, to the next unit.

[0033] In the embodiments of the present application, Figure 3 The figure shows a schematic diagram of the structure of the cyclic gating unit, wherein the counter is specifically a 4-bit binary counter, and the multiplexed analog switch is specifically a 16-channel multiplexed analog switch, wherein the I0 to I15 ports of the multiplexed analog switch are connected to the multi-channel temperature sampling unit, the OUT interface of the multiplexed analog switch is connected to the signal conversion unit, the ENB port of the multiplexed analog switch is grounded, the S0 port of the multiplexed analog switch is connected to the QA port of the counter, the S1 port of the multiplexed analog switch is connected to the QB port of the counter, the S2 port of the multiplexed analog switch is connected to the QC port of the counter, the S3 port of the multiplexed analog switch is connected to the QD port of the counter, the A to D ports of the counter are all grounded, and the QA port, QB port, QC port and QD port are all connected to the NAND gate, Figure 3 The figure shows a 4-input NAND gate. If the number of temperature sampling paths is different, the specifications of the NAND gate and the counter will be adjusted accordingly, for example, adjusted to an 8-input NAND gate and an 8-bit binary counter.

[0034] Specifically, the counter connects the A~D set terminals to the ground (logic 0), and the counter counts by detecting the CLK clock signal. Each clock edge will jump once, and the QA-QD ports will output 16 groups of binary data from 0000 to 1111 in sequence, namely the Ctr signal. When the data 1111 appears, the calculation result of the NAND gate is 0, and the CLR clear port performs the count clearing action. The QA-QD port returns to 0000 and continues to count and cycle (if the number of channels is less than 16, the logic circuit needs to be adjusted, for example: 8 channels, connect QA and QB to the AND gate to the CLR terminal, and after counting from 0000 to 1100, a total of 8 groups of data, it will be cleared and return to 0000).

[0035] The multiplexing analog switch unit receives 16 groups of four-bit binary signals of 0000 to 1111 that are continuously circulated, and then starts to select 16 input ports I0 to I15 in sequence, and the analog signals T1 to T16 are output through the OUT port in sequence, that is, they are re-fitted into the Tse1 signal output.

[0036] In the embodiments of the present application, Figure 4 FIG. 1 is a schematic diagram of the structure of a signal conversion unit, wherein the signal conversion unit specifically comprises:

[0037] The COMPIN port of the voltage-frequency conversion chip is connected to the multiplexed analog switch through a low-pass filter, and the THRESH port of the voltage-frequency conversion chip is connected to the threshold voltage of the voltage-frequency conversion chip through an adaptation resistor. Figure 4 The RL resistor in the voltage-frequency conversion chip is the reference voltage Vt, that is, the threshold voltage required by the voltage-frequency conversion chip. The adapter resistor enters the middle of the voltage-frequency conversion chip. It is used to condition the signal and is an equivalent resistor. In practical applications, it can also be a combination of multiple resistors. The I REF port of the voltage-frequency conversion chip is grounded through a current limiting resistor, that is, the Rs resistor. The FOUT port of the voltage-frequency conversion chip is connected to the signal transmission unit. The RC ports of the voltage-frequency conversion chip are respectively connected to the frequency adjustment resistor, that is, Figure 4 One end of the Rt resistor and the frequency adjustment capacitor, that is, Figure 4 One end of the Ct capacitor is connected, the other end of the frequency adjustment resistor is connected to the working power supply, and the other end of the frequency adjustment capacitor is grounded. The basic frequency is adjusted by adjusting the parameters of the Rt resistor and the Ct capacitor.

[0038] Specifically, the analog temperature signal Tse1 after the cyclic gating process first passes through the RC low-pass filter, and after the signal is adjusted, it is sent to the COMPIN port to enter the voltage-frequency conversion chip. The Rt and Ct of the RC port can adjust the base frequency fo, and the resistance values ​​of the RL and Rs resistors connected to the THRESH port and the I REF port can adjust the transformation ratio N. Finally, the frequency signal Scon=Tse1*N*fo output by the FOUT port. According to the different measured temperature ranges and the frequency ranges required by the main control, the parameters affecting the resistance and capacitance related to N and fo can be appropriately adjusted.

[0039] In the embodiments of the present application, Figure 5 The figure shows a schematic diagram of the structure of a signal transmission unit, wherein the signal transmission unit includes an optical coupling isolation transmission module and an optical fiber isolation transmission module, wherein the optical coupling isolation transmission module includes a first driving unit and a high-speed optical coupling, and the optical fiber isolation transmission module includes a second driving unit and an optical fiber terminal, wherein one end of the first driving unit and one end of the second driving unit are both connected to the other side of the signal conversion unit, the other end of the first driving unit is connected to the high-speed optical coupling, and the other end of the second driving unit is connected to the optical fiber terminal.

[0040] Specifically, the converted Scon frequency signal is transmitted as an electrical signal SoV through an optical coupler isolation transmission module, and is transmitted as an optical signal SoL through an optical fiber isolation transmission module.

[0041] The Scon signal first passes through the drive unit to increase the load capacity. The drive unit uses a common push-pull circuit or low-side driver chip to amplify the signal power so that it can drive the high-speed optical coupler or optical fiber terminal of the subsequent stage. Finally, the Scon signal outputs the isolated electrical signal SoV and optical signal SoL through two units for medium and long distance transmission to the main control.

[0042] That is to say, after the cyclic gating processing, the analog temperature signal is converted into a frequency signal with a fixed amplitude through the voltage-frequency converter of the signal conversion unit and its related circuits, that is, the temperature is realized by the speed of the frequency (the duty cycle remains unchanged at 50%). In this way, even if the level signal is interfered with during long-distance transmission, it does not affect the frequency determination, thereby improving the signal's anti-interference ability. The optical fiber transmission unit in the signal transmission unit uses optical signals for medium and long-distance transmission, further reducing the complex electromagnetic interference in the system and improving the signal quality again. The optocoupler device in the optocoupler transmission unit is also isolated by optical isolation, isolating the output electrical signal SoV and the input Scon signal, that is, the serial signal, to solve the crosstalk introduced on the line and improve the signal quality.

[0043] It should be understood that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or there may be an intervening element at the same time; when an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element at the same time. In addition, the "connection" used here may include wireless connection; the term "and / or" used includes any unit and all combinations of one or more associated listed items.

[0044] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0045] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

[0046] The above contents are further detailed descriptions of the present invention in combination with specific preferred implementations, and the specific implementation of the present invention cannot be considered to be limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A multi-channel temperature sampling circuit, characterized in that: The circuit comprises: A multi-channel temperature sampling unit of at least two temperature sampling modules, used for performing temperature sampling on the object to be measured; A cyclic gating unit, comprising a counter and a multiplexing analog switch, wherein one side of the multiplexing analog switch is connected to the multi-channel temperature sampling unit, and the other side of the multiplexing analog switch is connected to one side of the counter; A signal conversion unit, one side of which is connected to one side of the multiplexing analog switch, and is used to convert the analog quantity signal into a frequency signal; The signal transmission unit is connected to the other side of the signal conversion unit.

2. The multi-channel temperature sampling circuit according to claim 1, characterized in that: Each temperature sampling module in the multi-channel temperature sampling unit has the same structure, and the temperature sampling module specifically includes: one end of the thermistor is grounded, the other end of the thermistor is respectively connected to one end of a voltage divider resistor and one end of a low-pass filter, the other end of the voltage divider resistor is connected to a working power supply, and the other end of the low-pass filter is connected to the multiplexed analog switch.

3. The multi-channel temperature sampling circuit according to claim 1, characterized in that: The counter is specifically a 4-bit binary counter, and the multiplexed analog switch is specifically a 16-channel multiplexed analog switch, wherein the I0 to I15 ports of the multiplexed analog switch are connected to the multi-channel temperature sampling unit, the OUT interface of the multiplexed analog switch is connected to the signal conversion unit, the ENB port of the multiplexed analog switch is grounded, the S0 port of the multiplexed analog switch is connected to the QA port of the counter, the S1 port of the multiplexed analog switch is connected to the QB port of the counter, the S2 port of the multiplexed analog switch is connected to the QC port of the counter, the S3 port of the multiplexed analog switch is connected to the QD port of the counter, the A to D ports of the counter are all grounded, and the QA port, QB port, QC port and QD port are all connected to a NAND gate.

4. The multi-channel temperature sampling circuit according to claim 3, characterized in that: The counter further comprises a CLK port, which is connected to the frequency-adjustable clock unit.

5. The multi-channel temperature sampling circuit according to claim 1, characterized in that: The signal conversion unit specifically includes: The COMPIN port of the voltage-frequency conversion chip is connected to the multiplexed analog switch through a low-pass filter, the THRESH port of the voltage-frequency conversion chip is connected to the threshold voltage of the voltage-frequency conversion chip through an adaptation resistor, the IREF port of the voltage-frequency conversion chip is grounded through a current-limiting resistor, the FOUT port of the voltage-frequency conversion chip is connected to a signal transmission unit, the RC port of the voltage-frequency conversion chip is respectively connected to one end of the frequency adjustment resistor and one end of the frequency adjustment capacitor, the other end of the frequency adjustment resistor is connected to a working power supply, and the other end of the frequency adjustment capacitor is grounded.

6. The multi-channel temperature sampling circuit according to claim 1, characterized in that: The signal transmission unit includes an optical coupling isolation transmission module and an optical fiber isolation transmission module, the optical coupling isolation transmission module includes a first driving unit and a high-speed optical coupler, the optical fiber isolation transmission module includes a second driving unit and an optical fiber terminal, one end of the first driving unit and one end of the second driving unit are both connected to the other side of the signal conversion unit, the other end of the first driving unit is connected to the high-speed optical coupler, and the other end of the second driving unit is connected to the optical fiber terminal.

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