A thermostat control circuit

Abstract

The application discloses a constant temperature control circuit. The constant temperature control circuit comprises a power supply, a DC-DC voltage conversion module, a linear voltage stabilizing module, a load, a temperature detection module and a controller. The DC-DC voltage conversion module is electrically connected with the output end of the power supply and the input end of the linear voltage stabilizing module respectively, and the output end of the linear voltage stabilizing module is electrically connected with the load. The temperature detection module is electrically connected with the controller and is used for transmitting the acquired temperature information of the load to the controller. The controller is connected with the linear voltage stabilizing module and is used for controlling the output voltage of the linear voltage stabilizing module according to the temperature information, so that the temperature information of the load is controlled within a preset temperature range. The DC-DC voltage conversion module is also used for controlling the input voltage of the linear voltage stabilizing module according to the output voltage of the linear voltage stabilizing module, so that the input and output voltage difference of the linear voltage stabilizing module is controlled within a preset range. The constant temperature control circuit can realize low power consumption, high efficiency and low switching ripple interference simultaneously.

Description

Technical Field

[0001] This invention relates to the field of electronic circuit technology, and in particular to a constant temperature control circuit. Background Technology

[0002] In precision instruments such as high-precision inertial measurement units, the core components, such as precision inertial elements, have temperature effects of varying degrees. In order to suppress the impact of ambient temperature changes on their working performance, temperature control methods are generally used to achieve constant temperature control of precision inertial elements.

[0003] However, a high-precision inertial component is highly susceptible to environmental electromagnetic interference, which can affect its performance. Existing temperature control solutions mainly fall into three categories:

[0004] 1. The switch control mode is used, which is subject to interference from the electromagnetic switches with fixed or time-varying frequencies, and it is difficult to remove the interference through filtering methods.

[0005] 2. A near-linear voltage regulation mode can be achieved by using the linear region of a transistor or by using an adjustable linear regulator. This method can effectively avoid electromagnetic interference and provide a better electromagnetic environment for precision inertial components. However, in temperature control with variable load power, the constant temperature control circuit itself has a large heat dissipation and power loss, and it cannot work reliably for a long time in extreme high temperature environments.

[0006] 3. An adjustable non-isolated DC-DC voltage converter is used to achieve the voltage regulation temperature control mode. This method can achieve high conversion efficiency and the switching ripple can be suppressed to a small value, but the switching ripple still exists and causes interference.

[0007] It is evident that existing temperature control solutions cannot simultaneously achieve low switching ripple, high efficiency, and low power consumption. Summary of the Invention

[0008] This invention provides a constant temperature control circuit to solve the problem that existing temperature control solutions cannot simultaneously achieve low switching ripple, high efficiency, and low power consumption.

[0009] This invention provides a constant temperature control circuit, including: a power supply, a DC-DC voltage conversion module, a linear voltage regulator module, a load, a temperature detection module, and a controller;

[0010] The output terminal of the power supply is electrically connected to the input terminal of the DC-DC voltage conversion module, the output terminal of the DC-DC voltage conversion module is electrically connected to the input terminal of the linear voltage regulator module, and the output terminal of the linear voltage regulator module is electrically connected to the load.

[0011] The temperature detection module is mounted on the load and electrically connected to the controller, and is used to acquire the temperature information of the load and transmit the temperature information to the controller.

[0012] The controller is communicatively connected to the control terminal of the linear voltage regulator module and is used to control the output voltage of the linear voltage regulator module according to the temperature information, so as to control the temperature information of the load within a preset temperature range.

[0013] The DC-DC voltage conversion module is further configured to control the input voltage of the linear voltage regulator module based on the output voltage of the linear voltage regulator module, so as to control the input-output voltage difference of the linear voltage regulator module within a preset range.

[0014] Optionally, a PAC converter is also included;

[0015] The linear regulator module includes an LDO voltage manager and a voltage regulating resistor; the LDO voltage manager includes an output voltage setting pin; the first terminal of the voltage regulating resistor is electrically connected to the output voltage setting pin, and the second terminal of the voltage regulating resistor is grounded;

[0016] The PAC converter is connected between the controller and the output voltage setting pin, and is used to convert the pulse control signal output by the controller into an analog control signal, wherein the analog control signal includes a current control signal or a voltage control signal;

[0017] The output voltage of the linear regulator module satisfies the following relationship:

[0018] ;

[0019] or, ;

[0020] in, This represents the output voltage of the linear regulator module. This indicates the output voltage gain of the LDO voltage manager. This refers to the current control signal. This indicates the voltage control signal. This represents the internal current of the voltage regulating resistor. This indicates the resistance value of the voltage regulating resistor. This indicates the control voltage gain of the LDO voltage manager.

[0021] Optionally, the PAC converter includes a full-scale accuracy calibration pin;

[0022] The constant temperature control circuit also includes a precision resistor; the precision resistor is electrically connected between the full-amplitude accuracy calibration pin and ground.

[0023] The pulse control signal output by the controller and the current control signal satisfy the following correspondence:

[0024] ;

[0025] The pulse control signal output by the controller and the voltage control signal satisfy the following correspondence:

[0026] ;

[0027] in, This indicates the duty cycle of the pulse control signal, which is a pulse width modulation signal. This indicates the resistance value of the precision resistor. This refers to the reference voltage reference of the voltage control signal output by the PAC converter, and satisfies: 0V ≤ ≤12V.

[0028] Optionally, the DC-DC voltage conversion module includes a DC-DC voltage conversion manager, an inductor, a first capacitor, a first resistor, and a second resistor; the DC-DC voltage conversion manager includes a switching node pin and an output voltage feedback sampling pin.

[0029] The LDO voltage manager also includes an LDO voltage input pin and an IO power supply input pin;

[0030] The switching node pin is electrically connected to the first end of the inductor; the second end of the inductor is electrically connected to the first end of the first capacitor and the LDO voltage input pin, respectively, for outputting voltage to the input terminal of the linear regulator module; the second end of the first capacitor is grounded; the first end of the first resistor is electrically connected to the IO power supply input pin; the second end of the first resistor is electrically connected to the first end of the second resistor and the output voltage feedback sampling pin, respectively; the second end of the second resistor is grounded.

[0031] The output voltage of the DC-DC voltage conversion module, the input voltage of the linear regulator module, and the output voltage of the linear regulator module satisfy the following correspondence:

[0032] ;

[0033] This represents the input voltage of the linear regulator module. This indicates the output voltage of the DC-DC voltage conversion module. This indicates the resistance value of the first resistor. This indicates the resistance value of the second resistor. This indicates the internal power amplification gain of the DC-DC voltage conversion manager.

[0034] Optionally, the DC-DC voltage conversion module further includes a second capacitor; the DC-DC voltage conversion manager further includes a DC-DC voltage input pin;

[0035] The power supply is electrically connected to the first terminal of the second capacitor and the DC-DC voltage input pin, respectively; the second terminal of the second capacitor is grounded.

[0036] Optionally, the linear regulator module further includes a third capacitor; the LDO voltage manager further includes an LDO voltage output pin;

[0037] The LDO voltage output pin is electrically connected to the first terminal of the third capacitor and the load, respectively; the second terminal of the third capacitor and the load are both grounded.

[0038] Optionally, the linear voltage regulator module includes a fourth capacitor; the first terminal of the fourth capacitor is electrically connected to the first terminal of the voltage regulating resistor;

[0039] The second terminal of the fourth capacitor is grounded.

[0040] Optionally, it also includes an optocoupler isolator;

[0041] The optocoupler isolator connects the controller and the PAC converter.

[0042] Optionally, diodes may also be included;

[0043] The anode of the diode is electrically connected to the PAC converter, and the cathode of the diode is electrically connected to the control terminal of the linear voltage regulator module.

[0044] Optionally, the temperature detection module includes a thermistor, a temperature measuring unit, and an analog-to-digital converter.

[0045] The thermistor is disposed on the load and is electrically connected to the temperature measuring unit;

[0046] The temperature measuring unit is also electrically connected to the analog-to-digital converter unit, and is used to sense the voltage information of the thermistor and convert the voltage information to the analog-to-digital converter unit;

[0047] The analog-to-digital conversion unit is used to convert the voltage information into the temperature information.

[0048] The technical solution of this invention, by setting a controller to control the voltage output of the linear regulator module to the load according to the load temperature information, thereby controlling the load temperature within a preset temperature range, can provide the load with a highly efficient and dynamically linearly adjustable voltage with extremely low electromagnetic interference. By setting a DC-DC voltage conversion module to control the input voltage of the linear regulator module according to the output voltage of the linear regulator module, the input-output voltage difference of the linear regulator module can be controlled within a preset range, which helps to reduce the voltage drop of the linear regulator module, reduce the power consumption of the constant temperature control circuit, and solve the problem that existing temperature control solutions cannot simultaneously achieve low switching ripple, high efficiency and low power consumption.

[0049] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0051] Figure 1 This is a schematic diagram of a constant temperature control circuit provided in an embodiment of the present invention;

[0052] Figure 2 This is a schematic diagram of another constant temperature control circuit provided in an embodiment of the present invention. Detailed Implementation

[0053] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0054] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices. The terms "upper," "lower," "left," "right," etc., indicate orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings and are only used to describe the relative positional relationships between components or constituent parts, and do not specifically limit the specific installation orientation of each component or constituent part.

[0055] Figure 1 This is a schematic diagram of a constant temperature control circuit provided in an embodiment of the present invention, with reference to... Figure 1 The constant temperature control circuit in this embodiment of the invention includes: a power supply 10, a DC-DC voltage conversion module 20, a linear voltage regulator module 30, a load 40, a temperature detection module 50, and a controller 60; the output terminal of the power supply 10 is electrically connected to the input terminal of the DC-DC voltage conversion module 20, the output terminal of the DC-DC voltage conversion module 20 is electrically connected to the input terminal of the linear voltage regulator module 30, and the output terminal of the linear voltage regulator module 30 is electrically connected to the load 40; the temperature detection module 50 is disposed on the load 40 and electrically connected to the controller 60, and is used to acquire the temperature information of the load 40 and transmit the temperature information to the controller 60; the controller 60 is communicatively connected to the control terminal of the linear voltage regulator module 30, and is used to control the output voltage of the linear voltage regulator module 30 according to the temperature information, so as to control the temperature of the load 40 within a preset temperature range; the DC-DC voltage conversion module 20 is also used to control the input voltage of the linear voltage regulator module 30 according to the output voltage of the linear voltage regulator module 30, so as to control the input-output voltage difference of the linear voltage regulator module 30 within a preset range.

[0056] For example, in embodiments of the present invention, an ultra-low electromagnetic interference, high-efficiency DC-DC voltage conversion module 20 can be used to realize the first-stage adjustable power supply voltage output, providing input for the second-stage linear voltage regulator module 30; an ultra-low noise, ultra-high power supply rejection ratio linear voltage regulator module 30 can be used as the second-stage power supply voltage output, acting on the load 40 (e.g., a precision inertial element).

[0057] It is understood that the voltage applied to the load 40 can affect the temperature of the load 40. To ensure that the temperature of the load 40 remains stable within a preset temperature range unaffected by the environment, this embodiment of the invention can achieve this by adjusting the voltage applied to the load 40. Specifically, in this embodiment of the invention, the controller 60 can control the voltage output to the load 40 by the linear regulator module 30 based on the acquired temperature information of the load 40. For example, if the acquired temperature of the load 40 is less than the minimum temperature in the preset temperature range, the output voltage of the linear regulator module 30 is increased to increase the power of the load 40, thereby raising the temperature of the load 40; if the acquired temperature of the load 40 is greater than the maximum temperature in the preset temperature range, the output voltage of the linear regulator module 30 is decreased to reduce the power of the load 40, thereby lowering the temperature of the load 40. It should be noted that this embodiment of the invention does not limit the preset temperature range; the minimum and maximum temperatures can be the same or different, and those skilled in the art can set them as they see fit.

[0058] It is understandable that if the output voltage of the linear regulator module 30 changes while its input voltage remains constant, the input-output voltage difference will change. If the input-output voltage difference increases, its power consumption will increase. To avoid this situation, the DC-DC voltage conversion module 20 in this embodiment adjusts its output voltage according to the output voltage of the linear regulator module 30, thereby adjusting the input voltage of the linear regulator module 30 to control the input-output voltage difference within a preset range, thus ensuring that the power consumption of the linear regulator module 30 is maintained within a low range. It should be noted that this embodiment does not limit the preset temperature range; its minimum and maximum values ​​can be the same or different, and those skilled in the art can set them themselves.

[0059] The technical solution of this invention, by setting the controller 60 to control the voltage output of the linear regulator module 30 to the load 40 according to the temperature information of the load 40, thereby controlling the temperature information of the load 40 within a preset temperature range, can provide the load 40 with a highly efficient and dynamically linearly adjustable voltage with extremely low electromagnetic interference. By setting the DC-DC voltage conversion module 20 to control the input voltage of the linear regulator module 30 according to the output voltage of the linear regulator module 30, the input-output voltage difference of the linear regulator module 30 can be controlled within a preset range, which helps to reduce the voltage drop of the linear regulator module 30, reduce the power consumption of the constant temperature control circuit, and solve the problem that the existing constant temperature control circuit cannot simultaneously achieve low switching ripple, high efficiency and low power consumption.

[0060] Figure 2 This is a schematic diagram of another temperature control circuit provided in an embodiment of the present invention, with reference to... Figure 2The constant temperature control circuit in this embodiment of the invention further includes a PAC converter 70; the linear regulator module 30 includes an LDO voltage manager 31 and a voltage adjustment resistor Rset; the LDO voltage manager 31 includes an output voltage setting pin set; the first end of the voltage adjustment resistor Rset is electrically connected to the output voltage setting pin set, and the second end of the voltage adjustment resistor Rset is grounded; the PAC converter 70 is connected between the controller 60 and the output voltage setting pin set, and is used to convert the pulse control signal output by the controller 60 into an analog control signal, wherein the analog control signal includes a current control signal or a voltage control signal; wherein the output voltage of the linear regulator module 30 satisfies the following correspondence: ;or, ;in, This indicates the output voltage of the linear regulator module 30. This indicates the output voltage gain of the LDO voltage manager 31. Indicates current control signal, Indicates voltage control signal, This indicates the internal current of the voltage regulation resistor Rset. This indicates the resistance value of the voltage regulation resistor Rset. This indicates the control voltage gain of the LDO voltage manager 31.

[0061] It should be noted that the output voltage of the linear voltage regulator module 30 in this embodiment of the invention can be the output voltage of the LDO voltage manager 31.

[0062] The LDO voltage manager 31 in this embodiment of the invention can be an LDO regulator of model LT3045-1, whose external voltage regulation resistor Rset has a voltage... With the current control signal output by PAC converter 70 The following correspondence can be satisfied: It should be noted that the internal current of the voltage regulation resistor Rset in this formula... The resistance value of the voltage adjustment resistor Rset is fixed and can be 100μA. The voltage is a fixed constant value that can be set by the user. Therefore, in this embodiment of the invention, the voltage of the voltage regulating resistor Rset is... Depends on the current control signal output by PAC converter 70 Combining this with the output voltage calculation formula of the linear regulator module 30 mentioned above: It can be seen that the output voltage of the linear regulator module 30 is determined by the voltage across the voltage regulation resistor Rset. and the output voltage gain of the LDO voltage manager 31 The output voltage gain of the LDO voltage manager 31 is determined by... The value is a fixed value, which can be 1. In summary, the output voltage of the linear regulator module 30 is controlled by the current control signal output by the PAC converter 70. Decide.

[0063] The voltage of the external voltage regulation resistor Rset of the LDO voltage manager 31 in this embodiment of the invention. With the voltage control signal output by PAC converter 70 The following correspondence can be satisfied: It should be noted that the control voltage gain of the LDO voltage manager 31 in this formula... It can be a fixed preset value; therefore, in this embodiment of the invention, the voltage of the voltage regulating resistor Rset is... Depends on the voltage control signal output by PAC converter 70 Combining this with the above formula for calculating the output current of the linear regulator module 30: It can be seen that the output voltage of the linear regulator module 30 is determined by the voltage across the voltage regulation resistor Rset. and the output voltage gain of the LDO voltage manager 31 The output voltage gain of the LDO voltage manager 31 is a fixed value, which can be 1. Therefore, the output voltage of the linear regulator module 30 is determined by the voltage control signal output by the PAC converter 70. Decide.

[0064] As one possible implementation method, please refer to [reference]. Figure 2 The PAC converter 70 in this embodiment of the invention includes a full-amplitude accuracy calibration pin set-i; the constant temperature control circuit also includes a precision resistor Rset-i; the precision resistor Rset-i is electrically connected between the full-amplitude accuracy calibration pin set-i and ground; the pulse control signal and the current control signal output by the controller 60 satisfy the following correspondence: The pulse control signal and voltage control signal output by controller 60 satisfy the following correspondence: ;in, This indicates the duty cycle of the pulse control signal, which is a pulse width modulation signal. This indicates the resistance value of the precision resistor Rset-i. This represents the reference voltage for the voltage control signal output by the PAC converter 70, and satisfies: 0V ≤ ≤12V.

[0065] It should be noted that the duty cycle of the pulse control signal ranges from 0% to 100%, and its specific value is related to the temperature information of the load 40 obtained by the controller 60. For example, if the obtained temperature of the load 40 is less than the minimum temperature in the preset temperature range, the duty cycle of the pulse control signal will be increased; if the obtained temperature of the load 40 is greater than the maximum temperature in the preset temperature range, the duty cycle of the pulse control signal will be decreased.

[0066] The calculation formulas for the pulse control signal and the current control signal are as follows: It can be seen that the resistance value of the precision resistor Rset-i determines the output range of the current control signal, which in turn affects the adjustable voltage range of the load 40. This is further explained by the output voltage calculation formula of the linear regulator module 30 mentioned above. It can be seen that the resistance value of the voltage regulation resistor Rset also affects the adjustable voltage range of the load 40. This is based on the calculation formulas for the pulse control signal and the voltage control signal mentioned above: It is understood that the value of the reference voltage reference determines the output range of the voltage control signal, thereby affecting the adjustable voltage range of the load 40. Therefore, it should be noted that the embodiments of the present invention do not limit the values ​​of the voltage regulating resistor Rset, the precision resistor Rset-i, and the reference voltage reference. Those skilled in the art can select appropriate voltage regulating resistor Rset, precision resistor Rset-i, and reference voltage reference according to the adjustable voltage range of the load 40.

[0067] Optional, see reference Figure 2 The DC-DC voltage conversion module 20 in this embodiment of the invention includes a DC-DC voltage conversion manager 21, an inductor L1, a first capacitor C1, a first resistor R1, and a second resistor R2. The DC-DC voltage conversion manager 21 includes a switching node pin SW and an output voltage feedback sampling pin FB. The LDO voltage manager 31 also includes an LDO voltage input pin Vin-LDO and an IO power supply input pin VIOC. The switching node pin SW is electrically connected to the first end of the inductor L1. The second end of the inductor L1 is electrically connected to the first end of the first capacitor C1 and the LDO voltage input pin Vin-LDO, respectively, for outputting voltage to the input terminal of the linear regulator module 30. The second end of the first capacitor C1 is grounded. The first end of the first resistor R1 is electrically connected to the IO power supply input pin VIOC. The second end of the first resistor R1 is electrically connected to the first end of the second resistor R2 and the output voltage feedback sampling pin FB, respectively. The second end of the second resistor R2 is grounded. The output voltage of the DC-DC voltage conversion module 20, the input voltage of the linear regulator module 30, and the output voltage of the linear regulator module 30 satisfy the following correspondence: ; This indicates the input voltage of the linear regulator module 30. This indicates the output voltage of the DC-DC voltage conversion module 20. This indicates the resistance value of the first resistor R1. This indicates the resistance value of the second resistor, R2. This indicates the internal power amplification gain of the DC-DC voltage conversion manager 21.

[0068] The DC-DC voltage conversion manager 21 in this embodiment of the invention can be a DC-DC voltage conversion manager 21 of model LT8640S.

[0069] It should be noted that the output voltage of the DC-DC voltage conversion module 20 refers to the voltage at the connection point of inductor L1 and first capacitor C1, and the input voltage of the linear regulator module 30 refers to the voltage at the LDO voltage input pin Vin-LDO. Since the connection point of inductor L1 and first capacitor C1 is directly electrically connected to the LDO voltage input pin Vin-LDO, the output voltage of the DC-DC voltage conversion module 20 and the input voltage of the linear regulator module 30 are the same.

[0070] The correspondence between the output voltage of the DC-DC voltage conversion module 20, the input voltage of the linear regulator module 30, and the output voltage of the linear regulator module 30 can be derived step by step as follows:

[0071] First, the input voltage of the linear regulator module 30 The output voltage of the linear voltage regulator module 30 The voltage of the VIOC power supply input pin of the LDO voltage manager 31 and the voltage of the output voltage feedback sampling pin FB of the DC-DC voltage conversion manager 21 The following correspondence is satisfied:

[0072] .

[0073] Secondly, regarding the above formula: After deformation, the following formula can be obtained:

[0074] .

[0075] Then, the output voltage of the DC-DC voltage conversion manager 21 Input voltage of linear regulator module 30 The voltage of the output voltage feedback sampling pin FB of the DC-DC voltage conversion manager 21 The following relationship must be satisfied:

[0076] .

[0077] Next, the formula: With formula: Combining these, we get:

[0078] .

[0079] For the above formula: After modification, the corresponding relationship between the output voltage of the DC-DC voltage converter module 20, the input voltage of the linear regulator module 30, and the output voltage of the linear regulator module 30 can be obtained:

[0080] .

[0081] As can be seen from the above formula, the embodiment of the present invention can adjust the output voltage of the DC-DC voltage conversion module 20 (i.e., the input voltage of the linear voltage regulator module 30) based on the output voltage of the linear voltage regulator module 30, thereby controlling the input and output voltage drop of the linear voltage regulator module 30 to a small value and ensuring low loss.

[0082] Optional, see reference Figure 2 In this embodiment, the DC-DC voltage converter manager 21 also includes a SYNC / MODE pin, and the controller 60 is electrically connected to the SYNC / MODE pin, which can control the operating mode of the DC-DC voltage converter manager 21 according to the pulse control signal. It should be noted that the DC-DC voltage converter manager 21 in this embodiment has three operating modes: the Bucks mode with the highest efficiency under light load, the Pulse-Skipping mode with stable ripple and low noise, and the Spread Spectrum mode with low electromagnetic interference.

[0083] It is understandable that the duty cycle of the pulse control signal is proportional to the output voltage of the linear regulator module 30. The duty cycle of the pulse control signal can be used to determine whether the temperature control is in a light, medium, or heavy load state, and thus the operating mode of the DC-DC voltage converter manager 21 can be controlled accordingly. Specifically, the operating mode of the DC-DC voltage converter manager 21 can be controlled by switching the pin connected to the SYNC / MODE pin in the controller 60 between high, low, and floating modes to meet different load requirements and suppress ripple.

[0084] For example, in the duty cycle of the pulse control signal Satisfy: 0≤ When ≤a, the pin connected to the SYNC / MODE pin in controller 60 outputs a low level, and the DC-DC voltage conversion manager 21 operates in Bucks mode; the duty cycle of the pulse control signal... Satisfy: a < When b ≤ b, the pin connected to the SYNC / MODE pin in controller 60 outputs a high level, and the DC-DC voltage conversion manager 21 operates in Spread Spectrum mode; when b < b When ≤1, the pin connected to the SYNC / MODE pin in controller 60 is left floating, the output is in a high impedance state, and the working mode of DC-DC voltage conversion manager 21 is Pulse-Skipping mode.

[0085] It should be noted that the specific values ​​of a and b mentioned above are not limited in the embodiments of the present invention, and those skilled in the art can set them according to actual application needs.

[0086] Optional, see reference Figure 2 In this embodiment of the invention, the DC-DC voltage conversion module 20 further includes a second capacitor C2; the DC-DC voltage conversion manager 21 further includes a DC-DC voltage input pin Vin-DC / DC; the power supply 10 is electrically connected to the first end of the second capacitor C2 and the DC-DC voltage input pin Vin-DC / DC respectively; the second end of the second capacitor C2 is grounded.

[0087] In this embodiment of the invention, the second capacitor C2 can filter the voltage signal output from the power supply 10 to the DC-DC voltage conversion manager 21 to filter out high-frequency interference and suppress voltage fluctuations, thereby ensuring that the voltage signal received by the DC-DC voltage conversion manager 21 is stable and clean.

[0088] Optionally, the linear regulator module 30 also includes a third capacitor C3; the LDO voltage manager 31 also includes an LDO voltage output pin OUT; the LDO voltage output pin OUT is electrically connected to the third capacitor C3 and the first terminal of the load 40 respectively; the second terminal of the third capacitor C3 and the load 40 are both grounded.

[0089] In this embodiment of the invention, the third capacitor C3 can filter the voltage signal output from the LDO voltage manager 31 to the load 40 to filter out high-frequency interference and suppress voltage fluctuations, thereby ensuring that the voltage signal received by the load 40 is stable and clean.

[0090] Optional, see reference Figure 2 The linear voltage regulator module 30 in this embodiment of the invention includes a fourth capacitor C4; the first terminal of the fourth capacitor C4 is electrically connected to the first terminal of the voltage regulation resistor Rset; and the second terminal of the fourth capacitor C4 is grounded.

[0091] By connecting the fourth capacitor C4 in parallel with the voltage regulation resistor Rset, this invention can filter out high-frequency interference and suppress noise, thereby improving the stability and accuracy of the LDO voltage manager 31.

[0092] Optional, see reference Figure 2 The present invention also includes an optocoupler 80; the optocoupler 80 is connected between the controller 60 and the PAC converter 70.

[0093] In this embodiment of the invention, by setting an optocoupler 80 between the PWM pins of the controller 60 and the PAC converter 70, electrical isolation between the controller 60 and the PAC converter 70 can be achieved, blocking interference and surges between high and low voltages, while not affecting the transmission of pulse control signals from the controller 60 to the PAC converter 70.

[0094] Optional, see reference Figure 2 The embodiment of the present invention also includes a diode V1; the anode of the diode V1 is electrically connected to the PAC converter 70, and the cathode of the diode V1 is electrically connected to the control terminal of the linear voltage regulator module 30.

[0095] For example, in this embodiment of the invention, by placing a diode V1 between the control terminal of the PAC converter 70 and the linear regulator module 30, the voltage backflow at the control terminal of the linear regulator module 30 can be prevented from damaging the PAC converter 70.

[0096] Optional, see reference Figure 2 In this embodiment of the invention, the temperature detection module 50 includes a thermistor Rt, a temperature measuring unit 51, and an analog-to-digital converter 52. The thermistor Rt is disposed on the load 40 and electrically connected to the temperature measuring unit 51. The temperature measuring unit 51 is also electrically connected to the analog-to-digital converter 52 and is used to sense the voltage information of the thermistor Rt and convert the voltage information to the analog-to-digital converter 52. The analog-to-digital converter 52 is used to convert the voltage information into temperature information.

[0097] For example, a thermistor Rt can be attached to the surface of the load 40, and its resistance changes with the temperature of the load 40. It is understood that when the resistance of the thermistor Rt changes, its voltage information also changes. Therefore, different temperatures of the load 40 will result in different voltage information for the thermistor Rt, and there is a corresponding relationship between the two. In this embodiment of the invention, the temperature information of the load 40 can be determined by the voltage information of the thermistor Rt. Specifically, the temperature measuring unit 51 first transmits the collected voltage information of the thermistor Rt to the analog-to-digital conversion unit 52, and the analog-to-digital conversion unit 52 converts the acquired voltage information into temperature information (e.g., the actual temperature value).

[0098] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A constant temperature control circuit, characterized in that, include: Power supply, DC-DC voltage conversion module, linear regulator module, load, temperature detection module and controller; The output terminal of the power supply is electrically connected to the input terminal of the DC-DC voltage conversion module, the output terminal of the DC-DC voltage conversion module is electrically connected to the input terminal of the linear voltage regulator module, and the output terminal of the linear voltage regulator module is electrically connected to the load. The temperature detection module is mounted on the load and electrically connected to the controller, and is used to acquire the temperature information of the load and transmit the temperature information to the controller. The controller is communicatively connected to the control terminal of the linear voltage regulator module and is used to control the output voltage of the linear voltage regulator module according to the temperature information, so as to control the temperature information of the load within a preset temperature range. The DC-DC voltage conversion module is also used to control the input voltage of the linear regulator module according to the output voltage of the linear regulator module, so as to control the input-output voltage difference of the linear regulator module within a preset range; It also includes a PAC converter; The linear regulator module includes an LDO voltage manager and a voltage regulating resistor; the LDO voltage manager includes an output voltage setting pin; the first terminal of the voltage regulating resistor is electrically connected to the output voltage setting pin, and the second terminal of the voltage regulating resistor is grounded; The PAC converter is connected between the controller and the output voltage setting pin, and is used to convert the pulse control signal output by the controller into an analog control signal, wherein the analog control signal includes a current control signal or a voltage control signal; The output voltage of the linear regulator module satisfies the following relationship: ； or, ; in, This represents the output voltage of the linear regulator module. This indicates the output voltage gain of the LDO voltage manager. This refers to the current control signal. This indicates the voltage control signal. This represents the internal current of the voltage regulating resistor. This indicates the resistance value of the voltage regulating resistor. This indicates the control voltage gain of the LDO voltage manager; The DC-DC voltage conversion module includes a DC-DC voltage conversion manager, an inductor, a first capacitor, a first resistor, and a second resistor; the DC-DC voltage conversion manager includes a switching node pin and an output voltage feedback sampling pin. The LDO voltage manager also includes an LDO voltage input pin and an IO power supply input pin; The switching node pin is electrically connected to the first end of the inductor; the second end of the inductor is electrically connected to the first end of the first capacitor and the LDO voltage input pin, respectively, for outputting voltage to the input terminal of the linear regulator module; the second end of the first capacitor is grounded; the first end of the first resistor is electrically connected to the IO power supply input pin; the second end of the first resistor is electrically connected to the first end of the second resistor and the output voltage feedback sampling pin, respectively; the second end of the second resistor is grounded. The output voltage of the DC-DC voltage conversion module, the input voltage of the linear regulator module, and the output voltage of the linear regulator module satisfy the following correspondence: ； This represents the input voltage of the linear regulator module. This indicates the output voltage of the DC-DC voltage conversion module. This indicates the resistance value of the first resistor. This indicates the resistance value of the second resistor. This indicates the internal power amplification gain of the DC-DC voltage conversion manager.

2. The constant temperature control circuit according to claim 1, characterized in that, The PAC converter includes a full-scale accuracy calibration pin; The constant temperature control circuit also includes a precision resistor; the precision resistor is electrically connected between the full-amplitude accuracy calibration pin and ground. The pulse control signal output by the controller and the current control signal satisfy the following correspondence: ； The pulse control signal output by the controller and the voltage control signal satisfy the following correspondence: ； in, This indicates the duty cycle of the pulse control signal, which is a pulse width modulation signal. This indicates the resistance value of the precision resistor. This refers to the reference voltage reference of the voltage control signal output by the PAC converter, and satisfies: 0V ≤ ≤12V.

3. The constant temperature control circuit according to claim 1, characterized in that, The DC-DC voltage conversion module further includes a second capacitor; the DC-DC voltage conversion manager further includes a DC-DC voltage input pin. The power supply is electrically connected to the first terminal of the second capacitor and the DC-DC voltage input pin, respectively; the second terminal of the second capacitor is grounded.

4. The constant temperature control circuit according to claim 1, characterized in that, The linear regulator module also includes a third capacitor; the LDO voltage manager also includes an LDO voltage output pin. The LDO voltage output pin is electrically connected to the first terminal of the third capacitor and the load, respectively; the second terminal of the third capacitor and the load are both grounded.

5. The constant temperature control circuit according to claim 1, characterized in that, The linear voltage regulator module includes a fourth capacitor; the first terminal of the fourth capacitor is electrically connected to the first terminal of the voltage regulating resistor. The second terminal of the fourth capacitor is grounded.

6. The constant temperature control circuit according to claim 1, characterized in that, It also includes optocoupler isolators; The optocoupler isolator connects the controller and the PAC converter.

7. The constant temperature control circuit according to claim 1, characterized in that, It also includes diodes; The anode of the diode is electrically connected to the PAC converter, and the cathode of the diode is electrically connected to the control terminal of the linear voltage regulator module.

8. The constant temperature control circuit according to claim 1, characterized in that, The temperature detection module includes a thermistor, a temperature measuring unit, and an analog-to-digital conversion unit; The thermistor is disposed on the load and is electrically connected to the temperature measuring unit; The temperature measuring unit is also electrically connected to the analog-to-digital converter unit, and is used to sense the voltage information of the thermistor and convert the voltage information to the analog-to-digital converter unit; The analog-to-digital conversion unit is used to convert the voltage information into the temperature information.

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