Temperature controller soft start circuit and method

Abstract

The application relates to the technical field of integrated circuit design, and particularly discloses a temperature controller slow start circuit and method, wherein the input end of the slow start circuit is electrically connected with the output end of a temperature detection unit, the output end is electrically connected with a power drive and a semiconductor refrigerator in sequence, and the slow start circuit comprises a first switch, a second switch, a third switch and a fourth switch, a plurality of resistors and a plurality of capacitors, a slow start operational amplifier, a same-phase input end of the slow start operational amplifier is electrically connected with the blade end of the second switch, an opposite-phase input end of the slow start operational amplifier is electrically connected with one end of one resistor in the plurality of resistors and the blade end of the third switch, and the output end of the slow start operational amplifier is electrically connected with the voltage control end of the power drive, one fixed end of the third switch and one end of two capacitors in the plurality of capacitors. The application controls the opening and closing of the plurality of analog switches and the enablement of the power drive, so that the temperature controller can be started at zero current under various initial temperatures, thereby reducing the pressure of the system power supply and the current demand to the greatest extent.

Description

Technical Field

[0001] This invention relates to the field of integrated circuit design technology, and specifically to a temperature controller soft-start circuit and method. Background Technology

[0002] When using a temperature controller to achieve a specified temperature for the controlled target, a closed-loop PID control system is generally used.

[0003] In applications such as optical modules and amplifiers used in optical communication systems, and laser gas sensors, a thermostat is generally used to drive a thermoelectric cooler (TEC) to maintain a constant operating temperature for the laser.

[0004] A thermoelectric cooler (TEC)-based temperature controller typically consists of a TEC, a thermistor (NTC), a power driver, and a control circuit (PID). These components form a negative feedback system, where the thermistor measures the current temperature V of the controlled object. OUT1 The controlled target temperature is set to V. TSET Their difference is conditioned by a PID control circuit and output as V. OUT2 V OUT2 The control power drive (DRIVER) drives the thermoelectric cooler (TEC) to heat or cool the target, thereby raising the temperature V of the controlled target. OUT1 Gradually approaching and eventually equaling the temperature set value V TSET .

[0005] Because the ambient temperature of the controlled target is unpredictable and may vary greatly (such as spring, summer, autumn, winter and latitude differences), and there is a gap between it and the set temperature target, the temperature controller will generate a large cooling or heating current at the moment of start-up. This will impact the power supply of the product, which may make the system less stable or even prevent it from working properly.

[0006] The existing system block diagram of a temperature controller based on a semiconductor cooler is as follows: Figure 1 Generally, an operational amplifier and resistors and capacitors are used to form a negative feedback PID loop (hereinafter referred to as: analog PID) to achieve constant temperature control.

[0007] Output voltage V of the power drive module TEC With input voltage V OUT2 The transfer function is assumed to be V. TEC = 5 (V) OUT2_init - V OUT2 For the sake of convenience, we assume V OUT2_init If the voltage is equal to 1.25V, then the transfer function is V. TEC = 5 (1.25V - V) OUT2 The output voltage V of the power drive module TEC With input voltage V OUT2 Relationship such as Figure 2 V during system startup OUT2 When the voltage is equal to 1.25V, the starting voltage V of the TEC is... TEC The starting current I of the TEC is 0V. TEC It is 0.

[0008] Analog PID controllers contain electronic components such as operational amplifiers and capacitors. During system power-on startup, due to the randomness of the initial and set temperatures of the operational amplifiers, capacitors, and the controlled target, the voltage V at the moment of circuit startup... OUT2 It could be a voltage value other than 1.25V. The power drive module may generate a very large cooling or heating current on the TEC. TEC Excessive current may exceed the maximum current limit of the system power supply VDD, causing the system power supply voltage to collapse.

[0009] Based on this technical background, the present invention proposes a thermostat soft-start circuit and method. Summary of the Invention

[0010] To address the shortcomings of existing technologies, this invention proposes a soft-start circuit and method for a temperature controller. This soft-start circuit can accurately and quickly achieve zero-current start-up of a simulated PID temperature control system at various initial temperatures, thereby minimizing the pressure on the concurrent current demand of the system power supply.

[0011] To achieve the above objectives, a first aspect of the present invention provides a thermostat soft-start circuit, comprising:

[0012] Multiple analog switches, including a first switch, a second switch, a third switch, and a fourth switch;

[0013] A resistor-capacitor network, consisting of multiple resistors and multiple capacitors;

[0014] The soft-start operational amplifier has its non-inverting input terminal electrically connected to the blade end of the second switch, its inverting input terminal electrically connected to one end of one of the multiple resistors and the blade end of the third switch, and its output terminal electrically connected to the voltage control terminal of the power drive, one stationary terminal of the third switch, and one end of two of the multiple capacitors.

[0015] The controller is used to control the opening and closing of the plurality of analog switches and the enabling of the power drive, so that the temperature controller can start with zero current at various initial temperatures, thereby minimizing the pressure on the concurrent current demand of the system power supply.

[0016] A second aspect of the present invention provides a method for slow-starting a temperature controller in the aforementioned slow-start circuit, comprising:

[0017] A negative feedback PID loop is built using a temperature detection unit, power drive, semiconductor cooler, multiple analog switches, RC network and soft-start operational amplifier;

[0018] By controlling the opening and closing of the multiple analog switches and the disabling or enabling of the power drive, the temperature controller can achieve zero-current start-up at various initial temperatures, thereby minimizing the pressure on the concurrent current demand of the system power supply.

[0019] The beneficial effects of this invention include:

[0020] The temperature controller soft-start circuit proposed in this invention can accurately and quickly achieve zero-current start-up of the simulated PID temperature control system at various initial temperatures, thereby minimizing the pressure on the concurrent current demand of the system power supply.

[0021] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0022] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the invention.

[0023] Figure 1 This is a schematic diagram of a common temperature controller system that uses analog PID.

[0024] Figure 2 This is a schematic diagram of the transfer function between the output VTEC and the input VOUT2 of the power drive module in a common temperature controller system that uses analog PID.

[0025] Figure 3 This is a schematic diagram of a specific embodiment of the thermostat soft-start circuit proposed in this invention.

[0026] Figure 4 This is a schematic diagram of the equivalent circuit connection during the initial cold start of a specific embodiment of the thermostat soft-start circuit proposed in this invention.

[0027] Figure 5 This is a schematic diagram showing the temperature controller soft-start circuit according to a specific embodiment of the present invention, which restores the normal PID connection state after a cold start.

[0028] Figure 6 This is a schematic diagram of the cold start control process in a specific embodiment of the temperature controller soft start circuit proposed in this invention.

[0029] Explanation of reference numerals in the attached figures:

[0030] A1 - Detection op-amp, A2 - Soft-start op-amp, R F -Feedback resistor, R NTC -Thermistor, R C - Compensation resistor, R SET_init - Set the resistor, R I - Integrating resistor, R D - Differential resistance, R P -Proportional resistor, C D - Differential capacitance, C I - Integrating capacitor, C F - Feedback capacitor, S1- First switch, S2- Second switch, S3- Third switch, S4- Fourth switch, Driver- Power drive, TEC- Semiconductor cooler;

[0031] S1A - First stationary terminal of the first switch, S1B - Second stationary terminal of the first switch, S1C - Knife terminal of the first switch, S2A - First stationary terminal of the second switch, S2B - Second stationary terminal of the second switch, S2C - Knife terminal of the second switch, S3A - First stationary terminal of the third switch, S3B - Second stationary terminal of the third switch, S3C - Knife terminal of the third switch, S4A - Knife terminal of the fourth switch, S4B - Stationary terminal of the fourth switch, EN - Enable control terminal, VCTL - Voltage control terminal, OUT+, OUT- - Differential output terminals of the power drive module;

[0032] VDD - Power supply, GND - Ground, V REF - Output terminal of the reference voltage source, V REF / 2 - Half-potential output terminal of the reference voltage source, V TSET - Voltage corresponding to the target set temperature, V OUT1 -Detect the output voltage of the op-amp, V OUT1_init - Detect the initial output voltage of the op-amp, V OUT2 - Output voltage of the soft-start op-amp, V OUT2_init - Initial output voltage of the soft-start op-amp, V TEC - Voltage across the semiconductor cooler, I TEC - Cooling or heating current. Detailed Implementation

[0033] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0034] In this invention, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its normal operating state, while "inner" and "outer" refer to their position relative to the device's outline. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0035] This invention provides a soft-start circuit for a temperature controller. The input terminal of the soft-start circuit is electrically connected to the output terminal of a temperature detection unit, and the output terminal is sequentially electrically connected to a power driver and a semiconductor cooler (TEC). Figure 1 As shown, it includes:

[0036] Multiple analog switches, including a first switch S1, a second switch S2, a third switch S3, and a fourth switch S4;

[0037] A resistor-capacitor network, consisting of multiple resistors and multiple capacitors;

[0038] The soft-start operational amplifier A2 has its non-inverting input terminal electrically connected to the blade end S2C of the second switch, its inverting input terminal electrically connected to one end of one of the multiple resistors and the blade end S3C of the third switch, and its output terminal electrically connected to the voltage control terminal VCTL of the power drive, one stationary terminal of the third switch, and one end of two of the multiple capacitors.

[0039] The controller is used to control the opening and closing of multiple analog switches and enable the power drive driver, enabling the temperature controller to start with zero current at various initial temperatures, thereby minimizing the pressure on the concurrent current demand of the system power supply.

[0040] This invention can accurately and quickly achieve zero-current start-up of the simulated PID temperature control system at various initial temperatures, thereby minimizing the pressure on the concurrent current demand of the system power supply.

[0041] According to the present invention, the plurality of resistors includes a setting resistor R. SET_init Integrating resistor R I Differential resistance R D and proportional resistor R P ;

[0042] Multiple capacitors, including differential capacitor C D Integrating capacitor C I and feedback capacitor C F ;

[0043] The first switch S1, the second switch S2 and the third switch S3 are all single-pole double-throw switches;

[0044] The fourth switch, S4, is a single-pole single-throw switch.

[0045] According to the present invention, the blade end S1C of the first switch is electrically connected to the output terminal of the temperature detection unit, and the first stationary end is simultaneously connected to the setting resistor R. SET_init One end, integrating resistor R I One end and differential resistor R D One end is electrically connected, and the second stationary end is simultaneously connected to the differential capacitor C. D One end, feedback capacitor C F One end of the switch, the first stationary terminal S3A of the third switch, the stationary terminal S4B of the fourth switch, and the proportional resistor R. P One end is electrically connected;

[0046] The first stationary terminal S2A of the second switch is related to the initial voltage V of the soft-start operational amplifier. OUT2_init Electrical connection, the second stationary terminal is connected to the set resistor R SET_init The other end is electrically connected;

[0047] The second stationary terminal S3B of the third switch is simultaneously electrically connected to the output terminal of the soft-start operational amplifier A2.

[0048] The knife end S4A of the fourth switch is simultaneously connected to the integrating capacitor C. I One end, proportional resistor R P The other end is electrically connected;

[0049] Integrating capacitor C I The other end, feedback capacitor C F The other end is electrically connected to the output terminal of the soft-start operational amplifier A2;

[0050] Differential resistance R D The other end is connected to the differential capacitor C D The other end is electrically connected.

[0051] According to the present invention, the temperature detection unit includes:

[0052] The operational amplifier A1 is tested. Its non-inverting input is electrically connected to the half-potential output terminal VREF / 2 of the reference voltage source, and its output terminal is electrically connected to the blade end S1C of the first switch.

[0053] Feedback resistor R F One end is electrically connected to the inverting input terminal of the detection operational amplifier A1, and the other end is electrically connected to the output terminal of the detection operational amplifier A1.

[0054] Thermistor R NTC One end is electrically connected to the inverting input terminal of the detection operational amplifier A1, and the other end is connected to ground.

[0055] Compensation resistor R C One end is connected to the output terminal V of the reference voltage source. REF One end is electrically connected, and the other end is electrically connected to the inverting input terminal of the detection operational amplifier A1.

[0056] According to the present invention, the power driver is provided with an enable control terminal EN, a voltage control terminal VCTL, and differential output terminals OUT+ and OUT-.

[0057] The voltage control terminal VCTL is electrically connected to the output terminal of the soft-start operational amplifier A2.

[0058] The differential output terminals OUT+ and OUT- are electrically connected to a pair of control ports of the semiconductor cooler.

[0059] According to the present invention, it further includes:

[0060] The digital-to-analog converter has its output terminal electrically connected to the second stationary terminal S2B of the second switch. It is used to control the controlled object to reach the target temperature at a specific speed by adjusting the step size and step speed of the analog output voltage at the output terminal.

[0061] The present invention also provides a method for slow-starting a temperature controller in the above-mentioned slow-start circuit, comprising:

[0062] A negative feedback PID loop is built using a temperature detection unit, a power drive, a semiconductor cooler (TEC), multiple analog switches, a resistor-capacitor network, and a soft-start operational amplifier (A2).

[0063] By controlling the opening and closing of multiple analog switches and disabling or enabling the power drive driver, the temperature controller can achieve zero-current start-up at various initial temperatures, thereby minimizing the pressure on the concurrent current demand of the system power supply.

[0064] According to the present invention, controlling the opening and closing of multiple analog switches and disabling or enabling the power drive driver via a controller includes:

[0065] After the temperature controller is powered on, it disables the power drive driver through the controller. Simultaneously, it connects the blade end S1C of the first switch to its second stationary end, the blade end S2C of the second switch to its first stationary end, the blade end S3C of the third switch to its second stationary end, and the blade end S4A of the fourth switch to its stationary end, thus causing V... OUT1 =V OUT1_init =V REF / 2 (1+R F / R NTC -R F / R C ), and V OUT2 =VOUT2_init , where V OUT1 To detect the output voltage of the operational amplifier, V OUT2 To adjust the output voltage of the soft-start op-amp, R F For the feedback resistor, R NTC For thermistors, R C To compensate for the resistance, V OUT1_init To detect the initial voltage of the operational amplifier, V OUT2_init The initial voltage for the soft-start operational amplifier;

[0066] The integrating capacitor C I Charge until the set time is reached, or monitor the integrating capacitor C. I When the voltage across the terminals reaches a set threshold, the knife end S1C of the first switch is electrically connected to its first stationary terminal, the knife end S2C of the second switch is electrically connected to its second stationary terminal, the knife end S3C of the third switch is electrically connected to its first stationary terminal, and the knife end S4A of the fourth switch is electrically disconnected from its stationary terminal, so that the VTSET voltage equals V. OUT1 Voltage, i.e., V TSET = V OUT1_init And V OUT2 = V TSET + V CI = V OUT1_init +V OUT2_init - V OUT1_init = V OUT2_init , where V TSET To set the voltage;

[0067] The controller enables the power drive driver, causing V to... OUT2 =V OUT2_init At this time, the voltage V across the semiconductor cooler is TEC Both current and current are 0, completing the cold start.

[0068] According to the present invention, when the knife end S1C of the first switch is electrically connected to its second stationary end, the knife end S2C of the second switch is electrically connected to its first stationary end, the knife end S3C of the third switch is electrically connected to its second stationary end, and the knife end S4A of the fourth switch is electrically connected to its stationary end, the thermistor R... NTC The resistance value is determined by the initial temperature Tinit of the controlled object, denoted as R. NTC_init At this time, V OUT1 The initial voltage is denoted as V. OUT1_init V OUT1 =V OUT1_init .

[0069] According to the present invention, after the system cold start is completed, the output terminal of the digital-to-analog converter is electrically connected to the second stationary terminal S2B of the second switch, and the controlled object is controlled to reach the target temperature at a specific speed by adjusting the step size and step speed of the analog output voltage at its output terminal.

[0070] The present invention will now be described in more detail through specific embodiments.

[0071] Example 1

[0072] like Figure 3 As shown, this embodiment provides a thermostat soft-start circuit, which is commonly used in thermostat systems employing analog PID control (such as...). Figure 1 Based on the above, by adding four analog switches (first switch S1, second switch S2, third switch S3, and fourth switch S4) and setting the resistor RSET_init, in conjunction with... Figure 6 The control logic enables the simulated PID temperature control system to have fully controllable cold start current at any ambient temperature.

[0073] When the system power supply VDD is powered on, the control enable terminal EN disables the power drive driver, detects that op-amp A1 and soft-start op-amp A2 have started to work, and controls the first switch's blade end S1C to be electrically connected to its second stationary end, the second switch's blade end S2C to its first stationary end, the third switch's blade end S3C to its second stationary end, and the fourth switch's blade end S4A to its stationary end.

[0074] At this point, the equivalent connection relationship is as follows: Figure 4 Detect the output V of operational amplifier A1 OUT1 =V REF / 2 (1+R F / R NTC -R F / R C The resistance value R of the NTC temperature resistor NTC Determined by the initial temperature Tinit of the controlled object, denoted as R NTC_init Then V OUT1 The initial voltage is denoted as V. OUT1_init V OUT1 Directly connected to the integrating capacitor C I The left pin;

[0075] The soft-start operational amplifier A2 forms a voltage follower, V OUT2 =V OUT2_init V OUT2 Directly connected to the integrating capacitor C I The right-hand pin;

[0076] Therefore, after time tci, the integrating capacitor CI It is quickly charged to a balanced state, and its voltage V is... CI =V OUT2 -V OUT1 =V OUT2_init -V OUT1_init Waiting for the integrating capacitor C I Once charging is complete, proceed to the next step. Figure 6 Integrating capacitor C I The condition for determining charging completion is just an example; this condition can also be determined by monitoring the integrating capacitor C. I Voltage V at both ends CI Is it related to V? OUT2_init -V OUT1_init The comparison can be determined by whether the values ​​are equal or sufficiently close (by setting a threshold), or it can be automatically proceeded to the next step after a simple fixed charging time (TCI).

[0077] Next, first control the knife end S4A of the fourth switch to disconnect its electrical connection with its stationary end, and then simultaneously control the knife end S1C of the first switch to connect its electrical connection with its first stationary end, the knife end S2C of the second switch to connect its electrical connection with its second stationary end, and the knife end S3C of the third switch to connect its electrical connection with its first stationary end.

[0078] At this point, the equivalent connection relationship is as follows: Figure 5 V TSET Voltage equals V OUT1 Voltage, i.e., V TSET = V OUT1_init V OUT2 =V TSET + V CI = V OUT1_init + V OUT2_init - V OUT1_init = V OUT2_init = 1.25V;

[0079] At this time, the power control driver is enabled by controlling the enable control terminal EN, from Figure 2 From the transfer function curve, we can see that V OUT2 The voltage is 1.25V, the voltage across the TEC is 0, and the TEC current is 0, indicating that the system cold start is complete. After the system cold start, a certain strategy can be used, such as using a digital-to-analog converter (DAC) to output a step-by-step analog control voltage to V. TSET The step size and step speed of the DAC output are adjusted to control the controlled object to reach the target temperature at a specific speed.

[0080] The temperature controller soft-start circuit proposed in the embodiments of the present invention can accurately and quickly realize zero-current start-up of the simulated PID temperature control system at various initial temperatures, thereby minimizing the pressure on the concurrent current demand of the system power supply.

[0081] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A soft-start circuit for a temperature controller, wherein the input terminal of the soft-start circuit is electrically connected to the output terminal of a temperature detection unit, and the output terminal is sequentially electrically connected to a power drive and a semiconductor cooler, characterized in that, include: Multiple analog switches, including a first switch, a second switch, a third switch, and a fourth switch; A resistor-capacitor network, consisting of multiple resistors and multiple capacitors; The soft-start operational amplifier has its non-inverting input terminal electrically connected to the blade end of the second switch, its inverting input terminal electrically connected to one end of one of the multiple resistors and the blade end of the third switch, and its output terminal electrically connected to the voltage control terminal of the power drive, one stationary terminal of the third switch, and one end of two of the multiple capacitors. The controller is used to control the opening and closing of the multiple analog switches and the enabling of the power drive, so that the temperature controller can start with zero current at various initial temperatures, thereby minimizing the pressure on the concurrent current demand of the system power supply. The plurality of resistors includes a set resistor, a proportional resistor, a differential resistor, and an integrating resistor; The capacitors include differentiating capacitors, integrating capacitors, and feedback capacitors; The first switch, the second switch, and the third switch are all single-pole double-throw switches; The fourth switch is a single-pole single-throw switch; The blade end of the first switch is electrically connected to the output end of the temperature detection unit, and the first stationary end is simultaneously electrically connected to one end of the setting resistor, one end of the integrating resistor and one end of the differential resistor. The second stationary end is simultaneously electrically connected to one end of the differential capacitor, one end of the feedback capacitor, the first stationary end of the third switch, the stationary end of the fourth switch and one end of the integrating resistor. The first stationary terminal of the second switch is electrically connected to the initial voltage of the soft-start operational amplifier, and the second stationary terminal is electrically connected to the other end of the setting resistor; The second stationary terminal of the third switch is simultaneously electrically connected to the output terminal of the soft-start operational amplifier. The blade end of the fourth switch is electrically connected to one end of the integrating capacitor and the other end of the integrating resistor. The other end of the integrating capacitor and the other end of the feedback capacitor are electrically connected to the output terminal of the soft-start operational amplifier. The other end of the differential resistor is electrically connected to the other end of the differential capacitor.

2. The soft-start circuit according to claim 1, characterized in that, The temperature detection unit includes: The operational amplifier is tested, with its non-inverting input terminal electrically connected to the half-potential output terminal of the reference voltage source, and its output terminal electrically connected to the blade end of the first switch. The feedback resistor has one end electrically connected to the inverting input terminal of the detection operational amplifier, and the other end electrically connected to the output terminal of the detection operational amplifier. One end of the thermistor is electrically connected to the inverting input terminal of the detection operational amplifier, and the other end is connected to ground. The compensation resistor has one end electrically connected to the output terminal of the reference voltage source and the other end electrically connected to the inverting input terminal of the detection operational amplifier.

3. The soft-start circuit according to claim 1, characterized in that, The power drive is provided with an enable control terminal, a voltage control terminal, and a differential output terminal; The voltage control terminal is electrically connected to the output terminal of the soft-start operational amplifier; The differential output terminal is electrically connected to a pair of control ports of the semiconductor cooler.

4. The soft-start circuit according to claim 1, characterized in that, Also includes: The digital-to-analog converter has its output terminal electrically connected to the second stationary terminal of the second switch. It is used to control the controlled object to reach the target temperature at a specific speed by adjusting the step size and step speed of the analog output voltage at the output terminal.

5. A method for slow-starting a temperature controller in the slow-start circuit according to any one of claims 1-4, characterized in that, include: A negative feedback PID loop is built using a temperature detection unit, power drive, semiconductor cooler, multiple analog switches, RC network and soft-start operational amplifier; By controlling the opening and closing of the multiple analog switches and the disabling or enabling of the power drive, the temperature controller can achieve zero-current start-up at various initial temperatures, thereby minimizing the pressure on the concurrent current demand of the system power supply.

6. The method according to claim 5, characterized in that, Controlling the opening and closing of the plurality of analog switches and disabling or enabling the power drive via the controller includes: After the temperature controller is powered on, it disables the power drive via the controller. Simultaneously, it connects the blade end of the first switch to its second stationary terminal, the blade end of the second switch to its first stationary terminal, the blade end of the third switch to its second stationary terminal, and the blade end of the fourth switch to its stationary terminal, thus causing V... OUT1 =V OUT1_init =V REF / 2 * (1+R F / R NTC -R F / R C ), and V OUT2 =V OUT2_init , where V OUT1 To detect the output voltage of the operational amplifier, V OUT2 To adjust the output voltage of the soft-start op-amp, R F For the feedback resistor, R NTC For thermistors, R C To compensate for the resistance, V OUT1_init To detect the initial voltage of the operational amplifier, V OUT2_init The initial voltage for the soft-start operational amplifier; The integrating capacitor is charged to a set time, or the voltage across the integrating capacitor is monitored to reach a set threshold. This triggers the electrical connection of the blade end of the first switch to its first stationary terminal, the blade end of the second switch to its second stationary terminal, the blade end of the third switch to its first stationary terminal, and the blade end of the fourth switch to its stationary terminal, thus disconnecting V. TSET =V OUT1_init And V OUT2 =V TSET +V CI =V OUT1_init +V OUT2_init -V OUT1_init =V OUT2_init , where V TSET To set the voltage; The controller enables power drive, so that V OUT2 =V OUT2_init At this point, both the voltage and current across the semiconductor cooler are 0, completing the cold start.

7. The method according to claim 6, characterized in that, When the knife end of the first switch is electrically connected to its second stationary terminal, the knife end of the second switch is electrically connected to its first stationary terminal, the knife end of the third switch is electrically connected to its second stationary terminal, and the knife end of the fourth switch is electrically connected to its stationary terminal, the resistance value of the thermistor is determined by the initial temperature Tinit of the controlled object, denoted as R. NTC_init At this time, V OUT1 The initial voltage is denoted as V. OUT1_init V OUT 1=V OUT1_init .

8. The method according to claim 6, characterized in that, After the system completes its cold start, the output terminal of the digital-to-analog converter is electrically connected to the second stationary terminal of the second switch. By adjusting the step size and speed of the analog output voltage at its output terminal, the controlled object is controlled to reach the target temperature at a specific speed.

Images