Peltier element driver and Peltier element control system

Abstract

A low-cost Peltier device driver and control system is provided. [Solution] This is a device that controls the heating and cooling of a Peltier element based on a heating signal and a cooling signal from a temperature regulator, and includes: a first switch 20a that is provided between the power supply side 11 of the DC power supply 10 and the first pole 31 of the Peltier element 30 and opens and closes based on the heating signal; a second switch 20b that is provided between the power supply side 11 of the DC power supply 10 and the second pole 32 of the Peltier element 30 and opens and closes based on the cooling signal; a third switch 20c that is provided between the GND side 12 of the DC power supply 10 and the first pole 31 of the Peltier element 30 and opens and closes based on the cooling signal; and a fourth switch 20d that is provided between the GND side 12 of the DC power supply 10 and the second pole 32 of the Peltier element 30 and opens and closes based on the heating signal, and the first to fourth switches 20a to 20d are solid-state relays.

Description

[Technical Field]

[0001] The present invention relates to a Peltier element driver and a Peltier element control system. [Background technology]

[0002] Conventionally, a heating / cooling method using a Peltier element has been used. When a direct current is passed through a Peltier element in a certain direction, one side of the element absorbs heat (cools) and the other side generates heat (heats). Furthermore, when the direction of the direct current is changed, the cooling and heating sides are swapped. This characteristic is used in the heating and cooling processes of semiconductors to control the temperature during product manufacturing and inspection processes.

[0003] A known driving circuit for such a Peltier element is an H-bridge circuit in which two circuits, each with two open / close switches connected in series between a power supply and GND (ground), are formed in parallel, with a Peltier element located midway between the two midpoints (see, for example, Figure 3 of Patent Document 1 and Figure 1 of Patent Document 2). By closing only two diagonally positioned switches in this H-bridge circuit, a current flows in one direction through the Peltier element, for example, to heat it, and by closing only the other two switches, a current flows in the other direction through the Peltier element, for example, to cool it. The heating power or cooling power is adjusted by periodically opening and closing the two diagonally positioned switches or the other two switches and PWM-controlling the opening and closing time ratio. The opening and closing control and PWM control of these switches are performed by signals input to each switch from the temperature regulator. Patent Document 3 will be described later. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-91214 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-129873 [Patent Document 3] Japanese Patent Application Laid-Open No. 2002-157949 Summary of the Invention [Problem to be solved by the invention]

[0005] In the Peltier element drive circuits of Patent Documents 1 and 2, there is no specific mention of switches in an H-bridge circuit for switching the direction of the supply current to the Peltier element and adjusting power, but the mention of FET and bipolar transistor types suggests that transistors are assumed. For example, when an FET transistor is used as a switch, applying an input voltage (input signal) to the gate causes the voltage (potential difference) between the gate and source to exceed a threshold, changing the drain-source state from a closed state to an open state. For this reason, to open and close an FET transistor as a switch, it is necessary to share the GND of the input signal wiring from the temperature regulator to the gate with the GND on the Peltier element drive circuit (H-bridge) side, and input a signal of an appropriate potential. However, the source potentials of the power supply side switches and ground side switches in an H-bridge differ relative to ground, and the potentials of the input signals required for opening and closing also differ. In particular, the source potential of the power supply side switches changes depending on the open / close state of the ground side switches, so the potential of the input signals required for opening and closing also changes accordingly. For these reasons, when a transistor is used as a switch in a Peltier element drive circuit, it is difficult to use a general-purpose temperature regulator, and a dedicated machine designed to integrate the Peltier element drive circuit and temperature regulator is required, which creates the problem of being expensive.

[0006] SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to provide a low-cost Peltier element driver and a Peltier element control system using the same. [Means for solving the problem]

[0007] In order to solve the above problems, the Peltier element driving device of the present invention is a Peltier element control device that controls heating and cooling of a Peltier element based on a heating signal and a cooling signal input from a temperature regulator, and includes: a DC power supply that supplies direct current to a Peltier element; a first switch that is arranged to connect the power supply side of the DC power supply and a first pole of the Peltier element and opens and closes based on the heating signal; a second switch that is arranged to connect the power supply side of the DC power supply and a second pole of the Peltier element and opens and closes based on the cooling signal; a third switch that is arranged to connect the GND side of the DC power supply and the first pole of the Peltier element and opens and closes based on the cooling signal; and a fourth switch that is arranged to connect the GND side of the DC power supply and the second pole of the Peltier element and opens and closes based on the heating signal, and each of the first to fourth switches is composed of a solid-state relay whose input and output sides are insulated and have a signal input terminal and a GND input terminal as input side terminals.

[0008] The Peltier element control system of the present invention is a system including the Peltier element driving device, a temperature regulator that outputs a heating signal and a cooling signal, a heating signal input wiring that inputs the heating signal to the signal input terminals of each of the first and fourth switches, a cooling signal input wiring that inputs the cooling signal to the signal input terminals of each of the second and third switches, and a GND input wiring that connects the GND terminal of the temperature regulator and the GND input terminals of each of the first to fourth switches. [Effects of the Invention]

[0009] According to the Peltier element driver and Peltier element control system of the present invention, an H-bridge is formed using four solid-state relays (SSRs), making it possible to switch between heating and cooling of the Peltier element and adjust power using PWM control by inputting a signal from a temperature regulator. Because the input and output sides of each solid-state relay are insulated, the input signal wiring and the GND of this Peltier element driver can be separate, allowing signals of various potentials to be input from the temperature regulator, and general-purpose temperature regulators can be used. In addition, solid-state relays are general-purpose and inexpensive, making it possible to reduce the cost of the Peltier element control system. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a conceptual diagram showing an initial state of a Peltier element control system including a Peltier element driving device according to an embodiment of the present invention. [Figure 2] FIG. 1 is a conceptual diagram showing an example of a solid-state relay. [Figure 3] 2 is a conceptual diagram showing the heating state of one surface of a Peltier element in the system of FIG. 1. FIG. [Figure 4] 2 is a conceptual diagram showing the cooling state of one surface of a Peltier element in the system of FIG. 1. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] (Peltier element driver) A Peltier element driving device 1 according to an embodiment of the present invention will now be described with reference to Fig. 1. The Peltier element driving device 1 controls the heating and cooling of a Peltier element based on heating and cooling signals from a temperature regulator. As shown in Fig. 1, the Peltier element driving device 1 includes a DC power supply 10, a first switch 20a, a second switch 20b, a third switch 20c, and a fourth switch 20d. Furthermore, reference numeral 30 denotes the Peltier element to be driven, and reference numeral 40 denotes the temperature regulator, which is an external device.

[0012] In this embodiment, the Peltier element 30 has a first pole 31 and a second pole 32. When a direct current is passed from the first pole 31 to the second pole 32, heat is generated on one surface 33 of the element and heat is absorbed on the other surface 34. Furthermore, when the direction of the direct current is changed, the heating surface and the cooling surface are interchanged. A commercially available Peltier element can be used as the Peltier element 30.

[0013] The DC power supply 10 is a device that supplies direct current to the Peltier element 30, and has a power supply side terminal 11 and a GND (ground) side terminal 12. A general-purpose stabilized power supply or the like that can supply the amount of current required for the Peltier element 30 can be used.

[0014] The first to fourth switches 20a to 20d (collectively referred to as "switches 20") are arranged to form an H-bridge circuit between the power supply side terminal 11 and the GND side terminal 12 of the DC power supply 10, which switches the direction of current to the Peltier element 30. Specifically, the first switch 20a is provided to connect the power supply side terminal 11 of the DC power supply 10 and the first pole 31 of the Peltier element 30, the second switch 20b is provided to connect the power supply side terminal 11 of the DC power supply 10 and the second pole 32 of the Peltier element 30, the third switch 20c is provided to connect the GND side terminal 12 of the DC power supply 10 and the first pole 31 of the Peltier element 30, and the fourth switch 20d is provided to connect the GND side terminal 12 of the DC power supply 10 and the second pole 32 of the Peltier element 30.

[0015] Of these, the first switch 20a and the fourth switch 20d open and close based on the OFF / ON of a heating signal from the temperature regulator 40. Therefore, when the heating signal from the temperature regulator 40 turns ON, as shown in Fig. 3, the first switch 20a and the fourth switch 20d close (output terminals 22a and 22b are in a conductive state), and current flows from the first pole 31 to the second pole 32 of the Peltier element 30 as shown by the solid arrow, and one surface 33 of the Peltier element 30 is in a heated state (the other surface 34 is in a cooled state). On the other hand, the second switch 20b and the third switch 20c open and close based on the OFF / ON of the cooling signal from the temperature regulator 40. Therefore, when the cooling signal from the temperature regulator 40 turns ON, as shown in Fig. 4, the second switch 20b and the third switch 20c close (the output terminals 22a and 22b are in a conductive state), and current flows from the second pole 32 to the first pole 31 of the Peltier element 30 as shown by the solid arrow, and the one surface 33 of the Peltier element is in a cooled state (the other surface 34 is in a heated state).

[0016] In the present invention, each of the first to fourth switches 20a to 20d is a solid-state relay (also referred to as a "solid-state relay 20"). The input side and output side of this solid-state relay 20 are insulated, and the input side has a signal input terminal 21i and a GND input terminal 21g. An example of this solid-state relay circuit is shown in Figure 2 of Patent Document 3 in Figure 4, although the reference numerals have been changed to suit the present invention. This solid-state relay 20 includes a phototriac coupler 23 as an isolation circuit that isolates input terminals (21i, 21g) from output terminals 22a, 22b, a triac 24 as an output element (power element) that connects output terminals 22a, 22b, a snubber circuit 27 for noise removal consisting of a capacitor 25 and a resistor 26, and a gate resistor 28. In this solid-state relay 20, the input side (21i, 21g) and the output side (22a, 22b) are insulated, so the input signal wiring and the GND of this Peltier element driving device 1 can be separate, and input signals of various potentials can be input from the temperature regulator 40.

[0017] (Peltier element control system) As shown in FIG. 1, the Peltier element control system 2 of this embodiment includes a Peltier element driver 1, a temperature regulator 40, a heating signal input wiring 42, a cooling signal input wiring 44, and a GND input wiring 46.

[0018] The temperature regulator 40 is a device that outputs a heating signal and a cooling signal. However, since the heating signal and the cooling signal are both DC digital signals of a predetermined voltage that drive the solid-state relay 20, the temperature regulator 40 need only be a device that can output such signals independently on two channels according to a predetermined program. The heating signal input wiring 42 is connected to the heating signal output terminal 41 of the temperature regulator 40, and is a wiring for inputting a heating signal to the signal input terminal 21i of the first switch 20a and the fourth switch 20d. The cooling signal input wiring 44 is connected to the cooling signal output terminal 43 of the temperature regulator 40, and is a wiring for inputting a cooling signal to the signal input terminal 21i of the second switch 20b and the third switch 20c. The GND input wiring 46 is a wiring that connects the GND terminal 45 of the temperature regulator 40 and the GND input terminals 21g of the first to fourth switches. In this embodiment, the GND input wiring 46 is shown as a branch wiring that connects one GND terminal 45 and the GND input terminal 21g of each switch 20, but it may be wired in pairs with the heating signal input wiring 42 and the cooling signal input wiring 44, respectively.

[0019] The temperature regulator 40 controls the heating signal and cooling signal so that they are not turned on at the same time. It also adjusts the heating power by periodically turning the heating signal on and off and PWM-controlling the on / off time ratio. It also adjusts the cooling power by periodically turning the cooling signal on and off and PWM-controlling the on / off time ratio. The temperature regulator 40 may further have an input interface (not shown) for signals from a temperature sensor (not shown) and may be configured to adjust the heating power or cooling power according to the temperature detected by the temperature sensor (not shown). A commercially available temperature regulator can be used as this temperature regulator 40.

[0020] (Operation of Peltier element driver and Peltier element control system) Next, the operation of the Peltier element driving device 1 and the Peltier element control system 2 of this embodiment configured as described above will be described. 1, in the initial state, both the heating signal and the cooling signal from the temperature regulator 40 are OFF, and the first to fourth switches 20a to 20d are open. As a result, no current is supplied to the Peltier element 30, and the Peltier element is in a stopped state.

[0021] When the temperature regulator 40 turns on only the heating signal, the heating signal is input to the signal input terminals 21i of the first switch 20a and the fourth switch 20d through the heating signal input wiring 42, as shown by the dashed arrows in FIG. 3. This closes the first switch 20a and the fourth switch 20d (conduction between the output terminals 22a and 22b). Meanwhile, because the cooling signal is OFF at this time, the second switch 20b and the third switch 20c are open. As a result, current flows from the power supply terminal 11 of the DC power supply 10 through the first switch 20a, the Peltier element 30, and the fourth switch 20d to the GND terminal 12 of the DC power supply 10, as shown by the solid arrows. Inside the Peltier element 30, current flows from the first pole 31 to the second pole 32, causing one surface 33 of the Peltier element to be heated (the other surface 34 to be cooled).

[0022] In this state, the heating signal is turned ON / OFF periodically (for example, every several tens to several hundreds of milliseconds) and the ON / OFF time ratio is PWM-controlled, thereby PWM-controlling the first switch 20a and the fourth switch 20d, and thus the heating power can be adjusted. For example, the heating power can also be adjusted according to the temperature detected by a temperature sensor (not shown).

[0023] Next, when the temperature regulator 40 turns off the heating signal and turns on only the cooling signal, the cooling signal is input to the signal input terminals 21i of the second switch 20b and the third switch 20c through the cooling signal input wiring 44, as shown by the dashed arrows in FIG. 4. This closes the second switch 20b and the third switch 20c (the output terminals 22a and 22b are electrically connected). Meanwhile, because the heating signal is OFF at this time, the first switch 20a and the fourth switch 20d are open. As a result, current flows from the power supply terminal 11 of the DC power supply 10 through the second switch 20b, the Peltier element 30, and the third switch 20c to the GND terminal 12 of the DC power supply 10, as shown by the solid arrows. Within the Peltier element 30, current flows from the second pole 32 to the first pole 31, causing one surface 33 of the Peltier element to be cooled (and the other surface 34 to be heated).

[0024] In this state, the heating signal is turned ON / OFF periodically (for example, every several tens to several hundreds of milliseconds) and the ON / OFF time ratio is PWM controlled, thereby PWM controlling the second switch 20b and the third switch 20c, and therefore the heating power can be adjusted. For example, the heating power can also be adjusted according to the temperature detected by a temperature sensor (not shown).

[0025] When the temperature regulator 40 turns off the heating signal and the cooling signal, the state returns to the initial state shown in FIG. 1, and the Peltier element 30 goes into a stopped state.

[0026] According to the Peltier element driver 1 and Peltier element control system 2 of the present invention, an H-bridge is formed using four solid-state relays 20, making it possible to switch between heating and cooling of the Peltier element 30 and adjust power through PWM control by inputting a signal from the temperature regulator 40. The input side (21i, 21g) and output side (22a, 22b) of each solid-state relay 20 are insulated, so the input signal wiring and the GND of the Peltier element driver 1 can be separate, allowing input signals of various potentials from the temperature regulator 40 to be input, and a general-purpose temperature regulator 40 can be used. Furthermore, the solid-state relays 30 are general-purpose and inexpensive. This allows for cost reductions in the Peltier element driver 1 and Peltier element control system 2.

[0027] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific examples, and various modifications and variations are possible within the scope of the gist of the present invention as described in the claims. [Industrial Applicability]

[0028] The Peltier element driving device 1 according to the present invention and the Peltier element control system 2 according to the present invention can be widely used in industrial fields such as temperature control in semiconductor manufacturing processes. [Explanation of symbols]

[0029] 1 Peltier element driver 2 Peltier element control system 10 DC power supply 11 Power side terminal 12 GND terminal 20 Switches (Solid State Relays) 20a First switch 20b Second switch 20c Third Switch 20d Fourth Switch 21i signal input terminal 21g GND input terminal 22a, 22b output terminals 23 Phototriac coupler 24 Triac 25 capacitors 26 Resistance 27 Snubber circuit 28 Gate resistor 30 Peltier element 31 First Pole 32 The Second Pole 33 One Side 34 The Other Side 40 Temperature regulator 41 Heating signal output terminal 42 Heating signal input wiring 43 Cooling signal output terminal 44 Cooling signal input wiring 45 GND terminal 46 GND input wiring

Claims

1. A Peltier element control device that controls heating and cooling of a Peltier element based on a heating signal and a cooling signal input from a temperature regulator, a DC power supply that supplies direct current to the Peltier element; a first switch that is provided to connect a power supply side of the DC power supply and a first pole of the Peltier element and that opens and closes based on the heating signal; a second switch that is provided to connect the power supply side of the DC power supply and a second pole of the Peltier element and that opens and closes based on the cooling signal; a third switch that is provided to connect a GND side of the DC power supply and the first pole of the Peltier element and that opens and closes based on the cooling signal; a fourth switch that is provided to connect the GND side of the DC power supply and the second pole of the Peltier element and that opens and closes based on the heating signal; Including, A Peltier element driving device, wherein each of the first to fourth switches is a solid-state relay whose input side and output side are insulated and which has a signal input terminal and a GND input terminal as input side terminals.

2. The Peltier element driving device according to claim 1 ; the temperature regulator that outputs a heating signal and a cooling signal; a heating signal input wiring for inputting the heating signal to the signal input terminal of each of the first and fourth switches; a cooling signal input wiring for inputting the cooling signal to the signal input terminal of each of the second and third switches; a GND input wiring that connects a GND terminal of the temperature regulator and the GND input terminals of each of the first to fourth switches; A Peltier element control system including:

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