An over-temperature protection circuit, driving method and in-vitro diagnostic medical device

Abstract

The present application relates to the field of circuit protection, in particular to an over-temperature protection circuit, a driving method and an in-vitro diagnosis medical device, the present application circuit comprises: a temperature probe, a level holding unit, an interlocking unit and a first relay, wherein the first end of the interlocking unit is cut-offly connected to the first power supply through the temperature probe; the second end of the interlocking unit is connected to the first end of the holding unit through the first node; the third end of the interlocking unit is grounded; the fourth end of the interlocking unit is grounded through the first resistor; and the first relay is connected in parallel with the first resistor. The driving method of the present application comprises a power-on heating stage and an over-temperature protection stage. The present application can realize over-temperature protection without complex mechanical design and can be easily reset.

Description

Technical Field

[0001] This invention relates to the field of circuit protection, specifically providing an over-temperature protection circuit, a driving method, and an in vitro diagnostic medical device. Background Technology

[0002] In electronic circuits, many components will be damaged or malfunction when the temperature is too high, and in severe cases, it may even cause accidents. Therefore, it is necessary to implement over-temperature protection to prevent components from being damaged due to overheating.

[0003] Over-temperature protection (OTP) is a common electronic protection function, typically used to protect circuits and electronic devices from damage caused by high temperatures. When the temperature of a circuit or device rises above a preset threshold, OTP automatically triggers to control the temperature drop and prevent further heating by disconnecting the power supply or limiting the current.

[0004] Regulations for in vitro diagnostic (IVD) medical devices require that over-temperature protection devices should not be automatically reset. (The regulation YY 0648-2008 Safety Requirements for Electrical Equipment for Measurement, Control and Laboratory Use - Part 2-101 - Particular Requirements for In Vitro Diagnostic (IVD) Medical Devices stipulates that over-temperature protection devices in self-testing IVD medical devices should not be automatically reset.) Currently, the two types of non-automatically reset over-temperature protection devices on the market are thermal fuses or temperature switch limiters. They need to be installed inside or on the surface of the heating element and connected in series with the heating circuit. The larger the heating power, the larger the size, requiring significant design space. Thermal fuses are disposable, requiring disassembly and soldering for replacement. Temperature switch limiters are large, limiting installation location and size, making miniaturization of the heating module in IVD medical devices difficult, and requiring complex transmission mechanisms for manual reset from outside the device.

[0005] While the two existing solutions are simple, the thermal fuse is destructive, requiring replacement by professional technicians. Temperature switch limiters place high demands on the structural design of the protection system, and they cannot be installed in some situations.

[0006] There is a need to develop an over-temperature protection technology that can achieve over-temperature protection without complex mechanical design and can be easily reset. Summary of the Invention

[0007] To overcome the above-mentioned defects, this invention discloses an over-temperature protection circuit, a driving method, and an in vitro diagnostic medical device, which can achieve over-temperature protection without complex mechanical design.

[0008] In a first aspect, the present invention provides an over-temperature protection circuit, comprising: a temperature probe, a level holding unit, an interlock unit, and a first relay, wherein,

[0009] The first end of the interlock unit is disconnectably connected to the first power source via the temperature probe;

[0010] The second end of the interlocking unit is connected to the first end of the holding unit via the first node;

[0011] The third terminal of the interlock unit is grounded;

[0012] The fourth terminal of the interlock unit is grounded through the first resistor;

[0013] The first relay is connected in parallel with the first resistor.

[0014] When the circuit is powered on, the level holding unit maintains the level of the first node so that the interlocking unit remains in an interlocked state, thereby closing the first relay to connect the heating circuit of the heating device.

[0015] When the temperature probe senses that the temperature of the environment where the heating device is located exceeds a preset value and cuts off the connection between the first power supply and the interlocking unit, the interlocking unit releases the interlocking state, thereby causing the first relay to disconnect.

[0016] Furthermore, the interlocking unit includes:

[0017] The system comprises a first three-terminal switching element, a second three-terminal switching element, a second resistor, and a third resistor, wherein...

[0018] The first end of the second resistor is connected to the first node;

[0019] The second end of the second resistor is connected to the control terminal of the second three-terminal switching element;

[0020] The input terminal of the second three-terminal switching element is connected to the temperature probe as the first terminal of the interlock unit;

[0021] The output terminal of the second and third terminal switching element is connected to the fourth terminal of the interlocking unit;

[0022] The second end of the third resistor is connected to the fourth end;

[0023] The first end of the third resistor is connected to the control end of the first three-terminal switching element;

[0024] The input terminal of the first three-terminal switch element is connected to the first node;

[0025] The output terminal of the first three-terminal switch element is grounded as the third terminal of the interlock unit.

[0026] Furthermore, the first three-terminal switching element and the second three-terminal switching element are both MOSFETs;

[0027] The first three-terminal switching element and the second three-terminal switching element are both bipolar transistors; or

[0028] The first three-terminal switching element and the second three-terminal switching element are IGBT transistors.

[0029] Furthermore, the level-holding unit includes: a fourth resistor, a fifth resistor, a first diode, and a capacitor, wherein...

[0030] The first end of the fourth resistor is connected to the second power supply.

[0031] The second end of the fourth resistor is connected to the second node (A);

[0032] The first end of the fifth resistor is connected to the third power supply.

[0033] The second end of the fifth resistor is connected to the first node (B);

[0034] The anode of the first diode is connected to the first node, and the cathode of the first diode is connected to the second node;

[0035] The first end of the capacitor is connected to the second node;

[0036] The second terminal of the capacitor is grounded.

[0037] Furthermore, it also includes a second relay, wherein the first end of the second relay is connected to the second node, the second end of the second relay is grounded, and when the reset terminal of the second relay is pressed, the first end and the second end of the second relay are connected, thereby restoring the interlocking state of the interlocking unit.

[0038] Furthermore, it also includes a second diode, wherein the anode of the second diode is grounded and the cathode of the second diode is connected to the fourth terminal of the interlocking unit.

[0039] Furthermore, the temperature probe is a self-resetting thermal fuse or a self-resetting temperature switch.

[0040] Furthermore, the temperature probe is disposed inside or on the surface of the heating device.

[0041] Furthermore, the first power supply, the second power supply, and the third power supply are the same power supply.

[0042] In a second aspect, the present invention provides a driving method for an over-temperature protection circuit, comprising:

[0043] During the power-on heating stage: the level holding unit maintains the level of the first node so that the interlocking unit remains in an interlocked state, thereby closing the first relay to connect the heating circuit of the heating device;

[0044] Over-temperature protection stage: When the temperature probe senses that the temperature of the environment where the heating device is located exceeds the preset value and cuts off the connection between the first power supply and the interlocking unit, the interlocking unit releases the interlocking state, thereby causing the first relay to disconnect.

[0045] Furthermore, it also includes:

[0046] Reset phase: When the reset terminal of the second relay is pressed, connecting the first and second terminals of the second relay, the interlocking state of the interlocking unit is restored.

[0047] In a third aspect, the present invention provides an in vitro diagnostic medical device, comprising:

[0048] The circuit mentioned above; and

[0049] Heating device;

[0050] Heating circuit.

[0051] The above-described technical solutions of the present invention have at least one or more of the following beneficial effects:

[0052] This invention combines an interlock circuit with a temperature probe. When the temperature is too high, the connection between the first power supply and the interlock unit is cut off, the first relay will disconnect, and the heating circuit will not work, thus fully ensuring the safety of the circuit design.

[0053] The interlock circuit and the heating circuit are isolated by the first relay, so a fault in the heating circuit will not affect the normal operation of the protection circuit.

[0054] Upon overheating, the first relay disconnects, cutting off the heating circuit of the heating device and stopping it from heating. The temperature of the environment surrounding the heating device no longer rises and naturally cools down under ambient temperature. When the temperature probe detects that the natural temperature drop of the environment surrounding the heating device has not exceeded a preset value, the first power supply is connected to the interlocking unit. At this time, the interlocking unit remains unlocked, no longer triggering the relay to close, no longer driving the heating device, and the temperature will not rise. This invention's overheat protection device, which meets the regulatory requirements for in vitro diagnostic medical devices, should not require automatic reset.

[0055] When the present invention requires a reset, pressing the reset terminal of the second relay connects the first and second terminals of the second relay, thereby restoring the interlocking state of the interlocking unit. The manual reset method is simple and can achieve the reset without complex mechanical design. Attached Figure Description

[0056] The disclosure of this invention will become more readily understood with reference to the accompanying drawings. It will be readily understood by those skilled in the art that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. Furthermore, similar numbers in the drawings are used to denote similar components, wherein:

[0057] Figure 1 This is a schematic diagram of an interlocking unit according to an embodiment of the present invention;

[0058] Figure 2 This is a schematic diagram of the connection between the interlocking unit and the pre-temperature probe S1 according to an embodiment of the present invention;

[0059] Figure 3 This is a schematic diagram showing the connection between the level holding unit, the second power supply, and the third power supply according to an embodiment of the present invention;

[0060] Figure 4 This is a schematic diagram of a circuit structure including a second relay K2 according to an embodiment of the present invention;

[0061] Figure 5 This is a schematic diagram of a circuit structure including a second diode D2 according to an embodiment of the present invention;

[0062] Figure 6 This is a schematic diagram of a driving method according to an embodiment of the present invention;

[0063] Figure 7 This is a schematic diagram of the structure of an in vitro diagnostic medical device according to an embodiment of the present invention.

[0064] List of reference numerals :

[0065] 100: Heating circuit. Detailed Implementation

[0066] Some embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0067] In the description of this invention, "module" and "processor" can include hardware, software, or a combination of both. A module can include hardware circuitry, various suitable sensors, communication ports, memory, and may also include software components, such as program code, or a combination of software and hardware. A processor can be a central processing unit, microprocessor, image processor, digital signal processor, or any other suitable processor. The processor has data and / or signal processing capabilities. The processor can be implemented in software, in hardware, or a combination of both. Non-transitory computer-readable storage media includes any suitable medium capable of storing program code, such as magnetic disks, hard disks, optical disks, flash memory, read-only memory, random access memory, etc. The term "A and / or B" means all possible combinations of A and B, such as only A, only B, or A and B. The terms "at least one A or B" or "at least one of A and B" have a similar meaning to "A and / or B" and can include only A, only B, or A and B. The singular terms "a" or "this" can also include plural forms.

[0068] This invention discloses an over-temperature protection circuit, comprising: a temperature probe S1, a level holding unit, an interlock unit, and a first relay K1, wherein,

[0069] The first end of the interlock unit is disconnectably connected to the first power supply VCC1 via the temperature probe S1;

[0070] The second end of the interlocking unit is connected to the first end of the holding unit via the first node;

[0071] The third terminal of the interlock unit is grounded;

[0072] The fourth terminal of the interlock unit is grounded through the first resistor;

[0073] The first relay K1 is connected in parallel with the first resistor R5.

[0074] When the circuit is powered on, the level holding unit maintains the level of the first node B so that the interlocking unit remains in an interlocked state, thereby closing the first relay K1 to connect the heating circuit of the heating device H1.

[0075] When the temperature probe senses that the temperature of the environment where the heating device is located exceeds a preset value and cuts off the connection between the first power supply and the interlocking unit, the interlocking unit releases the interlocking state, thereby causing the first relay to disconnect.

[0076] In one application scenario, the heating device is used in an in vitro diagnostic medical device. When the circuit is powered on, the level holding unit maintains the level of the first node B at a high level. At this time, the interlocking unit is connected, maintaining the interlocked state, thereby causing the first relay to close and connect the heating circuit of the heating device. Since the heating circuit is connected, the heating device continues to work and heats its surrounding environment. Because the heating temperature cannot be too high, a temperature probe is needed to sense whether the temperature of the environment where the heating device is located exceeds a preset value. If the temperature probe senses that the temperature of the environment where the heating device is located exceeds the preset value, the connection between the first power supply and the interlocking unit is cut off. At this time, the level holding unit maintains the level of the first node B at a low level, the interlocking unit is disconnected, and the interlocked state is released, thereby causing the first relay to open. After the first relay opens, the heating circuit of the heating device is cut off, causing the heating device to stop heating. The temperature of the environment where the heating device is located no longer continues to rise, and under the natural heat dissipation of room temperature, the temperature of the environment where the heating device is located naturally drops.

[0077] YY 0648-2008 Safety requirements for electrical equipment for measuring, controlling and laboratory use - Part 2-101 - Particular requirements for in vitro diagnostic (IVD) medical devices 14.3 Over-temperature protection: In self-testing in vitro diagnostic medical devices, the over-temperature protection device should not be automatically reset. The over-temperature protection circuit of this invention can automatically stop heating when the temperature is too high, and will not automatically turn on.

[0078] In one application scenario, temperature probe S1 is a normally closed self-recovering temperature probe.

[0079] In one embodiment, reference is made to Figure 1-2 The interlocking unit includes:

[0080] The components include a first three-terminal switching element Q1, a second three-terminal switching element Q2, a second resistor R3, and a third resistor R4, wherein...

[0081] The first end of the second resistor R3 is connected to the first node B;

[0082] The second end of the second resistor R3 is connected to the control terminal C of the second three-terminal switching element Q2;

[0083] The input terminal of the second three-terminal switching element Q2 is connected to the temperature probe S1 as the first terminal of the interlock unit;

[0084] The output terminal of the second three-terminal switching element Q2 is connected to the fourth terminal D of the interlocking unit;

[0085] The second terminal of the third resistor R4 is connected to the fourth terminal D;

[0086] The first end of the third resistor R4 is connected to the control terminal E of the first three-terminal switching element Q1;

[0087] The input terminal of the first three-terminal switch element Q1 is connected to the first node B;

[0088] The output terminal of the first three-terminal switching element Q1 is grounded as the third terminal of the interlocking unit.

[0089] From the connection relationship of each component in this embodiment, it can be seen that the first three-terminal switch element Q1 and the second three-terminal switch element Q2 are simultaneously turned on or simultaneously turned off.

[0090] In one embodiment, the first three-terminal switching element and the second three-terminal switching element are both MOSFETs.

[0091] MOS is an abbreviation for MOSFET. MOSFET stands for Metal-Oxide-Semiconductor Field-Effect Transistor. A MOSFET is a metal-oxide-semiconductor field-effect transistor, or a metal-insulator-semiconductor transistor. The source and drain of a MOSFET can be interchanged; both are N-type regions formed within a P-type backgate. In most cases, these two regions are identical, and swapping them will not affect the device's performance.

[0092] The first three-terminal switching element and the second three-terminal switching element are both bipolar transistors.

[0093] A bipolar junction transistor (BJT) is a transistor consisting of two back-to-back PN junctions used to obtain voltage, current, or signal gain. Originating from the point-contact transistor invented in 1948, it evolved into the junction transistor, now known as the bipolar junction transistor, in the early 1950s. There are two basic structures for bipolar junction transistors: PNP and NPN. In these three semiconductor layers, the middle layer is called the base region, and the two outer layers are called the emitter and collector regions, respectively. When a small current is injected into the base region, a larger current is generated between the emitter and collector regions; this is the amplification effect of the transistor.

[0094] or

[0095] The first and second three-terminal switching elements are IGBTs (Insulated Gate Bipolar Transistors), which are composite, fully controllable, voltage-driven power semiconductor devices composed of BJTs (Bipolar Junction Transistors) and MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors). They combine the advantages of high input impedance of MOSFETs and low on-state voltage drop of GTRs. GTRs have low saturation voltage and high current density, but require a large drive current; MOSFETs have very low drive power and fast switching speed, but a large on-state voltage drop and low current density. IGBTs combine the advantages of both devices, offering low drive power and low saturation voltage. They are ideally suited for applications in DC voltage converter systems of 600V and above, such as AC motors, frequency converters, switching power supplies, lighting circuits, and traction drives.

[0096] IGBT modules are modular semiconductor products that are packaged by bridging IGBT (Insulated Gate Bipolar Transistor) chips and FWD (Foil Diode) chips through a specific circuit. The packaged IGBT modules are directly used in equipment such as frequency converters and UPS uninterruptible power supplies.

[0097] IGBT modules are characterized by energy saving, convenient installation and maintenance, and stable heat dissipation. Most of the products sold on the market today are modular products of this type, and the term IGBT generally refers to IGBT modules. With the advancement of concepts such as energy conservation and environmental protection, these products will become increasingly common in the market.

[0098] In one application scenario, the first three-terminal switching element Q1 is an NPN transistor.

[0099] The second and third terminal switching element Q2 is a PNP transistor.

[0100] The control terminal of the first three-terminal switching element Q1 is the base, the input terminal of the first three-terminal switching element Q1 is the collector, and the output terminal of the first three-terminal switching element Q1 is the emitter.

[0101] The control terminal of the second three-terminal switching element Q2 is the base, the input terminal of the second three-terminal switching element Q2 is the emitter, and the output terminal of the second three-terminal switching element Q2 is the collector.

[0102] In one embodiment, reference is made to Figure 3 The level-holding unit includes: a fourth resistor R1, a fifth resistor R2, a first diode D1, and a capacitor C1, wherein...

[0103] The first end of the fourth resistor R1 is connected to the second power supply VCC2;

[0104] The second end of the fourth resistor R1 is connected to the second node A;

[0105] The first end of the fifth resistor R2 is connected to the third power supply VCC3;

[0106] The second end of the fifth resistor R2 is connected to the first node B;

[0107] The anode of the first diode D1 is connected to the first node B, and the cathode of the first diode D1 is connected to the second node A;

[0108] The first end of the capacitor C1 is connected to the second node A;

[0109] The second terminal of the capacitor C1 is grounded.

[0110] Upon initial power-on, the power supply voltage charges capacitor C1 through two branches: circuit branch 1 (fifth resistor R2 and first diode D1) and circuit branch 2 (fourth resistor R1). The voltage at the second node A gradually increases, and at the moment of startup, the second node A is at a low level. The forward voltage of the first diode D1 decreases, and the first node B is also at a low level, thus the interlocking unit operates. When capacitor C1 is fully charged, the second node A becomes high. Due to the single-phase conductivity of the diode, circuit branch 1 (fifth resistor R2 and first diode D1) is cut off and no longer operates. The low level at the first node B is unaffected by the high level at the second node A.

[0111] In one embodiment, the first power supply, the second power supply, and the third power supply are the same power supply.

[0112] In one embodiment, the first power supply, the second power supply, and the third power supply are three different power supplies.

[0113] The first power source, the second power source, and the third power source can be the same or different. Any two of the first power source, the second power source, and the third power source can be the same power source.

[0114] In one embodiment, reference is made to Figure 4 It also includes a second relay K2, wherein the first end of the second relay K2 is connected to the second node A, the second end of the second relay K2 is grounded, and when the reset terminal of the second relay K2 is pressed, the first end and the second end of the second relay K2 are connected, thus restoring the interlocking state of the interlocking unit.

[0115] In one application scenario, the second relay K2 is a jog switch; it closes when pressed and opens when released.

[0116] In one embodiment, reference is made to Figure 5 It also includes a second diode D2, wherein the anode of the second diode is grounded and the cathode of the second diode D2 is connected to the fourth terminal D of the interlocking unit.

[0117] The second diode D2 is used as a freewheeling diode. When S1 is turned off, a directional electromotive force (EMF) is generated across the inductor coil of the first relay K1. The reverse EMF generated by the first relay K1 can reach three times the power supply voltage, seriously threatening the reliability of the circuit. The turn-off overvoltage generated by the relay coil can be discharged through the freewheeling diode D2, thereby suppressing the turn-off overvoltage.

[0118] In one embodiment, the temperature probe is a self-resetting thermal fuse or a self-resetting temperature switch.

[0119] In one application scenario, the temperature probe is a normally closed self-recovering temperature probe.

[0120] In one application scenario, the first relay K1 is a normally open relay.

[0121] In one application scenario, the second resistor R3, the third resistor R4, the fourth resistor R1, the fifth resistor R2, and the first resistor R5 are resistors.

[0122] In one embodiment, the temperature probe is disposed inside or on the surface of the heating device. The temperature probe is used to sense the temperature inside or on the surface of the heating device. Since the heating temperature cannot be too high, a temperature probe is needed to sense whether the temperature of the environment in which the heating device is located exceeds a preset value.

[0123] The working principle of the circuit of this invention is as follows:

[0124] When the circuit is powered on for the first time, the interlocking unit is triggered to maintain the interlocking state, the first relay K1 is closed to connect the heating circuit of the heating device H1, and the heating circuit works normally.

[0125] When the temperature continues to rise due to a malfunction in the heating circuit, and the temperature probe S1 senses that the temperature of the environment where the heating device H1 is located exceeds a preset value, thus cutting off the connection between the first power supply VCC1 and the interlocking unit, the interlocking unit releases the interlocking state, thereby causing the first relay K1 to disconnect and the heating device H1 to stop heating.

[0126] After the heating circuit is disconnected, the temperature gradually drops after a period of time, and the self-recovery temperature protection probe S1 returns to normal. The temperature probe S1 is connected to the first power supply VCC1, but at this time the first relay K1 is still not closed, and the heating circuit is still disconnected.

[0127] Only when the circuit is powered on again or the second relay K2 is pressed, triggering the interlock unit, will the first relay K1 close, and the heating circuit can return to normal.

[0128] Specific steps:

[0129] Upon initial power-on: the second power supply VCC2 charges capacitor C1 through circuit branch 2 (fourth resistor R1), the third power supply VCC3 charges capacitor C1 through circuit branch 1 (fifth resistor R2 and first diode D1).

[0130] The voltage at node A gradually increases, and at startup, node A is at a low level. The forward voltage of the first diode D1 decreases, and node B also becomes low, triggering the interlocking unit to perform interlocking operations.

[0131] When capacitor C1 is fully charged, the second node A becomes high. Due to the single-phase conductivity of the first diode D1, circuit branch 1 (the fifth resistor R2 and the first diode D1) is cut off and no longer works. The low level of the first node B is not affected by the high level of the second node A.

[0132] In this step, when the circuit is powered on, the level holding unit maintains the level of the first node B in a state that keeps the interlocking unit in an interlocked state. The first end of the interlocking unit is disconnectably connected to the first power supply through the temperature probe.

[0133] Temperature probe sensing: The first end of the interlock unit is disconnectably connected to the first power source through the temperature probe. If the temperature probe senses that the temperature of the environment where the heating device is located does not exceed a preset value, then the first end of the interlock unit is connected to the first power source through the temperature probe.

[0134] Heating device heating: When the circuit is powered on, the level holding unit maintains the level of the first node so that the interlocking unit remains in an interlocked state, thereby closing the first relay to connect the heating circuit of the heating device.

[0135] The interlocking principle is as follows: When the first node B is at a low level, the emitter of the second three-terminal switching element Q2 is connected to the first power supply VCC1 through the normally closed self-recovering temperature probe S1. The current flows through S1, point C, and the second resistor R3 to the first node B. Point C is at a low level, and the PNP transistor Q2 is turned on. After it is turned on, the fourth terminal D of the interlocking unit is at a high level.

[0136] Point D is at a high level, the emitter of the first three-terminal switching element Q1 is grounded, and the current flows to ground through S1, Q2, R4, and Q1, so point E is also at a high level. NPN transistor Q1 is turned on, and point B is at a low level after it is turned on.

[0137] Therefore, a low level at point B causes the second three-terminal switch element Q2 to conduct, Q2 conducts, which in turn causes a low level at point E, which in turn causes the first three-terminal switch element Q1 to conduct, and Q1 conducts, which in turn causes a low level at point B, thus entering an interlocked state.

[0138] After entering the interlock state, the first three-terminal switch element Q1 is turned on, and the current flows through S1 and Q2 to the relay K1. The relay K1 is closed, realizing the closure of the heating circuit and driving the heating device H1 to work, so as to perform heating control.

[0139] Over-temperature protection: When the temperature probe senses that the temperature of the environment where the heating device is located exceeds a preset value and cuts off the connection between the first power supply and the interlocking unit, the interlocking unit releases the interlocking state, thereby causing the first relay to disconnect and the heating device H1 to stop heating.

[0140] When the temperature probe senses that the temperature of the environment where the heating device is located has naturally dropped below a preset value, the first power supply is connected to the interlocking unit. At this time, the interlocking unit is still in the interlocked state, and the relay K1 is no longer triggered to close, and the heating device H1 is no longer driven to work, so the temperature will not rise.

[0141] The circuit principle is as follows:

[0142] When S1 changes from a normally closed state to a normally open state due to excessive temperature, no current flows through relay K1, relay K1 disconnects, the heating circuit is disconnected from H1, and H1 cannot heat. At the same time as S1 disconnects, the interlock circuit is also disconnected.

[0143] The details are as follows: Point D is grounded through the first resistor R5 and is at a low level. Point E is also at a low level, and Q1 is cut off. After Q1 is cut off, point C is connected to the power supply VCC3 through R3 and R2 and is at a high level. Q2 is cut off. At this time, even if S1 changes from normally open to normally closed due to temperature recovery, point D is still at a low level and will no longer trigger Q1 to close, thus no longer triggering Q2 to close.

[0144] The over-temperature protection device required by the regulations for in vitro diagnostic medical devices in this invention should not be automatically reset. The regulation YY 0648-2008 Safety requirements for electrical equipment for measurement, control and laboratory use – Part 2-101 – Particular requirements for in vitro diagnostic (IVD) medical devices stipulates that in self-testing in vitro diagnostic medical devices, the over-temperature protection device should not be automatically reset.

[0145] Manual reset: When the reset terminal of the second relay is pressed, the first and second terminals of the second relay K2 are connected, thus restoring the interlocking state of the interlocking unit.

[0146] The circuit principle is as follows:

[0147] Manual recovery: When K2 is pressed, point A is at a low level, and current flows to point A through R2 and D1. The diode forward voltage drops, and point B is also at a low level. The interlock unit performs interlocking operation again, and the first relay K1 closes.

[0148] After releasing S1, point A returns to a high level, the first diode D1 is reverse-biased and cut off, and the low level at point B in the interlock circuit is not affected by the high level at point A.

[0149] The level holding unit maintains the level at point B so that the interlocking unit remains in an interlocked state, i.e., a low level, thereby causing the first relay K1 to close and connect the heating circuit of the heating device H1.

[0150] This invention separates the temperature probe and the protective circuit, resulting in a simple circuit structure and low cost. The temperature probe is unaffected by the heating power, and the high current operation is controlled by closing the relay.

[0151] Even if the over-temperature protection circuit fails, the first relay will disconnect, and the heating circuit will not work, thus fully ensuring the safety of the circuit design.

[0152] The protection circuit, i.e., the interlock circuit, is isolated from the heating circuit by the first relay. A fault in the heating circuit will not affect the normal operation of the protection circuit.

[0153] Only a small temperature probe needs to be installed inside or on the surface of the heating element to achieve reset, without the need for complex mechanical design. The manual reset method is simple.

[0154] The present invention also provides a driving method for an over-temperature protection circuit, comprising:

[0155] Power-on heating stage: When powered on, the level holding unit maintains the level of the first node so that the interlocking unit remains in an interlocked state, thereby closing the first relay to connect the heating circuit of the heating device;

[0156] Over-temperature protection stage: When the temperature probe senses that the temperature of the environment where the heating device is located exceeds the preset value and cuts off the connection between the first power supply and the interlocking unit, the interlocking unit releases the interlocking state, thereby causing the first relay to disconnect.

[0157] In one embodiment, the driving method further includes:

[0158] Reset Phase: When the reset terminal of the second relay is pressed, connecting the first and second terminals of the second relay, the interlocking state of the interlocking unit is restored. See the schematic diagram of the driving method in this embodiment. Figure 6 .

[0159] Reference Figure 7 The present invention also provides an in vitro diagnostic medical device, comprising:

[0160] The circuit mentioned above; and

[0161] Heating device;

[0162] A heating circuit is provided; when the heating circuit is connected, the heating device is activated to heat the device.

[0163] When the circuit is powered on, the level holding unit maintains the level of the first node so that the interlocking unit remains in an interlocked state, thereby closing the first relay to connect the heating circuit of the heating device, and the heating device starts heating.

[0164] This invention simplifies the structural design of the heating module in in vitro diagnostic equipment, solving the problem that the heating module of in vitro diagnostic equipment cannot be miniaturized due to manual reset (non-destructive).

[0165] The circuit is safe and reliable.

[0166] Save on maintenance and repair costs.

[0167] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. An over-temperature protection circuit, characterized in that, include: The components include a temperature probe (S1), a level holding unit, an interlock unit, and a first relay (K1). The first end of the interlock unit is disconnectably connected to the first power source via the temperature probe; The second end of the interlock unit is connected to the first end of the level holding unit through the first node (B); The third terminal of the interlock unit is grounded; The fourth terminal of the interlock unit is grounded through the first resistor (R5); The first relay is connected in parallel with the first resistor. When the circuit is powered on, the level holding unit maintains the level of the first node so that the interlocking unit remains in an interlocked state, thereby closing the first relay to connect the heating circuit of the heating device. When the temperature probe senses that the temperature of the environment where the heating device is located exceeds a preset value and cuts off the connection between the first power supply and the interlocking unit, the interlocking unit releases the interlocking state, thereby causing the first relay to disconnect. The interlocking unit includes: The components include a first three-terminal switching element (Q1), a second three-terminal switching element (Q2), a second resistor (R3), and a third resistor (R4), among which... The first end of the second resistor is connected to the first node; The second end of the second resistor is connected to the control terminal of the second three-terminal switching element; The input terminal of the second three-terminal switching element is connected to the temperature probe as the first terminal of the interlock unit; The output terminal of the second and third terminal switching element is connected to the fourth terminal of the interlocking unit; The second end of the third resistor is connected to the fourth end; The first end of the third resistor is connected to the control end of the first three-terminal switching element; The input terminal of the first three-terminal switch element is connected to the first node; The output terminal of the first three-terminal switch element is grounded as the third terminal of the interlock unit.

2. The circuit according to claim 1, characterized in that, The first three-terminal switching element and the second three-terminal switching element are both MOSFETs; or The first three-terminal switching element and the second three-terminal switching element are both bipolar transistors; or The first three-terminal switching element and the second three-terminal switching element are IGBT transistors.

3. The circuit according to any one of claims 1-2, characterized in that, The level-holding unit includes: a fourth resistor (R1), a fifth resistor (R2), a first diode (D1), and a capacitor, wherein... The first end of the fourth resistor is connected to the second power supply. The second end of the fourth resistor is connected to the second node (A); The first end of the fifth resistor is connected to the third power supply. The second end of the fifth resistor is connected to the first node (B); The anode of the first diode is connected to the first node, and the cathode of the first diode is connected to the second node; The first end of the capacitor is connected to the second node; The second terminal of the capacitor is grounded.

4. The circuit according to claim 3, characterized in that, The circuit also includes a second relay, wherein the first end of the second relay is connected to the second node, the second end of the second relay is grounded, and when the reset terminal of the second relay is pressed, the first end and the second end of the second relay are connected, thereby restoring the interlocking state of the interlocking unit.

5. The circuit according to claim 1, characterized in that, The circuit also includes a second diode (D2), wherein the anode of the second diode is grounded and the cathode of the second diode is connected to the fourth terminal of the interlocking unit.

6. The circuit according to claim 3, characterized in that, The first power supply, the second power supply, and the third power supply are the same power supply.

7. A driving method for an over-temperature protection circuit according to any one of claims 1-6, characterized in that, include: During the power-on heating stage: the level holding unit maintains the level of the first node so that the interlocking unit remains in an interlocked state, thereby closing the first relay to connect the heating circuit of the heating device; Over-temperature protection stage: When the temperature probe senses that the temperature of the environment where the heating device is located exceeds the preset value and cuts off the connection between the first power supply and the interlocking unit, the interlocking unit releases the interlocking state, thereby causing the first relay to disconnect.

8. The driving method according to claim 7, characterized in that, Also includes: Reset phase: When the reset terminal of the second relay is pressed, causing the first and second terminals of the second relay to connect, the interlocking state of the interlocking unit is restored.

9. An in vitro diagnostic medical device, characterized in that, include: The circuit according to any one of claims 1-6; as well as Heating device; Heating circuit.

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