Three-power-supply switching circuit of medical instrument and medical instrument

Abstract

The utility model provides a three-power-supply switching circuit of a medical instrument and the medical instrument, the circuit comprises a first protection circuit, a second protection circuit, a third protection circuit, a power supply switching circuit, a first switching circuit, a second switching circuit and a third switching circuit, the first protection circuit comprises a first P-type field effect transistor, the second protection circuit comprises a second P-type field effect transistor, and the third protection circuit comprises a second P-type field effect transistor. The source electrode of the first P-type field effect transistor serves as the other end of the first protection circuit to be connected with the first end of the first switching circuit, the drain electrode of the first p-type field effect transistor serves as one end of the first protection circuit to be connected with a first power source, and the grid electrode of the first p-type field effect transistor is connected with the source electrode of the first p-type field effect transistor. The second protection circuit comprises a second p-type field effect transistor, the grid electrode of the second p-type field effect transistor is connected with the source electrode of the second p-type field effect transistor, and the source electrode of the second p-type field effect transistor serves as one end of the second protection circuit to be connected with the other end of the third switching circuit. The drain electrode of the second p-type field effect transistor serves as the other end of the second protection circuit and is connected with a second power supply. The reliability of the circuit can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of power supply control for medical devices, and in particular to a three-power supply switching circuit for medical devices and the medical devices. Background Art

[0002] With the increasing popularity of medical devices and the influx of consumer electronics into every household, people are demanding more diverse power supplies for health-related electronic products. In the past, to maximize cost-effectiveness, these products were often designed with a single power source, such as dry cell batteries. However, with growing environmental awareness in recent years, people are choosing between disposable dry cell batteries and reusable or rechargeable batteries. This has led to a greater demand for diverse power supplies for traditional electronic products, such as dual and triple power supplies.

[0003] Currently, most medical devices on the market are powered by a single or dual power supply, and few are powered by three power supplies. In addition, the design of the circuits currently using three power supplies does not meet the certification requirements of medical devices. Their switching circuits use field-effect transistors as switching electronic switches, and field-effect transistors are extremely susceptible to electrostatic interference and cause failure. The failure mechanism is generally manifested as a short circuit, which can easily lead to a short circuit between the three power supplies and current cross-talk, thereby causing the medical device to fail and even threatening user safety. Utility Model Content

[0004] Given that most existing medical devices are powered by a single power supply, and the switching circuits of three power supplies are extremely susceptible to electrostatic interference, leading to failure and current crosstalk, which in turn causes medical device failure and even threatens user safety, this application proposes a three-power switching circuit for medical devices and medical devices.

[0005] In the first aspect, the present application proposes a three-power switching circuit for a medical device, comprising: a first protection circuit, a second protection circuit, a third protection circuit, a power switching circuit, a first switch circuit, a second switch circuit, and a third switch circuit, wherein one end of the first protection circuit is connected to the first power supply, the other end of the first protection circuit is connected to the first end of the first switch circuit, the second end of the first switch circuit is connected to the first end of the second switch circuit, the second end of the second switch circuit is connected to the first end of the third switch circuit, the second end of the third switch circuit is connected to one end of the second protection circuit, the other end of the second protection circuit is connected to the second power supply, the first end of the third protection circuit is connected to the third power supply, the second end of the third protection circuit is connected to the control end of the third switch circuit, the second end of the third protection circuit is connected to the second end of the second switch circuit, the third end of the third protection circuit is connected to the control end of the third switch circuit, the fourth end of the third protection circuit is connected to the first end of the power switching circuit, the fifth end of the third protection circuit is connected to one end of the second protection circuit, and the power switching The second end of the circuit is connected to the second end of the first switch circuit, the third end of the power switching circuit is connected to the control end of the first switch circuit and the control end of the second switch circuit respectively, the fourth end of the power switching circuit is connected to the first end of the second switch circuit, and a first connection point is formed between the other end of the second switch circuit and one end of the third switch circuit. The first connection point serves as the power supply end of the medical device, wherein the first protection circuit includes a first P-type field effect transistor, the source of the first P-type field effect transistor is connected to the first end of the first switch circuit as the other end of the first protection circuit, the drain of the first P-type field effect transistor is connected to the first power supply as one end of the first protection circuit, and the gate of the first P-type field effect transistor is connected to the source of the first P-type field effect transistor. The second protection circuit includes a second P-type field effect transistor, the gate of the second P-type field effect transistor is connected to the source of the second P-type field effect transistor, the source of the second P-type field effect transistor is connected to the other end of the third switch circuit as one end of the second protection circuit, and the drain of the second P-type field effect transistor is connected to the second power supply as the other end of the second protection circuit.

[0006] Optionally, the circuit also includes a fourth protection circuit, which includes a fourth TVS tube and a first resistor, wherein the cathode of the fourth TVS tube is connected to the first connection point, the anode of the fourth TVS tube is grounded, one end of the first resistor is connected to the first connection point, and the other end of the first resistor is grounded.

[0007] Optionally, the first protection circuit also includes a first switch, a fuse resistor, a first TVS tube and a second resistor, wherein one end of the first switch is connected to the first power supply as one end of the first protection circuit, the other end of the first switch is connected to one end of the fuse resistor, the other end of the fuse resistor is connected to the drain of the first p-type field effect transistor, the source of the first p-type field effect transistor is connected to the first end of the first switch circuit as the other end of the first protection circuit, the negative electrode of the first TVS tube is connected to the other end of the fuse resistor, the positive electrode of the first TVS tube is grounded, one end of the second resistor is connected to the negative electrode of the first TVS tube, and the other end of the second resistor is grounded.

[0008] Optionally, the second protection circuit further includes a second TVS tube and a second switch, wherein one end of the second switch is connected to the second power supply as the other end of the second protection circuit, the other end of the second switch is connected to the other end of the first switch circuit as one end of the second protection circuit, the negative electrode of the second TVS tube is connected to the other end of the second switch, and the positive electrode of the second TVS tube is grounded.

[0009] Optionally, the third protection circuit includes a third switch, a third resistor, a fourth resistor, a fifth resistor, a third TVS tube, a first diode, a second diode, and a third diode, wherein one end of the third switch is connected to the third power supply as the first end of the third protection circuit, the other end of the third switch is connected to the control end of the third switch circuit as the second end of the third protection circuit, the other end of the third switch is also connected to the anode of the first diode, the cathode of the first diode is connected to one end of the third switch circuit as the third end of the third protection circuit, the anode of the third TVS tube is grounded, the cathode of the third TVS tube is connected to the other end of the third switch, the anode of the second diode is connected to the other end of the third switch, the cathode of the second diode is connected to one end of the fourth resistor, the other end of the fourth resistor is connected to the first end of the power switching circuit as the fourth end of the third protection circuit, the anode of the third diode is connected to one end of the second protection circuit as the fifth end of the third protection circuit, one end of the fifth resistor is connected to the anode of the third diode, the other end of the fifth resistor is grounded, one end of the third resistor is connected to the other end of the third switch, and the other end of the third resistor is grounded.

[0010] Optionally, the power switching circuit includes a first N-type field effect transistor, a second N-type field effect transistor, a sixth resistor, a seventh resistor and an eighth resistor, wherein the gate of the first N-type field effect transistor is connected to the fourth end of the third protection circuit as the first end of the power switching circuit, the source of the first N-type field effect transistor is grounded, one end of the sixth resistor is connected to the gate of the first N-type field effect transistor, the other end of the sixth resistor is connected to the source of the first N-type field effect transistor, the drain of the first N-type field effect transistor is connected to the gate of the second N-type field effect transistor, the source of the second N-type field effect transistor is grounded, the drain of the second N-type field effect transistor is connected to the control end of the first switch circuit and the control end of the second switch circuit as the third end of the power switching circuit respectively, one end of the seventh resistor is connected to the gate of the second N-type field effect transistor, the other end of the seventh resistor is connected to the other end of the first switch circuit as the second end of the power switching circuit, one end of the eighth resistor is connected to the drain of the second N-type field effect transistor, and the other end of the eighth resistor is connected to one end of the second switch circuit as the fourth end of the power switching circuit.

[0011] Optionally, the power switching circuit further includes a ninth resistor, wherein one end of the ninth resistor is connected to the gate of the second N-type field effect transistor, and the other end of the ninth resistor is grounded.

[0012] Optionally, the first switching circuit includes a third p-type field-effect transistor, the second switching circuit includes a fourth p-type field-effect transistor, and the third switching circuit includes a fifth p-type field-effect transistor, wherein the gate of the third p-type field-effect transistor is connected to the third end of the power switching circuit as the control end of the first switching circuit, the drain of the third p-type field-effect transistor is connected to the other end of the first protection circuit as the first end of the first switching circuit, the source of the third p-type field-effect transistor is connected to the first end of the second switching circuit as the second end of the first switching circuit, the gate of the fourth p-type field-effect transistor is connected to the third end of the power switching circuit as the control end of the second switching circuit, the source of the fourth p-type field-effect transistor is connected to the second end of the first switching circuit as the first end of the second switching circuit, the drain of the fourth p-type field-effect transistor is connected to the first end of the third switching circuit as the second end of the second switching circuit, the gate of the fifth p-type field-effect transistor is connected to the third end of the third protection circuit as the control end of the third switching circuit, the drain of the fifth p-type field-effect transistor is connected to the second end of the second switching circuit as the first end of the third switching circuit, and the source of the p-type field-effect transistor is connected to one end of the second protection circuit as the second end of the third switching circuit.

[0013] Optionally, the first power supply is used to connect to an external power adapter, which is used to provide a 5V DC current; the second power supply is used to connect to a rechargeable battery, which is used to provide a 3.7V DC current; the third power supply is used to connect to a dry cell battery box, which is used to install multiple dry cells to provide a 4.5V-6V DC current.

[0014] In a second aspect, the present application proposes a medical device comprising a three-power switching circuit of the medical device in any of the above embodiments.

[0015] The three-power switching circuit and medical device of the medical device proposed in this application can meet the medical device application requirements of low voltage drop, low impedance and high current of the product power supply through the application of field effect transistors in the first protection circuit and the second protection circuit, thereby improving the reliability of the circuit.

[0016] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 Shows the schematic diagram of the three-power switching circuit of the medical device Figure 1 ;

[0019] Figure 2 Shows the schematic diagram of the three-power switching circuit of the medical device Figure 2 ;

[0020] Figure 3 Shows the schematic diagram of the three-power switching circuit of the medical device Figure 3 . DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application for which protection is claimed, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, each other embodiment obtained by those skilled in the art without making creative work falls within the scope of protection of the present application.

[0022] It should be noted that the term "comprising" will be used in the embodiments of the present application to indicate the existence of the features declared thereafter, but does not exclude the addition of other features.

[0023] The present application relates to a three-power switching circuit for medical devices and the medical device, which can meet the medical device application requirements of low voltage drop, low impedance, and high current of the product power supply through the application of field-effect transistors in the first protection circuit and the second protection circuit, thereby improving the reliability of the circuit.

[0024] See also Figure 1 , Figure 1 Schematic diagram of the three-power switching circuit 107 of the medical device Figure 1 .like Figure 1 As shown, the three power switching circuit 107 of the medical device provided in the embodiment of the present application includes: a first protection circuit 101, a second protection circuit 105, a third protection circuit 106, a power switching circuit 107, a first switch circuit 102, a second switch circuit 103, and a third switch circuit 104.

[0025] Wherein, one end of the first protection circuit 101 is connected to the first power supply VCC1, the other end of the first protection circuit 101 is connected to the first end of the first switch circuit 102, the second end of the first switch circuit 102 is connected to the first end of the second switch circuit 103, the second end of the second switch circuit 103 is connected to the first end of the third switch circuit 104, the second end of the third switch circuit 104 is connected to one end of the second protection circuit 105, the other end of the second protection circuit 105 is connected to the second power supply VCC2, the first end of the third protection circuit 106 is connected to the third power supply VCC3, the second end of the third protection circuit 106 is connected to the control end of the third switch circuit 104, and the second end of the third protection circuit 106 is connected to the second end of the second switch circuit 103 The third end of the third protection circuit 106 is connected to the control end of the third switch circuit 104, the fourth end of the third protection circuit 106 is connected to the first end of the power switching circuit 107, the fifth end of the third protection circuit 106 is connected to one end of the second protection circuit 105, the second end of the power switching circuit 107 is connected to the second end of the first switch circuit 102, the third end of the power switching circuit 107 is respectively connected to the control end of the first switch circuit 102 and the control end of the second switch circuit 103, the fourth end of the power switching circuit 107 is connected to the first end of the second switch circuit 103, and a first connection point is formed between the other end of the second switch circuit 103 and one end of the third switch circuit 104, and the first connection point serves as the power supply end of the medical device.

[0026] The first protection circuit 101 includes a first p-type field effect transistor PMOS1, the source of the first p-type field effect transistor PMOS1 serving as the other end of the first protection circuit 101 is connected to the first end of the first switch circuit 102, the drain of the first p-type field effect transistor PMOS1 serving as one end of the first protection circuit 101 is connected to the first power supply VCC1, and the gate of the first p-type field effect transistor PMOS1 is connected to the source of the first p-type field effect transistor PMOS1. The second protection circuit 105 includes a second p-type field effect transistor PMOS2, the gate of the second p-type field effect transistor PMOS2 is connected to the source of the second p-type field effect transistor PMOS2, the source of the second p-type field effect transistor PMOS2 serving as one end of the second protection circuit 105 is connected to the other end of the third switch circuit 104, and the drain of the second p-type field effect transistor PMOS2 serving as the other end of the second protection circuit 105 is connected to the second power supply VCC2.

[0027] Here, the first p-type field effect transistor PMOS1 and the second p-type field effect transistor PMOS2 are used as a diode in principle, but their characteristics are lower voltage drop and lower impedance than the diodes of general germanium tubes and silicon tubes, and they can pass a larger current.

[0028] Optionally, the circuit further includes a fourth protection circuit 201 , and the fourth protection circuit 201 includes a fourth TVS tube TVS4 and a first resistor R1 .

[0029] The cathode of the fourth TVS tube TVS4 is connected to the first connection point, the anode of the fourth TVS tube TVS4 is grounded, one end of the first resistor R1 is connected to the first connection point, and the other end of the first resistor R1 is grounded.

[0030] As an example, see Figure 2 , Figure 2 Schematic diagram of the three-power switching circuit 107 of the medical device Figure 2 .like Figure 2 As shown, the three power switching circuit 107 of the medical device provided in the embodiment of the present application includes: a first protection circuit 101, a second protection circuit 105, a third protection circuit 106, a power switching circuit 107, a first switch circuit 102, a second switch circuit 103, a third switch circuit 104 and a fourth protection circuit 201.

[0031] The fourth protection circuit 201 includes a fourth TVS transistor TVS4 and a first resistor R1.

[0032] The cathode of the fourth TVS tube TVS4 is connected to the first connection point, the anode of the fourth TVS tube TVS4 is grounded, one end of the first resistor R1 is connected to the first connection point, and the other end of the first resistor R1 is grounded.

[0033] For details, please refer to Figure 3 , Figure 3 Schematic diagram of the three-power switching circuit 107 of the medical device Figure 3 .like Figure 3 As shown, the three-power switching circuit 107 of the medical device provided in the embodiment of the present application includes: a first p-type field-effect transistor PMOS1, a second p-type field-effect transistor PMOS2, a fourth TVS transistor TVS4, a first resistor R1, a first switch SW1, a fuse resistor PTC, a first TVS transistor TVS1, a second resistor R2, a second TVS transistor TVS2, a second switch SW2, a third switch SW3, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a third TVS transistor TVS3, a first diode D1, a second diode D2, a third diode D3, a first N-type field-effect transistor NMOS1, a second N-type field-effect transistor NMOS2, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a third p-type field-effect transistor PMOS3, a fourth p-type field-effect transistor PMOS4, a fifth p-type field-effect transistor PMOS5, a first power supply VCC1, a second power supply VCC2, and a third power supply VCC3.

[0034] The first p-type field effect transistor PMOS1 constitutes the first protection circuit 101 .

[0035] Specifically, the source of the first p-type field effect transistor PMOS1 is connected to the first end of the first switch circuit 102 as the other end of the first protection circuit 101, the drain of the first p-type field effect transistor PMOS1 is connected to the first power supply VCC1 as one end of the first protection circuit 101, and the gate of the first p-type field effect transistor PMOS1 is connected to the source of the first p-type field effect transistor PMOS1.

[0036] The second p-type field effect transistor PMOS2 constitutes the second protection circuit 105 .

[0037] Specifically, the gate of the second p-type field effect transistor PMOS2 is connected to the source of the second p-type field effect transistor PMOS2, the source of the second p-type field effect transistor PMOS2 is connected to the other end of the third switch circuit 104 as one end of the second protection circuit 105, and the drain of the second p-type field effect transistor PMOS2 is connected to the second power supply VCC2 as the other end of the second protection circuit 105.

[0038] The fourth TVS tube TVS4 and the first resistor R1 form the fourth protection circuit 201 .

[0039] Specifically, the cathode of the fourth TVS tube TVS4 is connected to the first connection point, the anode of the fourth TVS tube TVS4 is grounded, one end of the first resistor R1 is connected to the first connection point, and the other end of the first resistor R1 is grounded.

[0040] The first protection circuit 101 is composed of the first switch SW1 , the fuse resistor PTC, the first TVS tube TVS1 and the second resistor R2 .

[0041] Specifically, one end of the first switch SW1 is connected to the first power supply VCC1 as one end of the first protection circuit 101, the other end of the first switch SW1 is connected to one end of the fuse resistor PTC, the other end of the fuse resistor PTC is connected to the drain of the first p-type field-effect transistor PMOS1, the source of the first p-type field-effect transistor PMOS1 is connected to the first end of the first switch circuit 102 as the other end of the first protection circuit 101, the cathode of the first TVS tube TVS1 is connected to the other end of the fuse resistor PTC, the positive electrode of the first TVS tube TVS1 is grounded, one end of the second resistor R2 is connected to the negative electrode of the first TVS tube TVS1, and the other end of the second resistor R2 is grounded.

[0042] The second TVS tube TVS2 and the second switch SW2 constitute the second protection circuit 105 .

[0043] Specifically, one end of the second switch SW2 is connected to the second power supply VCC2 as the other end of the second protection circuit 105, the other end of the second switch SW2 is connected to the other end of the first switch circuit 102 as one end of the second protection circuit 105, the negative electrode of the second TVS tube TVS2 is connected to the other end of the second switch SW2, and the positive electrode of the second TVS tube TVS2 is grounded.

[0044] Here, this application adopts the method of using the first p-type field effect transistor PMOS1 and the second p-type field effect transistor PMOS2 as diodes, maintaining the characteristics of low impedance and large current, and being protected from electrostatic interference by the TVS tube, which can effectively improve the safety and reliability of the circuit, enabling it to pass the certification of the medical device system and allow it to be used in the product terminals of medical devices.

[0045] The third switch SW3 , the third resistor R3 , the fourth resistor R4 , the fifth resistor R5 , the third TVS tube TVS3 , the first diode D1 , the second diode D2 , and the third diode D3 constitute the third protection circuit 106 .

[0046] Specifically, one end of the third switch SW3 serves as the first end of the third protection circuit 106 and is connected to the third power supply VCC3. The other end of the third switch SW3 serves as the second end of the third protection circuit 106 and is connected to the control end of the third switch circuit 104. The other end of the third switch SW3 is also connected to the anode of the first diode D1. The cathode of the first diode D1 serves as the third end of the third protection circuit 106 and is connected to one end of the third switch circuit 104. The anode of the third TVS tube TVS3 is grounded, the cathode of the third TVS tube TVS3 is connected to the other end of the third switch SW3, and the second diode D1 is grounded. An anode of the diode D2 is connected to the other end of the third switch SW3, a cathode of the second diode D2 is connected to one end of the fourth resistor R4, the other end of the fourth resistor R4 serves as the fourth end of the third protection circuit 106 and is connected to the first end of the power switching circuit 107, an anode of the third diode D3 serves as the fifth end of the third protection circuit 106 and is connected to one end of the second protection circuit 105, one end of the fifth resistor R5 is connected to the anode of the third diode D3, the other end of the fifth resistor R5 is grounded, one end of the third resistor R3 is connected to the other end of the third switch SW3, and the other end of the third resistor R3 is grounded.

[0047] The first N-type field effect transistor NMOS1 , the second N-type field effect transistor NMOS2 , the ninth resistor R9 , the sixth resistor R6 , the seventh resistor R7 and the eighth resistor R8 constitute the power switching circuit 107 .

[0048] Specifically, the gate of the first N-type field effect transistor NMOS1 is connected to the fourth end of the third protection circuit 106 as the first end of the power switching circuit 107, the source of the first N-type field effect transistor NMOS1 is grounded, one end of the sixth resistor R6 is connected to the gate of the first N-type field effect transistor NMOS1, the other end of the sixth resistor R6 is connected to the source of the first N-type field effect transistor NMOS1, the drain of the first N-type field effect transistor NMOS1 is connected to the gate of the second N-type field effect transistor NMOS2, the source of the second N-type field effect transistor NMOS2 is grounded, and the second N-type field effect transistor NMOS1 is connected to the gate of the second N-type field effect transistor NMOS2. The drain of S2 serves as the third end of the power switching circuit 107 and is connected to the control end of the first switch circuit 102 and the control end of the second switch circuit 103 respectively. One end of the seventh resistor R7 is connected to the G electrode of the second N-type field effect transistor NMOS2. The other end of the seventh resistor R7 serves as the second end of the power switching circuit 107 and is connected to the other end of the first switch circuit 102. One end of the eighth resistor R8 is connected to the drain of the second N-type field effect transistor NMOS2. The other end of the eighth resistor R8 serves as the fourth end of the power switching circuit 107 and is connected to one end of the second switch circuit 103.

[0049] One end of the ninth resistor R9 is connected to the gate of the second N-type field effect transistor NMOS2, and the other end of the ninth resistor R9 is grounded.

[0050] The third p-type field effect transistor PMOS3 constitutes the first switch circuit 102 , the fourth p-type field effect transistor PMOS4 constitutes the second switch circuit 103 , and the fifth p-type field effect transistor PMOS5 constitutes the third switch circuit 104 .

[0051] The gate of the third p-type field effect transistor PMOS3 is connected to the third end of the power switching circuit 107 as the control end of the first switch circuit 102, the drain of the third p-type field effect transistor PMOS3 is connected to the other end of the first protection circuit 101 as the first end of the first switch circuit 102, the source of the third p-type field effect transistor PMOS3 is connected to the first end of the second switch circuit 103 as the second end of the first switch circuit 102, the gate of the fourth p-type field effect transistor PMOS4 is connected to the third end of the power switching circuit 107 as the control end of the second switch circuit 103, and the source of the fourth p-type field effect transistor PMOS4 is connected to the third end of the power switching circuit 107 as the control end of the second switch circuit 103. A first end of the second switch circuit 103 is connected to a second end of the first switch circuit 102, a drain of the fourth p-type field-effect transistor PMOS4 is connected to a first end of the third switch circuit 104 as the second end of the second switch circuit 103, a gate of the fifth p-type field-effect transistor PMOS5 is connected to a third end of the third protection circuit 106 as the control end of the third switch circuit 104, a drain of the fifth p-type field-effect transistor PMOS5 is connected to a second end of the second switch circuit 103 as the first end of the third switch circuit 104, and a source of the p-type field-effect transistor is connected to one end of the second protection circuit 105 as the second end of the third switch circuit 104.

[0052] Among them, the first TVS tube TVS1, the second TVS tube TVS2, the third TVS tube TVS3, and the fourth TVS tube TVS4 are all used to block electrostatic interference from the power supply and protect the field effect tube.

[0053] The third power source VCC3 is used to connect to an external power adapter, and the external power adapter is used to provide a 5V direct current.

[0054] The second power supply VCC2 is used to connect to a rechargeable battery, and the rechargeable battery is used to provide a 3.7V direct current.

[0055] The first power source VCC1 is used to connect to a dry cell battery box, and the dry cell battery box is used to install a plurality of dry cells to provide a direct current of 4.5V-6V.

[0056] Since the first power source VCC1 is used to connect to the dry cell battery box, a protective resistor PTC is used to protect the dry cell battery from short circuit.

[0057] The second power source VCC2 is connected to a rechargeable battery. Generally, a rechargeable battery, such as a lithium battery, has a built-in protection board that can effectively prevent the battery from short circuiting and overcurrent, without the need to additionally set a fuse resistor PTC.

[0058] The third power supply VCC3 and the external power adapter have a circuit design that already supports short-circuit protection and current protection, so there is no need to set up an additional fuse resistor PTC.

[0059] As an example, when only the power of the third power supply VCC3 is connected to the three-power switching circuit 107 of the medical device and the third switch SW3 is closed, the 5V DC current is transmitted to the power supply end of the medical device through the first diode D1. At this time, the first N-type field effect transistor NMOS1 is turned on, the second N-type field effect transistor NMOS2 is turned off, the first p-type field effect transistor PMOS1 is turned off, the second p-type field effect transistor PMOS2 is turned off, the third p-type field effect transistor PMOS3 is turned off, the fourth p-type field effect transistor PMOS4 is turned off, and the fifth p-type field effect transistor PMOS5 is turned off. At this time, the medical device is powered by the third power supply VCC3.

[0060] As an example, when only the power of the second power supply VCC2 is connected to the three-power switching circuit 107 of the medical device and the second switch SW2 is closed, the 3.7V DC current of the second power supply VCC2 is transmitted to the power supply end of the medical device through the second P-type diode and the fifth P-type diode. At this time, the first N-type field effect transistor NMOS1 is turned on, the second N-type field effect transistor NMOS2 is turned off, the first p-type field effect transistor PMOS1 is turned off, the third p-type field effect transistor PMOS3 is turned off, and the fourth p-type field effect transistor PMOS4 is turned off. At this time, the second power supply VCC2 is used to power the medical device.

[0061] As an example, when only the first power supply VCC1 is connected to the three-power switching circuit 107 of the medical device and the first switch SW1 is closed, a DC current of 4.5V-6V is transmitted to the power supply end of the medical device through the first P-type diode, the third P-type diode, and the fourth P-type diode. At this time, the first N-type field effect transistor NMOS1 is turned off, the second N-type field effect transistor NMOS2 is turned on, the second p-type field effect transistor PMOS2 is turned off, and the fifth p-type field effect transistor PMOS5 is turned off. At this time, the medical device is powered by the first power supply VCC1.

[0062] Here, it should be noted that based on the three-power switching circuit 107 of the above-mentioned medical device, the priorities of the three power supplies for powering the medical device are: the third power supply VCC3 is the first priority, the second power supply VCC2 is the second priority, and the first power supply VCC1 is the third priority.

[0063] As an example, when the third power supply VCC3 and the second power supply VCC2 input electrical energy together, and the third switch SW3 and the second switch SW2 are both closed, at this time, the first N-type field effect transistor NMOS1 is turned on, the second N-type field effect transistor NMOS2 is turned off, the first p-type field effect transistor PMOS1 is turned off, the second p-type field effect transistor PMOS2 is turned off, the third p-type field effect transistor PMOS3 is turned off, the fourth p-type field effect transistor PMOS4 is turned off, and the fifth p-type field effect transistor PMOS5 is turned off. At this time, the medical device is powered by the third power supply VCC3.

[0064] As an example, when the first power supply VCC1 and the second power supply VCC2 both input electrical energy and the first switch SW1 and the second switch SW2 are both closed, at this time, the second P-type diode and the fifth P-type diode are both turned on, the first N-type field effect transistor NMOS1 is turned on, the second N-type field effect transistor NMOS2 is turned off, the first p-type field effect transistor PMOS1 is turned off, the third p-type field effect transistor PMOS3 is turned off, and the fourth p-type field effect transistor PMOS4 is turned off. At this time, the medical device is powered by the second power supply VCC2.

[0065] As an example, when the first power supply VCC1 and the third power supply VCC3 both input electrical energy, and the first switch SW1 and the third switch SW3 are both closed, the first N-type field effect transistor NMOS1 is turned on, the second N-type field effect transistor NMOS2 is turned off, the first p-type field effect transistor PMOS1 is turned off, the second p-type field effect transistor PMOS2 is turned off, the third p-type field effect transistor PMOS3 is turned off, the fourth p-type field effect transistor PMOS4 is turned off, and the fifth p-type field effect transistor PMOS5 is turned off. At this time, the medical device is powered by the third power supply VCC3.

[0066] As an example, when the first power supply VCC1, the second power supply VCC2 and the third power supply VCC3 all input electrical energy, and the first switch SW1, the second switch SW2 and the third switch SW3 are all closed, the first N-type field effect transistor NMOS1 is turned on, the second N-type field effect transistor NMOS2 is turned off, the first p-type field effect transistor PMOS1 is turned off, the second p-type field effect transistor PMOS2 is turned off, the third p-type field effect transistor PMOS3 is turned off, the fourth p-type field effect transistor PMOS4 is turned off, and the fifth p-type field effect transistor PMOS5 is turned off. At this time, the medical device is powered by the third power supply VCC3.

[0067] It should be noted that when the three-power switching circuit mentioned in this application is applied to general consumer products, the first p-type field-effect transistor and the second p-type field-effect transistor can be eliminated to save costs.

[0068] The three-power switching circuit and medical device of the medical device proposed in this application can meet the medical device application requirements of low voltage drop, low impedance and high current of the product power supply through the application of field effect transistors in the first protection circuit and the second protection circuit, thereby improving the reliability of the circuit.

[0069] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of this application and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0070] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0071] In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the fact that ordinary technicians in this field can implement them. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0072] The above description is only a preferred embodiment of the present application and does not limit the scope of protection of the present application. All equivalent structural transformations made based on the contents of the present application specification and drawings under the innovative concept of the present application, or direct / indirect application in other related technical fields are included in the scope of protection of the present application.

Claims

1. A three-power switching circuit for medical equipment, characterized in that: The circuit includes a first protection circuit, a second protection circuit, a third protection circuit, a power switching circuit, a first switch circuit, a second switch circuit, and a third switch circuit. One end of the first protection circuit is connected to the first power supply, the other end of the first protection circuit is connected to the first end of the first switch circuit, the second end of the first switch circuit is connected to the first end of the second switch circuit, the second end of the second switch circuit is connected to the first end of the third switch circuit, the second end of the third switch circuit is connected to one end of the second protection circuit, the other end of the second protection circuit is connected to the second power supply, the first end of the third protection circuit is connected to the third power supply, the second end of the third protection circuit is connected to the control end of the third switch circuit, the second end of the third protection circuit is connected to the second end of the second switch circuit, the third end of the third protection circuit is connected to the control end of the third switch circuit, the fourth end of the third protection circuit is connected to the first end of the power switching circuit, the fifth end of the third protection circuit is connected to one end of the second protection circuit, the second end of the power switching circuit is connected to the second end of the first switch circuit, the third end of the power switching circuit is connected to the control end of the first switch circuit and the control end of the second switch circuit respectively, and the fourth end of the power switching circuit is connected to the first end of the second switch circuit. A first connection point is formed between the other end of the second switch circuit and one end of the third switch circuit, and the first connection point serves as the power supply end of the medical device. In which, the first protection circuit includes a first P-type field effect transistor, the source of the first P-type field effect transistor is connected to the first end of the first switch circuit as the other end of the first protection circuit, the drain of the first P-type field effect transistor is connected to the first power supply as one end of the first protection circuit, and the gate of the first P-type field effect transistor is connected to the source of the first P-type field effect transistor. The second protection circuit includes a second P-type field effect transistor, the gate of the second P-type field effect transistor is connected to the source of the second P-type field effect transistor, the source of the second P-type field effect transistor is connected to the other end of the third switch circuit as one end of the second protection circuit, and the drain of the second P-type field effect transistor is connected to the second power supply as the other end of the second protection circuit.

2. The three-power switching circuit according to claim 1, wherein: The circuit further includes a fourth protection circuit, wherein the fourth protection circuit includes a fourth TVS tube and a first resistor. The cathode of the fourth TVS tube is connected to the first connection point, the anode of the fourth TVS tube is grounded, one end of the first resistor is connected to the first connection point, and the other end of the first resistor is grounded.

3. The three-power switching circuit according to claim 1, wherein: The first protection circuit also includes a first switch, a fuse resistor, a first TVS tube and a second resistor. One end of the first switch is connected to the first power supply as one end of the first protection circuit, the other end of the first switch is connected to one end of the fuse resistor, the other end of the fuse resistor is connected to the drain of the first p-type field-effect transistor, the source of the first p-type field-effect transistor is connected to the first end of the first switch circuit as the other end of the first protection circuit, the cathode of the first TVS tube is connected to the other end of the fuse resistor, the anode of the first TVS tube is grounded, one end of the second resistor is connected to the cathode of the first TVS tube, and the other end of the second resistor is grounded.

4. The three-power switching circuit according to claim 1, wherein: The second protection circuit also includes a second TVS tube and a second switch. One end of the second switch is connected to the second power supply as the other end of the second protection circuit, the other end of the second switch is connected to the other end of the first switch circuit as one end of the second protection circuit, the negative electrode of the second TVS tube is connected to the other end of the second switch, and the positive electrode of the second TVS tube is grounded.

5. The three-power switching circuit according to claim 1, wherein: The third protection circuit includes a third switch, a third resistor, a fourth resistor, a fifth resistor, a third TVS tube, a first diode, a second diode, and a third diode. One end of the third switch serves as the first end of the third protection circuit and is connected to the third power source. The other end of the third switch serves as the second end of the third protection circuit and is connected to the control end of the third switch circuit. The other end of the third switch is also connected to the anode of the first diode. The cathode of the first diode serves as the third end of the third protection circuit and is connected to one end of the third switch circuit. The anode of the third TVS diode is grounded. The cathode of the third TVS diode is connected to the other end of the third switch. The anode of the second diode is connected to the other end of the third switch. The cathode of the second diode is connected to one end of the fourth resistor. The other end of the fourth resistor serves as the fourth end of the third protection circuit and is connected to the first end of the power switching circuit. The anode of the third diode serves as the fifth end of the third protection circuit and is connected to one end of the second protection circuit. One end of the fifth resistor is connected to the anode of the third diode. The other end of the fifth resistor is grounded. One end of the third resistor is connected to the other end of the third switch. The other end of the third resistor is grounded.

6. The three-power switching circuit according to claim 1, wherein: The power switching circuit includes a first N-type field effect transistor, a second N-type field effect transistor, a sixth resistor, a seventh resistor and an eighth resistor. Among them, the gate of the first N-type field effect transistor is connected to the fourth end of the third protection circuit as the first end of the power switching circuit, the source of the first N-type field effect transistor is grounded, one end of the sixth resistor is connected to the gate of the first N-type field effect transistor, the other end of the sixth resistor is connected to the source of the first N-type field effect transistor, the drain of the first N-type field effect transistor is connected to the gate of the second N-type field effect transistor, the source of the second N-type field effect transistor is grounded, the drain of the second N-type field effect transistor is connected to the control end of the first switch circuit and the control end of the second switch circuit as the third end of the power switching circuit respectively, and one end of the seventh resistor is connected to the G of the second N-type field effect transistor. The other end of the seventh resistor is connected to the other end of the first switching circuit as the second end of the power switching circuit, one end of the eighth resistor is connected to the drain of the second N-type field effect transistor, and the other end of the eighth resistor is connected to one end of the second switching circuit as the fourth end of the power switching circuit.

7. The three-power switching circuit according to claim 6, wherein: The power switching circuit further includes a ninth resistor, One end of the ninth resistor is connected to the gate of the second N-type field effect transistor, and the other end of the ninth resistor is grounded.

8. The three-power switching circuit according to claim 1, wherein: The first switch circuit includes a third p-type field effect transistor, the second switch circuit includes a fourth p-type field effect transistor, and the third switch circuit includes a fifth p-type field effect transistor. The gate of the third p-type field-effect transistor is connected to the third end of the power switching circuit as the control end of the first switching circuit, the drain of the third p-type field-effect transistor is connected to the other end of the first protection circuit as the first end of the first switching circuit, the source of the third p-type field-effect transistor is connected to the first end of the second switching circuit as the second end of the first switching circuit, the gate of the fourth p-type field-effect transistor is connected to the third end of the power switching circuit as the control end of the second switching circuit, the source of the fourth p-type field-effect transistor is connected to the second end of the first switching circuit as the first end of the second switching circuit, the drain of the fourth p-type field-effect transistor is connected to the first end of the third switching circuit as the second end of the second switching circuit, the gate of the fifth p-type field-effect transistor is connected to the third end of the third protection circuit as the control end of the third switching circuit, the drain of the fifth p-type field-effect transistor is connected to the second end of the second switching circuit as the first end of the third switching circuit, and the source of the p-type field-effect transistor is connected to one end of the second protection circuit as the second end of the third switching circuit.

9. The three-power switching circuit according to claim 1, wherein: The first power supply is used to connect to an external power adapter, and the external power adapter is used to provide a 5V direct current; The second power supply is used to connect to a rechargeable battery, and the rechargeable battery is used to provide a 3.7V direct current; The third power source is used to be connected to a dry cell battery box, and the dry cell battery box is used to install a plurality of dry cells to provide a direct current of 4.5V-6V.

10. A medical device, characterized in that: The medical device includes the three-power switching circuit of the medical device according to any one of claims 1 to 9.

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