Medical equipment power supply control circuit and medical equipment

Abstract

The invention relates to a medical equipment power supply control circuit and medical equipment, which are used for solving the problem of supplying power to high-power medical equipment when a power grid is powered down. The control circuit comprises an AC-DC conversion module used for converting an input power grid end AC into a first DC and a second DC; the power failure detection module is used for detecting the power supply state of the power grid end, and the power supply state is one of the normal power grid and the power failure of the power grid; the power supply control module is used for supplying power to the medical equipment through the second path of direct current when the power grid is normal and enabling the plurality of direct current power supplies to be connected in parallel so as to charge the plurality of direct current power supplies connected in parallel through the first path of direct current; when the power grid is powered down, the plurality of direct-current power supplies are connected in series; and the direct current-direct current conversion module is used for converting the voltage of a series power supply group formed by connecting the plurality of direct current power supplies in series into a preset voltage and then supplying power to the medical equipment.

Description

Technical Field

[0001] The present invention relates to a power supply system for medical equipment, and in particular to a power supply control circuit for medical equipment and medical equipment. Background Art

[0002] With the continuous advancement of medical technology, medical devices are becoming increasingly powerful, placing correspondingly higher demands on power supply systems. High-power medical devices, such as ultrasound equipment, are particularly important. They must not only operate stably during normal grid power supply, but also maintain operation during power outages to ensure continuity of medical care and patient safety.

[0003] Currently, medical equipment typically uses a power supply system that combines AC grid power with backup power from a DC power supply. When the grid is functioning properly, the equipment receives power from the grid and charges the backup power supply. In the event of a grid power outage, the backup power supply automatically switches to the backup power supply. This power supply method has been widely adopted in a variety of medical devices.

[0004] However, existing technologies suffer from systemic flaws: The International Air Transport Association (IATA)'s strict regulations on lithium-ion batteries limit the energy density of a single battery pack to below a critical value of 100Wh. This energy supply significantly conflicts with the power consumption requirements of medical electronic equipment. For example, an ultrasound diagnostic instrument, whose core components include a high-voltage generator, pulse control circuitry, and transducer array, typically consumes over 300W of peak power.

[0005] Therefore, there is an urgent need for an improved medical device power supply control circuit that can power higher-power medical devices when the power grid is down. Summary of the Invention

[0006] In order to solve the problem of supplying power to a medical device with a relatively high power when the power grid is powered off, the present invention provides a medical device power supply control circuit and a medical device.

[0007] The technical solution adopted by the present invention to solve its technical problem is: A medical device power supply control circuit is provided, wherein the medical device is powered by direct current provided by a direct current power supply group or alternating current input from a power grid, the direct current power supply group including multiple direct current power supplies, and the control circuit including: an alternating current to direct current (AC to DC) module for converting the input alternating current from the power grid into a first direct current (DC) and a second direct current (DC); a power failure detection module for detecting the power supply status of the power grid, wherein the power supply status is one of a normal power grid and a power failure; a power supply control module for supplying power to the medical device via the second DC power when the power grid is normal, and for connecting the multiple DC power supplies in parallel so as to charge the multiple parallel DC power supplies via the first DC power; and for connecting the multiple DC power supplies in series when the power grid fails; and a direct current to direct current (DC to DC) module for converting the voltage of the series power supply group formed by the multiple DC power supplies in series to a preset voltage before supplying power to the medical device.

[0008] Furthermore, the power supply control module includes: a microprocessor, used to obtain the power supply status of the grid end and output a first control signal or a second control signal according to the power supply status; a DC-to-DC control switch, the DC-to-DC control switch is respectively connected to the microprocessor and the DC-to-DC module, and is used to control the DC-to-DC module to start working when receiving the first control signal, and control the DC-to-DC module to stop working when receiving the second control signal.

[0009] Preferably, the power supply control module further includes: a plurality of series-parallel conversion switches, the plurality of series-parallel conversion switches are all connected to the microprocessor, and one series-parallel conversion switch is connected between each of the DC power supplies, the series-parallel conversion switches have a first state and a second state, the series-parallel conversion switch switches to the first state upon receiving a first control signal, and switches to the second state upon receiving a second control signal, the first state corresponds to a state in which the power grid is powered off, and the second state corresponds to a state in which the power grid is normal, the series-parallel conversion switches are configured as follows: in the first state, each of the series-parallel conversion switches respectively connects the negative pole of the upstream DC power supply to which it is connected and the positive pole of the downstream DC power supply to connect the plurality of DC power supplies in series; in the second state, each of the series-parallel conversion switches respectively grounds the negative pole of the upstream DC power supply to which it is connected, so that the plurality of DC power supplies are connected in parallel.

[0010] Furthermore, the control circuit also includes: a charger module, the charger module including an input end and multiple output ends, the number of the output ends is consistent with the number of the DC power supplies, the input end of the charger module is connected to the AC-DC conversion module, and the multiple output ends of the charger module are respectively connected to each of the DC power supplies to charge each of the DC power supplies, wherein the charger module is configured so that its maximum charging current is not greater than the maximum charging current allowed by any one of the multiple DC power supplies.

[0011] Preferably, the control circuit further includes an isolation diode module, which includes multiple isolation diodes. The number of the isolation diodes is consistent with the number of the DC power supplies. The multiple output ends of the charger module are each connected to the corresponding DC power supply through one of the isolation diodes, so as to isolate each charging circuit when the multiple DC power supplies are charged in parallel.

[0012] Furthermore, the number of the isolation diodes is 3, wherein the withstand voltage of the first isolation diode is greater than a single maximum output voltage of the DC power supply, the withstand voltage of the second isolation diode is greater than 2 times the maximum output voltage of the DC power supply, and the withstand voltage of the third isolation diode is greater than 3 times the maximum output voltage of the DC power supply.

[0013] Preferably, the control circuit may further include: a plurality of backup diodes, the number of the backup diodes being consistent with the number of the DC power supplies, and each of the DC power supplies being connected in parallel with one backup diode, so as to keep the power supply circuits of the multiple DC power supplies conductive when the multiple DC power supplies are connected in series and one or more of the multiple DC power supplies fail.

[0014] Furthermore, the number of the backup diodes is 3, and the withstand voltage of each of the backup diodes is greater than 3 times the maximum output voltage of the DC power supply.

[0015] Preferably, the control circuit may further include: a surge limiting resistor, the surge limiting resistor being connected in parallel to the input and output ends of the DC-to-DC control switch, and when the input and output ends of the DC-to-DC control switch are connected, the DC-to-DC module starts to work, and when the input and output ends of the DC-to-DC control switch are disconnected, the DC-to-DC module stops working; and a capacitor, one end of the capacitor being connected to the output end of the DC-to-DC control switch, and the other end of the capacitor being grounded.

[0016] The beneficial effects of the present invention are: By adopting a solution of parallel charging and series discharging of battery packs, when the power grid is normal, multiple battery packs are charged in parallel, and when the power grid is powered off, multiple battery packs are discharged in series. Only one DC-to-DC converter module is needed to meet the requirements. This not only solves the problem of powering higher-power medical equipment when the power grid is powered off, but also has the advantage of low system design complexity, effectively reducing product costs.

[0017] In addition, the present invention improves the reliability of the system by providing a backup diode to keep the circuit conductive when a battery pack fails; and by providing a surge limiting resistor, it can limit the transient surge current when the battery pack changes from parallel to series connection, thereby protecting the circuit safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram showing the structural principle of a power supply control circuit for medical equipment provided by an embodiment of the present invention is shown; Figure 2 A schematic diagram showing the structural principle of a power supply control module 300 of a power supply control circuit for medical equipment provided by one embodiment of the present invention is shown; Figure 3 Another schematic diagram showing the structural principle of a medical device power supply control circuit provided by an embodiment of the present invention is shown; Figure 4 A schematic diagram of the circuit principle of a medical device power supply control circuit provided by yet another embodiment of the present invention is shown. DETAILED DESCRIPTION

[0019] The technical solutions of the present invention will be described clearly and completely below with reference to the accompanying drawings and embodiments. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are also within the scope of protection of the present invention. Example

[0020] Figure 1 The schematic diagram of the structure principle of a medical device power supply control circuit provided by an embodiment of the present invention is shown. Figure 1 As shown, the medical device is powered by DC power provided by a DC power supply group or AC power input from the power grid. Specifically, the medical device body can be selectively powered by DC power provided by a DC power supply group, or by DC power converted from AC power input from the power grid.

[0021] The DC power supply group may include multiple DC power supplies. The control circuit may include an AC to DC conversion module 100 , a power failure detection module 200 , a power supply control module 300 and a DC to DC conversion module 400 .

[0022] The AC-DC module 100 is used to convert the input AC power from the grid into a first DC power source and a second DC power source. The AC-DC module 100 uses power electronic conversion technology to convert 220V / 50Hz AC power into two DC power sources of different voltage levels. The first DC power source is mainly used to charge the DC power supply group. The voltage value of the first DC power source can be determined based on the charging voltage of the DC power supply group. For example, its voltage value can be set to 12V. The second DC power source is mainly used to power the medical equipment during normal operation. The voltage value of the second DC power source can be determined based on the operating voltage of the medical equipment group. For example, its voltage value can be set to 36V. The AC-DC module 100 integrates components such as a transformer, a rectifier bridge, and a filter capacitor, which can achieve stable conversion from AC to DC power.

[0023] The power outage detection module 200 is used to detect the power supply status of the power grid, which can be either normal or power outage. The power outage detection module 200 determines whether the power grid is operating normally by monitoring the voltage at the power grid. A power outage is detected when the power grid voltage is below a preset threshold, such as 180V, and persists for a preset time, such as 20ms. A power outage is detected. A normal power grid is detected when the power grid voltage returns to above a preset threshold for a preset time. The power outage detection module 200 can be implemented using a voltage comparator circuit, which features fast response speed and high detection accuracy.

[0024] The power supply control module 300 is used to power the medical device via the second DC power when the power grid is normal, and to connect multiple DC power supplies in parallel to charge the multiple parallel DC power supplies via the first DC power; when the power grid is powered off, the multiple DC power supplies are connected in series. The power supply control module 300 is the core part of the entire control circuit and is responsible for switching different power supply modes according to the power grid status. When the power grid is normal, the medical device directly uses the second DC power from the AC-DC conversion module 100 to operate, while multiple DC power supplies are charged in parallel; when the power grid is powered off, the power supply control module 300 quickly switches the power connection mode, connecting multiple DC power supplies in series to form a higher voltage power supply group to provide emergency power for the medical device.

[0025] The DC-to-DC module 400 is used to convert the voltage of a series power supply group, formed by multiple DC power supplies connected in series, to a preset voltage to power the medical device. The DC-to-DC module 400 can utilize a Buck-Boost circuit topology, stably converting the high voltage of the series power supply group into the operating voltage required by the medical device. The preset voltage is the same as the voltage of the second DC power source, 36V. This ensures that when the power grid fails and the DC power supply group is switched to, the medical device can smoothly transition to normal operation without being affected by voltage fluctuations.

[0026] Figure 2 FIG1 shows a schematic diagram of the structure and principle of a power supply control module 300 of a power supply control circuit for medical equipment provided by an embodiment of the present invention. Figure 2 As shown, the power supply control module 300 may specifically include a microprocessor 310 and a DC-to-DC control switch 320 .

[0027] Microprocessor 310 is used to obtain the power supply status of the power grid and output a first control signal or a second control signal based on the power supply status. Microprocessor 310 can be a low-power 32-bit ARM processor with a rich peripheral interface and powerful data processing capabilities. Microprocessor 310 uses an internal analog-to-digital converter to collect the power grid status signal provided by power failure detection module 200 in real time. After processing it through a software algorithm, it outputs the corresponding control signal. When a power failure is detected, microprocessor 310 outputs a first control signal; when a normal power grid is detected, microprocessor 310 outputs a second control signal.

[0028] The DC-to-DC control switch 320 is connected to the microprocessor 310 and the DC-to-DC module 400, respectively. It is configured to control the DC-to-DC module 400 to start operating upon receiving a first control signal and to stop operating upon receiving a second control signal. The DC-to-DC control switch 320 can be implemented using a power MOSFET, which features fast switching speed and low on-resistance. Upon receiving the first control signal (high level) output by the microprocessor 310, the DC-to-DC control switch 320 turns on, and the DC-to-DC module 400 begins operating, converting the voltage of the series power supply group to the operating voltage required by the medical device. Upon receiving the second control signal (low level) output by the microprocessor 310, the DC-to-DC control switch 320 turns off, and the DC-to-DC module 400 stops operating. The medical device is now powered by the second DC power source from the AC-to-DC module 100.

[0029] See also Figure 2 As shown, the power supply control module 300 may further include multiple series-parallel conversion switches 330. Each of the multiple series-parallel conversion switches 330 is connected to the microprocessor 310, and a series-parallel conversion switch 330 is connected between each pair of DC power supplies. The series-parallel conversion switches 330 have a first state and a second state. The series-parallel conversion switches 330 switch to the first state upon receiving a first control signal, and switch to the second state upon receiving a second control signal. The first state corresponds to a power outage in the power grid, and the second state corresponds to a normal power grid.

[0030] In this embodiment, the DC power supply group includes three DC power supplies: a first DC power supply, a second DC power supply, and a third DC power supply. Each DC power supply has a rated voltage of 12V and a capacity of 2000mAh. Accordingly, there are two series-parallel transfer switches 330: a first series-parallel transfer switch and a second series-parallel transfer switch. The first series-parallel transfer switch is connected between the first and second DC power supplies, and the second series-parallel transfer switch is connected between the second and third DC power supplies.

[0031] The series-parallel converter switches 330 are configured such that: in a first state, each series-parallel converter connects the negative electrode of its connected upstream DC power source to the positive electrode of its downstream DC power source, thereby connecting the multiple DC power sources in series; and in a second state, each series-parallel converter connects the negative electrode of its connected upstream DC power source to ground, thereby connecting the multiple DC power sources in parallel. Specifically, when the series-parallel converter switches are in the first state, the first series-parallel converter switch connects the negative electrode of the first DC power source to the positive electrode of the second DC power source, and the second series-parallel converter switch connects the negative electrode of the second DC power source to the positive electrode of the third DC power source, thereby connecting the three DC power sources in series to form a 36V high-voltage power supply group; when the series-parallel converter switches are in the second state, the first series-parallel converter switch connects the negative electrode of the first DC power source to ground, the second series-parallel converter switch connects the negative electrode of the second DC power source to ground, and the negative electrode of the third DC power source is also grounded, thereby connecting the three DC power sources in parallel to facilitate simultaneous charging.

[0032] The series-parallel switch 330 can be implemented using a power MOSFET, which features fast switching speed and low on-resistance. It can also be implemented using a relay, which features low contact resistance and high reliability. The relay's coil is controlled by the microprocessor 310. Upon receiving a first control signal, the relay closes, switching to a first state. Upon receiving a second control signal, the relay releases, switching to a second state.

[0033] Figure 3 FIG2 shows another structural principle diagram of a medical device power supply control circuit provided by an embodiment of the present invention. Figure 3 As shown, the control circuit further includes a charger module 500 .

[0034] The charger module 500 includes an input and multiple outputs, with the number of outputs matching the number of DC power supplies. The input of the charger module 500 is connected to the AC-DC converter module 100, while the multiple outputs of the charger module 500 are connected to the DC power supplies to charge them. In this embodiment, the charger module 500 has three outputs, each connected to one of the three DC power supplies.

[0035] The charger module 500 is configured so that its maximum charging current does not exceed the maximum allowable charging current of any of the multiple DC power supplies. In this embodiment, each DC power supply has a maximum allowable charging current of 1A, so the maximum charging current of the charger module 500 is set to 0.8A to ensure that the DC power supplies are not damaged during the charging process. The charger module 500 uses a constant current and constant voltage charging method. Initially, the charging method uses a constant current mode. When the DC power supply voltage approaches full charge, the device automatically switches to a constant voltage mode, ensuring safe and efficient charging.

[0036] See also Figure 3 As shown, the control circuit further includes an isolation diode module 600 .

[0037] The isolation diode module 600 may include multiple isolation diodes. The number of isolation diodes matches the number of DC power supplies. Each of the multiple output terminals of the charger module 500 is connected to a corresponding DC power supply via an isolation diode, isolating each charging circuit when multiple DC power supplies are connected in parallel. In this embodiment, there are three isolation diodes: a first isolation diode, a second isolation diode, and a third isolation diode. The first isolation diode connects the first output terminal of the charger module 500 to the first DC power supply, the second isolation diode connects the second output terminal of the charger module 500 to the second DC power supply, and the third isolation diode connects the third output terminal of the charger module 500 to the third DC power supply.

[0038] Specifically, the number of isolation diodes can be three, with the first isolation diode having a withstand voltage greater than a single DC power supply's maximum output voltage, the second isolation diode having a withstand voltage greater than twice the DC power supply's maximum output voltage, and the third isolation diode having a withstand voltage greater than three times the DC power supply's maximum output voltage. For example, if the maximum output voltage of each DC power supply is 14V (fully charged), the first isolation diode's withstand voltage greater than 14V would require a 20V withstand voltage diode; the second isolation diode's withstand voltage greater than 28V would require a 40V withstand voltage diode; and the third isolation diode's withstand voltage greater than 42V would require a 60V withstand voltage diode. Schottky diodes are used as isolation diodes, which feature low forward voltage drop and fast switching speed, reducing energy loss during charging.

[0039] The control circuit may also include multiple backup diodes. The number of backup diodes matches the number of DC power supplies, with each DC power supply connected in parallel to a backup diode. This ensures that the power supply circuits for the multiple DC power supplies remain conductive when the multiple DC power supplies are connected in series and one or more of the multiple DC power supplies fail. In this embodiment, there are three backup diodes: a first backup diode, a second backup diode, and a third backup diode. The first backup diode is connected in parallel to the first DC power supply, the second backup diode is connected in parallel to the second DC power supply, and the third backup diode is connected in parallel to the third DC power supply.

[0040] The number of backup diodes is three, and the withstand voltage of each backup diode is greater than three times the maximum output voltage of the DC power supply. Specifically, the maximum output voltage of each DC power supply is 14V, which is three times 42V. Therefore, the withstand voltage of each backup diode is greater than 42V, and a 60V withstand voltage diode is selected. Under normal circumstances, the backup diodes are reverse biased and non-conductive. If a DC power supply fails, such as an internal short circuit or open circuit, the corresponding backup diode conducts, ensuring that the power supply circuit of the entire series power supply group remains conductive, improving system reliability.

[0041] The control circuit may also include a surge limiting resistor and a capacitor. The surge limiting resistor is connected in parallel to the input and output of the DC-to-DC control switch. When the input and output of the DC-to-DC control switch are connected, the DC-to-DC module 400 begins operation. When the input and output of the DC-to-DC control switch 320 are disconnected, the DC-to-DC module 400 stops operation. The surge limiting resistor has a resistance of 10 kΩ and a power of 1 W. It is used to limit the current surge generated during the switching process of the DC-to-DC control switch 320, protecting the control switch 320 and the DC-to-DC module 400.

[0042] One end of the capacitor is connected to the output of the DC-DC converter control switch 320, and the other end of the capacitor is grounded. The capacitor can have a capacitance of 100 μF and a withstand voltage of 50 V. It is used to filter out voltage ripple at the input of the DC-DC converter module 400, providing a stable input voltage to ensure the normal operation of the DC-DC converter module 400.

[0043] The medical device power supply control circuit of this embodiment converts AC power from the power grid into two DC power lines through an AC-DC converter module: one for powering the medical device and one for charging the DC power pack. A power failure detection module monitors the power grid status in real time. The power supply control module automatically switches the power supply mode based on the grid status, using AC power and charging the DC power pack when the grid is normal, and quickly switching to the DC power pack when the grid fails. The DC-DC converter module converts the voltage of the DC power pack to the operating voltage required by the medical device. The entire control circuit has a reasonable structure and comprehensive functions, ensuring that the medical device can continue to operate normally even in the event of a power failure, thereby improving the reliability and safety of the medical device. Example

[0044] Figure 4 FIG2 shows a schematic diagram of the structure and principle of a power supply control circuit for medical equipment provided by another embodiment of the present invention. Figure 4 As shown in the figure, the control circuit adopts a dual-output structure. That is, the output of the ACDC module is divided into two independent branches: the first branch is connected to the charger and is dedicated to charging the battery pack; the second branch directly powers the medical device (SYS), and the output terminal is marked as VOUT_1.

[0045] The ACDC module has a built-in AC_FAIL signal detection unit, which can be implemented based on the OC gate circuit. When the power grid is normal, the OC gate is turned on; when the power grid is off, the OC gate is turned off.

[0046] The MCU monitors the AC_FAIL signal in real time and controls the switch action according to the signal status.

[0047] In normal grid mode, parallel charging is used. In this case, the battery pack connection state is SWITCH grounded, forming a parallel topology for the battery packs (BATTERY_PACK1 / 2 / 3). The charger charges the parallel battery packs through isolation diodes D1, D2, and D3. The maximum output current of the charger is ≤ the maximum allowable charging current of a single battery pack. Under certain operating conditions, the charging current may flow only to a single battery pack.

[0048] In grid power-off mode, the battery packs discharge in series. When the MCU detects the AC_FAIL signal, it switches to the SWITCH state, switching the battery packs to a series topology. The total output voltage of the series battery packs rises to 3×Vbatmax, where Vbatmax is the maximum voltage of a single pack. Initially, the current is limited by surge suppression resistor R1 to prevent sudden voltage changes on capacitor C1 (Vbatmax → 3×Vbatmax), which could damage the circuit. After reaching steady state, the MCU closes the R1 bypass switch, directing the current through the DC-DC module to boost the voltage, and output VOUT_2 to power the device.

[0049] When a single battery pack fails, such as BATTERY_PACK2, the backup diode D5 turns on, forming a redundant path from BATTERY_PACK1 to D5 and then to BATTERY_PACK3 to maintain system power supply.

[0050] When the grid recovers, the MCU switches the SWITCH state to the parallel state, restoring the parallel connection of the battery pack. The DCDC module is disabled in one of the following ways: hardware shutdown, for example, setting the startup voltage to > Vbatmax; or software control, which means the MCU actively shuts down. Example

[0051] A medical device includes the medical device power supply control circuit described in Example 1. The medical device may be an ultrasound device, a ventilator, a monitor, an infusion pump, or other medical device requiring continuous and stable power supply.

[0052] Through the power supply control circuit described in Example 1, the medical device is powered by the power grid and charges the backup power supply when the power grid is normal, and automatically switches to the backup power supply when the power grid fails, ensuring the continuous and stable operation of the medical device and improving the reliability and safety of the medical device.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A power supply control circuit for medical equipment, wherein the medical equipment is powered by direct current provided by a direct current power supply group or alternating current input from a power grid, wherein the direct current power supply group includes multiple direct current power supplies, characterized in that: The control circuit comprises: The AC-DC converter module is used to convert the input grid-end AC power into a first DC power and a second DC power; A power failure detection module is used to detect the power supply status of the power grid end, where the power supply status is one of the power grid being normal and the power grid being down; a power supply control module, configured to, when the power grid is normal, power the medical device via the second DC power supply, connect the multiple DC power supplies in parallel, and charge the multiple DC power supplies in parallel via the first DC power supply; and connect the multiple DC power supplies in series when the power grid is down; The DC-to-DC module is used to convert the voltage of the series power supply group formed by the multiple DC power supplies connected in series into a preset voltage to supply power to the medical device.

2. The control circuit according to claim 1, wherein: The power supply control module includes: a microprocessor, configured to obtain a power supply status of the grid end and output a first control signal or a second control signal according to the power supply status; A DC-to-DC control switch is connected to the microprocessor and the DC-to-DC module, respectively, and is used to control the DC-to-DC module to start working when receiving a first control signal, and to control the DC-to-DC module to stop working when receiving a second control signal.

3. The control circuit according to claim 2, characterized in that: The power supply control module further includes: A plurality of series-parallel conversion switches are connected to the microprocessor, and one series-parallel conversion switch is connected between every two DC power supplies. The series-parallel conversion switches have a first state and a second state. The series-parallel conversion switches switch to the first state upon receiving a first control signal and switch to the second state upon receiving a second control signal. The first state corresponds to a power outage state of the power grid, and the second state corresponds to a normal power grid state. The series-parallel conversion switches are configured as follows: In the first state, each of the series-parallel conversion switches connects the negative electrode of the upstream DC power supply to the positive electrode of the downstream DC power supply, so that the multiple DC power supplies are connected in series; In the second state, each of the series-parallel conversion switches grounds the negative electrode of the upstream DC power source to which it is connected, so that the multiple DC power sources are connected in parallel.

4. The control circuit according to claim 3, characterized in that: The control circuit further includes: A charger module, wherein the charger module includes an input end and multiple output ends, the number of the output ends being the same as the number of the DC power supplies, the input end of the charger module being connected to the AC-DC conversion module, and the multiple output ends of the charger module being respectively connected to each of the DC power supplies to charge each of the DC power supplies, wherein the charger module is configured so that its maximum charging current is no greater than the maximum charging current allowed by any one of the multiple DC power supplies.

5. The control circuit according to claim 4, characterized in that: The control circuit further includes: The isolation diode module includes multiple isolation diodes. The number of the isolation diodes is consistent with the number of the DC power supplies. The multiple output ends of the charger module are each connected to the corresponding DC power supply through an isolation diode to isolate each charging circuit when the multiple DC power supplies are charged in parallel.

6. The control circuit according to claim 5, characterized in that: The number of the isolation diodes is 3, wherein the withstand voltage of the first isolation diode is greater than a single maximum output voltage of the DC power supply, the withstand voltage of the second isolation diode is greater than 2 times the maximum output voltage of the DC power supply, and the withstand voltage of the third isolation diode is greater than 3 times the maximum output voltage of the DC power supply.

7. The control circuit according to claim 5, characterized in that: The control circuit further includes: Multiple backup diodes, the number of which is consistent with the number of the DC power supplies, and each of the DC power supplies is connected in parallel with a backup diode to keep the power supply circuits of the multiple DC power supplies conductive when the multiple DC power supplies are connected in series and one or more of the multiple DC power supplies fail.

8. The control circuit according to claim 7, characterized in that: The number of the backup diodes is 3, and the withstand voltage of each of the backup diodes is greater than 3 times the maximum output voltage of the DC power supply.

9. The control circuit according to claim 3, characterized in that: The control circuit further includes: a surge limiting resistor connected in parallel to the input and output of the DC-to-DC control switch, wherein when the input and output of the DC-to-DC control switch are connected, the DC-to-DC module starts to operate, and when the input and output of the DC-to-DC control switch are disconnected, the DC-to-DC module stops operating; A capacitor, one end of which is connected to the output end of the DC-DC control switch, and the other end of which is grounded.

10. A medical device, characterized in that: The medical device comprises the medical device power supply control circuit according to any one of claims 1 to 9.

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