A capsule endoscope power supply system capable of automatically switching boost circuits

Abstract

The present invention discloses a capsule endoscope power supply system capable of automatically switching a boost circuit, comprising a battery, a switch control unit, an automatic switching boost unit and a functional module; the battery is used to supply power to the functional module and realize the on-off of the power supply through the switch control unit; when the switch control unit is activated, the battery voltage is monitored by the automatic switching boost unit, and when the battery voltage is higher than the set voltage, the capsule endoscope power supply is powered by the battery voltage and operates; when the battery voltage is lower than the set voltage, the automatic switching boost unit starts to start the boost circuit, and the boost circuit can continue to maintain the capsule endoscope working. The automatic switching boost circuit of the present invention can automatically start the boost circuit under the condition of lower than the set voltage, and the battery can still maintain the normal operation of the capsule endoscope through the boost circuit, which not only improves the battery energy utilization rate, but also can keep the brightness of the fill light sufficient and extend the shelf life and use time of the capsule endoscope.

Description

Technical Field

[0001] The invention relates to a capsule endoscope power supply system capable of automatically switching a boost circuit, belonging to the technical field of power supply control. Background Art

[0002] Capsule endoscopes are powered by batteries. Due to the size of the capsule endoscope, the design needs to reduce the number and volume of batteries used, so they are generally powered by a single battery. The capacity of such batteries is greatly limited. The battery capacity is not too high. In addition, the voltage of a single battery is very low, such as a 3V lithium manganese dioxide battery.

[0003] The existing solution is generally to directly supply the battery voltage to the power input port of the IC (such as a CMOS chip). After the capsule endoscope has been working for a period of time, the battery voltage will drop to a minimum voltage that cannot meet the IC's working requirements. For example, the minimum voltage of a 3V-powered IC (such as a CMOS chip) is generally required to be greater than 2.6V. When the battery voltage drops below 2.6V, the remaining power in the battery cannot be used. It is difficult to improve the shelf life and usage time of the capsule endoscope, which also causes a waste of resources.

[0004] In addition, capsule endoscopes are equipped with fill lights to help the camera capture the internal gastrointestinal conditions of the human body. Since light-emitting diodes have a certain voltage drop, in such products, the anode of the light-emitting diode is usually connected to the positive electrode of the battery at 3V. When the battery power decreases, the voltage decreases, and the current flowing through the light-emitting diode will also decrease, and then the brightness of the light-emitting diode will also become dimmer, resulting in the problem of insufficient fill light. Summary of the invention

[0005] The present invention provides a capsule endoscope power supply system capable of automatically switching a boost circuit, which effectively prolongs the shelf life and use time of the capsule endoscope during the entire life cycle of the battery.

[0006] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0007] A capsule endoscope power supply system capable of automatically switching a boost circuit comprises: a battery, a switch control unit, an automatic switching boost unit and a functional module;

[0008] The battery is used to power the functional modules and is also the energy source of the entire capsule endoscope power supply system. The power is turned on and off through the switch control unit, which is beneficial to saving power loss. When the switch control unit is activated, the battery voltage is automatically switched to the boost unit for monitoring. When the battery voltage is higher than the set voltage, the capsule endoscope power supply is powered by the battery voltage. When the battery voltage is lower than the set voltage, the boost unit is automatically switched to start the boost circuit, and the boost circuit can continue to maintain the operation of the capsule endoscope.

[0009] The above functional modules are a collection of functional part chips of the capsule, and are also a collection of power consumption generating components.

[0010] The present invention can effectively improve the working time and battery utilization rate of the capsule endoscope and save energy; secondly, during the operation of the capsule endoscope, the sufficiency and stability of the fill light are guaranteed, thus avoiding the problem of poor image quality caused by insufficient fill light.

[0011] The switch control unit includes: an activation circuit, an upper switch tube Q1, a lower switch tube Q2, a pull-up resistor R1, a pull-down resistor R3, a current limiting resistor R2, a current limiting resistor R4 and a filter capacitor C2;

[0012] The activation circuit includes a magnetic sensor U1, a current limiting resistor R5 and a capacitor C1; the first end of the magnetic sensor U1 is connected to the first end of the capacitor C1 and the positive electrode of the battery, the second end of the magnetic sensor U1 is connected to the second end of the capacitor C1 and the negative electrode of the battery and grounded, and the output end of the fourth end of the magnetic sensor U1 is connected to the first end of the current limiting resistor R5;

[0013] The second end of the current limiting resistor R5 is connected to the first end of the filter capacitor C2, the first end of the pull-down resistor R3 and the first end of the lower switch tube Q2, the second end of the lower switch tube Q2 is grounded, and the second end of the filter capacitor C2 and the second end of the pull-down resistor R3 are grounded;

[0014] The first end of the current limiting resistor R4 is connected to the first end of the filter capacitor C2, the first end of the pull-down resistor R3 and the first end of the lower switch tube Q2, and the second end of the current limiting resistor R4 is connected to the main control MCU to realize software control;

[0015] The third end of the lower switch tube Q2 is connected to the second end of the pull-up resistor R1, the second end of the pull-up resistor R1 is connected to the second end of the current limiting resistor R2, and the first end of the pull-up resistor R1 is connected to the positive electrode of the battery;

[0016] The first end of the current limiting resistor R2 is connected to the first end of the upper switch tube Q1, the second end of the upper switch tube Q1 is connected to the positive electrode of the battery, and the third end of the upper switch tube Q1 is the output end of the switch control unit circuit.

[0017] Using the above solution, the process of the switch control unit controlling the power on and off is as follows:

[0018] When the magnetic sensor U1 is within the magnetic field range, the magnetic field strength is greater than the threshold of the magnetic sensor U1, and its fourth output terminal is at a low level. At this time, the current limiting resistor R5 is pulled down, and the first end of the lower switch tube Q2 (NMOS) connected to the current limiting resistor R5 is also pulled down. At this time, the Vgs of the lower switch tube Q2 (NMOS) is less than Vgsth, and the lower switch tube Q2 (NMOS) is not turned on. The third end of the lower switch tube Q2 (NMOS) is connected to the pull-up resistor R1, and the pull-up resistor R1 is connected to the positive electrode of the battery. At this time, the first end of the upper switch tube Q1 (PMOS) is pulled to a high level through the current limiting resistor R2 and the pull-up resistor R1, and the Vgs of the upper switch tube Q1 (PMOS) is greater than Vgsth, and the upper switch tube Q1 (PMOS) is not turned on;

[0019] On the contrary, when the magnetic sensor U1 is not within the magnetic field range, the magnetic field strength is less than the threshold of the magnetic sensor U1, and the fourth end outputs a high level. At this time, the current limiting resistor R5 is pulled to a high level, and the first end of the lower switch tube Q2 (NMOS) connected to the current limiting resistor R5 is also pulled high. At this time, the Vgs of the lower switch tube Q2 (NMOS) is greater than Vgsth, the lower switch tube Q2 (NMOS) is turned on, the third end of the lower switch tube Q2 (NMOS) is connected to the second end of the lower switch Q2 (NMOS) and grounded, and the current limiting resistor R2 connected to the third end of the lower switch tube Q2 (NMOS) is pulled low. At this time, the first end of the upper switch tube Q1 (PMOS) is pulled low through the current limiting resistor R2, the Vgs of the upper switch tube Q1 (PMOS) is less than Vgsth, and the upper switch tube Q1 (PMOS) is turned on.

[0020] As another implementation scheme, the activation circuit includes a photosensor P1 and a current limiting resistor R5, the first end of the photosensor P1 is connected to the positive electrode of the battery, the second end of the photosensor P1 is connected to the first end of the current limiting resistor R5, the second end of the current limiting resistor R5 is connected to the first end of the filter capacitor C2, the first end of the pull-down resistor R3 and the first end of the lower switch tube Q2, the second end of the lower switch tube Q2 is grounded, and the second end of the filter capacitor C2 and the second end of the pull-down resistor R3 are grounded.

[0021] Using the above solution, the process of the switch control unit controlling the power on and off is as follows:

[0022] The current limiting resistor R5 and the pull-down resistor R3 connected to the photosensor P1 together form a voltage divider circuit. The node voltage of the current limiting resistor R5 and the pull-down resistor R3 is the voltage Vgs of the first end of the lower switch tube Q2 (NMOS). When the photosensor P1 is in a lightless or dim environment, the resistance of the photosensor is very large. In this voltage divider circuit, the node voltage Vgs of the current limiting resistor R5 and the pull-down resistor R3 becomes smaller. When the Vgs of the lower switch tube Q2 (NMOS) is less than Vgsth, the lower switch tube Q2 (NMOS) is not turned on, and the third end of the lower switch tube Q2 (NMOS) is connected to the pull-up resistor R1, and the pull-up resistor R1 is connected to the positive electrode of the battery. At this time, the first end of the upper switch tube Q1 (PMOS) is pulled to a high level through the current limiting resistor R2 and the pull-up resistor R1, and the Vgs of the upper switch tube Q1 (PMOS) is greater than Vgsth, and the upper switch tube Q1 (PMOS) is not turned on;

[0023] On the contrary, when the photosensor P1 is in a bright light environment, the resistance of the photosensor P1 decreases with the light intensity. In this voltage divider circuit, the node voltage Vgs of the current limiting resistor R5 and the pull-down resistor R3 increases. When the Vgs of the lower switch tube Q2 (NMOS) is greater than Vgsth, the lower switch tube Q2 (NMOS) is turned on, the third end of the lower switch tube Q2 (NMOS) and the second end of the lower switch Q2 (NMOS) are connected to ground, and the current limiting resistor R2 connected to the third end of the lower switch tube Q2 (NMOS) is pulled down. At this time, the first end of the upper switch tube Q1 (PMOS) is pulled down through the current limiting resistor R2, the Vgs of the upper switch tube Q1 (PMOS) is less than Vgsth, and the upper switch tube Q1 (PMOS) is turned on.

[0024] The lower switch tube Q2 is an NMOS, with a first end as a gate, a second end as a source, and a third end as a drain; the upper switch tube Q1 is a PMOS, with a first end as a gate, a second end as a source, and a third end as a drain.

[0025] The above-mentioned automatic switching boost unit includes: a battery voltage monitoring subcircuit, a switch control subcircuit and a boost unit subcircuit;

[0026] The subcircuit for monitoring the battery voltage includes: a voltage-dividing resistor and a comparator U2 with a reference voltage;

[0027] The voltage-dividing resistor includes: a first resistor R7 and a second resistor R6, wherein a first end of the first resistor R7 is connected to the output end of the switch control unit circuit, i.e., the third end of the upper switch tube Q1, a second end of the first resistor R7 is connected to a first end of the second resistor R6 and an A2 end of a comparator U2 with a reference voltage, a second end of the second resistor R6 is grounded, and an A1 end of the comparator U2 with a reference voltage is an output end of a subcircuit for monitoring battery voltage, and is connected to a first end of a current-limiting resistor R9 of a switch control subcircuit;

[0028] When the node voltage IN+ of the voltage-dividing resistors R7 and R6 (the first resistor R7 and the second resistor R6) is greater than the reference voltage of the reference voltage comparator U2, the output of the A1 terminal of the reference voltage comparator U2 is a high level; when the node voltage IN+ of the voltage-dividing resistors R7 and R6 is less than the reference voltage of the reference voltage comparator U2, the output of the A1 terminal of the reference voltage comparator U2 is a low level.

[0029] The switch control subcircuit includes: a switch tube Q3, a pull-up resistor R8 and a current limiting resistor R9; a first end of the current limiting resistor R9 is connected to the output end of the battery voltage monitoring subcircuit, a second end of the current limiting resistor R9 is connected to the second end of the pull-up resistor R8 and the first end of the switch tube Q3, the first end of the pull-up resistor R8 and the second end of the switch tube Q3 are connected to the output end of the switch control unit circuit, that is, the third end of the upper switch tube Q1, and the third end of the switch tube Q3 is the output end of the switch control subcircuit;

[0030] The switch tube Q3 is a PMOS, a first end is a gate, a second end is a source, and a third end is a drain.

[0031] When the first terminal of the current limiting resistor R9 connected to DCDC_EN is at a high level, the first terminal of the switch tube Q3 maintains a high level, the switch tube Q3 works in the cut-off region, and the third terminal of the switch tube Q3 has no voltage; when the first terminal of the current limiting resistor R9 connected to DCDC_EN is at a low level, the first terminal of the switch tube Q3 becomes a low level, the switch tube Q3 is turned on, and the voltage of the third terminal DCDC_IN of the switch tube Q3 is equal to the voltage BAT_IN of the first terminal of the switch tube Q3.

[0032] The boost unit subcircuit includes: a diode D2, a boost DCDC circuit, a diode D1 and a LDO2;

[0033] The first end of the diode D2 is connected to the output end of the switch control unit circuit, that is, the third end of the upper switch tube Q1, and the second end of the diode D2 is the output end and connected to the functional module;

[0034] The input end of the boost DCDC circuit is connected to the output end of the switch control subcircuit, that is, the third end of the switch tube Q3. The output end of the boost DCDC circuit is connected to the first end of the diode D1. The second end of the diode D1 is the output end of the boost circuit and is connected to the functional module. The input end of LDO2 is connected to the second end of the diode D1, and the output end of LDO2 supplies power to the functional module.

[0035] Using the above solution, the process of automatically switching the boost unit to monitor the battery voltage and boost is as follows:

[0036] The voltage-dividing resistor inputs the node voltage of the first resistor R7 and the second resistor R6 (i.e., the voltage of the battery voltage after being divided by the resistor voltage divider) to the A2 port of the comparator U2 with a reference voltage in real time. The comparator U2 with a reference voltage compares the voltage value received at the A2 port with the internal reference voltage. If the voltage value received at the A2 port of the comparator U2 with a reference voltage is greater than the internal reference voltage of the comparator U2 with a reference voltage, it means that the battery voltage has not been reduced to the set voltage value at this time. At this time, the A1 terminal of the comparator U2 with a reference voltage outputs a high level, the current limiting resistor R9 of the switch control subcircuit is pulled to a high level, and the first terminal of the switch tube Q3 (PMOS) connected to the current limiting resistor R9 is also pulled high. At this time, the Vgs of the switch tube Q3 (PMOS) is greater than Vgsth, and the switch tube Q3 (PMOS) is not turned on; the boost DCDC circuit of the boost unit subcircuit connected to the third terminal of the switch tube Q3 (PMOS) has no power input, so the boost DCDC circuit does not work;

[0037] On the contrary, if the voltage value received by the A2 port of U2 with a reference voltage comparator is less than the internal reference voltage of U2, it means that the battery voltage has been reduced to the set voltage value. At this time, the A1 terminal of the comparator U2 with a reference voltage outputs a low level, the current limiting resistor R9 of the switch control sub-circuit is pulled to a low level, and the first end of the switch tube Q3 (PMOS) connected to the current limiting resistor R9 is also pulled low. At this time, the Vgs of the switch tube Q3 (PMOS) is less than Vgsth, and the switch tube Q3 (PMOS) is turned on; the boost DCDC circuit of the boost unit sub-circuit connected to the third end of the switch tube Q3 (PMOS) has power input, and the boost DCDC circuit starts to enter the boost operation.

[0038] The first end of the diodes D1 and D2 is a positive electrode, and the second end is a negative electrode.

[0039] As another implementation scheme, the battery voltage monitoring subcircuit includes: a voltage dividing resistor, LDO1 and an operational amplifier U3;

[0040] The voltage-dividing resistor includes: a first resistor R7 and a second resistor R6; a first end of the first resistor R7 is connected to the output end of the switch control unit circuit, that is, the third end of the upper switch tube Q1, a second end of the first resistor R7 is connected to the first end of the second resistor R6 and the first end of the operational amplifier U3, a second end of the second resistor R6 is grounded, a third end of the operational amplifier U3 is connected to the output of LDO1, and a fourth end of the operational amplifier U3 is the output end of the battery voltage monitoring subcircuit, connected to the first end of the current limiting resistor R9 of the switch control subcircuit.

[0041] When the node voltage IN+ of the voltage-dividing resistors R7 and R6 (the first resistor R7 and the second resistor R6) is greater than the reference voltage of the operational amplifier U3, that is, the LDO1 output voltage VREF, the fourth terminal output DCDC_EN of the operational amplifier U3 is a high level; when the node voltage IN+ of the voltage-dividing resistors R7 and R6 is less than the reference voltage of the operational amplifier U3, that is, the LDO1 output voltage VREF, the fourth terminal output DCDC_EN of the operational amplifier U3 is a low level.

[0042] Using the above solution, the process of automatically switching the boost unit to monitor the battery voltage and boost is as follows:

[0043] The voltage-dividing resistor inputs the node voltage of the first resistor R7 and the second resistor R6 (i.e., the voltage of the battery voltage after being divided by the resistor voltage divider) to the first end of the operational amplifier U3 in real time. The output end of the LDO1 is used as the operational amplifier reference voltage VREF. The voltage IN+ received by the first end of the operational amplifier U3 is compared with the operational amplifier reference voltage VREF. If the voltage IN+ received by the first end of the operational amplifier U3 is greater than the operational amplifier reference voltage VREF, it means that the battery voltage has not been reduced to the set voltage value at this time. At this time, the fourth end of the operational amplifier U3 outputs a high level, and the current limiting resistor R9 of the switch control sub-circuit connected to the fourth end of the operational amplifier U3 is pulled to a high level. The first end of the switch tube Q3 (PMOS) connected to the current limiting resistor R9 is also pulled high. At this time, the Vgs of the switch tube Q3 (PMOS) is greater than Vgsth, and the switch tube Q3 (PMOS) is not turned on; the boost DCDC circuit of the boost unit sub-circuit connected to the third end of the switch tube Q3 (PMOS) has no power input, so the boost DCDC circuit does not work;

[0044] On the contrary, if the voltage IN+ received by the first terminal of the operational amplifier U3 is less than the operational amplifier reference voltage VREF, it means that the battery voltage has been reduced to the set voltage value at this time. At this time, the fourth terminal of the operational amplifier U3 outputs a low level, and the current limiting resistor R9 of the switch control sub-circuit connected to the fourth terminal of the operational amplifier U3 is pulled to a low level, and the first terminal of the switch tube Q3 (PMOS) connected to the current limiting resistor R9 is also pulled low. At this time, the Vgs of the switch tube Q3 (PMOS) is less than Vgsth, and the switch tube Q3 (PMOS) is turned on; the boost DCDC circuit of the boost unit sub-circuit connected to the third terminal of the switch tube Q3 (PMOS) has power input, and the boost DCDC circuit starts to enter the boost operation.

[0045] The technologies not mentioned in the present invention are all referred to the prior art.

[0046] In the prior art, due to the minimum operating voltage limit of ICs such as CMOS, the battery voltage must be guaranteed to be above 2.6V to maintain the operation of the capsule endoscope. When the battery voltage drops below 2.6V, the capsule endoscope cannot continue to work, and as the battery voltage decreases, the brightness of the fill light gradually dims, which may cause the image quality to deteriorate due to insufficient fill light and result in the risk of missing lesions. The automatic switching boost circuit of the present application can automatically start the boost circuit under conditions lower than the set voltage, so that even if the battery voltage drops below 2.6V, the battery can still maintain the normal operation of the capsule endoscope through the boost circuit, which not only improves the battery energy utilization rate, but also maintains sufficient brightness of the fill light and achieves the purpose of extending the shelf life and use time of the capsule endoscope. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a structural schematic diagram of a capsule endoscope power supply system capable of automatically switching a boost circuit according to the present invention;

[0048] Figure 2 It is a schematic diagram of the structure of the switch control unit of the present invention;

[0049] Figure 3 The structure of the activation circuit of the switch control unit of the present invention is schematically shown. Figure 1 ;

[0050] Figure 4 The structure of the activation circuit of the switch control unit of the present invention is schematically shown. Figure 2 ;

[0051] Figure 5 It is a structural schematic diagram of a boost unit subcircuit of the automatic switching boost unit of the present invention;

[0052] Figure 6 It is a structural schematic diagram of a switch control subcircuit of an automatic switching boost unit of the present invention;

[0053] Figure 7 The structure of the monitoring battery voltage subcircuit of the automatic switching boost unit of the present invention is schematically shown. Figure 1 ;

[0054] Figure 8 The structure of the monitoring battery voltage subcircuit of the automatic switching boost unit of the present invention is schematically shown. Figure 2 ;

[0055] In the figure, 01 is a comparator U2 with a reference voltage, 02 is a voltage-dividing resistor, 03 is a switch control unit, 04 is an activation circuit, 05 is a switch control subcircuit, 06 is a boost unit subcircuit, and 07 is a battery voltage monitoring subcircuit. DETAILED DESCRIPTION

[0056] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0057] Example 1

[0058] Figure 1 As shown, the present invention provides a schematic structural diagram of a capsule endoscope power supply system capable of automatically switching a boost circuit, wherein the capsule endoscope system comprises: a battery, a switch control unit, an automatically switching boost unit and a functional module;

[0059] The battery is used to power the functional modules and to switch the power on and off through the switch control unit, which is beneficial to saving power loss; when the switch control unit is activated, the battery voltage is automatically switched to the boost unit for monitoring, and when the battery voltage is higher than the set voltage, the capsule endoscope power supply is powered by the battery voltage; when the battery voltage is lower than the set voltage, the boost unit is automatically switched to start the boost circuit, and the boost circuit can continue to maintain the operation of the capsule endoscope.

[0060] Figure 2 As shown, the present invention provides a switch control unit circuit, the switch control unit includes: an activation circuit, an upper switch tube Q1, a lower switch tube Q2, a pull-up resistor R1, a pull-down resistor R3, a current limiting resistor R2, a current limiting resistor R4, and a filter capacitor C2;

[0061] The lower switch tube Q2 is an NMOS, the first end is a gate, the second end is a source, and the third end is a drain;

[0062] The upper switch tube Q1 is a PMOS, the first end is a gate, the second end is a source, and the third end is a drain;

[0063] like Figure 3 As shown, the activation circuit includes a magnetic sensor U1, a current limiting resistor R5, and a capacitor C1; the first end of the magnetic sensor U1 is connected to the first end of the capacitor C1 and the positive electrode of the battery, the second end of the magnetic sensor U1 is connected to the second end of the capacitor C1 and the negative electrode of the battery, and the output end of the fourth end of the magnetic sensor U1 is connected to the first end of the current limiting resistor R5;

[0064] exist Figure 2 In the circuit of part 03, the second end of the current limiting resistor R5 is connected to the first end of the filter capacitor C2, the first end of the pull-down resistor R3 and the first end of the lower switch tube Q2, the second end of the lower switch tube Q2 is grounded, and the second end of the filter capacitor C2 and the second end of the pull-down resistor R3 are grounded;

[0065] The first end of the current limiting resistor R4 is connected to the first end of the filter capacitor C2, the first end of the pull-down resistor R3 and the first end of the lower switch tube Q2, and the second end of the current limiting resistor R4 is connected to the main control MCU to realize software control;

[0066] The third end of the lower switch tube Q2 is connected to the second end of the pull-up resistor R1, the second end of the pull-up resistor R1 is connected to the second end of the current limiting resistor R2, and the first end of the pull-up resistor R1 is connected to the positive electrode BAT+ of the battery;

[0067] The first end of the current limiting resistor R2 is connected to the first end of the upper switch tube Q1 , the second end of the upper switch tube Q1 is connected to the positive electrode of the battery, and the third end of the upper switch tube Q1 is the output end BAT_IN of the switch control unit circuit.

[0068] The process of the switch control unit controlling the power on and off is as follows:

[0069] When the magnetic sensor U1 is within the magnetic field range, the magnetic field strength is greater than the threshold of the magnetic sensor U1, and its fourth output terminal is at a low level. At this time, the current limiting resistor R5 is pulled down, and the first end of the lower switch tube Q2 (NMOS) connected to the current limiting resistor R5 is also pulled down. At this time, the Vgs of the lower switch tube Q2 (NMOS) is less than Vgsth, and the lower switch tube Q2 (NMOS) is not turned on. The third end of the lower switch tube Q2 (NMOS) is connected to the pull-up resistor R1, and the pull-up resistor R1 is connected to the positive electrode of the battery. At this time, the first end of the upper switch tube Q1 (PMOS) is pulled to a high level through the current limiting resistor R2 and the pull-up resistor R1, and the Vgs of the upper switch tube Q1 (PMOS) is greater than Vgsth, and the upper switch tube Q1 (PMOS) is not turned on;

[0070] On the contrary, when the magnetic sensor U1 is not within the magnetic field range, the magnetic field strength is less than the threshold of the magnetic sensor U1, and the fourth end outputs a high level. At this time, the current limiting resistor R5 is pulled to a high level, and the first end of the lower switch tube Q2 (NMOS) connected to the current limiting resistor R5 is also pulled high. At this time, the Vgs of the lower switch tube Q2 (NMOS) is greater than Vgsth, the lower switch tube Q2 (NMOS) is turned on, the third end of the lower switch tube Q2 (NMOS) is connected to the second end of the lower switch Q2 (NMOS) and grounded, and the current limiting resistor R2 connected to the third end of the lower switch tube Q2 (NMOS) is pulled low. At this time, the first end of the upper switch tube Q1 (PMOS) is pulled low through the current limiting resistor R2, the Vgs of the upper switch tube Q1 (PMOS) is less than Vgsth, and the upper switch tube Q1 (PMOS) is turned on.

[0071] Reference Figure 5 , Figure 6 , Figure 7 , Figure 8 The present invention provides an automatic switching boost unit circuit, which includes: a battery voltage monitoring subcircuit, a switch control subcircuit, and a boost unit subcircuit.

[0072] like Figure 7, the battery voltage monitoring subcircuit includes: a voltage dividing resistor, a comparator U2 with a reference voltage;

[0073] exist Figure 7 On the basis of, the voltage dividing resistor includes: a first resistor R7 and a second resistor R6, the first end of the first resistor R7 is connected to the output end of the switch control unit circuit, that is, the third end of the upper switch tube Q1, the second end of the first resistor R7 is connected to the first end of the second resistor R6 and the A2 end of the comparator U2 with a reference voltage, the second end of the second resistor R6 is grounded, and the A1 end of the comparator U2 with a reference voltage is the output end of the battery voltage monitoring subcircuit, connected to the first end of the current limiting resistor R9 of the switch control subcircuit;

[0074] When the voltage IN+ at the node between the voltage-dividing resistors R7 and R6 is greater than the reference voltage of the reference voltage comparator U2, the output of the A1 terminal of the reference voltage comparator U2 is a high level; when the voltage IN+ at the node between the voltage-dividing resistors R7 and R6 is less than the reference voltage of the reference voltage comparator U2, the output of the A1 terminal of the reference voltage comparator U2 is a low level.

[0075] like Figure 6 , the switch control subcircuit includes: a switch tube Q3, a pull-up resistor R8, and a current limiting resistor R9; the first end of the current limiting resistor R9 is connected to the output end DCDC_EN of the monitoring battery voltage subcircuit, the second end of the current limiting resistor R9 is connected to the second end of the pull-up resistor R8 and the first end of the switch tube Q3, the first end of the pull-up resistor R8 and the second end of the switch tube Q3 are connected to the output end BAT_IN of the above-mentioned switch control unit circuit, that is, the third end of the upper switch tube Q1, and the third end of the switch tube Q3 is the output end DCDC_IN of the switch control subcircuit;

[0076] The switch tube Q3 is a PMOS, the first end is a gate, the second end is a source, and the third end is a drain;

[0077] When the first terminal of the current limiting resistor R9 connected to DCDC_EN is at a high level, the first terminal of the switch tube Q3 maintains a high level, the switch tube Q3 works in the cut-off region, and the third terminal of the switch tube Q3 has no voltage; when the first terminal of the current limiting resistor R9 connected to DCDC_EN is at a low level, the first terminal of the switch tube Q3 becomes a low level, the switch tube Q3 is turned on, and the voltage of the third terminal DCDC_IN of the switch tube Q3 is equal to the voltage BAT_IN of the first terminal of the switch tube Q3.

[0078] like Figure 5 , the boost unit sub-circuit includes: a diode D2, a boost DCDC circuit, a diode D1, and an LDO2;

[0079] The first end of the diode D2 is connected to the output end of the switch control unit circuit, that is, the third end of the upper switch tube Q1, and the second end of the diode D2 is the output end VDD;

[0080] The input end of the boost DCDC circuit is connected to the output end DCDC_IN of the switch control subcircuit, i.e., the third end of the switch tube Q3. The output end of the boost DCDC circuit is connected to the first end of the diode D1. The second end of the diode D1 is the output end VDD of the boost circuit. The input end of LDO2 is connected to the second end of the diode D1, i.e., VDD. The output end of LDO2 is used to power the functional module. In this example, it is assumed that the output is 1.8V, but it is not limited to this voltage value, and it can also be other voltage values ​​or multiple voltage values.

[0081] The process of automatically switching the boost unit to monitor the battery voltage and boost is as follows:

[0082] The voltage-dividing resistor inputs the node voltage of the first resistor R7 and the second resistor R6 (i.e., the voltage of the battery voltage after being divided by the resistor voltage divider) to the A2 port of the comparator U2 with a reference voltage in real time. The comparator U2 with a reference voltage compares the voltage value received at the A2 port with the internal reference voltage. If the voltage value received at the A2 port of the comparator U2 with a reference voltage is greater than the internal reference voltage of the comparator U2 with a reference voltage, it means that the battery voltage has not been reduced to the set voltage value at this time. At this time, the A1 terminal of the comparator U2 with a reference voltage outputs a high level, the current limiting resistor R9 of the switch control subcircuit is pulled to a high level, and the first terminal of the switch tube Q3 (PMOS) connected to the current limiting resistor R9 is also pulled high. At this time, the Vgs of the switch tube Q3 (PMOS) is greater than Vgsth, and the switch tube Q3 (PMOS) is not turned on; the boost DCDC circuit of the boost unit subcircuit connected to the third terminal of the switch tube Q3 (PMOS) has no power input, so the boost DCDC circuit does not work;

[0083] On the contrary, if the voltage value received by the A2 port of U2 with a reference voltage comparator is less than the internal reference voltage of U2, it means that the battery voltage has been reduced to the set voltage value. At this time, the A1 terminal of the comparator U2 with a reference voltage outputs a low level, the current limiting resistor R9 of the switch control sub-circuit is pulled to a low level, and the first end of the switch tube Q3 (PMOS) connected to the current limiting resistor R9 is also pulled low. At this time, the Vgs of the switch tube Q3 (PMOS) is less than Vgsth, and the switch tube Q3 (PMOS) is turned on; the boost DCDC circuit of the boost unit sub-circuit connected to the third end of the switch tube Q3 (PMOS) has power input, and the boost DCDC circuit starts to enter the boost operation.

[0084] Example 2

[0085] The difference from Example 1 is that: Figure 4As shown, the activation circuit includes a photosensor P1 and a current limiting resistor R5, the first end of the photosensor P1 is connected to the positive electrode of the battery, the second end of the photosensor P1 is connected to the first end of the current limiting resistor R5, the second end of the current limiting resistor R5 is connected to the first end of the filter capacitor C2, the first end of the pull-down resistor R3 and the first end of the lower switch tube Q2, the second end of the lower switch tube Q2 is grounded, and the second end of the filter capacitor C2 and the second end of the pull-down resistor R3 are grounded. The rest are all referred to Example 1.

[0086] The process of the switch control unit controlling the power on and off is as follows:

[0087] The current limiting resistor R5 and the pull-down resistor R3 connected to the photosensor P1 together form a voltage divider circuit. The node voltage of the current limiting resistor R5 and the pull-down resistor R3 is the voltage Vgs of the first end of the lower switch tube Q2 (NMOS). When the photosensor P1 is in a lightless or dim environment, the resistance of the photosensor is very large. In this voltage divider circuit, the node voltage Vgs of the current limiting resistor R5 and the pull-down resistor R3 becomes smaller. When the Vgs of the lower switch tube Q2 (NMOS) is less than Vgsth, the lower switch tube Q2 (NMOS) is not turned on, and the third end of the lower switch tube Q2 (NMOS) is connected to the pull-up resistor R1, and the pull-up resistor R1 is connected to the positive electrode of the battery. At this time, the first end of the upper switch tube Q1 (PMOS) is pulled to a high level through the current limiting resistor R2 and the pull-up resistor R1, and the Vgs of the upper switch tube Q1 (PMOS) is greater than Vgsth, and the upper switch tube Q1 (PMOS) is not turned on;

[0088] On the contrary, when the photosensor P1 is in a bright light environment, the resistance of the photosensor P1 decreases with the light intensity. In this voltage divider circuit, the node voltage Vgs of the current limiting resistor R5 and the pull-down resistor R3 increases. When the Vgs of the lower switch tube Q2 (NMOS) is greater than Vgsth, the lower switch tube Q2 (NMOS) is turned on, the third end of the lower switch tube Q2 (NMOS) and the second end of the lower switch Q2 (NMOS) are connected to ground, and the current limiting resistor R2 connected to the third end of the lower switch tube Q2 (NMOS) is pulled down. At this time, the first end of the upper switch tube Q1 (PMOS) is pulled down through the current limiting resistor R2, the Vgs of the upper switch tube Q1 (PMOS) is less than Vgsth, and the upper switch tube Q1 (PMOS) is turned on.

[0089] Example 3

[0090] The difference from Example 1 is that: Figure 8 , the battery voltage monitoring subcircuit includes: a voltage dividing resistor, LDO1, and an operational amplifier U3;

[0091] exist Figure 8On the basis of, the voltage dividing resistor includes: a first resistor R7 and a second resistor R6; the first end of the first resistor R7 is connected to the output end of the switch control unit circuit, that is, the third end of the upper switch tube Q1, the second end of the first resistor R7 is connected to the first end of the second resistor R6 and the first end of the operational amplifier U3, the second end of the second resistor R6 is grounded, the third end of the operational amplifier U3 is connected to the LDO output, and the fourth end of the operational amplifier U3 is the output end of the battery voltage monitoring subcircuit, connected to the first end of the current limiting resistor R9 of the switch control subcircuit;

[0092] same Figure 7 According to the principle in the embodiment, when the voltage IN+ of the node of the voltage-dividing resistors R7 and R6 is greater than the reference voltage of the operational amplifier U3, that is, the output voltage VREF of LDO1, the fourth terminal of the operational amplifier U3 outputs DCDC_EN at a high level; when the voltage IN+ of the node of the voltage-dividing resistors R7 and R6 is less than the reference voltage of the operational amplifier U3, that is, the output voltage VREF of LDO1, the fourth terminal of the operational amplifier U3 outputs DCDC_EN at a low level. The rest are all referred to Example 1.

[0093] The process of automatically switching the boost unit to monitor the battery voltage and boost is as follows:

[0094] The voltage-dividing resistor inputs the node voltage of the first resistor R7 and the second resistor R6 (i.e., the voltage of the battery voltage after being divided by the resistor voltage divider) to the first end of the operational amplifier U3 in real time. The output end of the LDO1 is used as the operational amplifier reference voltage VREF. The voltage IN+ received by the first end of the operational amplifier U3 is compared with the operational amplifier reference voltage VREF. If the voltage IN+ received by the first end of the operational amplifier U3 is greater than the operational amplifier reference voltage VREF, it means that the battery voltage has not been reduced to the set voltage value at this time. At this time, the fourth end of the operational amplifier U3 outputs a high level, and the current limiting resistor R9 of the switch control sub-circuit connected to the fourth end of the operational amplifier U3 is pulled to a high level. The first end of the switch tube Q3 (PMOS) connected to the current limiting resistor R9 is also pulled high. At this time, the Vgs of the switch tube Q3 (PMOS) is greater than Vgsth, and the switch tube Q3 (PMOS) is not turned on; the boost DCDC circuit of the boost unit sub-circuit connected to the third end of the switch tube Q3 (PMOS) has no power input, so the boost DCDC circuit does not work;

[0095] On the contrary, if the voltage IN+ received by the first terminal of the operational amplifier U3 is less than the operational amplifier reference voltage VREF, it means that the battery voltage has been reduced to the set voltage value at this time. At this time, the fourth terminal of the operational amplifier U3 outputs a low level, and the current limiting resistor R9 of the switch control sub-circuit connected to the fourth terminal of the operational amplifier U3 is pulled to a low level, and the first terminal of the switch tube Q3 (PMOS) connected to the current limiting resistor R9 is also pulled low. At this time, the Vgs of the switch tube Q3 (PMOS) is less than Vgsth, and the switch tube Q3 (PMOS) is turned on; the boost DCDC circuit of the boost unit sub-circuit connected to the third terminal of the switch tube Q3 (PMOS) has power input, and the boost DCDC circuit starts to enter the boost operation.

[0096] In order to facilitate understanding of the effects of the present invention, further supplementary explanation is given below with specific examples, but the uses and effects of the present invention are not limited thereto.

[0097] Take the lithium manganese dioxide battery mentioned above, model CR9885, 120mAh as an example. When the battery is continuously discharged at a total power consumption of 12mA, if there is no automatic switching boost unit, the cut-off voltage is 2.6V (IC minimum operating voltage). In theory, the capsule endoscope can be kept running for 10 hours, but the brightness of the fill light is insufficient in the second half of the time. The actual high-quality image is only in the first 6 hours of working time. Moreover, the remaining battery power is below 2.6V, about 25mAh, and cannot be used any more. If an automatic switching boost unit is added, the minimum operating voltage of the boost chip is 0.5V, and the setting voltage is 0.5V. When the battery voltage is lower than 2.85V, the boost circuit is automatically started. At this time, even if the battery voltage drops below 2.6V, the battery can still continue to maintain the normal operation of the capsule endoscope through the boost circuit until the battery voltage is lower than 0.5V. The life of the capsule endoscope (the length of time for obtaining high-quality images) is extended from 6 hours to more than 12 hours, and it is ensured that the brightness of the fill light will not dim due to the reduction of battery voltage, ensuring high-quality generation of images during the life cycle of the capsule endoscope. Compared with not adding an automatic switching boost unit, the life is extended by more than 6 hours while ensuring high-quality image production.

Claims

1. A capsule endoscope power supply system capable of automatically switching a boost circuit, characterized in that: include: Battery, switch control unit, automatic switching boost unit and functional modules; The battery is used to power the functional module and to switch the power on and off through the switch control unit; when the switch control unit is activated, the battery voltage is automatically switched to the boost unit for monitoring. When the battery voltage is higher than the set voltage, the capsule endoscope power supply is powered by the battery voltage; when the battery voltage is lower than the set voltage, the boost unit is automatically switched to start the boost circuit.

2. The capsule endoscope power supply system capable of automatically switching the boost circuit according to claim 1, characterized in that: The switch control unit includes: an activation circuit, an upper switch tube Q1, a lower switch tube Q2, a pull-up resistor R1, a pull-down resistor R3, a current limiting resistor R2, a current limiting resistor R4 and a filter capacitor C2; The activation circuit includes a magnetic sensor U1, a current limiting resistor R5 and a capacitor C1; the first end of the magnetic sensor U1 is connected to the first end of the capacitor C1 and the positive electrode of the battery, the second end of the magnetic sensor U1 is connected to the second end of the capacitor C1 and the negative electrode of the battery and grounded, and the output end of the fourth end of the magnetic sensor U1 is connected to the first end of the current limiting resistor R5; The second end of the current limiting resistor R5 is connected to the first end of the filter capacitor C2, the first end of the pull-down resistor R3 and the first end of the lower switch tube Q2, the second end of the lower switch tube Q2 is grounded, and the second end of the filter capacitor C2 and the second end of the pull-down resistor R3 are grounded; The first end of the current limiting resistor R4 is connected to the first end of the filter capacitor C2, the first end of the pull-down resistor R3 and the first end of the lower switch tube Q2, and the second end of the current limiting resistor R4 is connected to the main control MCU to realize software control; The third end of the lower switch tube Q2 is connected to the second end of the pull-up resistor R1, the second end of the pull-up resistor R1 is connected to the second end of the current limiting resistor R2, and the first end of the pull-up resistor R1 is connected to the positive electrode of the battery; The first end of the current limiting resistor R2 is connected to the first end of the upper switch tube Q1, the second end of the upper switch tube Q1 is connected to the positive electrode of the battery, and the third end of the upper switch tube Q1 is the output end of the switch control unit circuit.

3. The capsule endoscope power supply system capable of automatically switching the boost circuit according to claim 2, characterized in that: The process of the switch control unit controlling the power on and off is as follows: When the magnetic sensor U1 is within the magnetic field range, the magnetic field strength is greater than the threshold of the magnetic sensor U1, and its fourth output terminal is at a low level. At this time, the current limiting resistor R5 is pulled down, and the first end of the lower switch tube Q2 (NMOS) connected to the current limiting resistor R5 is also pulled down. At this time, the Vgs of the lower switch tube Q2 (NMOS) is less than Vgsth, and the lower switch tube Q2 (NMOS) is not turned on. The third end of the lower switch tube Q2 (NMOS) is connected to the pull-up resistor R1, and the pull-up resistor R1 is connected to the positive electrode of the battery. At this time, the first end of the upper switch tube Q1 (PMOS) is pulled to a high level through the current limiting resistor R2 and the pull-up resistor R1, and the Vgs of the upper switch tube Q1 (PMOS) is greater than Vgsth, and the upper switch tube Q1 (PMOS) is not turned on; On the contrary, when the magnetic sensor U1 is not within the magnetic field range, the magnetic field strength is less than the threshold of the magnetic sensor U1, and the fourth end outputs a high level. At this time, the current limiting resistor R5 is pulled to a high level, and the first end of the lower switch tube Q2 (NMOS) connected to the current limiting resistor R5 is also pulled high. At this time, the Vgs of the lower switch tube Q2 (NMOS) is greater than Vgsth, the lower switch tube Q2 (NMOS) is turned on, the third end of the lower switch tube Q2 (NMOS) is connected to the second end of the lower switch Q2 (NMOS) and grounded, and the current limiting resistor R2 connected to the third end of the lower switch tube Q2 (NMOS) is pulled low. At this time, the first end of the upper switch tube Q1 (PMOS) is pulled low through the current limiting resistor R2, the Vgs of the upper switch tube Q1 (PMOS) is less than Vgsth, and the upper switch tube Q1 (PMOS) is turned on.

4. The capsule endoscope power supply system capable of automatically switching the boost circuit according to claim 2, characterized in that: The activation circuit includes a photosensor P1 and a current limiting resistor R5, wherein the first end of the photosensor P1 is connected to the positive electrode of the battery, the second end of the photosensor P1 is connected to the first end of the current limiting resistor R5, the second end of the current limiting resistor R5 is connected to the first end of the filter capacitor C2, the first end of the pull-down resistor R3 and the first end of the lower switch tube Q2, the second end of the lower switch tube Q2 is grounded, and the second end of the filter capacitor C2 and the second end of the pull-down resistor R3 are grounded.

5. The capsule endoscope power supply system capable of automatically switching the boost circuit according to claim 4 is characterized in that: The process of the switch control unit controlling the power on and off is as follows: The current limiting resistor R5 and the pull-down resistor R3 connected to the photosensor P1 together form a voltage divider circuit. The node voltage of the current limiting resistor R5 and the pull-down resistor R3 is the voltage Vgs of the first end of the lower switch tube Q2 (NMOS). When the photosensor P1 is in a lightless or dim environment, the resistance of the photosensor is very large. In this voltage divider circuit, the node voltage Vgs of the current limiting resistor R5 and the pull-down resistor R3 becomes smaller. When the Vgs of the lower switch tube Q2 (NMOS) is less than Vgsth, the lower switch tube Q2 (NMOS) is not turned on, and the third end of the lower switch tube Q2 (NMOS) is connected to the pull-up resistor R1, and the pull-up resistor R1 is connected to the positive electrode of the battery. At this time, the first end of the upper switch tube Q1 (PMOS) is pulled to a high level through the current limiting resistor R2 and the pull-up resistor R1, and the Vgs of the upper switch tube Q1 (PMOS) is greater than Vgsth, and the upper switch tube Q1 (PMOS) is not turned on; On the contrary, when the photosensor P1 is in a bright light environment, the resistance of the photosensor P1 decreases with the light intensity. In this voltage divider circuit, the node voltage Vgs of the current limiting resistor R5 and the pull-down resistor R3 increases. When the Vgs of the lower switch tube Q2 (NMOS) is greater than Vgsth, the lower switch tube Q2 (NMOS) is turned on, the third end of the lower switch tube Q2 (NMOS) and the second end of the lower switch Q2 (NMOS) are connected to ground, and the current limiting resistor R2 connected to the third end of the lower switch tube Q2 (NMOS) is pulled down. At this time, the first end of the upper switch tube Q1 (PMOS) is pulled down through the current limiting resistor R2, the Vgs of the upper switch tube Q1 (PMOS) is less than Vgsth, and the upper switch tube Q1 (PMOS) is turned on.

6. The capsule endoscope power supply system capable of automatically switching the boost circuit according to any one of claims 2 to 5, characterized in that: The automatic switching boost unit includes: a battery voltage monitoring subcircuit, a switch control subcircuit and a boost unit subcircuit; The subcircuit for monitoring the battery voltage includes: a voltage-dividing resistor and a comparator U2 with a reference voltage; The voltage-dividing resistor includes: a first resistor R7 and a second resistor R6, wherein a first end of the first resistor R7 is connected to the output end of the switch control unit circuit, i.e., the third end of the upper switch tube Q1, a second end of the first resistor R7 is connected to a first end of the second resistor R6 and an A2 end of a comparator U2 with a reference voltage, a second end of the second resistor R6 is grounded, and an A1 end of the comparator U2 with a reference voltage is an output end of a subcircuit for monitoring battery voltage, and is connected to a first end of a current-limiting resistor R9 of a switch control subcircuit; The switch control subcircuit includes: a switch tube Q3, a pull-up resistor R8 and a current limiting resistor R9; a first end of the current limiting resistor R9 is connected to the output end of the battery voltage monitoring subcircuit, a second end of the current limiting resistor R9 is connected to the second end of the pull-up resistor R8 and the first end of the switch tube Q3, the first end of the pull-up resistor R8 and the second end of the switch tube Q3 are connected to the output end of the switch control unit circuit, that is, the third end of the upper switch tube Q1, and the third end of the switch tube Q3 is the output end of the switch control subcircuit; The boost unit subcircuit includes: a diode D2, a boost DCDC circuit, a diode D1 and a LDO2; The first end of the diode D2 is connected to the output end of the switch control unit circuit, that is, the third end of the upper switch tube Q1, and the second end of the diode D2 is the output end and connected to the functional module; The input end of the boost DCDC circuit is connected to the output end of the switch control subcircuit, that is, the third end of the switch tube Q3. The output end of the boost DCDC circuit is connected to the first end of the diode D1. The second end of the diode D1 is the output end of the boost circuit and is connected to the functional module. The input end of LDO2 is connected to the second end of the diode D1, and the output end of LDO2 supplies power to the functional module.

7. The capsule endoscope power supply system capable of automatically switching the boost circuit according to claim 6, characterized in that: The process of automatically switching the boost unit to monitor the battery voltage and boost is as follows: The voltage-dividing resistor inputs the node voltage of the first resistor R7 and the second resistor R6 (i.e., the voltage of the battery voltage after being divided by the resistor voltage divider) to the A2 port of the comparator U2 with a reference voltage in real time. The comparator U2 with a reference voltage compares the voltage value received at the A2 port with the internal reference voltage. If the voltage value received at the A2 port of the comparator U2 with a reference voltage is greater than the internal reference voltage of the comparator U2 with a reference voltage, it means that the battery voltage has not been reduced to the set voltage value at this time. At this time, the A1 terminal of the comparator U2 with a reference voltage outputs a high level, the current limiting resistor R9 of the switch control subcircuit is pulled to a high level, and the first terminal of the switch tube Q3 (PMOS) connected to the current limiting resistor R9 is also pulled high. At this time, the Vgs of the switch tube Q3 (PMOS) is greater than Vgsth, and the switch tube Q3 (PMOS) is not turned on; the boost DCDC circuit of the boost unit subcircuit connected to the third terminal of the switch tube Q3 (PMOS) has no power input, so the boost DCDC circuit does not work; On the contrary, if the voltage value received by the A2 port of U2 with a reference voltage comparator is less than the internal reference voltage of U2, it means that the battery voltage has been reduced to the set voltage value. At this time, the A1 terminal of the comparator U2 with a reference voltage outputs a low level, the current limiting resistor R9 of the switch control sub-circuit is pulled to a low level, and the first end of the switch tube Q3 (PMOS) connected to the current limiting resistor R9 is also pulled low. At this time, the Vgs of the switch tube Q3 (PMOS) is less than Vgsth, and the switch tube Q3 (PMOS) is turned on; the boost DCDC circuit of the boost unit sub-circuit connected to the third end of the switch tube Q3 (PMOS) has power input, and the boost DCDC circuit starts to enter the boost operation.

8. The capsule endoscope power supply system capable of automatically switching the boost circuit according to any one of claims 2 to 5, characterized in that: The battery voltage monitoring subcircuit includes: voltage divider resistor, LDO1 and operational amplifier U3; The voltage-dividing resistor includes: a first resistor R7 and a second resistor R6; a first end of the first resistor R7 is connected to the output end of the switch control unit circuit, that is, the third end of the upper switch tube Q1, a second end of the first resistor R7 is connected to the first end of the second resistor R6 and the first end of the operational amplifier U3, a second end of the second resistor R6 is grounded, a third end of the operational amplifier U3 is connected to the output of LDO1, and a fourth end of the operational amplifier U3 is the output end of the battery voltage monitoring subcircuit, connected to the first end of the current limiting resistor R9 of the switch control subcircuit.

9. The capsule endoscope power supply system capable of automatically switching the boost circuit according to claim 8, characterized in that: The process of automatically switching the boost unit to monitor the battery voltage and boost is as follows: The voltage-dividing resistor inputs the node voltage of the first resistor R7 and the second resistor R6 (i.e., the voltage of the battery voltage after being divided by the resistor voltage divider) to the first end of the operational amplifier U3 in real time. The output end of the LDO1 is used as the operational amplifier reference voltage VREF. The voltage IN+ received by the first end of the operational amplifier U3 is compared with the operational amplifier reference voltage VREF. If the voltage IN+ received by the first end of the operational amplifier U3 is greater than the operational amplifier reference voltage VREF, it means that the battery voltage has not been reduced to the set voltage value at this time. At this time, the fourth end of the operational amplifier U3 outputs a high level, and the current limiting resistor R9 of the switch control sub-circuit connected to the fourth end of the operational amplifier U3 is pulled to a high level. The first end of the switch tube Q3 (PMOS) connected to the current limiting resistor R9 is also pulled high. At this time, the Vgs of the switch tube Q3 (PMOS) is greater than Vgsth, and the switch tube Q3 (PMOS) is not turned on; the boost DCDC circuit of the boost unit sub-circuit connected to the third end of the switch tube Q3 (PMOS) has no power input, so the boost DCDC circuit does not work; On the contrary, if the voltage IN+ received by the first terminal of the operational amplifier U3 is less than the operational amplifier reference voltage VREF, it means that the battery voltage has been reduced to the set voltage value at this time. At this time, the fourth terminal of the operational amplifier U3 outputs a low level, and the current limiting resistor R9 of the switch control sub-circuit connected to the fourth terminal of the operational amplifier U3 is pulled to a low level, and the first terminal of the switch tube Q3 (PMOS) connected to the current limiting resistor R9 is also pulled low. At this time, the Vgs of the switch tube Q3 (PMOS) is less than Vgsth, and the switch tube Q3 (PMOS) is turned on; the boost DCDC circuit of the boost unit sub-circuit connected to the third terminal of the switch tube Q3 (PMOS) has power input, and the boost DCDC circuit starts to enter the boost operation.

Images