Charging input and electrical stimulation output multiplexing circuit

Abstract

The invention discloses a charging input and electrical stimulation output multiplexing circuit which comprises a first input terminal, a second input terminal, an electrical stimulation output circuit and a charging input circuit. A common electric plate wire or a magnetic charging wire can be input between the first input terminal and the second input terminal; in other words, one port can be used as charging input and can also be used as electrical stimulation output. A Hall switch U1 is adopted, and high and low levels are output by the Hall switch, so that charging and electrical stimulation can share one port. The switching effect of the Hall switch is controlled by utilizing whether the charging magnetic attraction line and the common electrode line have magnetic force or not, so that an electrical stimulation output circuit is not influenced during charging, and a charging loop is not influenced during normal electrical stimulation output.

Description

Technical Field

[0001] The present invention relates to the field of electrical stimulation therapy of wearable medical devices, and in particular to a charging input and electrical stimulation output multiplexing circuit. Background Art

[0002] In the field of electrical stimulation therapy for wearable medical devices, the charging port and the electrical stimulation port are independent of each other in current wired charging wearable medical devices. Such products have many defects: First, the complexity of the product increases. Multiple ports not only damage the appearance, but also increase the size and weight of the product, greatly reducing the wearability and portability. Second, reliability and safety are reduced. Multiple ports make the mechanical structure more complex, the ports are easily damaged by external forces, and the existence of multiple ports brings greater difficulties to waterproof design. Third, the difficulty of structural design increases. Engineers need to take into account the structural design of two independent ports at the same time to meet the functional and performance requirements of the product, which undoubtedly increases the difficulty and challenge of design.

[0003] Therefore, in view of such situations, it is necessary to design a circuit in which charging and electrical stimulation share one port in a portable electrical stimulation product. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a charging input and electrical stimulation output port multiplexing circuit, that is, one port can be used as a charging input and also as an electrical stimulation output.

[0005] The technical solution of the present invention is: a charging input and electric stimulation output multiplexing circuit, comprising a first input terminal, a second input terminal, an electric stimulation output circuit and a charging input circuit; a common electric plate line or a magnetic charging line can be input between the first input terminal and the second input terminal;

[0006] The electrical stimulation output circuit includes a first stimulation output terminal, a second stimulation output terminal, an ADC collector, a current sensing amplifier U3, a current limiting resistor R1, a DC blocking capacitor C1, a current limiting resistor R2 and a DC blocking capacitor C2; one end of the current limiting resistor R1 is connected to the first stimulation output terminal, and the other end is connected to one end of the DC blocking capacitor C1, and the other end of the DC blocking capacitor C1 is connected to the first input terminal; one end of the current limiting resistor R2 is connected to the second stimulation output terminal, and the other end is connected to one end of the DC blocking capacitor C2, and the other end of the DC blocking capacitor C2 is connected to the second input terminal; the positive and negative input terminals of the current sensing amplifier U3 are respectively connected to the two ends of the current limiting resistor R1, and the output end of the current sensing amplifier U3 is connected to the ADC collector;

[0007] When a common electric line is input between the first input terminal and the second input terminal and the product is attached to the skin, the skin is equivalent to a load, and the constant current source passes through the current limiting resistor R1, the DC blocking capacitor C1 and the load, and then passes through the DC blocking capacitor C2 and the current limiting resistor R2 to return to the input, and the output waveform is a positive square wave; the constant current source passes through the current limiting resistor R2, the DC blocking capacitor C2 and the load, and then passes through the DC blocking capacitor C1 and the current limiting resistor R1 to return to the input, and the output waveform is a negative square wave; the voltage across the current limiting resistor R1 is collected by the current sensing amplifier U3, and when the collected current is less than 0.1mA, it is judged that the load has fallen off and the stimulation output is stopped;

[0008] The charging input circuit includes a low-power Hall switch U1, a power supply, a current limiting resistor R4, a MOS tube Q1, a MOS tube Q2, an optocoupler U2, a pull-down resistor R7, a current limiting resistor R8 and a pull-down resistor R3; the output end of the low-power Hall switch U1 is connected to one end of the current limiting resistor R4, and the other end of the current limiting resistor R4 is respectively connected to the gate of the MOS tube Q1 and the gate of the MOS tube Q2; the gate of the MOS tube Q1 is grounded through the pull-down resistor R7, the source of the MOS tube Q1 is grounded, and the drain of the MOS tube Q1 is connected to the cathode of the light-emitting diode of the optocoupler U2; the anode of the light-emitting diode of the optocoupler U2 is connected to the positive electrode of the power supply through the current limiting resistor R8, the collector of the triode of the optocoupler U2 is connected to the first input terminal, and the emitter of the triode of the optocoupler U2 is connected to the positive electrode of the 5V voltage; the gate of the MOS tube Q2 is grounded through the pull-down resistor R3, the source of the MOS tube Q2 is grounded, and the drain of the MOS tube Q2 is connected to the second input terminal;

[0009] When there is no magnetic force input, the output end of the low-power Hall switch U1 outputs a low level, and the voltage across the gate source of the MOS tube Q1 is pulled to 0 by the pull-down resistor R7, which is less than the threshold voltage, and the MOS tube Q1 is turned off; similarly, the voltage across the gate source of the MOS tube Q2 is pulled to 0 by the pull-down resistor R3, which is less than the threshold voltage, and the MOS tube Q2 is turned off; when the MOS tube Q1 is turned off, the light-emitting diode of the optocoupler U2 is turned off, and then the triode of the optocoupler U2 is turned off;

[0010] When the magnetic charging line is input, the low-power Hall switch U1 detects the magnetic field and outputs a high level, and then the high level passes through the current limiting resistor R4 and is input to the gate of the MOS tube Q1 and the MOS tube Q2. Then the voltage across the gate source of the MOS tube Q1 and the MOS tube Q2 is greater than the threshold voltage, and the drain and source of the MOS tube Q1 and the MOS tube Q2 are turned on; then the positive electrode of the power supply passes through the current limiting resistor R8 and the optocoupler U2 to the ground, and the light-emitting diode of the optocoupler U2 lights up, and the light-emitting diode emits light to turn on the collector and emitter of the transistor of the optocoupler U2, and the 5V at the emitter end is input to the subsequent circuit through the optocoupler U2; at the same time, the cathode of the light-emitting diode of the optocoupler U2 is grounded and turned on by the mainboard ground, and charging starts randomly.

[0011] Furthermore, the power source is a lithium battery.

[0012] Furthermore, when there is no magnetic force input, the power consumption of the low-power Hall switch U1 is less than 10uA, thus ensuring the low power consumption of the circuit.

[0013] The beneficial effects of the present invention are:

[0014] The present invention adopts a Hall switch U1, and uses the high and low levels of the Hall switch output to realize that charging and electrical stimulation can share a port. That is, the switching effect of the Hall switch is controlled by whether the charging magnetic wire and the ordinary electrode wire carry magnetic force, so that the electrical stimulation output circuit is not affected during charging, and the charging circuit is not affected during normal electrical stimulation output.

[0015] The present invention uses a current sensing amplifier U3 to determine whether the load is off by collecting the current at both ends of R1. If the load is off, the electrical stimulation stops. This function can prevent the charging circuit and the electrical stimulation output circuit from affecting each other and causing circuit abnormalities.

[0016] The present invention adopts an optocoupler U2 and an NMOS tube Q2, wherein the withstand voltage across the drain and source of Q2 is 60V, and the withstand voltage across the collector and emitter of the optocoupler is 80V, that is, when the electric stimulation works normally, the charging circuit can allow the electric stimulation output voltage to be output at a maximum of 60V, and this maximum output voltage can be determined according to the withstand voltage of the selected device. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is the overall schematic diagram of the circuit;

[0018] Figure 2 This is a schematic diagram of the charging input principle;

[0019] Figure 3 Schematic diagram of the electrical stimulation output principle;

[0020] Figure 4 Schematic diagram of electrical stimulation output waveform. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with the accompanying drawings.

[0022] like Figure 1 As shown, a charging input and electrical stimulation output multiplexing circuit includes a first input terminal 01, a second input terminal 02, an electrical stimulation output circuit 03 and a charging input circuit 04. A common electric plate line or a magnetic charging line can be input between the first input terminal 01 and the second input terminal 02.

[0023] The electrical stimulation output circuit 03 includes a first stimulation output terminal, a second stimulation output terminal, an ADC collector, a current sensing amplifier U3, a current limiting resistor R1, a DC blocking capacitor C1, a current limiting resistor R2 and a DC blocking capacitor C2. One end of the current limiting resistor R1 is connected to the first stimulation output terminal, and the other end is connected to one end of the DC blocking capacitor C1, and the other end of the DC blocking capacitor C1 is connected to the first input terminal 01. One end of the current limiting resistor R2 is connected to the second stimulation output terminal, and the other end is connected to one end of the DC blocking capacitor C2, and the other end of the DC blocking capacitor C2 is connected to the second input terminal 02. The positive and negative input terminals of the current sensing amplifier U3 are respectively connected to the two ends of the current limiting resistor R1, and the output end of the current sensing amplifier U3 is connected to the ADC collector.

[0024] When a common electric wire is input between the first input terminal 01 and the second input terminal 02 and the product is attached to the skin, the skin is equivalent to a load. After the constant current source passes through the current limiting resistor R1, the DC blocking capacitor C1 and the load, it passes through the DC blocking capacitor C2 and the current limiting resistor R2 and returns to the input. At this time, the output waveform is a positive square wave. After the constant current source passes through the current limiting resistor R2, the DC blocking capacitor C2 and the load, it passes through the DC blocking capacitor C1 and the current limiting resistor R1 and returns to the input. At this time, the output waveform is a negative square wave. The voltage across the current limiting resistor R1 is collected through the current sensing amplifier U3. When the collected current is less than 0.1mA, it is judged that the load has fallen off and the stimulation output is stopped.

[0025] The voltage collected by ADC is I*R1*A, where A is the amplification factor of U3. That is, if I*R1*A is less than 0.1mA, it means the load has dropped.

[0026] The 03 electrical stimulation output waveform is a positive and negative pulse waveform, such as Figure 4 As shown. R1 and R2 are current limiting resistors to prevent output 01 and 02 from short-circuiting and damaging the front-end circuit. C1 and C2 are used to isolate DC from AC. Generally, the electrical stimulation waveform is a low-frequency pulse square wave. The capacitance values ​​of C1 and C2 can be adjusted according to the actual electrical stimulation output frequency, which can output the electrical stimulation waveform normally and prevent the front-end circuit from being damaged when 5V DC charging is input to ports 01 and 02.

[0027] Specific as Figure 3 , S6 is a common electrode line. The Hall switch U1 detects that S5 has no magnetic field and outputs a low level. The U2 optocoupler and Q2 MOS tube are turned off. At this time, when outputting positive square wave stimulation, the circuit is S8. When outputting negative square wave stimulation, the circuit is S7. For positive and negative square wave stimulation, when the current on R1 is detected to be less than 0.1mA, the electrical stimulation stops. Otherwise, the electrical stimulation is output normally.

[0028] The charging input circuit 04 includes a low-power Hall switch U1, a lithium battery power supply, a current limiting resistor R4, a MOS tube Q1, a MOS tube Q2, an optocoupler U2, a pull-down resistor R7, a current limiting resistor R8 and a pull-down resistor R3. The output end of the low-power Hall switch U1 is connected to one end of the current limiting resistor R4, and the other end of the current limiting resistor R4 is respectively connected to the gate of the MOS tube Q1 and the gate of the MOS tube Q2. The gate of the MOS tube Q1 is grounded through the pull-down resistor R7, the source of the MOS tube Q1 is grounded, and the drain of the MOS tube Q1 is connected to the cathode of the light-emitting diode of the optocoupler U2. The anode of the light-emitting diode of the optocoupler U2 is connected to the positive pole of the power supply through the current limiting resistor R8, the collector of the triode of the optocoupler U2 is connected to the first input terminal 01, and the emitter of the triode of the optocoupler U2 is connected to the positive pole of the 5V voltage. The gate of the MOS tube Q2 is grounded through the pull-down resistor R3, the source of the MOS tube Q2 is grounded, and the drain of the MOS tube Q2 is connected to the second input terminal 02.

[0029] When there is no magnetic force input, the output terminal VOUT of the low-power Hall switch U1 outputs a low level, and the power consumption of this chip is within 10uA, ensuring the low power consumption of the circuit. The voltage across the gate source of MOS tube Q1 is pulled to 0 by the pull-down resistor R7, which is less than the threshold voltage, and MOS tube Q1 is turned off. Similarly, the voltage across the gate source of MOS tube Q2 is pulled to 0 by the pull-down resistor R3, which is less than the threshold voltage, and MOS tube Q2 is turned off. Among them, U2 is an optocoupler. When MOS tube Q1 is turned off, the light-emitting diodes at both ends of pins 1 and 2 of optocoupler U2 are turned off, and the triodes at both ends of pins 3 and 4 of optocoupler U2 are turned off.

[0030] When the magnetic charging line is input, the low-power Hall switch U1 detects the magnetic field and outputs a high level, and then the high level passes through the current limiting resistor R4 and is input to the gate of the MOS tube Q1 and the MOS tube Q2. The voltage across the gate source of the MOS tube Q1 and the MOS tube Q2 is greater than the threshold voltage, and the drain and source of the MOS tube Q1 and the MOS tube Q2 are turned on. The positive pole of the power supply VCC passes through the current limiting resistor R8 and the optocoupler U2 to the ground, and the light-emitting diode of the optocoupler U2 lights up. The light-emitting diode emits light to turn on the collector and emitter of the transistor of the optocoupler U2, and the 5V at the emitter end is input to the subsequent circuit through the optocoupler U2. At the same time, the cathode of the light-emitting diode of the optocoupler U2 is grounded and the motherboard ground is turned on, and charging starts randomly.

[0031] Specific as Figure 2 , S1 is a magnetic charging line, i.e. 5V input. The Hall switch U1 detects the magnetic field of S9 and outputs a high level. This turns on the U2 optocoupler and the Q2 MOS tube. S3 is the 5V input path, and S4 is the GND input path. When 5V DC is input, the C1 and C2 capacitors isolate the DC to prevent damage to the front-stage electrical stimulation generation circuit.

[0032] The present invention adopts a Hall switch U1, and uses the high and low levels of the Hall switch output to realize that charging and electrical stimulation can share a port. That is, the switching effect of the Hall switch is controlled by whether the charging magnetic wire and the ordinary electrode wire carry magnetic force, so that the electrical stimulation output circuit is not affected during charging, and the charging circuit is not affected during normal electrical stimulation output.

[0033] The present invention uses a current sensing amplifier U3 to determine whether the load is off by collecting the current at both ends of R1. If the load is off, the electrical stimulation stops. This function can prevent the charging circuit and the electrical stimulation output circuit from affecting each other and causing circuit abnormalities.

[0034] The present invention adopts an optocoupler U2 and an NMOS tube Q2, wherein the withstand voltage across the drain and source of Q2 is 60V, and the withstand voltage across the collector and emitter of the optocoupler is 80V, that is, when the electric stimulation works normally, the charging circuit can allow the electric stimulation output voltage to be output at a maximum of 60V, and this maximum output voltage can be determined according to the withstand voltage of the selected device.

[0035] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A charging input and electrical stimulation output multiplexing circuit, characterized in that: It comprises a first input terminal (01), a second input terminal (02), an electrical stimulation output circuit (03) and a charging input circuit (04); a common electric plate line or a magnetic charging line can be input between the first input terminal (01) and the second input terminal (02); The electrical stimulation output circuit (03) comprises a first stimulation output terminal, a second stimulation output terminal, an ADC collector, a current sensing amplifier U3, a current limiting resistor R1, a DC blocking capacitor C1, a current limiting resistor R2 and a DC blocking capacitor C2; one end of the current limiting resistor R1 is connected to the first stimulation output terminal, and the other end is connected to one end of the DC blocking capacitor C1, and the other end of the DC blocking capacitor C1 is connected to the first input terminal (01); one end of the current limiting resistor R2 is connected to the second stimulation output terminal, and the other end is connected to one end of the DC blocking capacitor C2, and the other end of the DC blocking capacitor C2 is connected to the second input terminal (02); the positive and negative input terminals of the current sensing amplifier U3 are respectively connected to the two ends of the current limiting resistor R1, and the output end of the current sensing amplifier U3 is connected to the ADC collector; When a common electric plate line is input between the first input terminal (01) and the second input terminal (02) and the product is attached to the skin, the skin is equivalent to a load, and the constant current source passes through the current limiting resistor R1, the DC blocking capacitor C1 and the load, and then passes through the DC blocking capacitor C2 and the current limiting resistor R2 to return to the input, and the output waveform is a positive square wave; the constant current source passes through the current limiting resistor R2, the DC blocking capacitor C2 and the load, and then passes through the DC blocking capacitor C1 and the current limiting resistor R1 to return to the input, and the output waveform is a negative square wave; the voltage across the current limiting resistor R1 is collected by the current sensing amplifier U3, and when the collected current is less than 0.1mA, it is determined that the load has fallen off and the stimulation output is stopped; The charging input circuit (04) comprises a low-power Hall switch U1, a power supply, a current limiting resistor R4, a MOS tube Q1, a MOS tube Q2, an optocoupler U2, a pull-down resistor R7, a current limiting resistor R8 and a pull-down resistor R3; the output end of the low-power Hall switch U1 is connected to one end of the current limiting resistor R4, and the other end of the current limiting resistor R4 is respectively connected to the gate of the MOS tube Q1 and the gate of the MOS tube Q2; the gate of the MOS tube Q1 is grounded through the pull-down resistor R7, the source of the MOS tube Q1 is grounded, and the drain of the MOS tube Q1 is connected to the cathode of the light-emitting diode of the optocoupler U2; the anode of the light-emitting diode of the optocoupler U2 is connected to the positive electrode of the power supply through the current limiting resistor R8, the collector of the triode of the optocoupler U2 is connected to the first input terminal (01), and the emitter of the triode of the optocoupler U2 is connected to the positive electrode of the 5V voltage; the gate of the MOS tube Q2 is grounded through the pull-down resistor R3, the source of the MOS tube Q2 is grounded, and the drain of the MOS tube Q2 is connected to the second input terminal (02); When there is no magnetic force input, the output end of the low-power Hall switch U1 outputs a low level, and the voltage across the gate source of the MOS tube Q1 is pulled to 0 by the pull-down resistor R7, which is less than the threshold voltage, and the MOS tube Q1 is turned off; similarly, the voltage across the gate source of the MOS tube Q2 is pulled to 0 by the pull-down resistor R3, which is less than the threshold voltage, and the MOS tube Q2 is turned off; when the MOS tube Q1 is turned off, the light-emitting diode of the optocoupler U2 is turned off, and then the triode of the optocoupler U2 is turned off; When the magnetic charging line is input, the low-power Hall switch U1 detects the magnetic field and outputs a high level, and then the high level passes through the current limiting resistor R4 and is input to the gate of the MOS tube Q1 and the MOS tube Q2. Then the voltage across the gate source of the MOS tube Q1 and the MOS tube Q2 is greater than the threshold voltage, and the drain and source of the MOS tube Q1 and the MOS tube Q2 are turned on; then the positive electrode of the power supply passes through the current limiting resistor R8 and the optocoupler U2 to the ground, and the light-emitting diode of the optocoupler U2 lights up, and the light-emitting diode emits light to turn on the collector and emitter of the transistor of the optocoupler U2, and the 5V at the emitter end is input to the subsequent circuit through the optocoupler U2; at the same time, the cathode of the light-emitting diode of the optocoupler U2 is grounded and turned on by the mainboard ground, and charging starts randomly.

2. A charging input and electrical stimulation output multiplexing circuit according to claim 1, characterized in that: The power source is a lithium battery.

3. The charging input and electrical stimulation output multiplexing circuit according to claim 1, characterized in that: When there is no magnetic input, the power consumption of the low-power Hall switch U1 is less than 10uA.

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