Electrostimulation device

Abstract

In an electrostimulation unit 10 of this electrostimulation device 1, a first coupling capacitor Cc1 is inserted between a first connection point N1 and a first electrode part P1 of an H-bridge circuit, and galvanically isolates the first connection point N1 from the first electrode part P1. A second coupling capacitor Cc2 is inserted between a second connection point N2 and a second electrode part P2 of the H-bridge circuit, and galvanically isolates the second connection point N2 from the second electrode part P2.

Description

Electrical stimulation device

[0001] The present invention relates to an electrical stimulation device.

[0002] BACKGROUND ART Electrical stimulation devices that apply electrical stimulation to a user's muscles are known. Electrical stimulation devices can passively move muscles by passing a weak current through the muscles to tense and relax them.

[0003] Patent Document 1 discloses a circuit configuration in which a stimulus buffer circuit 13, in which a capacitor and a resistor are connected in series, is connected to the output terminal of an H-bridge circuit. Patent Document 1 also discloses a method in which electric charges temporarily stored in the human body due to stimulus pulses applied to the human body are discharged via switching elements 10 and 12 on the low side of the H-bridge circuit.

[0004] Japanese Patent Application Publication No. 9-182805

[0005] In the circuit configuration disclosed in Patent Document 1, the stimulus buffer circuit 13, which includes a capacitor capable of blocking DC current, is connected to only one side, and DC current may flow into the human body when the human body is in contact with another conductor. If a large DC current flows into the human body, it can cause skin problems.

[0006] The present invention has been made in light of this situation, and one exemplary purpose of an embodiment thereof is to provide an electrical stimulation device with enhanced safety.

[0007] In order to solve the above problems, an electrical stimulation device according to one embodiment of the present invention includes a first switching element and a second switching element connected in series between a high-side reference line and a low-side reference line of a DC power supply unit, a first electrode unit connected to a first connection point between the first switching element and the second switching element and to be brought into contact with a part of the human body, a third switching element and a fourth switching element connected in series between the high-side reference line and the low-side reference line of the DC power supply unit, and a second electrode unit connected to a second connection point between the third switching element and the fourth switching element and to be brought into contact with another part of the human body, a first coupling capacitor inserted between the first connection point and the first electrode unit to provide DC insulation between the first connection point and the first electrode unit, and a second coupling capacitor inserted between the second connection point and the second electrode unit to provide DC insulation between the second connection point and the second electrode unit.

[0008] Any combination of the above components, or mutual substitution of the components or expressions of the present invention between methods, devices, systems, etc., are also valid aspects of the present invention.

[0009] According to the present invention, an electrical stimulation device with enhanced safety can be provided.

[0010] 4 is a diagram showing a basic circuit configuration of an electrical stimulation device according to an embodiment. FIG. 4 is a diagram for explaining an AC voltage waveform applied between a pair of first and second electrode units. FIG. 4 is a diagram showing circuit configuration example 1 of an electrical stimulation unit. FIG. 4 is a diagram showing circuit configuration example 2 of an electrical stimulation unit. FIG. 4 is a diagram showing an example of an AC pulse waveform output from a control unit to an H-bridge circuit, a voltage waveform applied to a human body, and a current waveform flowing through the human body when a discharge circuit is not provided. FIG. 4 is a diagram showing an example of an AC pulse waveform output from a control unit to an H-bridge circuit, a waveform of a discharge signal, a voltage waveform applied to a human body, and a current waveform flowing through the human body when a discharge circuit is provided. FIG. 4 is a diagram showing circuit configuration example 3 of an electrical stimulation unit. FIG. 4 is a diagram showing an example of an AC pulse voltage waveform applied from multiple systems of electrical stimulation units when a control method according to a comparative example is adopted in circuit configuration example 3 of the electrical stimulation unit. FIG. 4 is a diagram showing an example of an AC pulse voltage waveform applied from multiple systems of electrical stimulation units when a control method according to an example is adopted in circuit configuration example 3 of the electrical stimulation unit. 13 is a diagram showing a first circuit configuration example of a control unit used in the electrical stimulation device of FIG. 10. It is a diagram showing a truth table that defines the relationship between the logic of the SEL_A signal line and the SEL_B signal line and the switching elements that are turned on. It is a diagram showing the circuit configuration of an electrical stimulation device including two systems of electrical stimulation units that employ the circuit configuration example 1 shown in FIG. 3. It is a diagram showing a second circuit configuration example of a control unit used in the electrical stimulation device of FIG. 13. It is a diagram showing a third circuit configuration example of a control unit used in the electrical stimulation device of FIG. 13. It is a diagram showing a first circuit configuration example of a DC power supply unit. It is a diagram showing a second circuit configuration example of a DC power supply unit. It is a diagram showing an example circuit configuration of a switching regulator. It is a diagram showing an example timing chart of the step-up chopper shown in FIG. 18. It is a diagram showing a first circuit configuration example of a linear regulator. It is a diagram showing an example timing chart of the series regulator shown in FIG. 20. It is a diagram showing an example circuit configuration of the low-pass filter of FIG. 20. It is a diagram showing an example timing chart of the second-order RC low-pass filter shown in FIG. 22. It is a diagram showing a second circuit configuration example of a linear regulator. It is a diagram showing a modified example of the circuit configuration of the DC power supply unit.

[0011] The present invention will be described below based on preferred embodiments with reference to the drawings. The embodiments are illustrative and do not limit the invention, and all features and combinations described in the embodiments are not necessarily essential to the invention. In the embodiments and modifications, the same or equivalent components and members are designated by the same reference numerals, and redundant descriptions will be omitted where appropriate.

[0012] (Basic Circuit Configuration of Electrical Stimulation Device 1) FIG. 1 is a diagram showing the basic circuit configuration of electrical stimulation device 1 according to an embodiment. Electrical stimulation device 1 is an EMS (Electrical Muscle Stimulation) device that applies electrical stimulation to the muscles of a user. Electrical stimulation device 1 includes an electrical stimulation unit 10, a DC power supply unit 20, a control unit 30, and a first drive circuit Dr1 to a fourth drive circuit Dr4. Electrical stimulation unit 10 includes an H-bridge-connected first switching element Q1 to a fourth switching element Q4, and a pair of first and second electrode portions P1 and P2.

[0013] The electrical stimulation device 1 is used with a pair of first and second electrodes P1 and P2 in contact with any part of the human body Hd. By contacting the first electrode P1 with one part of the human body Hd and the second electrode P2 with another part of the human body Hd, a current path is formed with the human body Hd as a load.

[0014] The pair of first and second electrode portions P1 and P2 are electrodes that do not require consumable gel pads, specifically, cloth electrodes. Cloth electrodes are used while soaked in water. Cloth electrodes have a long lifespan, meaning they can be used many times before their lifespan expires. Furthermore, cloth electrodes are washable. The pair of first and second electrode portions P1 and P2 may be electrodes other than cloth electrodes, such as metal. The pair of first and second electrode portions P1 and P2 may also be electrodes that require gel pads. The pair of first and second electrode portions P1 and P2 may be rubber electrodes made of EPDM (Ethylene Propylene Diene Monomer) rubber, conductive polyurethane, or the like. Rubber electrodes can be used without soaking in water.

[0015] A first switching element Q1 and a second switching element Q2 connected in series, and a third switching element Q3 and a fourth switching element Q4 connected in series, are connected in parallel between a high-side reference line and a low-side reference line of the DC power supply unit 20. A first connection point N1 between the first switching element Q1 and the second switching element Q2 is connected to a first electrode portion P1. A second connection point N2 between the third switching element Q3 and the fourth switching element Q4 is connected to a second electrode portion P2.

[0016] The first switching element Q1 to the fourth switching element Q4 may be semiconductor switching elements such as bipolar transistors, MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors), IGBTs (Insulated Gate Bipolar Transistors), etc. In the following, an example will be assumed in which PNP bipolar transistors (hereinafter simply referred to as PNP transistors) are used for the first switching element Q1 and the third switching element Q3, and NPN bipolar transistors (hereinafter simply referred to as NPN transistors) are used for the second switching element Q2 and the fourth switching element Q4.

[0017] In this case, the emitter terminal of the first switching element Q1 is connected to the high-side reference line, the emitter terminal of the second switching element Q2 is connected to the low-side reference line, and the connection point between the collector terminal of the first switching element Q1 and the collector terminal of the second switching element Q2 is the first connection point N1. Similarly, the emitter terminal of the third switching element Q3 is connected to the high-side reference line, the emitter terminal of the fourth switching element Q4 is connected to the low-side reference line, and the connection point between the collector terminal of the third switching element Q3 and the collector terminal of the fourth switching element Q4 is the second connection point N2.

[0018] The control unit 30 controls the entire electrical stimulation device 1. The control unit 30 can be configured using any one or any combination of a microcontroller, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), a gate IC, or other LSIs. The first drive circuit Dr1 to the fourth drive circuit Dr4 generate drive signals for the first switching element Q1 to the fourth switching element Q4 based on control signals for the first switching element Q1 to the fourth switching element Q4 input from the control unit 30, respectively, to drive the first switching element Q1 to the fourth switching element Q4.

[0019] In this embodiment, bipolar transistors are used for the first switching element Q1 to the fourth switching element Q4, and therefore the first drive circuit Dr1 to the fourth drive circuit Dr4 are circuits that generate base currents supplied to the base terminals of the first switching element Q1 to the fourth switching element Q4, respectively. If MOSFETs are used for the first switching element Q1 to the fourth switching element Q4, the first drive circuit Dr1 to the fourth drive circuit Dr4 are circuits that generate gate voltages supplied to the gate terminals of the first switching element Q1 to the fourth switching element Q4, respectively. If the control unit 30 includes a gate IC or the like and has sufficient drive capacity, the first drive circuit Dr1 to the fourth drive circuit Dr4 can be configured only with passive elements such as resistors.

[0020] The control unit 30 controls the first switching element Q1 and the fourth switching element Q4 to an ON state and the second switching element Q2 and the third switching element Q3 to an OFF state, thereby applying a positive voltage between the first electrode portion P1 and the second electrode portion P2. The control unit 30 controls the first switching element Q1 and the fourth switching element Q4 to an OFF state and the second switching element Q2 and the third switching element Q3 to an ON state, thereby applying a negative voltage between the first electrode portion P1 and the second electrode portion P2.

[0021] In the present embodiment, control unit 30 controls electrostimulation unit 10 as follows. In one cycle, control unit 30 applies a positive pulse voltage and a negative pulse voltage alternately multiple times between first electrode P1 and second electrode P2, followed by an interval period. More specifically, in one cycle, control unit 30 applies a positive pulse voltage and a negative pulse voltage alternately an odd number of times between first electrode P1 and second electrode P2, followed by an interval period. In the next cycle, control unit 30 applies an odd number of pulse voltages with the phases of the odd number of pulse voltages inverted, followed by an interval period.

[0022] 2 is a diagram illustrating the AC voltage waveform applied between the pair of first electrode portion P1 and second electrode portion P2. The voltage waveform shown in FIG. 2 is composed of a combination of positive and negative basic pulses with a time width t1. A positive basic pulse causes a current to flow in a positive direction from one of the pair of first electrode portion P1 and second electrode portion P2 to the other, and a negative basic pulse causes a current to flow in a negative direction from the other electrode portion to the one.

[0023] A pause period of time width t2 is provided between positive and negative basic pulses. The applied voltage during this pause period is zero. In this waveform, a basic pulse group having a time width t3 (= 5 x t1 + 5 x t2) including five basic pulses and five pause periods is formed. This basic pulse group, together with the interval period of time width t4 provided after it, forms a basic waveform of one cycle (time width) t5 (= t3 + t4).

[0024] For example, if the time width t1 is set to 100 us and the time width t2 is set to 100 us, the time width t3 will be 1 ms. In this embodiment, the user can select between Mode A (20 Hz mode) and Mode B (4 Hz mode). When Mode A is selected, the time width t5 will be 50 ms (= 20 Hz) and the time width t4 (interval period) will be 49 ms. When Mode B is selected, the time width t5 will be 250 ms (= 4 Hz) and the time width t4 (interval period) will be 249 ms.

[0025] In the example shown in FIG. 2 , the voltage polarity of the basic pulse is reversed for each waveform group. That is, if a positive pulse voltage is output three times and a negative pulse voltage is output twice in a given waveform group, the next waveform group alternates between the positive pulse voltage being output two times and the negative pulse voltage being output three times. This allows the two waveform groups to be paired to suppress uneven charge distribution on the first electrode portion P1 and the second electrode portion P2 and to suppress corrosion of the first electrode portion P1 and the second electrode portion P2. Note that the pulse voltage application pattern shown in FIG. 2 is merely an example and is not limited to this application pattern. For example, a pattern in which positive and negative pulse voltages are applied consecutively multiple times rather than alternately may be used. Alternatively, a pattern in which the pulse voltage is applied an even number of times in one cycle may be used.

[0026] In the basic circuit configuration described above, if a failure or malfunction occurs in any of the first switching element Q1 to the fourth switching element Q4 and the current cannot be cut off, a direct current may flow into the human body Bd, which may cause skin problems or the like.

[0027] (Circuit Configuration Example 1 of Electrical Stimulation Unit 10) Fig. 3 is a diagram showing Circuit Configuration Example 1 of Electrical Stimulation Unit 10. In Circuit Configuration Example 1 of Electrical Stimulation Unit 10 shown in Fig. 3, a first coupling capacitor Cc1 and a second coupling capacitor Cc2 are added to the basic circuit of Electrical Stimulation Unit 10 shown in Fig. 1.

[0028] The first coupling capacitor Cc1 is inserted between the first connection point N1 and the first electrode P1 of the H-bridge circuit to provide DC insulation between the first connection point N1 and the first electrode P1. The second coupling capacitor Cc2 is inserted between the second connection point N2 and the second electrode P2 of the H-bridge circuit to provide DC insulation between the second connection point N2 and the second electrode P2.

[0029] By adding a first coupling capacitor Cc1 in series between the H-bridge circuit and the first electrode P1 and a second coupling capacitor Cc2 in series between the H-bridge circuit and the second electrode P2, it is possible to cut off the DC current flowing into the human body Hd from the electrical stimulation device 1. As described above, the EMS current supplied to the human body Hd from the electrical stimulation device 1 is an AC pulse, and therefore passes through the first coupling capacitor Cc1 and the second coupling capacitor Cc2 and does not affect steady-state operation.

[0030] (Circuit Configuration Example 2 of Electrical Stimulation Unit 10) Figure 4 is a diagram showing Circuit Configuration Example 2 of Electrical Stimulation Unit 10. In Circuit Configuration Example 1 of Electrical Stimulation Unit 10 shown in Figure 4, a first discharge switching element Qd1 and a second discharge switching element Qd2 are further added as discharge circuits to Circuit Configuration Example 2 of Electrical Stimulation Unit 10 shown in Figure 3.

[0031] The first discharge switching element Qd1 is connected between the wiring connecting the first coupling capacitor Cc1 and the first electrode portion P1 and the low-side reference line. The second discharge switching element Qd2 is connected between the wiring connecting the second coupling capacitor Cc2 and the second electrode portion P2 and the low-side reference line. NPN transistors are used for the first discharge switching element Qd1 and the second discharge switching element Qd2. When NPN transistors are used, base current flows, so there is no need to connect discharge resistors in series with the first discharge switching element Qd1 and the second discharge switching element Qd2. Furthermore, when MOSFETs are used instead of bipolar transistors, discharge resistors are connected in series with each element as needed.

[0032] In circuit configuration example 2, a fifth drive circuit Dr5 is added to the electrical stimulation device 1. The fifth drive circuit Dr5 generates drive signals for the first discharge switching element Qd1 and the second discharge switching element Qd2 based on control signals for the first discharge switching element Qd1 and the second discharge switching element Qd2 input from the control unit 30, thereby driving the first discharge switching element Qd1 and the second discharge switching element Qd2. The fifth drive circuit Dr5 generates base currents supplied to the base terminals of the first discharge switching element Qd1 and the second discharge switching element Qd2.

[0033] The control unit 30 controls the on / off of the first discharge switching element Qd1 and the second discharge switching element Qd2 in synchronization with each other. Therefore, as shown in Fig. 4, the first discharge switching element Qd1 and the second discharge switching element Qd2 can share a drive circuit. However, separate drive circuits may be provided for the first discharge switching element Qd1 and the second discharge switching element Qd2.

[0034] The control unit 30 applies a positive pulse voltage and a negative pulse voltage alternately multiple times between the first electrode portion P1 and the second electrode portion P2 in one cycle, and inserts a discharge period (a period during which the first discharge switching element Qd1 and the second discharge switching element Qd2 are in the ON state) in the interval period thereafter. By simultaneously turning on the first discharge switching element Qd1 and the second discharge switching element Qd2 in the interval period, the first electrode portion P1 and the second electrode portion P2 become at the same potential via the ground potential of the low-side reference line, and any charge remaining in the human body Hd can be discharged.

[0035] FIG. 5 is a diagram showing an example of an AC pulse waveform output from the control unit 30 to the H-bridge circuit, a voltage waveform applied to the human body Hd, and a current waveform flowing through the human body Hd when a discharge circuit is not provided.

[0036] In the example shown in FIG. 5 , the control unit 30 outputs an EMS signal to the H-bridge circuit to generate a basic pulse group including the five basic pulses shown in FIG. 2 , and the H-bridge circuit applies a voltage corresponding to the EMS signal between the first electrode P1 and the second electrode P2. Because the human body Hd is a capacitive load, the voltage does not instantly drop to zero even after the application period of the basic pulse ends. Instead, the charge gradually dissipates on the body surface, approaching zero. The residual charge from the first four basic pulses is reset when the next basic pulse is applied, but the residual charge from the fifth basic pulse is not reset until the first basic pulse of the next cycle is applied. During the interval, the charge is dissipated on the body surface. This charge is a DC component and is undesirable for the human body Hd.

[0037] Figure 6 shows an example of an AC pulse waveform output from the control unit 30 to the H-bridge circuit, a waveform of a discharge signal, a voltage waveform applied to the human body Hd, and a current waveform flowing through the human body Hd when a discharge circuit is provided.

[0038] 5 , the control unit 30 outputs an EMS signal to the H-bridge circuit to generate a basic pulse group including the five basic pulses shown in FIG. 2 , and the H-bridge circuit applies a voltage corresponding to the EMS signal between the first electrode portion P1 and the second electrode portion P2. After outputting the EMS signal for the basic pulse group, the control unit 30 turns on the discharge signal to turn on the first discharge switching element Qd1 and the second discharge switching element Qd2. This resets the residual charge from the fifth basic pulse without waiting for the application timing of the first basic pulse of the next cycle, and as with the first four basic pulses, the adverse effects of the residual charge can be minimized.

[0039] (Circuit Configuration Example 3 of Electrical Stimulation Unit 10) Figure 7 is a diagram showing Circuit Configuration Example 3 of Electrical Stimulation Unit 10. In Circuit Configuration Example 3 of Electrical Stimulation Unit 10 shown in Figure 7, multiple electrical stimulation units 10 are provided. Multiple electrical stimulation units 10 may be built into a single piece of fitness wear. Below, an example is assumed in which four systems of electrical stimulation units 10a-10d are provided.

[0040] For example, the first electrode P1a and the second electrode P2a of the first system electrical stimulation unit 10a are attached to the right arm, and the first system electrical stimulation unit 10a can electrically stimulate the biceps and triceps. The first electrode P1b and the second electrode P2b of the second system electrical stimulation unit 10b are attached to the abdomen (one of them may be attached to the lower back), and the second system electrical stimulation unit 10b can electrically stimulate the rectus abdominis and oblique abdominal muscles.

[0041] The first electrode P1c and the second electrode P2c of the third system electrical stimulation unit 10c are attached to the right foot (one may be attached to the buttocks), and the third system electrical stimulation unit 10c can provide electrical stimulation to the quadriceps and buttocks of the right foot. The first electrode P1d and the second electrode P2d of the fourth system electrical stimulation unit 10d are attached to the left foot (one may be attached to the buttocks), and the fourth system electrical stimulation unit 10d can provide electrical stimulation to the quadriceps and buttocks of the left foot.

[0042] The control unit 30 controls the DC power supply unit 20 to adjust the voltage levels output to the multiple electrical stimulation units 10a-10d. The configuration of the DC power supply unit 20 will be described later. The user can set the EMS intensity level for each system. For example, the user can set the EMS intensity level in 20 stages.

[0043] The control unit 30 controls the output voltage of the DC power supply unit 20 according to the set intensity level. For example, the control unit 30 controls the output voltage of the DC power supply unit 20 according to the intensity level as follows: Level 1: around 11 V, Level 2: around 12 V, Level 3: around 14 V, Level 4: around 16 V, Level 5: around 18 V, Level 6: around 19 V, Level 7: around 21 V, Level 8: around 23 V, Level 9: around 25 V, Level 10: around 26 V, Level 11: around 28 V, Level 12: around 30 V, Level 13: around 32 V, Level 14: around 33 V, Level 15: around 35 V, Level 16: around 37 V, Level 17: around 39 V, Level 18: around 40 V, Level 19: around 42 V, Level 20: around 44 V.

[0044] 8 shows an example of an AC pulse voltage waveform applied from multiple electrical stimulation units 10a-10c when a control method according to a comparative example is adopted in circuit configuration example 3 of electrical stimulation unit 10. In this example, three of four electrical stimulation units 10a-10d, namely, electrical stimulation units 10a-10c, are used. The intensity level of electrical stimulation unit 10a of the first system is set to level 20, the intensity level of electrical stimulation unit 10b of the second system is set to level 15, and the intensity level of electrical stimulation unit 10c of the third system is set to level 10.

[0045] The control unit 30 controls the DC power supply unit 20 to output a voltage of 44 V to the first system of electrical stimulation unit 10 a, controls the DC power supply unit 20 to output a voltage of 35 V to the second system of electrical stimulation unit 10 b, and controls the DC power supply unit 20 to output a voltage of 26 V to the third system of electrical stimulation unit 10 c.

[0046] In the control method according to the comparative example, the control unit 30 controls the H-bridge circuit of each of the electrical stimulation units 10a-10c so that synchronized basic pulse voltages are applied between the first electrode units P1a-P1c and the second electrode units P2a-P2c of each of the multiple systems of electrical stimulation units 10a-10c. In this case, a potential difference occurs between each pair of electrodes (P1a-P2a, P1b-P2b, P1c-P2c) of each of the systems of electrical stimulation units 10a-10c, and leakage current flows from the electrode unit with the higher potential to the electrode unit with the lower potential.

[0047] 8, leakage current flows from electrodes P1a and P2a of electrical stimulation unit 10a of the first system to electrodes P1b and P2b of electrical stimulation unit 10b of the second system and to electrodes P1c and P2c of electrical stimulation unit 10c of the third system, and leakage current flows from electrodes P1b and P2b of electrical stimulation unit 10b of the second system to electrodes P1c and P2c of electrical stimulation unit 10c of the third system. This leakage current causes an unpleasant tingling sensation to the user.

[0048] Furthermore, leakage current across the heart may cause cardiac rhythm abnormalities. For example, if the intensity level of electrical stimulation unit 10a of the first system across the heart is set to level 20 and the intensity level of electrical stimulation unit 10b of the second system across the heart is set to level 1, a potential difference of 33 V (= 44 - 11 V) is generated, and a current corresponding to the cardiac impedance of each individual user flows.

[0049] FIG. 9 shows an example of an AC pulse voltage waveform applied from the multiple systems of electrical stimulation units 10a-10c when the control method according to the embodiment is adopted in circuit configuration example 3 of the electrical stimulation unit 10. In the control method according to the embodiment, the control unit 30 controls the H-bridge circuits of each of the multiple systems of electrical stimulation units 10a-10c so that voltages of basic pulse groups with phase shifts are applied between the first electrode portions P1a-P1c and the second electrode portions P2a-P2c of the multiple systems of electrical stimulation units 10a-10c. For example, the control unit 30 shifts the drive timing of the H-bridge circuits between the multiple systems by 2 ms. That is, the control unit 30 outputs EMS signals with phase shifts of 2 ms to each H-bridge circuit of the multiple systems of electrical stimulation units 10a-10c.

[0050] When the circuit configuration example 2 of the electrical stimulation unit 10 shown in Figure 4 is used for the configuration of each electrical stimulation unit 10a-10c, the control unit 30 inserts a discharge period into the interval period inserted after the application of the voltage of the basic pulse group in each system. During the discharge period, the control unit 30 simultaneously turns on all of the first discharge switching elements Qd1a-Qd1c and second discharge switching elements Qd2a-Qd2c of the multiple operating electrical stimulation units 10a-10c.

[0051] An example of the circuit configuration of control unit 30 will be described below based on an example in which two systems of electrical stimulation units 10a-10b are provided.

[0052] (Circuit configuration example 1 of control unit 30) Figure 10 is a diagram showing the circuit configuration of electrical stimulation device 1 including two systems of electrical stimulation unit 10 employing circuit configuration example 2 shown in Figure 4. Figure 11 is a diagram showing circuit configuration example 1 of control unit 30 used in electrical stimulation device 1 of Figure 10. Control unit 30 includes a microcontroller 31 and a multiplexer 32.

[0053] The microcontroller 31 and multiplexer 32 are connected by four signal lines (EMS_H signal line, EMS_L signal line, SEL_A signal line, and SEL_B signal line). The EMS_H signal line is a signal line for turning on the high-side switching element of the H-bridge circuit, and the EMS_L signal line is a signal line for turning on the low-side switching element of the H-bridge circuit. The SEL_A signal line and SEL_B signal line are signal lines for transmitting a 2-bit control signal.

[0054] 12 is a truth table that defines the relationship between the logic of the SEL_A signal line and the SEL_B signal line and the switching elements that are turned on. When the logic of the SEL_A signal line and the SEL_B signal line are "L" and "L," multiplexer 32 connects the EMS_H signal line to the first drive circuit Dr1a of the first system and connects the EMS_L signal line to the fourth drive circuit Dr4a of the first system, thereby turning on first switching element Q1a and fourth switching element Q4a of electrical stimulation unit 10a of the first system.

[0055] When the logic of the SEL_A signal line and the SEL_B signal line is "H" or "L", the multiplexer 32 connects the EMS_H signal line to the third drive circuit Dr3a of the first system, and connects the EMS_L signal line to the second drive circuit Dr2a of the first system, thereby conducting the third switching element Q3a and the second switching element Q2a of the electrical stimulation unit 10a of the first system.

[0056] When the logic of the SEL_A signal line and the SEL_B signal line is "L" or "H", the multiplexer 32 connects the EMS_H signal line to the first drive circuit Dr1b of the second system, and connects the EMS_L signal line to the fourth drive circuit Dr4b of the second system, thereby conducting the first switching element Q1b and the fourth switching element Q4b of the electrical stimulation unit 10b of the second system.

[0057] When the logic of the SEL_A signal line and the SEL_B signal line is "H" and "H", the multiplexer 32 connects the EMS_H signal line to the third drive circuit Dr3b of the second system, and connects the EMS_L signal line to the second drive circuit Dr2b of the second system, thereby conducting the third switching element Q3b and the second switching element Q2b of the electrical stimulation unit 10b of the second system.

[0058] In addition, in the case of an electrical stimulation device 1 having four systems of electrical stimulation units 10 that adopt circuit configuration example 2 shown in Figure 4, the conduction pattern of the H-bridge circuit becomes eight patterns, so 3-bit logic is required and three SEL signal lines are required.

[0059] In the circuit configuration example 2 of the electrical stimulation unit 10 shown in Figure 4, a first discharge switching element Qd1 and a second discharge switching element Qd2 are added as a discharge circuit. In this regard, a configuration using a low-side second switching element Q2 and a fourth switching element Q4 as a discharge circuit is also possible.

[0060] The control unit 30 applies a positive pulse voltage and a negative pulse voltage alternately multiple times between the first electrode P1 and the second electrode P2 in one cycle, and inserts a discharge period during which the second switching element Q2 and the fourth switching element Q4 are turned on during the interval period. By simultaneously turning on the second switching element Q2 and the fourth switching element Q4 during the interval period, the first electrode P1 and the second electrode P2 have the same potential via the ground potential of the low-side reference line, and any charge remaining in the human body Hd can be discharged.

[0061] According to circuit configuration example 1 of control unit 30, it is possible to reduce the number of ports of microcontroller 31. Note that this configuration does not allow multiple electrical stimulation units 10a-10b to be turned on simultaneously.

[0062] (Circuit configuration example 2 of control unit 30) Figure 13 is a diagram showing the circuit configuration of electrical stimulation device 1 including two systems of electrical stimulation unit 10 employing circuit configuration example 1 shown in Figure 3. Figure 14 is a diagram showing circuit configuration example 2 of control unit 30 used in electrical stimulation device 1 of Figure 13. Control unit 30 includes a microcontroller 31, a multiplexer 32, and a plurality of OR gates 33a-33d.

[0063] The configuration of the multiplexer 32 is similar to that of the multiplexer 32 in circuit configuration example 1 shown in Fig. 11. In circuit configuration example 2 of the control unit 30, OR gates 33a to 33d are inserted between the four output terminals on the low side of the multiplexer 32 and the input terminals of the fourth drive circuit Dr4a of the first system, the second drive circuit Dr2a of the first system, the fourth drive circuit Dr4b of the second system, and the second drive circuit Dr2b of the second system, respectively.

[0064] A DISCHARGE signal is input to another input terminal of each of the OR gates 33a-33d. The OR gate is a logic gate that outputs "H" when at least one of a plurality of input signals includes "H" and outputs "L" when all of the input signals are "L." Therefore, when the DISCHARGE signal is "H," "H" is output to all of the fourth drive circuit Dr4a of the first system, the second drive circuit Dr2a of the first system, the fourth drive circuit Dr4b of the second system, and the second drive circuit Dr2b of the second system, and all of the fourth switching element Q4a of the first system, the second switching element Q2a of the first system, the fourth switching element Q4b of the second system, and the second switching element Q2b of the second system are turned on.

[0065] On the other hand, when the DISCHARGE signal is "L", the outputs of the OR gates 33a-33d have the same logic as the four outputs on the low side of the multiplexer 32, and the operation is the same as that of the circuit configuration example 1 of the control unit 30 shown in Figure 11.

[0066] According to the circuit configuration example 2 of the control unit 30, it is possible to provide a function of discharging residual charge while omitting the first discharge switching element Qd1 and the second discharge switching element Qd2.

[0067] 15 is a diagram showing a third circuit configuration example of the control unit 30 used in the electrical stimulation device 1 of FIG. 13. The control unit 30 includes a microcontroller 31, a high-side buffer 34a, and a low-side buffer 34b. The microcontroller 31 is connected in parallel to the high-side buffer 34a and the low-side buffer 34b by four signal lines (a1 signal line, b1 signal line, a2 signal line, and b2 signal line).

[0068] The a1 signal line is a signal line for conducting the first switching element Q1a and the fourth switching element Q4a of the first system of electrostimulation unit 10a. The a2 signal line is a signal line for conducting the third switching element Q3a and the second switching element Q2a of the first system of electrostimulation unit 10a. The b1 signal line is a signal line for conducting the first switching element Q1b and the fourth switching element Q4b of the second system of electrostimulation unit 10b. The b2 signal line is a signal line for conducting the third switching element Q3b and the second switching element Q2b of the second system of electrostimulation unit 10b.

[0069] In the case of an electrical stimulation device 1 having four systems of electrical stimulation units 10 employing circuit configuration example 1 shown in FIG. 3, the conduction pattern of the H-bridge circuit is eight patterns, and therefore the microcontroller 31 is connected in parallel to the high-side buffer 34a and the low-side buffer 34b via eight signal lines.

[0070] The microcontroller 31 and the high-side buffer 34a are connected by an EN_H signal line. When the logic of the EN_H signal line is "L", the high-side buffer 34a is enabled, and when it is "H", the high-side buffer 34a is disabled. The microcontroller 31 and the low-side buffer 34b are connected by an EN_L signal line. When the logic of the EN_L signal line is "L", the low-side buffer 34b is enabled, and when it is "H", the low-side buffer 34b is disabled.

[0071] The microcontroller 31 can generate a discharge state by outputting "H" from all four signal lines (signal line a1, signal line b1, signal line a2, and signal line b2), disabling the high-side buffer 34a, and enabling the low-side buffer 34b.

[0072] A drive circuit may be inserted into each of the four signal lines of the microcontroller 31. In this case, a configuration may be adopted in which current-limiting resistors are respectively connected between the high-side buffer 34a and the base terminals of the first switching element Q1a of the first system, the third switching element Q3a of the first system, the first switching element Q1b of the second system, and the third switching element Q3b of the second system, and between the low-side buffer 34b and the base terminals of the fourth switching element Q4a of the first system, the second switching element Q2a of the first system, the fourth switching element Q4b of the second system, and the second switching element Q2b of the second system.

[0073] According to circuit configuration example 3 of the control unit 30, by providing the high-side buffer 34a and the low-side buffer 34b, the number of signal lines can be reduced by half compared to when signal lines for each switching element are simply installed.

[0074] As described above, the H-bridge circuit can be DC-isolated from the human body Bd by providing the first coupling capacitor Cc1 and the second coupling capacitor Cc2 in the electrical stimulation unit 10. Furthermore, because the first coupling capacitor Cc1 and the second coupling capacitor Cc2 are connected to the output points on both sides of the H-bridge circuit, DC insulation between the human body Bd and the H-bridge circuit is complete, completely preventing the occurrence of a DC path from the H-bridge circuit to the human body Bd to other conductors.

[0075] The EMS signal is a pulsed AC waveform, but the residual charge remaining at the end of the pulse results in a waveform that appears to contain a DC component, and this DC component increases as the frequency increases. By providing a discharge circuit in the electrical stimulation unit 10, the residual charge can be discharged during the interval, and the AC voltage waveform applied between the first electrode P1 and the second electrode P2 becomes a waveform that does not contain a DC component. This prevents skin problems caused by DC current flowing near the body surface of the human body Bd.

[0076] Furthermore, when the first discharging switching element Qd1 is turned on to discharge the residual charge, the first coupling capacitor Cc1 cuts off the DC current flowing toward the first connection point N1, preventing a drop in the voltage at the first connection point N1. This prevents the collector-emitter voltage of the first switching element Q1 from exceeding its withstand voltage, preventing malfunctions in the first switching element Q1.

[0077] Similarly, when the second discharging switching element Qd2 is turned on to release the residual charge, the second coupling capacitor Cc2 cuts off the DC current flowing toward the second connection point N2, preventing a drop in the voltage at the second connection point N2. This prevents the collector-emitter voltage of the third switching element Q3 from exceeding its withstand voltage, preventing malfunction of the third switching element Q3.

[0078] In the circuit configuration example 3 of the electrical stimulation unit 10, when the intensity level is changed between systems, leakage current flows from the system with the higher level to the system with the lower level. This phenomenon occurs because the drive timing of each H-bridge circuit is the same for all systems. In response to this, by providing a discharge period and shifting the phase of the EMS signal supplied to the multiple H-bridge circuits to shift the drive timing of the multiple H-bridge circuits, leakage current flowing between systems can be prevented. This prevents the user from experiencing an unpleasant tingling sensation. Furthermore, even with electrode placement across the heart, the intensity level can be individually adjusted for each system, improving the usability of the electrical stimulation device 1.

[0079] The following describes the configuration of DC power supply unit 20. As described above, in order to be able to individually adjust the intensity level for each of multiple systems of electrical stimulation units 10a-10d, it is possible to provide a boost circuit for each of multiple systems of electrical stimulation units 10a-10d.

[0080] (Circuit Configuration Example 1 of DC Power Supply Unit 20) Figure 16 is a diagram showing Circuit Configuration Example 1 of DC Power Supply Unit 20. DC Power Supply Unit 20 includes a secondary battery 21 and multiple switching regulators 22a-22d. Hereinafter, an example will be assumed in which a single lithium-ion cell is used as secondary battery 21. The nominal voltage of the lithium-ion cell is 3.7V, and varies within a range of 3.4-4.2V depending on the SOC (State of Charge). The lithium-ion cell is charged with DC from a charger via a USB cable. Multiple switching regulators 22a-22d are connected in parallel to secondary battery 21 and are connected to multiple electrical stimulation units 10a-10d, respectively.

[0081] (Circuit Configuration Example 2 of DC Power Supply Unit 20) Figure 17 is a diagram showing Circuit Configuration Example 2 of DC power supply unit 20. DC power supply unit 20 includes secondary battery 21, switching regulator 22, and linear regulator 23. Switching regulator 22 is a DC / DC converter that converts the voltage of DC power supplied from secondary battery 21 to a predetermined voltage using a switching system. Linear regulator 23 is a DC / DC converter that is connected in parallel to multiple electrical stimulation units 10a-10d and that linearly steps down the voltage of DC power supplied from switching regulator 22 to a command voltage set by control unit 30.

[0082] Generally, linear regulators can only step down, have high losses (low efficiency), generate a lot of heat, have a fast response time, low noise, are simple to design, have a small circuit size, and are low cost, whereas switching regulators can step up and down, have low losses (high efficiency), generate little heat, have a slower response time than linear regulators, are louder, have a more complex design, have a larger circuit size, and are high cost.

[0083] (Circuit Configuration Example of Switching Regulator 22) Fig. 18 is a diagram showing a circuit configuration example of the switching regulator 22. In the circuit configuration example shown in Fig. 18, the switching regulator 22 is configured as a boost chopper. A boost chopper is a switching-type DC / DC converter that is only capable of boosting. The boost chopper includes, as its main components, an inductor L1, a diode D1, a first capacitor C1, and a first control switching element Qc1. An NPN transistor is used for the first control switching element Qc1.

[0084] An inductor L1 and a first control switching element Qc1 are connected in series across the secondary battery 21. The connection point between the inductor L1 and the first control switching element Qc1 is connected to the high-side reference line. Specifically, the collector terminal of the first control switching element Qc1 is connected to the connection point, the emitter terminal is connected to the low-side reference line, and the base terminal is connected to the controller 30 via a third resistor R3.

[0085] A diode D1 is inserted in the forward direction in the high-side reference line connected to the connection point. Specifically, the connection point side faces the anode terminal, and the output side of the boost chopper faces the cathode terminal. A first capacitor C1 is connected between the high-side reference line and the low-side reference line on the cathode terminal side of the diode D1. The first capacitor C1 is connected at a position closer to the output side than the diode D1. The first capacitor C1 is a smoothing capacitor, and may be, for example, an electrolytic capacitor.

[0086] A third discharge switching element Qd3 is connected in parallel with the first capacitor C1. An NPN transistor is used as the third discharge switching element Qd3. The base terminal of the third discharge switching element Qd3 is connected to the control unit 30 via a fourth resistor R4. The control unit 30 can reset the charge stored in the first capacitor C1 by outputting an ON signal to turn on the third discharge switching element Qd3.

[0087] A first voltage dividing circuit, in which a first resistor R1 and a second resistor R2 are connected in series, is connected across the secondary battery 21, and the voltage at the connection point between the first resistor R1 and the second resistor R2 is output to the control unit 30. The control unit 30 calculates the voltage of the secondary battery 21 (≈ the input voltage V of the boost chopper) based on the output voltage of the first voltage dividing circuit. ＩＮ Detect.

[0088] A second voltage dividing circuit, in which a fifth resistor R5 and a sixth resistor R6 are connected in series, is connected between the output terminals of the boost chopper, and the voltage at the connection point between the fifth resistor R5 and the sixth resistor R6 is output to the control unit 30. The control unit 30 calculates the output voltage V of the boost chopper based on the output voltage of the second voltage dividing circuit. ｏｕｔ Detect.

[0089] The control unit 30 controls the output voltage V of the boost chopper. ｏｕｔ The duty ratio of a PWM (Pulse Width Modulation) signal supplied to the base terminal of the first control switching element Qc1 is controlled so that the output voltage V ｏｕｔ is lower than the target voltage, the control unit 30 increases the duty ratio to increase the ratio of the on-time of the first control switching element Qc1. ｏｕｔ is higher than the target voltage, the control unit 30 reduces the duty ratio to reduce the ratio of the on time of the first control switching element Qc1.

[0090] When the first control switching element Qc1 is in the on state, a current flows through the path of the secondary battery 21, the inductor L1, and the first control switching element Qc1, and energy is charged in the inductor L1. Even when the first control switching element Qc1 is switched to the off state, the same current continues to flow, so the output voltage increases by the amount corresponding to the increase in impedance on the load side including the first capacitor C1.

[0091] 19 is a diagram showing an example of a timing chart of the boost chopper shown in FIG. 18. Control unit 30 sets the output target voltage of the boost chopper to a voltage obtained by adding a margin to the output voltage of electrostimulation unit 10 of the system set to the maximum intensity level. In the example shown in FIGS. 8 and 9, the intensity level set for electrostimulation unit 10a of the first system is the maximum, level 20 is set for electrostimulation unit 10a of the first system, and the voltage applied to human body Hd from electrostimulation unit 10a of the first system set to level 20 is 44 V. Control unit 30 adds a margin to 44 V to set the output target voltage of the boost chopper to approximately 50 V.

[0092] In the example shown in FIG. 19, the input voltage V ＩＮ is the output voltage of the secondary battery 21, 3.7 V. During the ON period of the first control switching element Qc1, a collector current I Ｅ increases over time. During the OFF period of the first control switching element Qc1, the collector current I Ｅ is cut off, the diode D1 is turned on, and the current I Ｄ decreases over time.

[0093] In the example shown in FIG. 19, the forward voltage Vf of the diode D1 is taken into consideration, and the collector voltage V between the collector and emitter during the off period of the first control switching element Qc1 is Ｃ The output voltage of the boost chopper is controlled to be 55V. ｏｕｔ is smoothed by the first capacitor C1 and controlled to an average of 53V.

[0094] (Circuit Configuration Example 1 of Linear Regulator 23) Fig. 20 is a diagram showing Circuit Configuration Example 1 of the linear regulator 23. In Circuit Configuration Example 1 shown in Fig. 20, the linear regulator 23 is configured as a series regulator. The series regulator includes, as main components, a second control switching element Qc2, a third control switching element Qc3, a ninth resistor R9, a tenth resistor R10, a fourth control switching element Qc4, an eleventh resistor R11, an operational amplifier OP1, a fourth voltage divider circuit in which a twelfth resistor R12 and a thirteenth resistor R13 are connected in series, and a low-pass filter 231.

[0095] A control switching unit, in which a second control switching element Qc2 and a third control switching element Qc3 are Darlington-connected, is inserted into the high-side reference line between the input terminal and output terminal of the series regulator. An NPN transistor is used for the second control switching element Qc2, and a PNP transistor is used for the third control switching element Qc3. The collector terminal of the second control switching element Qc2 is connected to the input terminal of the series regulator, and the emitter terminal of the second control switching element Qc2 is connected to the output terminal of the series regulator. The emitter terminal of the third control switching element Qc2 is connected to the collector terminal of the second control switching element Qc2, and the collector terminal of the third control switching element Qc2 is connected to the base terminal of the second control switching element Qc2. The Darlington-connected control switching unit is equivalent to a PNP Darlington transistor with an increased current gain.

[0096] On the collector terminal side of the second control switching element Qc2, a ninth resistor R9, a tenth resistor R10, and a fourth control switching element Qc4 are connected in series between the high-side reference line and the low-side reference line. The fourth control switching element Qc4 is an NPN transistor. The connection point between the ninth resistor R9 and the tenth resistor R10 is connected to the base terminal of a PNP Darlington transistor (third control switching element Qc3).

[0097] A fourth voltage dividing circuit, in which a twelfth resistor R12 and a thirteenth resistor R13 are connected in series, is connected between the high-side reference line and the low-side reference line on the emitter terminal side of the second control switching element Qc2.

[0098] The connection point between the twelfth resistor R12 and the thirteenth resistor R13 is connected to the inverting input terminal of the operational amplifier OP1. The non-inverting input terminal of the operational amplifier OP1 is connected to the control unit 30 via a low-pass filter 231. The output terminal of the operational amplifier OP1 is connected to the base terminal of the fourth control switching element Qc4 via an eleventh resistor R11. The emitter terminal of the fourth control switching element Qc4 is connected to the low-side reference line, and the collector terminal of the fourth control switching element Qc4 is connected to the tenth resistor R10.

[0099] The operational amplifier OP1 receives the feedback voltage V output from the fourth voltage divider circuit. ＦＢ and the reference voltage V supplied from the control unit 30 via the low-pass filter 231. ＲＥＦ A base current according to the output voltage of the operational amplifier OP1 and the resistance value of the eleventh resistor R11 is supplied to the base terminal of the fourth control switching element Qc4.

[0100] A second capacitor C2 is connected between the input terminals of the series regulator. A third capacitor C3 is connected between the output terminals of the series regulator. The second capacitor C2 is connected to the input voltage V ＩＮ The third capacitor C3 is a capacitor for smoothing the output voltage V ｏｕｔ The second capacitor C2 and the third capacitor C3 are capacitors for smoothing the voltage. For example, electrolytic capacitors are used as the second capacitor C2 and the third capacitor C3.

[0101] A fourth discharge switching element Qd4 is connected in parallel with the third capacitor C3. The base terminal of the fourth discharge switching element Qd4 is connected to the control unit 30 via a fourteenth resistor R14. The control unit 30 can reset the charge stored in the third capacitor C3 by outputting an ON signal to turn on the fourth discharge switching element Qd4.

[0102] A third voltage dividing circuit, in which a seventh resistor R7 and an eighth resistor R8 are connected in series, is connected between the input terminals of the series regulator, and the voltage at the connection point between the seventh resistor R7 and the eighth resistor R8 is output to the control unit 30. The control unit 30 calculates the input voltage V of the series regulator based on the output voltage of the third voltage dividing circuit. ＩＮ Detect.

[0103] A fifth voltage dividing circuit, in which a fifteenth resistor R15 and a sixteenth resistor R16 are connected in series, is connected between the output terminals of the series regulator, and the voltage at the connection point between the fifteenth resistor R15 and the sixteenth resistor R16 is output to the control unit 30. The control unit 30 calculates the output voltage V of the series regulator based on the output voltage of the fifth voltage dividing circuit. ｏｕｔ Detect.

[0104] The control unit 30 generates a reference voltage V ＲＥＦ is input to the non-inverting input terminal of the operational amplifier OP1. The command voltage is a voltage that is set according to the intensity level set by the user. In the example described above, when the intensity level set by the user is level 1, the command voltage is set to 11 V.

[0105] When the output current of the series regulator increases due to a load fluctuation, the output voltage V ｏｕｔ decreases, and the feedback voltage V ＦＢ The feedback voltage V ＦＢ is the reference voltage V ＲＥＦ When the voltage Vc1 drops below 1 V, the output voltage of the operational amplifier OP1 rises, the base current of the fourth control switching element Qc4 increases, and the collector current of the fourth control switching element Qc4 increases. This increases the base current of the control switching unit (PNP Darlington transistor), reduces the collector voltage between the collector and emitter of the control switching unit (PNP Darlington transistor), and reduces the output voltage Vc1 of the series regulator. ｏｕｔ rises.

[0106] Conversely, when the output current of the series regulator decreases due to a load fluctuation, the output voltage V ｏｕｔ rises, and the feedback voltage V ＦＢ The feedback voltage V ＦＢ is the reference voltage VＲＥＦ When the voltage Vcc becomes higher, the output voltage of the operational amplifier OP1 drops, the base current of the fourth control switching element Qc4 decreases, and the collector current of the fourth control switching element Qc4 decreases. As a result, the base current of the control switching unit (PNP Darlington transistor) decreases, the collector voltage between the collector and emitter of the control switching unit (PNP Darlington transistor) increases, and the output voltage Vcc of the series regulator decreases. ｏｕｔ decreases.

[0107] 21 is a diagram showing an example of a timing chart of the series regulator shown in FIG. 20. In the example shown in FIG. 21, the twelfth resistor R12 is set to 190 kΩ, the thirteenth resistor R13 is set to 10 kΩ, and the feedback voltage V ＦＢ is the output voltage V of the series regulator ｏｕｔ In this case, the control unit 30 sets the reference voltage V to 1 / 20 of the command voltage. ＲＥＦ is input to the non-inverting input terminal of the operational amplifier OP1. The series regulator receives an input voltage V of about 50 V from the boost chopper in the previous stage. ＩＮ is assumed to be supplied.

[0108] The example shown in Figure 21 shows an example in which the first system electrical stimulation unit 10a and the second system electrical stimulation unit 10b are operating, and the intensity level of the first system electrical stimulation unit 10a is set to level 20, and the intensity level of the second system electrical stimulation unit 10b is set to level 1.

[0109] The control unit 30 applies a reference voltage V of 2.2 V to the non-inverting input terminal of the operational amplifier OP1 during the period when the EMS signal is output to the H-bridge circuit of the first system electrical stimulation unit 10a. ＲＥＦ This supplies the output voltage V ｏｕｔ However, it is controlled to 44V corresponding to level 20.

[0110] The control unit 30 applies a reference voltage V of 0.55 V to the non-inverting input terminal of the operational amplifier OP1 during the period when the EMS signal is output to the H-bridge circuit of the second system electrical stimulation unit 10b. ＲＥＦ This supplies the output voltage V ｏｕｔis controlled to 11V according to level 1.

[0111] The control unit 30 maintains a constant voltage output during the time width t3 during which the basic pulse group is applied, and changes the voltage level during the interval period of time width t4. Note that since the series regulator needs to ensure a voltage difference of at least 2 V between the input and output, the control unit 30, including a margin, ＩＮ ≧V ｏｕｔ Control to maintain the +5 state.

[0112] In this way, control unit 30 controls the command voltage set in the series regulator, and can adjust the voltage levels output to multiple systems of electrical stimulation units 10a-10d. ＲＥＦ is input to the non-inverting input terminal of the operational amplifier OP1. The operational amplifier OP1 outputs the output voltage V ｏｕｔ The control circuit 100 outputs a voltage for controlling the second control switching element Qc2 so that the output voltage of the second control switching element Qc2 coincides with the command voltage.

[0113] (Circuit Configuration Example of Low-Pass Filter 231) Fig. 22 is a diagram showing an example of the circuit configuration of the low-pass filter 231 of Fig. 20. In the circuit configuration example shown in Fig. 22, the low-pass filter 231 is configured as a second-order RC low-pass filter. As a first-stage RC low-pass filter, a seventeenth resistor R17 and a fourth capacitor C4 are connected in series between the general-purpose I / O port of the control unit 30 and the low-side reference line. As a second-stage RC low-pass filter, an eighteenth resistor R18 and a fifth capacitor C5 are connected in series between the low-side reference line and a connection point Na of the seventeenth resistor R17 and the fourth capacitor C4. The voltage at a connection point Nb of the eighteenth resistor R18 and the fifth capacitor C5 is set to a reference voltage V ＲＥＦ The signal is input to the non-inverting input terminal of the operational amplifier OP1 as a 19th resistor R19. A 19th resistor R19 is connected between the non-inverting input terminal of the operational amplifier OP1 and the low-side reference line. The control unit 30 outputs a PWM signal from a general-purpose I / O port to a second-order RC low-pass filter to generate a pseudo DC voltage.

[0114] Fig. 23 is a diagram showing an example of a timing chart of the second-order RC low-pass filter shown in Fig. 22. In the example shown in Fig. 23, an example of generating a pseudo DC voltage of 0.5 V is considered, assuming that the seventeenth resistor R17 is set to 1 kΩ, the fourth capacitor C4 is set to 0.01 μF, the eighteenth resistor R18 is set to 300 Ω, the fifth capacitor C5 is set to 0.1 μF, and the nineteenth resistor R19 is set to 2 kΩ.

[0115] The control unit 30 outputs a PWM signal from a general-purpose I / O port, with a high level being the power supply voltage (3.3 V), a low level being 0 V, and a frequency of 4 MHz. The power supply voltage (3.3 V) for the control unit 30 is generated by stepping down the output voltage (3.7 V) of the secondary battery 21 using another linear regulator (for example, a three-terminal regulator).

[0116] The voltage at node Na, which is the output voltage of the first-stage RC low-pass filter, is a triangular wave with a center voltage of 0.58 V. The voltage at node Nb, which is the output voltage of the second-stage RC low-pass filter, is a pseudo DC voltage of 0.5 V. Note that low-pass filter 231 used in the series regulator of FIG. 22 is preferably a second-order or higher low-pass filter, and the frequency of the PWM signal is preferably 1 MHz or higher.

[0117] (Circuit Configuration Example 2 of Linear Regulator 23) Fig. 24 is a diagram showing Circuit Configuration Example 2 of the linear regulator 23. In Circuit Configuration Example 2 shown in Fig. 24, a D / A converter 232 is used instead of the low-pass filter 231 shown in Fig. 20. Circuit Configuration Example 2 is premised on the fact that the control unit 30 is equipped with a serial communication port. The control unit 30 receives a reference voltage V ＲＥＦ The D / A converter 232 outputs the reference voltage V ＲＥＦ The D / A converter 232 converts the digital value of the analog signal into an analog voltage and outputs it to the non-inverting input terminal of the operational amplifier OP1. The D / A converter 232 may be built into the control unit 30.

[0118] As described above, by adopting Circuit Configuration Example 2 for the DC power supply unit 20, the switching regulators 22 can be consolidated into one system, thereby reducing the size and cost of the DC power supply unit 20. The inductor L1 and first capacitor C1 used in the switching regulator 22 are large in size and hinder miniaturization. In contrast, Circuit Configuration Example 1 requires switching regulators 22 according to the number of systems, which increases the size of the DC power supply unit 20 and costs.

[0119] By providing a linear regulator 23 downstream of the switching regulator 22, it is possible to change the voltage instantaneously. The response time of the linear regulator 23 is approximately equal to the response time of the control switching unit (PNP Darlington transistor), and the transient response speed is fast. In contrast, the switching regulator 22 must take into account the charge speed of the first capacitor C1 in addition to the response time of the first control switching element Qc1, and therefore has a slower transient response speed than the linear regulator 23.

[0120] When the above-described control of shifting the drive timing of the H-bridge circuit between multiple systems is adopted, even if one linear regulator 23 is shared by multiple systems of electrical stimulation units 10a-10d, the intensity level of each system can be adjusted individually. Furthermore, by using the linear regulator 23, it is possible to rapidly change the output voltage of the DC power supply unit 20, making it possible to apply AC voltages of various shapes other than pulse waves (e.g., shapes similar to sine waves) from the electrical stimulation unit 10 to the human body Hd. This allows for various flavors to be added to the bodily stimulation experienced by the user. Therefore, circuit configuration example 2 of the DC power supply unit 20 is also an effective power supply configuration for an electrical stimulation device 1 having a single system of electrical stimulation unit 10.

[0121] The present invention has been described above based on an embodiment. This embodiment is merely an example, and it will be understood by those skilled in the art that various modifications are possible in the combination of each component and each treatment process, and that such modifications are also within the scope of the present disclosure. Such modifications will be described below.

[0122] 25 is a diagram showing a modified circuit configuration of the DC power supply unit 20. In this modified example, an AC power supply is used instead of the secondary battery 21. The DC power supply unit 20 includes a rectifier circuit 24, a smoothing circuit 25, a PFC (Power Factor Correction) circuit 26, a switching regulator 22, and a linear regulator 23.

[0123] The rectifier circuit 24 full-wave rectifies the AC voltage supplied from the commercial power system 2. The smoothing circuit 25 smoothes the voltage output from the rectifier circuit 24. The PFC circuit 26 improves the power factor of the power output from the smoothing circuit 25. The switching regulator 22 steps down the voltage of the DC power supplied from the PFC circuit 26 to a predetermined voltage. An isolated DC / DC converter capable of stepping down or a step-down chopper can be used as the switching regulator 22. In a modified example, a wired connection to the commercial power system 2 is required, but stable power can be obtained from the commercial power system 2.

[0124] The present invention relates to an electrical stimulation device.

[0125] 1 Electrical stimulation device, 10 Electrical stimulation unit, 20 DC power supply unit, 21 Secondary battery, 22 Switching regulator, 23 Linear regulator, 231 Low-pass filter, 232 D / A converter, 24 Rectifier circuit, 25 Smoothing circuit, 26 PFC circuit, 30 Control unit, 31 Microcontroller, 32 Multiplexer, 33a-33d OR gate, 34a High-side buffer, 34b Low-side buffer, Q1-Q4 Switching element, P1 First electrode unit, P2 Second electrode unit, Dr1-Dr5 Drive circuit, Qd1-Qd4 Discharge switching element, Qc1-Qc4 Control switching element, Cc1 First coupling capacitor, Cc2 Second coupling capacitor, Hd Human body, L1 Inductor, C1-C5 Capacitor, D1 Diode, OP1 operational amplifier, R1-R19 resistors.

Claims

1. An electrical stimulation device comprising: a first switching element and a second switching element connected in series between a high-side reference line and a low-side reference line of a DC power supply; a first electrode unit connected to a first connection point between the first switching element and the second switching element and to be brought into contact with a part of a human body; a third switching element and a fourth switching element connected in series between the high-side reference line and the low-side reference line of the DC power supply; a second electrode unit connected to a second connection point between the third switching element and the fourth switching element and to be brought into contact with another part of the human body; a first coupling capacitor inserted between the first connection point and the first electrode unit to provide DC insulation between the first connection point and the first electrode unit; and a second coupling capacitor inserted between the second connection point and the second electrode unit to provide DC insulation between the second connection point and the second electrode unit.

2. The electrical stimulation device of claim 1, further comprising: a first discharge switching element connected between wiring connecting the first coupling capacitor and the first electrode unit and the low-side reference line; and a second discharge switching element connected between wiring connecting the second coupling capacitor and the second electrode unit and the low-side reference line.

3. The electrical stimulation device of claim 2, further comprising a control unit that controls the first switching element and the fourth switching element, and the first discharge switching element and the second discharge switching element, wherein the control unit is capable of controlling the first switching element and the fourth switching element to an on state and the second switching element and the third switching element to an off state, thereby applying a positive pulse voltage between the first electrode unit and the second electrode unit, and controlling the first switching element and the fourth switching element to an off state and the second switching element and the third switching element to an on state, thereby applying a negative pulse voltage between the first electrode unit and the second electrode unit, wherein the positive pulse voltage and the negative pulse voltage are applied alternately a plurality of times in one cycle, and a period in which the first discharge switching element and the second discharge switching element are in an on state is inserted in the interval period thereafter.

4. The electrical stimulation device comprises a plurality of electrical stimulation units and a control unit that controls the plurality of electrical stimulation units, each of which includes the first switching element, the fourth switching element, the first electrode unit, the second electrode unit, the first coupling capacitor, and the second coupling capacitor, the control unit is capable of controlling the first switching element and the fourth switching element to an on state and the second switching element and the third switching element to an off state, and applying a positive pulse voltage between the first electrode unit and the second electrode unit, and controlling the first switching element and the fourth switching element to an off state and the second switching element and the third switching element to an on state, and applying a negative pulse voltage between the first electrode unit and the second electrode unit, and is capable of adjusting the voltage levels output to the plurality of electrical stimulation units, and applying the positive pulse voltage and the negative pulse voltage alternately a plurality of times in one cycle, and inserting an interval period after applying the plurality of pulse voltages, 2. The electrical stimulation device according to claim 1, wherein the first switching element-the fourth switching element of the plurality of electrical stimulation units are controlled so that the plurality of pulse voltages out of phase are applied between the first electrode unit and the second electrode unit of each of the plurality of electrical stimulation units.

5. The electrical stimulation device comprises a plurality of electrical stimulation units and a control unit that controls the plurality of electrical stimulation units, each of which includes the first switching element and the fourth switching element, the first discharge switching element and the second discharge switching element, the first electrode unit, the second electrode unit, the first coupling capacitor, and the second coupling capacitor, the control unit is capable of controlling the first switching element and the fourth switching element to an on state and the second switching element and the third switching element to an off state, and applying a positive pulse voltage between the first electrode unit and the second electrode unit, and controlling the first switching element and the fourth switching element to an off state and the second switching element and the third switching element to an on state, and applying a negative pulse voltage between the first electrode unit and the second electrode unit, and is capable of adjusting the voltage levels output to the plurality of electrical stimulation units, and applying the positive pulse voltage and the negative pulse voltage alternately a plurality of times in one cycle, and inserting periods in which the first discharge switching element and the second discharge switching element are in an on state in interval periods after applying the plurality of pulse voltages, The electrical stimulation device according to claim 2, wherein the first switching element-the fourth switching element of the plurality of electrical stimulation units are controlled so that the plurality of pulse voltages out of phase are applied between the first electrode unit and the second electrode unit of each of the plurality of electrical stimulation units.

6. The electrical stimulation device of claim 1, further comprising a control unit that controls the first switching element and the fourth switching element, wherein the control unit is capable of controlling the first switching element and the fourth switching element to an on state and the second switching element and the third switching element to an off state, thereby applying a positive pulse voltage between the first electrode unit and the second electrode unit, and controlling the first switching element and the fourth switching element to an off state and the second switching element and the third switching element to an on state, thereby applying a negative pulse voltage between the first electrode unit and the second electrode unit, wherein the positive pulse voltage and the negative pulse voltage are applied alternately a plurality of times in one cycle, and a period in which the second switching element and the fourth switching element are in an on state is inserted in the interval period thereafter.

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