Control Circuit of Electric Tilting Nursing Bed

Abstract

The present invention relates to the technical field of electric side-tilting nursing beds, and more particularly to a control circuit for an electric side-tilting nursing bed. The control circuit comprises a power input and rectification circuit, a battery charging circuit, a battery undervoltage protection circuit, a main circuit current protection circuit, four relay control circuits, a circuit for electric push rod M4 to control electric push rod M1, a circuit for electric push rod M1 to control electric push rod M4, and a circuit for electric push rod M4 to stop at an intermediate position. This control circuit for an electric side-tilting nursing bed employs switches within the controlled push rods to determine whether each push rod has reached a designated position, thereby preventing interference damage caused by improperly positioned components. This allows for safe operation of complex mechanisms at a minimal cost.

Description

Technical Field

[0001] The present invention relates to a control circuit, in particular to a control circuit of an electric side-turning nursing bed. Background Art

[0002] As the aging population continues to accelerate, the proportion of young people continues to decrease, while the number of disabled elderly people is increasing. Many patients with limited mobility need to remain in bed for extended periods. In clinical practice, for patients with hemiplegia, paraplegia, and the elderly and frail, bedridden patients often require one or two medical staff members or family members to manually turn and reposition them every one to two hours to improve blood circulation and prevent bedsores. Manual turning, leg bending, and assistance with sitting are not only laborious but also prone to bedsores if not properly turned and repositioned. Furthermore, bedridden patients who fail to frequently turn and reposition are prone to complications such as pulmonary infections. To address the care challenges of bedridden patients, various electric nursing beds have been developed both domestically and internationally in recent years, but these systems lack a high degree of automation. Summary of the Invention

[0003] The present invention aims to solve the above-mentioned defects and provides a control circuit for an electric side-turning nursing bed.

[0004] In order to overcome the defects existing in the background technology, the technical solution adopted by the present invention to solve its technical problems is: the control circuit of this electric side-turning nursing bed includes a power input and rectification circuit, a battery charging circuit, a battery undervoltage protection circuit, a main circuit current protection circuit, 4 groups of relay group control circuits, an electric push rod M4 restricting electric push rod M1 circuit, an electric push rod M1 restricting electric push rod M4 circuit and an electric push rod M4 intermediate position stop circuit, which is characterized in that: the power input and rectification circuit is connected in series with the battery charging circuit, the battery charging circuit is connected in series with the battery undervoltage protection circuit, the battery undervoltage protection circuit is connected in series with the main circuit current protection circuit, the main circuit current protection circuit is connected in parallel with the 4 groups of relay group control circuits, and the connection points on the M4 restricting M1 circuit, the M1 restricting M4 circuit and the M4 intermediate position stop circuit are connected to the corresponding connection points on the battery undervoltage protection circuit, the main circuit current protection circuit and the 4 groups of relay group control circuits.

[0005] According to another embodiment of the present invention, the power input and rectification circuit further includes a transformer t, input terminals 1 and 2 of the transformer t are connected to 220V, 50Hz AC power, output terminals 3 and 4 of the transformer t are connected to terminals 1 and 3 of the rectifier bridge BD1, terminal 4 of the rectifier bridge BD1 is grounded, and terminal 2 of the rectifier bridge BD1 is connected to the positive electrode of the electrolytic capacitor C6, the positive electrode of the electrolytic capacitor C6-1, and the Vin terminal of the voltage regulator LM317.

[0006] According to another embodiment of the present invention, the battery charging circuit further includes a voltage regulator LM317, the ADJ terminal of the voltage regulator LM317 is connected to the resistor R8 and one end of the resistor R7, the other end of the resistor R8 is grounded, the other end of the resistor R7 is connected to the OUT terminal of the voltage regulator LM317, the OUT terminal of the voltage regulator LM317 is also connected to the positive electrode of the electrolytic capacitor C9 and the anode of the diode D5, the negative electrode of the electrolytic capacitor C9 is grounded, and the cathode of the diode D5 is connected to the positive electrode of the two battery packs connected in series.

[0007] According to another embodiment of the present invention, the battery undervoltage protection circuit further includes the following: the positive electrode of the battery pack is connected to the anode of the diode D3, the source of the MOS transistor Q1, and one end of the resistor R1; the cathode of the diode D3 is connected to the cathode of the diode D2, the positive electrode of the electrolytic capacitor C5, the external hand controller interface con1, and the connection point VH; the negative electrode of the electrolytic capacitor C5 is grounded; the external hand controller interface con includes connection points S1, S2, S3, S4, S5, S6, S7, and S8; the anode of the diode D2 is connected to the cathode of the diode D4; the anode of the diode D4 is connected to the drain of the MOS transistor Q1 and one end of the resistor R12; the gate of the MOS transistor Q1 is connected to the other end of the resistor R1 and one end of the resistor R2; the other end of the resistor R12 is connected to one end of the resistor R10, one end of the capacitor C7, and pin 2 of the operational amplifier LM358; pin 1 of the operational amplifier LM358 is connected to the anode of the diode D6; the cathode of the diode D6 is connected to one end of the resistor R3; the other end of the resistor R3 is connected to Connect the positive electrode of electrolytic capacitor C3, one end of resistor R4, and the base of transistor Q3. The other ends of electrolytic capacitor C3 and resistor R4 are grounded. The other end of resistor R10 and the other end of capacitor C7 are grounded. The other end of resistor R2 is connected to the collector of transistor Q2. The emitter of transistor Q2 is grounded. The base of transistor Q2 is connected to the collector of transistor Q3, one end of capacitor C4, and one end of resistor R5. The other end of capacitor C4 is grounded. The other end of resistor R5 is connected to the cathode of diode D8. The anode of D8 is connected to the positive electrode of electrolytic capacitor C10, one end of resistor R13, connection point 12V, one end of resistor R15, and the cathode of Zener diode DZ1. The negative electrode of electrolytic capacitor C10 is grounded, and the anode of Zener diode DZ1 is grounded. The other end of resistor R13 is connected to one end of resistor R11, one end of capacitor C8, and pin 3 of voltage regulator LM358. The other end of capacitor C8 is grounded. The other end of resistor R11 is connected to one end of resistor R11A, and the other end of resistor R11A is grounded.

[0008] According to another embodiment of the present invention, the main circuit current protection circuit further includes the other end of the resistor R15 connected to the cathode of the diode D10 and the connection point RA, the anode of the diode D10 is connected to the cathode of the diode D11, the cathode of the diode D12, the cathode of the diode D13, the cathode of the diode D14, the cathode of the diode D15, the cathode of the diode D16, the cathode of the diode D17, the cathode of the diode D18, and one end of the resistor R18, the anode of the diode D11 is provided with a connection point S1, the anode of the diode D12 is provided with a connection point S2, the anode of the diode D13 is provided with a connection point S3, the anode of the diode D14 is provided with a connection point S4, the anode of the diode D15 is provided with a connection point S5, the anode of the diode D16 is provided with a connection point S6, the anode of the diode D17 is provided with a connection point S7, and the anode of the diode D18 is provided with a connection point S8, and the other end of the resistor R18 is connected to the collector of the transistor Q5 , the collector of transistor Q4, one end of capacitor C13, and the base of transistor Q6. The base of transistor Q5 is connected to one end of capacitor C11, one end of resistor R17, and one end of resistor R16. The emitter of transistor Q5 is grounded. The other end of capacitor C13 is grounded. The other end of capacitor C11 is grounded. The other end of resistor R17 is grounded. The other end of resistor R16 is connected to the collector of transistor Q6 and one end of resistor R22. The emitter of transistor Q6 is grounded. The other end of resistor R22 is connected to the four-group relay group control circuit. The emitter of transistor Q4 is grounded. The base of transistor Q4 is connected to the positive electrode of electrolytic capacitor C12, one end of resistor R48, and one end of resistor R47. The negative electrode of electrolytic capacitor C12 is grounded. The other end of resistor R48 is grounded. The other end of resistor R47 is connected to one end of resistor R19. The other end of resistor R19 is connected to one end of resistor R20 and a connection point VSS. The other end of resistor R20 is grounded.

[0009] According to another embodiment of the present invention, the four relay group control circuits further include:

[0010] A first relay group consisting of a relay K1, a relay K2, a diode D21, a diode D22, and an external interface M1, wherein the coil of relay K1 is connected in parallel to the diode D21, the coil of relay K2 is connected in parallel to the diode D22, the common terminal of relay K1 is connected to one end of the varistor RV1 and terminal 1 of the external interface M1, the normally closed terminal of relay K1 is provided with a connection point VSS, the normally open terminal of relay K1 is provided with a connection point VCC, the common terminal of relay K2 is connected to the other end of the varistor RV1 and terminal 2 of the external interface M1, the normally closed terminal of relay K2 is provided with a connection point VSS, the normally open terminal of relay K2 is provided with a connection point VCC, terminal 3 of external interface M1 is connected to one end of the resistor R23, one end of the capacitor C14, and a connection point m1, the other end of the resistor R23 is connected to the cathode of diode D31, the anode of diode D31 is provided with a connection point RA, the other end of capacitor C14 is grounded, the cathode of diode D21 is provided with a connection point S22, and the cathode of diode D22 is provided with a connection point S1;

[0011] A second relay group consisting of a relay K3, a relay K4, a diode D23, a diode D24, and an external interface M2, wherein the coil of relay K3 is connected in parallel to the diode D23, the coil of relay K4 is connected in parallel to the diode D24, the common terminal of relay K3 is connected to one end of the varistor RV2 and terminal 1 of the external interface M2, the normally closed terminal of relay K3 is provided with a connection point VSS, and the normally open terminal of relay K3 is provided with a connection point VCC, the common terminal of relay K4 is connected to the other end of the varistor RV2 and terminal 2 of the external interface M2, the normally closed terminal of relay K4 is provided with a connection point VSS, and the normally open terminal of relay K4 is provided with a connection point VCC, the cathode of diode D23 is provided with a connection point S3, and the cathode of diode D24 is provided with a connection point S4;

[0012] A third relay group consisting of a relay K5, a relay K6, a diode D25, a diode D26, and an external interface M3, wherein the coil of relay K5 is connected in parallel to the diode D25, the coil of relay K6 is connected in parallel to the diode D26, the common terminal of relay K5 is connected to one end of the varistor RV3 and terminal 1 of the external interface M3, the normally closed terminal of relay K5 is provided with a connection point VSS, the normally open terminal of relay K5 is provided with a connection point VCC, the common terminal of relay K6 is connected to the other end of the varistor RV3 and terminal 2 of the external interface M3, the normally closed terminal of relay K6 is provided with a connection point VSS, the normally open terminal of relay K6 is provided with a connection point VCC, the cathode of diode D25 is provided with a connection point S5, and the cathode of diode D26 is provided with a connection point S6;

[0013] A fourth relay group consists of a relay K7, a relay K8, a diode D27, a diode D27, and an external interface M4. The coil of the relay K7 is connected in parallel to the diode D27, the coil of the relay K8 is connected in parallel to the diode D28, the common terminal of the relay K7 is connected to one end of the varistor RV4 and the terminal 1 of the external interface M4, the normally closed terminal of the relay K7 is provided with a connection point VSS, the normally open terminal of the relay K7 is provided with a connection point VCC, the common terminal of the relay K8 is connected to the other end of the varistor RV4 and the terminal 2 of the external interface M4, the normally closed terminal of the relay K8 is provided with a connection point VSS, the normally open terminal of the relay K8 is provided with a connection point VCC, the terminal 3 of the external interface M4 is provided with a connection point VG, the terminal 4 of the external interface M4 is provided with a connection point m4, the cathode of the diode D27 is provided with a connection point S77, and the cathode of the diode D28 is provided with a connection point S88.

[0014] According to another embodiment of the present invention, the electric push rod M4 further includes a circuit for restricting the electric push rod M1, including a transistor Q7, a resistor R25 is connected between the emitter and base of the transistor Q7, the emitter of the transistor Q7 is provided with a connection point S2, the collector of the transistor Q7 is connected to the anode of the diode D32, the cathode of the diode D32 is provided with a connection point S22, the base of the transistor Q7 is connected to one end of the resistor R29, the other end of the resistor R29 is connected to the anode of the diode D36, the cathode of the diode D36 is connected to one end of the resistor R34 and the collector of the transistor Q10, the other end of the resistor R34 is provided with a connection point RA, the emitter of the transistor Q10 is grounded, and the transistor Q10 The base of the transistor is connected to one end of the capacitor C17, one end of the resistor R38, and one end of the resistor R39. The other end of the capacitor C17 is grounded. The other end of the resistor R38 is grounded. The other end of the resistor R39 is connected to the collector of the transistor Q14. The emitter of the transistor Q14 is connected to one end of the resistor R41 and a connection point m4. The other end of the resistor R41 is connected to the base of the transistor Q14 and one end of the resistor R44. The other end of the resistor R44 is connected to the collector of the transistor Q16. The base of the transistor Q16 is connected to one end of the capacitor C20 and one end of the resistor R46. The other end of the capacitor C20 is grounded. The other end of the resistor R46 is provided with a connection point RA. The emitter of the transistor Q16 is grounded.

[0015] According to another embodiment of the present invention, the electric push rod M1 further includes a circuit for restricting the electric push rod M4, including: a resistor R26 is connected between the emitter and base of the transistor Q8, the emitter of the transistor Q8 is provided with a connection point S7, the collector of the transistor Q8 is connected to the anode of the diode D33, the cathode of the diode D33 is provided with a connection point S77, the base of the transistor Q8 is connected to one end of the resistor R30, the other end of the resistor R30 is connected to the anode of the diode D37, the cathode of the diode D37 is connected to the cathode of the diode D42, the collector of the transistor Q11, and one end of the resistor R35, the other end of the resistor R35 is provided with a connection point RA, the anode of the diode D42 is connected to one end of the resistor R31, the other end of the resistor R31 is connected to the base of the transistor Q9 and one end of the resistor R27, the other end of the resistor R27 is connected to the emitter of the transistor Q9 and the connection point S8, the transistor The collector of Q9 is connected to the anode of diode D34, and the cathode of diode D34 is connected to a connection point S88. The base of transistor Q11 is connected to one end of resistor R37, one end of capacitor C18, one end of resistor R40, and the collector of transistor Q13. The other end of resistor R37 is grounded, the other end of capacitor C18 is grounded, and the other end of resistor R40 is connected to a connection point RA. The emitter of transistor Q13 is grounded. The base of transistor Q13 is connected to one end of resistor R43, one end of capacitor C19, and one end of resistor R45. The other end of resistor R43 is grounded, the other end of capacitor C19 is grounded, and the other end of resistor R45 is connected to the cathode of diode D40 and the cathode of diode D41. The anode of diode D40 is connected to the cathode of diode D40-A, the cathode of diode D40-A is connected to a connection point m1, and the anode of diode D41 is connected to a connection point MID4.

[0016] According to another embodiment of the present invention, the intermediate position stop circuit of the electric push rod M4 further includes: one end of the resistor R53 is connected to the connection point 12V, the other end of the resistor R53 is connected to one end of the electrolytic capacitor C21 and the positive electrode of the buzzer SPK, the negative electrode of the electrolytic capacitor C21 is grounded, the negative electrode of the buzzer SPK is connected to the anode of the diode D43, the cathode of the diode D43 is connected to one end of the resistor R36 and the collector of the transistor Q12, the other end of the resistor R36 is connected to the cathode of the diode D39, the anode of the diode D39 is connected to one end of the resistor R42 and the base of the transistor Q15, the other end of the resistor R42 is connected to the emitter of the transistor Q15, and a connection point RA is provided. The emitter of the transistor Q12 is grounded, and the transistor Q1 2 is connected to one end of capacitor C16, one end of resistor R33, and one end of resistor R32. The other end of capacitor C16 is grounded. The other end of resistor R33 is grounded. The other end of resistor R32 is connected to the cathode of diode D35 and the cathode of diode D38. The anode of diode D38 is connected to the collector of transistor Q15 and a connection point MID4 is provided. The anode of diode D35 is connected to one end of resistor R28 and the negative electrode of electrolytic capacitor C15. The other end of resistor R28 is grounded. The positive electrode of electrolytic capacitor C15 is connected to the common terminal of switch SW and a connection point m4 is provided. The normally closed end of switch SW is connected to one end of resistor R24 and a connection point VG is provided. The other end of resistor R24 is grounded. The normally open end of switch SW is provided with a connection point VCC.

[0017] The beneficial effect of the present invention is that the control circuit of the electric side-tilting nursing bed determines whether each electric push rod has reached a specified position by adding a switch inside the controlled electric push rod, thereby avoiding interference damage caused by the movement of various mechanism components in unreasonable positions, and enabling safe movement between complex mechanisms at a small cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below with reference to the accompanying drawings and examples.

[0019] Figure 1 This is a schematic diagram of the connection structure of the power input and rectification circuit, battery charging circuit, battery undervoltage protection circuit, main circuit current protection circuit, and four groups of relay group control circuits in the present invention;

[0020] Figure 2 This is a schematic diagram of the structure of the electric push rod M4 restricting the electric push rod M1 circuit in the present invention;

[0021] Figure 3 This is a schematic diagram of the structure of the circuit in which the electric push rod M1 restricts the electric push rod M4 in the present invention;

[0022] Figure 4It is a structural diagram of the intermediate position stop circuit of the electric push rod M4 in the present invention. DETAILED DESCRIPTION

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art without creative effort based on the embodiments of the present invention are within the scope of protection of the present invention.

[0024] The control circuit of this electric side-turning nursing bed includes a power input and rectification circuit, a battery charging circuit, a battery undervoltage protection circuit, a main circuit current protection circuit, four groups of relay group control circuits, an electric push rod M4 restricting electric push rod M1 circuit, an electric push rod M1 restricting electric push rod M4 circuit and an electric push rod M4 intermediate position stop circuit, and is characterized in that: the power input and rectification circuit is connected in series with the battery charging circuit, the battery charging circuit is connected in series with the battery undervoltage protection circuit, the battery undervoltage protection circuit is connected in series with the main circuit current protection circuit, the main circuit current protection circuit is connected in parallel with the four groups of relay group control circuits, and the connection points on the M4 restricting M1 circuit, the M1 restricting M4 circuit and the M4 intermediate position stop circuit are connected to the corresponding connection points on the battery undervoltage protection circuit, the main circuit current protection circuit and the four groups of relay group control circuits.

[0025] like Figure 1 As shown, the power input and rectification circuit includes a transformer t, input terminals 1 and 2 of the transformer t are connected to 220V, 50Hz AC power, output terminals 3 and 4 of the transformer t are connected to terminals 1 and 3 of the rectifier bridge BD1, terminal 4 of the rectifier bridge BD1 is grounded, and terminal 2 of the rectifier bridge BD1 is connected to the positive electrode of the electrolytic capacitor C6, the positive electrode of the electrolytic capacitor C6-1, and the Vin terminal of the voltage regulator LM317.

[0026] like Figure 1 As shown, the battery charging circuit includes a voltage regulator LM317, the ADJ terminal of the voltage regulator LM317 is connected to the resistor R8 and one end of the resistor R7, the other end of the resistor R8 is grounded, the other end of the resistor R7 is connected to the OUT terminal of the voltage regulator LM317, the OUT terminal of the voltage regulator LM317 is also connected to the positive electrode of the electrolytic capacitor C9 and the anode of the diode D5, the negative electrode of the electrolytic capacitor C9 is grounded, and the cathode of the diode D5 is connected to the positive electrode of the two battery packs connected in series.

[0027] like Figure 1As shown, the battery undervoltage protection circuit includes a positive electrode of the battery pack connected to the anode of the diode D3, the source of the MOS tube Q1, and one end of the resistor R1, the cathode of the diode D3 is connected to the cathode of the diode D2, the positive electrode of the electrolytic capacitor C5, the external hand controller interface con1, and the connection point VH, the negative electrode of the electrolytic capacitor C5 is grounded, the external hand controller interface con includes connection points S1, S2, S3, S4, S5, S6, S7, and S8, the anode of the diode D2 is connected to the cathode of the diode D4, the anode of the diode D4 is connected to the drain of the MOS tube Q1 and one end of the resistor R12, the gate of the MOS tube Q1 is connected to the other end of the resistor R1 and one end of the resistor R2, the other end of the resistor R12 is connected to one end of the resistor R10, one end of the capacitor C7, and pin 2 of the operational amplifier LM358, pin 1 of the operational amplifier LM358 is connected to the anode of the diode D6, the cathode of the diode D6 is connected to one end of the resistor R3, and the other end of the resistor R3 is connected to the The positive electrode, one end of the resistor R4, the base of the transistor Q3, the electrolytic capacitor C3, and the other end of the resistor R4 are grounded. The other end of the resistor R10 and the other end of the capacitor C7 are grounded. The other end of the resistor R2 is connected to the collector of the transistor Q2. The emitter of the transistor Q2 is grounded. The base of the transistor Q2 is connected to the collector of the transistor Q3, one end of the capacitor C4, and one end of the resistor R5. The other end of the capacitor C4 is grounded. The other end of the resistor R5 is connected to the cathode of the diode D8. The anode of the diode D8 is connected to the cathode of the diode D8. The cathode of the electrolytic capacitor C10 is connected to the ground, the anode of the Zener diode DZ1 is grounded, the other end of the resistor R13 is connected to one end of the resistor R11, one end of the capacitor C8 and pin 3 of the voltage regulator LM358, the other end of the capacitor C8 is grounded, the other end of the resistor R11 is connected to one end of the resistor R11A, and the other end of the resistor R11A is grounded.

[0028] like Figure 1As shown, the main circuit current protection circuit includes the other end of the resistor R15 connected to the cathode of the diode D10 and the connection point RA, the anode of the diode D10 is connected to the cathode of the diode D11, the cathode of the diode D12, the cathode of the diode D13, the cathode of the diode D14, the cathode of the diode D15, the cathode of the diode D16, the cathode of the diode D17, the cathode of the diode D18, and one end of the resistor R18, the anode of the diode D11 is provided with a connection point S1, the anode of the diode D12 is provided with a connection point S2, the anode of the diode D13 is provided with a connection point S3, the anode of the diode D14 is provided with a connection point S4, the anode of the diode D15 is provided with a connection point S5, the anode of the diode D16 is provided with a connection point S6, the anode of the diode D17 is provided with a connection point S7, and the anode of the diode D18 is provided with a connection point S8, and the other end of the resistor R18 is connected to the collector of the transistor Q5 and the collector of the transistor Q4. The base of the transistor Q5 is connected to the positive electrode of the electrolytic capacitor C12, one end of the resistor R48, and one end of the resistor R47. The negative electrode of the electrolytic capacitor C12 is grounded. The other end of the resistor R48 is grounded. The other end of the resistor R48 is grounded. The other end of the resistor R47 is connected to one end of the resistor R19. The other end of the resistor R19 is connected to one end of the resistor R20 and a connection point VSS. The other end of the resistor R20 is grounded.

[0029] like Figure 1 As shown, the 4 relay group control circuits include:

[0030] A first relay group consisting of a relay K1, a relay K2, a diode D21, a diode D22, and an external interface M1, wherein the coil of relay K1 is connected in parallel to the diode D21, the coil of relay K2 is connected in parallel to the diode D22, the common terminal of relay K1 is connected to one end of the varistor RV1 and terminal 1 of the external interface M1, the normally closed terminal of relay K1 is provided with a connection point VSS, the normally open terminal of relay K1 is provided with a connection point VCC, the common terminal of relay K2 is connected to the other end of the varistor RV1 and terminal 2 of the external interface M1, the normally closed terminal of relay K2 is provided with a connection point VSS, the normally open terminal of relay K2 is provided with a connection point VCC, terminal 3 of external interface M1 is connected to one end of the resistor R23, one end of the capacitor C14, and a connection point m1, the other end of the resistor R23 is connected to the cathode of diode D31, the anode of diode D31 is provided with a connection point RA, the other end of capacitor C14 is grounded, the cathode of diode D21 is provided with a connection point S22, and the cathode of diode D22 is provided with a connection point S1;

[0031] A second relay group consisting of a relay K3, a relay K4, a diode D23, a diode D24, and an external interface M2, wherein the coil of relay K3 is connected in parallel to the diode D23, the coil of relay K4 is connected in parallel to the diode D24, the common terminal of relay K3 is connected to one end of the varistor RV2 and terminal 1 of the external interface M2, the normally closed terminal of relay K3 is provided with a connection point VSS, and the normally open terminal of relay K3 is provided with a connection point VCC, the common terminal of relay K4 is connected to the other end of the varistor RV2 and terminal 2 of the external interface M2, the normally closed terminal of relay K4 is provided with a connection point VSS, and the normally open terminal of relay K4 is provided with a connection point VCC, the cathode of diode D23 is provided with a connection point S3, and the cathode of diode D24 is provided with a connection point S4;

[0032] A third relay group consisting of a relay K5, a relay K6, a diode D25, a diode D26, and an external interface M3, wherein the coil of relay K5 is connected in parallel to the diode D25, the coil of relay K6 is connected in parallel to the diode D26, the common terminal of relay K5 is connected to one end of the varistor RV3 and terminal 1 of the external interface M3, the normally closed terminal of relay K5 is provided with a connection point VSS, the normally open terminal of relay K5 is provided with a connection point VCC, the common terminal of relay K6 is connected to the other end of the varistor RV3 and terminal 2 of the external interface M3, the normally closed terminal of relay K6 is provided with a connection point VSS, the normally open terminal of relay K6 is provided with a connection point VCC, the cathode of diode D25 is provided with a connection point S5, and the cathode of diode D26 is provided with a connection point S6;

[0033] A fourth relay group consists of a relay K7, a relay K8, a diode D27, a diode D27, and an external interface M4. The coil of the relay K7 is connected in parallel to the diode D27, the coil of the relay K8 is connected in parallel to the diode D28, the common terminal of the relay K7 is connected to one end of the varistor RV4 and the terminal 1 of the external interface M4, the normally closed terminal of the relay K7 is provided with a connection point VSS, the normally open terminal of the relay K7 is provided with a connection point VCC, the common terminal of the relay K8 is connected to the other end of the varistor RV4 and the terminal 2 of the external interface M4, the normally closed terminal of the relay K8 is provided with a connection point VSS, the normally open terminal of the relay K8 is provided with a connection point VCC, the terminal 3 of the external interface M4 is provided with a connection point VG, the terminal 4 of the external interface M4 is provided with a connection point m4, the cathode of the diode D27 is provided with a connection point S77, and the cathode of the diode D28 is provided with a connection point S88.

[0034] like Figure 2 As shown, the electric push rod M4 controls the electric push rod M1 circuit including a transistor Q7, a resistor R25 is connected between the emitter and base of the transistor Q7, the emitter of the transistor Q7 is provided with a connection point S2, the collector of the transistor Q7 is connected to the anode of the diode D32, the cathode of the diode D32 is provided with a connection point S22, the base of the transistor Q7 is connected to one end of the resistor R29, the other end of the resistor R29 is connected to the anode of the diode D36, the cathode of the diode D36 is connected to one end of the resistor R34 and the collector of the transistor Q10, the other end of the resistor R34 is provided with a connection point RA, the emitter of the transistor Q10 is grounded, and the base of the transistor Q10 is connected to the capacitor C1 7, one end of resistor R38, one end of resistor R39, the other end of capacitor C17 is grounded, the other end of resistor R38 is grounded, the other end of resistor R39 is connected to the collector of transistor Q14, the emitter of transistor Q14 is connected to one end of resistor R41 and a connection point m4, the other end of resistor R41 is connected to the base of transistor Q14 and one end of resistor R44, the other end of resistor R44 is connected to the collector of transistor Q16, the base of transistor Q16 is connected to one end of capacitor C20 and one end of resistor R46, the other end of capacitor C20 is grounded, the other end of resistor R46 is connected to a connection point RA, and the emitter of transistor Q16 is grounded.

[0035] like Figure 3As shown, the electric push rod M1 controls the electric push rod M4 circuit including: a resistor R26 is connected between the emitter and base of the transistor Q8, the emitter of the transistor Q8 is provided with a connection point S7, the collector of the transistor Q8 is connected to the anode of the diode D33, the cathode of the diode D33 is provided with a connection point S77, the base of the transistor Q8 is connected to one end of the resistor R30, the other end of the resistor R30 is connected to the anode of the diode D37, the cathode of the diode D37 is connected to the cathode of the diode D42, the collector of the transistor Q11, and one end of the resistor R35, the other end of the resistor R35 is provided with a connection point RA, the anode of the diode D42 is connected to one end of the resistor R31, the other end of the resistor R31 is connected to the base of the transistor Q9 and one end of the resistor R27, the other end of the resistor R27 is connected to the emitter of the transistor Q9 and the connection point S8, the collector of the transistor Q9 is connected The anode and cathode of diode D34 are connected to a connection point S88. The base of transistor Q11 is connected to one end of resistor R37, one end of capacitor C18, one end of resistor R40, and the collector of transistor Q13. The other end of resistor R37 is grounded. The other end of capacitor C18 is grounded. The other end of resistor R40 is connected to a connection point RA. The emitter of transistor Q13 is grounded. The base of transistor Q13 is connected to one end of resistor R43, one end of capacitor C19, and one end of resistor R45. The other end of resistor R43 is grounded. The other end of capacitor C19 is grounded. The other end of resistor R45 is connected to the cathode of diode D40 and the cathode of diode D41. The anode of diode D40 is connected to the cathode of diode D40-A. The cathode of diode D40-A is connected to a connection point m1. The anode of diode D41 is connected to a connection point MID4.

[0036] like Figure 4As shown, the intermediate position stop circuit of the electric push rod M4 includes: one end of the resistor R53 is connected to the connection point 12V, the other end of the resistor R53 is connected to one end of the electrolytic capacitor C21 and the positive electrode of the buzzer SPK, the negative electrode of the electrolytic capacitor C21 is grounded, the negative electrode of the buzzer SPK is connected to the anode of the diode D43, the cathode of the diode D43 is connected to one end of the resistor R36 and the collector of the transistor Q12, the other end of the resistor R36 is connected to the cathode of the diode D39, the anode of the diode D39 is connected to one end of the resistor R42 and the base of the transistor Q15, the other end of the resistor R42 is connected to the emitter of the transistor Q15 and is provided with a connection point RA, the emitter of the transistor Q12 is grounded, and the base of the transistor Q12 is connected to the capacitor One end of C16, one end of resistor R33, one end of resistor R32, and the other end of capacitor C16 are grounded. The other end of resistor R33 is grounded. The other end of resistor R32 is connected to the cathode of diode D35 and the cathode of diode D38. The anode of diode D38 is connected to the collector of transistor Q15 and a connection point MID4 is provided. The anode of diode D35 is connected to one end of resistor R28 and the negative electrode of electrolytic capacitor C15. The other end of resistor R28 is grounded. The positive electrode of electrolytic capacitor C15 is connected to the common end of switch SW and a connection point m4 is provided. The normally closed end of switch SW is connected to one end of resistor R24 and a connection point VG is provided. The other end of resistor R24 is grounded. The normally open end of switch SW is provided with a connection point VCC.

[0037] The connection points on each circuit are connected to each other.

[0038] The AC input is 220V, 50Hz, stepped down to 24V by a transformer, and then rectified to DC. The DC voltage is then stabilized by an LM317 voltage regulator and supplied to a two-cell 12V / 1.3AH battery pack connected in series. A voltage comparator, comprised of an LM358 operational amplifier, provides undervoltage protection for the battery pack. The positive and negative polarity of the four outputs is reversed by controlling the on / off switching of four relay coils. The logic control circuitry between the two outputs of the M4 control circuit and the M1 control circuit of the M4 circuit determines whether the corresponding relay coils can be controlled by obtaining signals from the internal limit switches of the electric actuators controlled by the two outputs.

[0039] During the movement, the electric push rod M4 stops at the designated position and the buzzer spk sounds a reminder. When the connection point S7 or connection point S8 in the external interface con becomes high and remains high, Figure 3 The M1 controls the M4 circuit, the collector of the transistor Q8 or the transistor Q9 is high level, the corresponding relay works, and the electric push rod is powered. Figure 4The middle position of M4 stops the circuit and presses the micro switch SW. The common terminal of the micro switch SW is connected to the normally open terminal. The voltage of the common terminal changes from low level to high level, and is coupled through the C15 capacitor. The transistor Q12 is turned on through the diode D35 and the resistor R32. The buzzer spk sounds, reminding that the middle designated position has been reached. The conduction of the transistor Q12 also turns on the transistor Q15, and the current state is locked through the diode D38. The collector of the transistor Q15 is at a high level at this time. Figure 3 The M1 controls the M4 circuit, causing the collector of the transistor Q8 to change from high level to low level, de-energizing the corresponding relay coil, and stopping the electric push rod. When the connection point S7 or connection point S8 in the external interface con1 changes from high level to low level, and then from low level to high level and maintains it, the common end of the micro switch SW continues to maintain a high level, and the electrolytic capacitor C15 does not play a coupling role, so the negative electrode of the electrolytic capacitor C15 remains at a low level. Figure 4 The M4 middle position stop circuit is not triggered, and the collector of transistor Q15 is low level, which does not affect Figure 3 M1 controls the conduction of transistor Q8 or transistor Q9 in the M4 circuit, the relay is activated, and the electric push rod continues to move.

[0040] Mutual constraint circuit of electric push rods M1 and M4: When the electric push rod M1 is not in the upper limit position, the signal m1 in the electric push rod M1 is always at a high level, and the high level m1 makes Figure 3 The transistors Q8 and Q9 in the M1 control M4 circuit are in the cut-off state, and the relay coil controlling the electric push rod M4 cannot be energized and work; when the electric push rod M1 is at the upper limit position, the signal m1 in the electric push rod M1 is always at a low level. When m1 and MID4 are both at a low level, Figure 3 The transistors Q8 and Q9 in the M4 circuit are in the on state, and the relay coil of the electric push rod M4 is energized and works;

[0041] When the electric push rod M4 is not in the middle position, the common end of the micro switch SW is connected to the normally closed end, and the signal m4 is low level. When the connection point S2 in the external interface con1 becomes high level, Figure 2 The M4 restricts the M1 circuit, the transistor Q7 will be in the cut-off state, and the relay that controls the retraction of the electric push rod M1 will not work;

[0042] When the electric push rod M4 is in the middle position, the common end of the micro switch is connected to the normally open end, and the signal m4 is high level. When the connection point S2 in the external interface con1 becomes high level, Figure 2 The M4 restricts the M1 circuit, the transistor Q7 will be in the on state, and the relay that controls the retraction of the electric push rod M1 can work normally.

[0043] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A control circuit for an electric side-turning nursing bed, comprising a power input and rectification circuit, a battery charging circuit, a battery undervoltage protection circuit, a main circuit current protection circuit, four relay control circuits, a circuit for electric push rod M4 to control electric push rod M1, a circuit for electric push rod M1 to control electric push rod M4, and a circuit for electric push rod M4 to stop at an intermediate position, characterized in that: The power input and rectification circuit is connected in series to the battery charging circuit, the battery charging circuit is connected in series to the battery undervoltage protection circuit, the battery undervoltage protection circuit is connected in series to the main circuit current protection circuit, the main circuit current protection circuit is connected in parallel to four groups of relay group control circuits, and the connection points on the electric push rod M4 restricting electric push rod M1 circuit, the electric push rod M1 restricting electric push rod M4 circuit, and the electric push rod M4 intermediate position stop circuit are connected to the corresponding connection points on the battery undervoltage protection circuit, the main circuit current protection circuit, and the four groups of relay group control circuits; The electric push rod M4 restricts the electric push rod M1 circuit including a transistor Q7, a resistor R25 is connected between the emitter and base of the transistor Q7, the emitter of the transistor Q7 is provided with a connection point S2, the collector of the transistor Q7 is connected to the anode of the diode D32, the cathode of the diode D32 is provided with a connection point S22, the base of the transistor Q7 is connected to one end of the resistor R29, the other end of the resistor R29 is connected to the anode of the diode D36, the cathode of the diode D36 is connected to one end of the resistor R34 and the collector of the transistor Q10, the other end of the resistor R34 is provided with a connection point RA, the emitter of the transistor Q10 is grounded, and the base of the transistor Q10 is connected to the capacitor C1 7, one end of resistor R38, one end of resistor R39, the other end of capacitor C17 is grounded, the other end of resistor R38 is grounded, the other end of resistor R39 is connected to the collector of transistor Q14, the emitter of transistor Q14 is connected to one end of resistor R41 and a connection point m4, the other end of resistor R41 is connected to the base of transistor Q14 and one end of resistor R44, the other end of resistor R44 is connected to the collector of transistor Q16, the base of transistor Q16 is connected to one end of capacitor C20 and one end of resistor R46, the other end of capacitor C20 is grounded, the other end of resistor R46 is connected to a connection point RA, and the emitter of transistor Q16 is grounded; The electric push rod M1 controls the electric push rod M4 circuit including: a resistor R26 connected between the emitter and base of the transistor Q8, the emitter of the transistor Q8 is provided with a connection point S7, the collector of the transistor Q8 is connected to the anode of the diode D33, the cathode of the diode D33 is provided with a connection point S77, the base of the transistor Q8 is connected to one end of the resistor R30, the other end of the resistor R30 is connected to the anode of the diode D37, the cathode of the diode D37 is connected to the cathode of the diode D42, the collector of the transistor Q11, and one end of the resistor R35, the other end of the resistor R35 is provided with a connection point RA, the anode of the diode D42 is connected to one end of the resistor R31, the other end of the resistor R31 is connected to the base of the transistor Q9 and one end of the resistor R27, the other end of the resistor R27 is connected to the emitter of the transistor Q9 and the connection point S8, the collector of the transistor Q9 is connected The anode of diode D34 and the cathode of diode D34 are connected to a connection point S88. The base of transistor Q11 is connected to one end of resistor R37, one end of capacitor C18, one end of resistor R40, and the collector of transistor Q13. The other end of resistor R37 is grounded. The other end of capacitor C18 is grounded. The other end of resistor R40 is connected to a connection point RA. The emitter of transistor Q13 is grounded. The base of transistor Q13 is connected to one end of resistor R43, one end of capacitor C19, and one end of resistor R45. The other end of resistor R43 is grounded. The other end of capacitor C19 is grounded. The other end of resistor R45 is connected to the cathode of diode D40 and the cathode of diode D41. The anode of diode D40 is connected to the cathode of diode D40-A. The cathode of diode D40-A is connected to a connection point m1. The anode of diode D41 is connected to a connection point MID4. The electric push rod M4 intermediate position stop circuit includes: one end of the resistor R53 is connected to the connection point 12V, the other end of the resistor R53 is connected to one end of the electrolytic capacitor C21 and the positive electrode of the buzzer SPK, the negative electrode of the electrolytic capacitor C21 is grounded, the negative electrode of the buzzer SPK is connected to the anode of the diode D43, the cathode of the diode D43 is connected to one end of the resistor R36 and the collector of the transistor Q12, the other end of the resistor R36 is connected to the cathode of the diode D39, the anode of the diode D39 is connected to one end of the resistor R42 and the base of the transistor Q15, the other end of the resistor R42 is connected to the emitter of the transistor Q15 and is provided with a connection point RA, the emitter of the transistor Q12 is grounded, and the base of the transistor Q12 is connected to the capacitor C One end of the resistor R16, one end of the resistor R33, one end of the resistor R32, the other end of the capacitor C16 is grounded, the other end of the resistor R33 is grounded, the other end of the resistor R32 is connected to the cathode of the diode D35 and the cathode of the diode D38, the anode of the diode D38 is connected to the collector of the transistor Q15, and a connection point MID4 is provided. The anode of the diode D35 is connected to one end of the resistor R28 and the negative electrode of the electrolytic capacitor C15, the other end of the resistor R28 is grounded, the positive electrode of the electrolytic capacitor C15 is connected to the common end of the switch SW, and a connection point m4 is provided. The normally closed end of the switch SW is connected to one end of the resistor R24, and a connection point VG is provided. The other end of the resistor R24 is grounded, and the normally open end of the switch SW is provided with a connection point VCC.

2. The control circuit of the electric side-turning nursing bed according to claim 1, characterized in that: The power input and rectification circuit includes a transformer t, wherein input terminals 1 and 2 of the transformer t are connected to 220V, 50Hz AC power, output terminals 3 and 4 of the transformer t are connected to terminals 1 and 3 of the rectifier bridge BD1, terminal 4 of the rectifier bridge BD1 is grounded, and terminal 2 of the rectifier bridge BD1 is connected to the positive electrode of the electrolytic capacitor C6, the positive electrode of the electrolytic capacitor C6-1, and the Vin terminal of the voltage regulator LM317.

3. The control circuit of the electric side-turning nursing bed according to claim 1, characterized in that: The battery charging circuit includes a voltage regulator LM317, the ADJ terminal of the voltage regulator LM317 is connected to the resistor R8 and one end of the resistor R7, the other end of the resistor R8 is grounded, and the other end of the resistor R7 is connected to the OUT terminal of the voltage regulator LM317. The OUT terminal of the voltage regulator LM317 is also connected to the positive electrode of the electrolytic capacitor C9 and the anode of the diode D5. The negative electrode of the electrolytic capacitor C9 is grounded, and the cathode of the diode D5 is connected to the positive electrode of the two battery packs connected in series.

4. The control circuit of the electric side-turning nursing bed according to claim 1, characterized in that: The battery undervoltage protection circuit includes a battery pack, wherein the positive electrode of the battery pack is connected to the anode of a diode D3, the source of a MOS transistor Q1, and one end of a resistor R1, the cathode of the diode D3 is connected to the cathode of a diode D2, the positive electrode of an electrolytic capacitor C5, an external hand controller interface con1, and a connection point VH, the negative electrode of the electrolytic capacitor C5 is grounded, the external hand controller interface con1 includes connection points S1, S2, S3, S4, S5, S6, S7, and S8, the anode of the diode D2 is connected to the cathode of the diode D4, the anode of the diode D4 is connected to the drain of the MOS transistor Q1 and one end of a resistor R12, the gate of the MOS transistor Q1 is connected to the other end of the resistor R1 and one end of the resistor R2, the other end of the resistor R12 is connected to one end of a resistor R10, one end of a capacitor C7, and pin 2 of an operational amplifier LM358, pin 1 of the operational amplifier LM358 is connected to the anode of a diode D6, the cathode of the diode D6 is connected to one end of a resistor R3, and the other end of the resistor R3 is connected to the electrolytic capacitor C 3, one end of the resistor R4, the base of the transistor Q3, the electrolytic capacitor C3 and the other end of the resistor R4 are grounded, the other end of the resistor R10 and the other end of the capacitor C7 are grounded, the other end of the resistor R2 is connected to the collector of the transistor Q2, the emitter of the transistor Q2 is grounded, the base of the transistor Q2 is connected to the collector of the transistor Q3, one end of the capacitor C4, one end of the resistor R5, the other end of the capacitor C4 is grounded, the other end of the resistor R5 is connected to the cathode of the diode D8, and the emitter of the transistor D8 is grounded. The anode is connected to the positive electrode of the electrolytic capacitor C10, one end of the resistor R13, the connection point 12V, one end of the resistor R15, and the cathode of the Zener diode DZ1. The negative electrode of the electrolytic capacitor C10 is grounded, the anode of the Zener diode DZ1 is grounded, the other end of the resistor R13 is connected to one end of the resistor R11, one end of the capacitor C8 and pin 3 of the voltage regulator LM358, the other end of the capacitor C8 is grounded, the other end of the resistor R11 is connected to one end of the resistor R11A, and the other end of the resistor R11A is grounded.

5. The control circuit of the electric side-turning nursing bed according to claim 1, characterized in that: The main circuit current protection circuit includes a resistor R15, the other end of which is connected to the cathode of the diode D10 and the connection point RA, the anode of the diode D10 is connected to the cathode of the diode D11, the cathode of the diode D12, the cathode of the diode D13, the cathode of the diode D14, the cathode of the diode D15, the cathode of the diode D16, the cathode of the diode D17, the cathode of the diode D18, and one end of the resistor R18, the anode of the diode D11 is provided with a connection point S1, the anode of the diode D12 is provided with a connection point S2, the anode of the diode D13 is provided with a connection point S3, the anode of the diode D14 is provided with a connection point S4, the anode of the diode D15 is provided with a connection point S5, the anode of the diode D16 is provided with a connection point S6, the anode of the diode D17 is provided with a connection point S7, and the anode of the diode D18 is provided with a connection point S8, and the other end of the resistor R18 is connected to the collector of the transistor Q5, the collector of the transistor Q4 The collector of the transistor, one end of the capacitor C13, and the base of the transistor Q6 are connected. The base of the transistor Q5 is connected to one end of the capacitor C11, one end of the resistor R17, and one end of the resistor R16. The emitter of the transistor Q5 is grounded. The other end of the capacitor C13 is grounded. The other end of the capacitor C11 is grounded. The other end of the resistor R17 is grounded. The other end of the resistor R16 is connected to the collector of the transistor Q6 and one end of the resistor R22. The emitter of the transistor Q6 is grounded. The other end of the resistor R22 is connected to the four relay group control circuits. The emitter of the transistor Q4 is grounded. The base of the transistor Q4 is connected to the positive electrode of the electrolytic capacitor C12, one end of the resistor R48, and one end of the resistor R47. The negative electrode of the electrolytic capacitor C12 is grounded. The other end of the resistor R48 is grounded. The other end of the resistor R47 is connected to one end of the resistor R19. The other end of the resistor R19 is connected to one end of the resistor R20 and a connection point VSS is provided. The other end of the resistor R20 is grounded.

6. The control circuit of the electric side-turning nursing bed according to claim 1, characterized in that: The four relay group control circuits include: A first relay group consisting of a relay K1, a relay K2, a diode D21, a diode D22, and an external interface M1, wherein the coil of relay K1 is connected in parallel to the diode D21, the coil of relay K2 is connected in parallel to the diode D22, the common terminal of relay K1 is connected to one end of the varistor RV1 and terminal 1 of the external interface M1, the normally closed terminal of relay K1 is provided with a connection point VSS, the normally open terminal of relay K1 is provided with a connection point VCC, the common terminal of relay K2 is connected to the other end of the varistor RV1 and terminal 2 of the external interface M1, the normally closed terminal of relay K2 is provided with a connection point VSS, the normally open terminal of relay K2 is provided with a connection point VCC, terminal 3 of external interface M1 is connected to one end of the resistor R23, one end of the capacitor C14, and a connection point m1, the other end of the resistor R23 is connected to the cathode of diode D31, the anode of diode D31 is provided with a connection point RA, the other end of capacitor C14 is grounded, the cathode of diode D21 is provided with a connection point S22, and the cathode of diode D22 is provided with a connection point S1; A second relay group consisting of a relay K3, a relay K4, a diode D23, a diode D24, and an external interface M2, wherein the coil of relay K3 is connected in parallel to the diode D23, the coil of relay K4 is connected in parallel to the diode D24, the common terminal of relay K3 is connected to one end of the varistor RV2 and terminal 1 of the external interface M2, the normally closed terminal of relay K3 is provided with a connection point VSS, and the normally open terminal of relay K3 is provided with a connection point VCC, the common terminal of relay K4 is connected to the other end of the varistor RV2 and terminal 2 of the external interface M2, the normally closed terminal of relay K4 is provided with a connection point VSS, and the normally open terminal of relay K4 is provided with a connection point VCC, the cathode of diode D23 is provided with a connection point S3, and the cathode of diode D24 is provided with a connection point S4; A third relay group consisting of a relay K5, a relay K6, a diode D25, a diode D26, and an external interface M3, wherein the coil of relay K5 is connected in parallel to the diode D25, the coil of relay K6 is connected in parallel to the diode D26, the common terminal of relay K5 is connected to one end of the varistor RV3 and terminal 1 of the external interface M3, the normally closed terminal of relay K5 is provided with a connection point VSS, the normally open terminal of relay K5 is provided with a connection point VCC, the common terminal of relay K6 is connected to the other end of the varistor RV3 and terminal 2 of the external interface M3, the normally closed terminal of relay K6 is provided with a connection point VSS, the normally open terminal of relay K6 is provided with a connection point VCC, the cathode of diode D25 is provided with a connection point S5, and the cathode of diode D26 is provided with a connection point S6; A fourth relay group consists of a relay K7, a relay K8, a diode D27, a diode D27, and an external interface M4. The coil of the relay K7 is connected in parallel to the diode D27, the coil of the relay K8 is connected in parallel to the diode D28, the common terminal of the relay K7 is connected to one end of the varistor RV4 and the terminal 1 of the external interface M4, the normally closed terminal of the relay K7 is provided with a connection point VSS, the normally open terminal of the relay K7 is provided with a connection point VCC, the common terminal of the relay K8 is connected to the other end of the varistor RV4 and the terminal 2 of the external interface M4, the normally closed terminal of the relay K8 is provided with a connection point VSS, the normally open terminal of the relay K8 is provided with a connection point VCC, the terminal 3 of the external interface M4 is provided with a connection point VG, the terminal 4 of the external interface M4 is provided with a connection point m4, the cathode of the diode D27 is provided with a connection point S77, and the cathode of the diode D28 is provided with a connection point S88.

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