CN210075092U

CN210075092U - Alternating current power supply constant-voltage device used for bedsore-preventing mattress controller

Info

Publication number: CN210075092U
Application number: CN201920953441.1U
Authority: CN
Inventors: 方清裕
Original assignee: Xiamen Sen Yang Industry & Trade Co Ltd
Current assignee: Xiamen Sen Yang Industry & Trade Co Ltd
Priority date: 2019-06-24
Filing date: 2019-06-24
Publication date: 2020-02-14
Anticipated expiration: 2029-06-24

Abstract

An alternating current power supply constant voltage device used by a bedsore-preventing mattress controller comprises an autotransformer and is characterized by also comprising a direct current power supply circuit, a detection circuit and an adjusting circuit; the autotransformer, the direct-current power supply circuit, the detection circuit and the adjusting circuit are arranged on a circuit board and connected through a lead, and the circuit board is arranged in an element box of the bedsore-prevention mattress controller. The utility model is suitable for a prevent supporting use of bedsore mattress controller, need not to carry out any operation before the use, both can work under exchanging 110V voltage, can also work under exchanging 220V voltage, brought the convenience for the user from this, the probability of preventing bedsore mattress controller damage has been reduced, and because the manufacture factory need not to prevent bedsore mattress controller to different power consumption country and regional production different operating voltage again, the producer of preventing bedsore mattress has brought the facility for the production, and manufacturing cost has been reduced. Based on the above, this is novel has good application prospect.

Description

Alternating current power supply constant-voltage device used for bedsore-preventing mattress controller

Technical Field

The utility model relates to a power supply unit field, a prevent alternating current power supply constant voltage equipment that bedsore mattress controller used very much.

Background

The bedsore-proof mattress is also called bedsore-proof air cushion, bedsore-proof air cushion bed, etc. The two air bags are inflated and deflated alternately at regular intervals during working, so that the nidation part of the body of a bedridden person is changed continuously, the effects of manual massage are achieved, blood circulation can be promoted, and muscular atrophy is prevented. In the world, due to different national conditions, some countries use a 110V ac power supply as a working power supply for household electric appliances (such as the united states); some countries adopt 220V alternating current power supplies as working power supplies of electric equipment (for example, China); some countries even have 220V and 110V ac power sources in parallel (e.g. brazil). Therefore, for the power supply voltage standards of different countries, manufacturers for producing the anti-bedsore mattresses need to produce anti-bedsore mattress controllers under different working voltages, the anti-bedsore mattresses with the working voltage of 110V are produced when being applied to the countries with the 110V power supply voltage, and the anti-bedsore mattresses with the working voltage of 220V are produced when being applied to the countries with the 220V power supply voltage, but when the anti-bedsore mattresses with the 110V power supply are applied to the countries with both 220V and 110V alternating current power supplies, if a user is careless or does not have related knowledge, the power supply plug of the anti-bedsore mattress controller with the 110V working voltage is inserted into the socket of the 220V power supply, and the problems that the controller is damaged, exploded, ignited, and the like and the life and property safety is damaged are caused.

SUMMERY OF THE UTILITY MODEL

In order to overcome the current bedsore prevention mattress controller and can't be applicable to 220V effectively simultaneously, the drawback that exists among the 110V alternating current power supply, the utility model provides a be applicable to prevent that bedsore mattress controller is supporting to be used, need not to carry out any operation before the use, both can work under alternating current 110V voltage, can also work under alternating current 220V voltage, it is convenient from this to have brought for the user, the probability of preventing bedsore mattress controller damage has been reduced, and because the manufacture factory need not to different power consumption voltage countries and regions again, produce different operating voltage's prevent bedsore mattress controller, the producer of preventing bedsore mattress has brought the facility, and the alternating current power supply constant voltage equipment who prevents bedsore mattress controller and use that has reduced manufacturing cost.

The utility model provides a technical scheme that its technical problem adopted is:

an alternating current power supply constant voltage device used by a bedsore-preventing mattress controller comprises an autotransformer and is characterized by also comprising a direct current power supply circuit, a detection circuit and an adjusting circuit; the autotransformer, the direct-current power supply circuit, the detection circuit and the regulating circuit are arranged on a circuit board and connected through a lead, and the circuit board is arranged in an element box of the bedsore-prevention mattress controller; one end of one group of output windings of the autotransformer is connected with a first control power input end of the regulating circuit, the other end of one group of output windings of the autotransformer is connected with a second control power input end of the regulating circuit, and a power output end of the regulating circuit, one end of the other input and output windings of the autotransformer and two power input ends of the bedsore-proof mattress controller are respectively connected; the two ends of the other group of output windings of the autotransformer are respectively connected with the two ends of the power input of the direct-current power supply circuit, the two ends of the power output of the direct-current power supply circuit are respectively connected with the two ends of the power input of the detection circuit and the two ends of the power input of the regulating circuit, and the signal output end of the detection circuit is connected with the signal input end of the regulating circuit.

Furthermore, two ends of the input winding of the autotransformer are connected with a voltage dependent resistor and a safety capacitor in parallel.

Further, the direct current power supply circuit comprises a rectifier bridge stack of a type KBL41, an electrolytic capacitor, a ceramic chip capacitor and a resistor, wherein the rectifier bridge stack, the electrolytic capacitor, the ceramic chip capacitor and the resistor are connected through a circuit board in a wiring mode, a positive power supply output end of the rectifier bridge stack is connected with one end of the resistor, a positive electrode of the electrolytic capacitor and one end of the ceramic chip capacitor, and a negative power supply output end of the rectifier bridge stack is connected with the other end of the resistor, the negative electrode of the.

Furthermore, the detection circuit comprises a voltage stabilizing integrated circuit with the model TL431, an electrolytic capacitor, a resistor, a diode and a voltage comparator with the model LM393AH, wherein the voltage stabilizing integrated circuit, the electrolytic capacitor, the resistor, the diode and the voltage comparator are connected through circuit board wiring, one end of a first resistor is connected with one end of a second resistor, one end of a fourth resistor and 8 pins at the positive power supply input end of the comparator, the other end of the first resistor is connected with 3 pins at the cathode of the voltage stabilizing integrated circuit, 1 pin at the reference electrode and 2 pins at the reverse input end of the comparator, the other end of the second resistor is connected with one end of a third resistor, one end of a sixth resistor, the anode of the voltage stabilizing integrated circuit, 2 pins at the anode of the voltage stabilizing integrated circuit, the cathode of the electrolytic capacitor and the other end of the sixth resistor, the other end of the third resistor is connected with the cathode of the diode, the other end of the fourth resistor, the output end, The 4-pin of the negative power input end of the comparator is grounded.

Furthermore, the regulating circuit comprises an NPN triode, a diode and a relay, wherein the NPN triode, the diode and the relay are connected through a circuit board in a wiring mode, a collector of the NPN triode is connected with a negative power input end of the relay and a positive electrode of the diode, a positive power input end of the relay is connected with a negative electrode of the diode, and an emitting electrode of the NPN triode is grounded.

Further, the voltage between one end of one set of output windings of the autotransformer and one end of the other input and output windings of the autotransformer is two times higher than the voltage between the other end of one set of output windings of the autotransformer and one end of the other input and output windings of the autotransformer.

The utility model has the advantages that: in the practical use of the novel auto-transformer, a power supply with the same voltage as the input end of the auto-transformer is output between one end of one group of output windings of the auto-transformer and one end of the other input and output windings of the auto-transformer, and a power supply with half voltage of the input end of the auto-transformer is output between the other end of one group of output windings of the auto-transformer and one end of the other input and output windings of the auto-transformer. Under the direct current power supply circuit, detection circuitry combined action, when input power is interchange 110V, regulating circuit is direct to carry the mains voltage of autotransformer input for preventing bedsore mattress controller power input both ends, then, prevent bedsore mattress controller and work under interchange 110V full voltage, when input power is interchange 220V, regulating circuit carries the mains voltage's of autotransformer input half for preventing bedsore mattress controller power input both ends, then, prevent bedsore mattress controller and work under half voltage, no matter input 220V power like this, still 110V power, this novel homoenergetic guarantees to prevent bedsore mattress controller and works under 110V voltage. The utility model is suitable for a prevent supporting use of bedsore mattress controller, need not to carry out any operation before the use, both can work under exchanging 110V voltage, can also work under exchanging 220V voltage, brought the convenience for the user from this, the probability of preventing bedsore mattress controller damage has been reduced, and because the manufacture factory need not to prevent bedsore mattress controller to different power consumption country and regional production different operating voltage again, the producer of preventing bedsore mattress has brought the facility for the production, and manufacturing cost has been reduced. Based on the above, this is novel has good application prospect.

Drawings

The invention will be further explained with reference to the drawings and examples.

Fig. 1 is a circuit diagram of embodiment 1 of the present invention.

Fig. 2 is a circuit diagram of embodiment 2 of the present invention.

Fig. 3 is a block diagram of the present invention.

Detailed Description

As shown in fig. 3, the ac power constant voltage device used by the bedsore-prevention mattress controller comprises an autotransformer, and further comprises a dc power circuit, a detection circuit and a regulation circuit; the autotransformer, the direct-current power supply circuit, the detection circuit and the regulating circuit are arranged on a circuit board and connected through a lead, and the circuit board is arranged in an element box of the bedsore-prevention mattress controller; one end of one group of output windings of the autotransformer is connected with a first control power input end of the regulating circuit, the other end of one group of output windings of the autotransformer is connected with a second control power input end of the regulating circuit, and a power output end of the regulating circuit, one end of the other input and output windings of the autotransformer and two power input ends of the bedsore-proof mattress controller are respectively connected; the two ends of the other group of output windings of the autotransformer are respectively connected with the two ends of the power input of the direct-current power supply circuit, the two ends of the power output of the direct-current power supply circuit are respectively connected with the two ends of the power input of the detection circuit and the two ends of the power input of the regulating circuit, and the signal output end of the detection circuit is connected with the signal input end of the regulating circuit.

In embodiment 1, as shown in fig. 1, a voltage dependent resistor MOV1 and a safety capacitor CX1 (mainly for protection against overvoltage, lightning, etc.) are connected in parallel across the input winding of the autotransformer T1. The direct current power supply circuit comprises a rectifier bridge stack BD1 with the model number KBL41, an electrolytic capacitor C2, a ceramic chip capacitor C3 and a resistor R2 which are connected through a circuit board in a wiring mode, wherein the positive power supply output end of the rectifier bridge stack BD1 is connected with one end of a resistor R2, the positive electrode of the electrolytic capacitor C2 and one end of the ceramic chip capacitor C3 are connected, and the negative power supply output end of the rectifier bridge stack BD1 is connected with the other end of the resistor R2, the negative electrode of the electrolytic capacitor C2 and the other end of the ceramic chip capacitor C3. The detection circuit comprises a voltage-stabilizing integrated circuit U1 with model TL431, an electrolytic capacitor C4, resistors R3, R4, R6, R7, R5 and R8, a diode D1 and a voltage comparator U2A with model LM393 AH; the circuit board is connected through wiring, one end of a first resistor R3 is connected with one end of a second resistor R4, one end of a fourth resistor R7 and the 8 pin of the positive power input end of a comparator U2A, the other end of the first resistor R3 is connected with the 3 pin of the cathode of a voltage stabilizing integrated circuit U1, the 1 pin of a reference electrode and the 2 pin of the reverse input end of the comparator U2A, the other end of the second resistor R4 is connected with one end of a third resistor R6, one end of a sixth resistor R5, the anode of an electrolytic capacitor C4 and the 3 pin of the non-inverting input end of the comparator U2A, the other end of the third resistor R6 is connected with the cathode of a diode D1, the anode of the diode D1 is connected with one end of the fourth resistor R7, the 1 pin of the output end of the comparator U2A and one end of a fifth resistor R8, and the anode 2 pin of the voltage stabilizing integrated circuit U2A is connected with the cathode of the electrolytic capacitor C4, the other end of the sixth resistor R58. The regulating circuit comprises an NPN triode Q1, a diode D2 and a relay K1 which are connected through circuit board wiring, the collector of the NPN triode Q1 is connected with the negative power input end of the relay K1 and the positive electrode of the diode D1, the positive power input end of the relay K1 is connected with the negative electrode of the diode D1, and the emitter of the NPN triode Q1 is grounded. The voltage between the AC-LOW terminal of one of the output windings of autotransformer T1 and the 0V port of the other input/output winding of autotransformer T1 is twice the voltage between the AC-HI terminal of the other of the output windings of autotransformer T3526 and the 0V port of the other input/output winding of autotransformer T1.

As shown in fig. 1, in embodiment 1, one end AC-LOW of one of the output windings of autotransformer T1 is connected to the normally closed contact end of the first control power input end relay K1 of the regulating circuit, the other end AC-HI of one of the output windings of autotransformer T1 is connected to the normally open contact end of the second control power input end relay K1 of the regulating circuit, the control power input end of the power output end relay K1 of the regulating circuit, the 0V port of the other input and output winding of autotransformer T1 are connected to the two ends of the power input of the bedsore-proof mattress controller a, the two ends 12Vac and 0V port of the other output winding of autotransformer are connected to the two ends of the power input of the rectifier bridge stack BD1 of the dc power supply circuit, the positive and negative poles of the electrolytic capacitor C2 at the two ends of the power output of the dc power supply circuit, one end of the power input resistor R3 of the detection circuit, The power input end of the regulating circuit, the positive power input end of a relay K1 and the emitting electrode of an NPN triode Q1 are respectively connected, and the other end of a signal output end resistor R8 of the detection circuit is connected with the base electrode of a signal input end NPN triode Q1 of the regulating circuit.

In the use of the present invention, as shown in fig. 1, in embodiment 1, after the input end of the autotransformer T1(1KW) is plugged into the AC output socket via the power plug, if the input power is 220V, the voltage between the AC-LOW end of one of the output windings of the autotransformer T1 and the 0V port of the other input/output winding of the autotransformer T1 is 220V, the voltage between the AC-HI end of the other output winding of the autotransformer T1 and the 0V port of the other input/output winding of the autotransformer T1 is about 110V, and the voltage between the 12Vac and 0V ports of the other output winding of the autotransformer T1 is about 12V; if the input power is 110V, the voltage between the AC-LOW end of one output winding of the autotransformer T1 and the 0V port at one end of the other input/output winding of the autotransformer T3526 is about 55V, and the voltage between the AC-HI end of one output winding of the autotransformer T1 and the 0V port at one end of the other input/output winding of the autotransformer T1 is about 6V. When a 12V or 6V power supply output from the ports of 12Vac and 0V at two ends of the other group of output windings of the autotransformer T1 enters the rectifier bridge stack BD1, under the action of the internal circuit of the rectifier bridge stack BD1, the direct-current power output end of the rectifier bridge stack BD1 outputs a rectified 12V or 6V direct-current power supply which enters two ends of the power supply input of the regulating circuit and the detection circuit, and therefore the regulating circuit and the detection circuit are in an electrified working state. In the direct-current power supply circuit, the electrolytic capacitor C2, the ceramic chip capacitor C3 and the resistor R2 form resistance-capacitance filtering, so that the stability of the output power supply of the rectifier bridge stack BD1 is ensured. After a 12V or 6V direct-current power supply output by a rectifier bridge stack BD1 of a direct-current power supply circuit enters a detection circuit, the positive pole of the 12V or 6V direct-current power supply enters a cathode 3 pin and a reference pole 1 pin of a voltage stabilizing integrated circuit U1 through a resistor R3 (the anode of the voltage stabilizing integrated circuit U1 is grounded), and under the combined action of an internal circuit of the voltage stabilizing integrated circuit U1 and a peripheral element resistor R3 (a reference resistor), 2.5V regulated power supply is generated at the cathode of the voltage stabilizing integrated circuit U1 and enters an inverting input end 2 pin of a voltage comparator U2A to serve as a voltage comparison reference voltage value. When a 12V or 6V direct-current power supply output by a rectifier bridge stack BD1 of the direct-current power supply circuit enters a voltage stabilizing integrated circuit U1, the 12V or 6V direct-current power supply can enter a pin 3 at the non-inverting input end of a comparator after being divided by resistors R4 and R5 (an electrolytic capacitor C4 plays a role in filtering), in the novel solar cell, when the input voltage of an autotransformer T1 is higher than 170V +/-3V (the fluctuation of a 220V power supply is about 170V), the voltage of the pin 3 entering the non-inverting input end of the comparator U2A after being divided by resistors R4 and R5 is higher than 2.5V (in actual conditions, the input power supply is lower than 167V, the voltage of the pin 3 entering the non-inverting input end of the comparator U2A after being divided by resistors R4 and R5 is lower than 2.5V, and a bedsore-proof mattress controller A can work just under 167), so that under the action of an internal circuit of the comparator U2A, the pin 1 of the comparator U2A can output a high; when the input voltage of the autotransformer T1 is lower than 160V +/-3V (the 110V power supply fluctuation is as high as 160V), the voltage of the pin 3 entering the non-inverting input end of the comparator U2A after being divided by the resistors R4 and R5 is lower than 2.5V, and then under the action of the internal circuit of the comparator U2A, the pin 1 of the comparator U2A does not output high level; when the input AC voltage needs to be higher than the AC170V + -3V detection circuit, the input power supply is judged to be AC220V, and the input AC voltage is lower than the AC160V + -3V detection circuit, the input power supply is judged to be AC 110V. In the direct current power circuit, a direct current power supply (VCC) rectified by a rectifier bridge stack BD1 is a direct current power supply for supplying the whole circuit, and is also a source for detecting high and low voltages input by a power supply of an autotransformer T1, a detection circuit judges that a critical point of the high and low voltages input by the power supply of the autotransformer T1 is set as AC165V, in order to prevent an unstable phenomenon of a critical point circuit of high and low voltage switching, a diode D1 and a resistor R6 form a hysteresis loop (a resistor R7 is a lifting resistor of the output voltage of a comparator U2A); the hysteresis loop operates on the principle that when the voltage at pin 3 of the comparator U2A is higher than (VF)2.5V, pin 1 of the comparator U2A outputs a high level, and at this time, current I6 is generated at VO > (V-1), so that current I5 flowing through the resistor R5 is equal to I4+ I6, which causes the voltage at (V-1) to be raised instantaneously, thereby preventing the critical point from being unstable, whereas when the voltage at (V-1) is lowered from the high level to be lower than 2.5V, pin 1 of the comparator U2A stops outputting a high level, and the voltage at V-1 is also lowered slightly again due to the reduction of the current I6, thereby preventing the unstable state. When the input power of the autotransformer T1 is alternating current 220V (namely, the mains supply is alternating current 220V and higher than 167V), after the high level is output by pin 1 of the comparator U2A, the high level is reduced and limited by voltage through the resistor R8 and enters the base of the NPN triode Q1, then the NPN triode Q1 conducts the collector and outputs the low level to enter the negative power input end of the relay K1, the relay K1 (the positive electrode is connected with the positive power output end of the rectifier bridge stack BD 1) is electrified and closed to pull in the control power input end and the normally open contact end (the diode D2 mainly has the function of preventing the sudden wave high voltage generated by the coil when the relay K1 pulls in and releases from damaging the triode Q1); because the AC-HI at the other end of one group of output windings of the autotransformer T1 is connected with the normally open contact end of the relay K1, and the control power input end of the relay K1, the 0V port at one end of the other input and output windings of the autotransformer T1 and the two ends of the power input of the anti-bedsore mattress controller A are respectively connected, at the moment, the 110V power supply output by the AC-HI at the other end of one group of output windings of the autotransformer T1 enters the two ends of the power input of the anti-bedsore mattress controller A after voltage reduction, so that the anti-bedsore mattress controller A is in a normal 110V power supply working state, and the normal use of the anti-bedsore mattress is ensured. When the input power of the autotransformer T1 is AC110V (namely, the mains supply is AC110V and lower than 167V), pin 1 of the comparator U2A does not output high level, the relay K1 is in a power-off state and controls the power input end and the normally closed contact end to be closed, because one end of one group of output windings of the autotransformer T1 AC-LOW is connected with the normally closed contact end of the relay K1, the control power input end of the relay K1, the 0V port at one end of the other input and output winding of the autotransformer T1 and the two ends of the power input of the bedsore-proof mattress controller A are respectively connected, therefore, at the moment, the 110V power supply output by the AC-LOW at one end of one group of output windings of the autotransformer T1 directly enters the two ends of the power supply input of the bedsore-proof mattress controller A, so that the bedsore-proof mattress controller A is in a normal 110V power supply working state, and the normal use of the bedsore-proof mattress is ensured.

As shown in fig. 2, in embodiment 2, the present invention may further adopt a rectifier bridge stack BD21, resistors R22, R23, R24, R25, an electrolytic capacitor C22, a tile capacitor C23, a zener diode ZD1 function detection circuit and a dc power supply circuit, an anode output end of the rectifier bridge stack is connected to one end of the first resistor R22, an anode of the electrolytic capacitor C22, one end of the tile capacitor C23, and a cathode of the zener diode ZD1, an anode of the zener diode ZD1, one end of the second resistor R23, one end of the third resistor R24, the other end of the third resistor R24 is connected to one end of the fourth resistor R25, a cathode output end of the rectifier bridge stack is connected to the other end of the first resistor R22, a cathode of the electrolytic capacitor C22, the other end of the tile capacitor C23, the other end of the third resistor R23, and one end of the fourth resistor R25 are grounded. When the input power of the autotransformer T1 is alternating current 220V (higher than 167V), the power output by the rectifier bridge stack BD21 is higher than 10V after resistance-capacitance filtering through the resistor R22, the electrolytic capacitor C22 and the ceramic chip capacitor C23, then the voltage stabilizing diode ZD1 is quickly conducted to output a direct current power and enters the base of the NPN triode Q21 after voltage division through the resistor R24 and the resistor R25 (the resistor R23 is one of the current limiting resistors of the voltage stabilizing diode ZD1 and is used for adjusting a proper voltage point of conduction of the NPN triode Q21; note: the current limiting resistor R23/{ R24+ R25} of the ZD 1), the NPN triode Q21 conducts a collector to output a low level and enters the negative power input end of the relay K1, the relay K1 is electrically attracted to control the power input end and the normally open contact end to be closed, at the moment, the 110V power output by the AC-HI output from the other end of one group of the output windings of the autotransformer T1, therefore, the bedsore-proof mattress controller A is in a normal 110V power supply working state, and normal use of the bedsore-proof mattress is ensured; when the input power of the autotransformer T1 is alternating current 110V (lower than 167V), the power output by the rectifier bridge stack BD21 is lower than 10V after resistance-capacitance filtering through the resistor R22, the electrolytic capacitor C22 and the ceramic chip capacitor C23, so that a small leakage current of the voltage stabilizing diode ZD1 cannot drive the NPN triode Q1 to be conducted, the relay K1 is in a power-off state and controls the power input end and the normally closed contact end to be closed, the 110V power output by AC-LOW at one end of one group of output windings of the autotransformer T1 directly enters the two ends of the power input of the bedsore-proof mattress controller A, and then the bedsore-proof mattress controller A is in a normal 110V power working state, and normal use of the bedsore-proof mattress is guaranteed. The utility model is suitable for a 110V prevents that bedsore mattress controller is supporting to be used, need not to carry out any operation before the use, both can work under exchanging 110V voltage, can also work under exchanging 220V voltage, brought the convenience for the user from this, the probability of preventing bedsore mattress controller damage has been reduced, and because the manufacture factory need not to different power consumption voltage countries and areas again, produce different operating voltage's bedsore mattress controller of preventing, the producer of preventing bedsore mattress has brought the facility for the production, and manufacturing cost has been reduced. The types of the elements of the present invention are labeled in the drawings, and are not described herein again.

The basic principles and essential features of the invention and the advantages of the invention have been shown and described above, it will be apparent to those skilled in the art that the invention is not limited to the details of the foregoing exemplary embodiments, but rather can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

1. An alternating current power supply constant voltage device used by a bedsore-preventing mattress controller comprises an autotransformer and is characterized by also comprising a direct current power supply circuit, a detection circuit and an adjusting circuit; the autotransformer, the direct-current power supply circuit, the detection circuit and the regulating circuit are arranged on a circuit board and connected through a lead, and the circuit board is arranged in an element box of the bedsore-prevention mattress controller; one end of one group of output windings of the autotransformer is connected with a first control power input end of the regulating circuit, the other end of one group of output windings of the autotransformer is connected with a second control power input end of the regulating circuit, and a power output end of the regulating circuit, one end of the other input and output windings of the autotransformer and two power input ends of the bedsore-proof mattress controller are respectively connected; the two ends of the other group of output windings of the autotransformer are respectively connected with the two ends of the power input of the direct-current power supply circuit, the two ends of the power output of the direct-current power supply circuit are respectively connected with the two ends of the power input of the detection circuit and the two ends of the power input of the regulating circuit, and the signal output end of the detection circuit is connected with the signal input end of the regulating circuit.

2. The ac voltage regulator for use in the bedsore-proof mattress controller according to claim 1, wherein the input winding of the autotransformer has a varistor and a safety capacitor connected in parallel across its ends.

3. The ac voltage regulator for the bedsore-proof mattress controller according to claim 1, wherein the dc power circuit comprises a bridge rectifier of type KBL41, an electrolytic capacitor, a ceramic capacitor and a resistor, which are wired together via a circuit board, wherein the positive power output terminal of the bridge rectifier is connected to one end of the resistor, the positive terminal of the electrolytic capacitor and one end of the ceramic capacitor, and the negative power output terminal of the bridge rectifier is connected to the other end of the resistor, the negative terminal of the electrolytic capacitor and the other end of the ceramic capacitor.

4. The ac voltage regulator for the bedsore-proof mattress controller according to claim 1, wherein the detection circuit comprises a voltage-stabilizing integrated circuit model TL431, an electrolytic capacitor, a resistor, a diode, and a voltage comparator model LM393AH, which are connected by circuit board wiring, wherein one end of the first resistor is connected to one end of the second resistor, one end of the fourth resistor, and 8 pins of the positive power input end of the comparator, the other end of the first resistor is connected to the cathode 3 pin, the reference electrode 1 pin, and the reverse input end 2 pins of the comparator, the other end of the second resistor is connected to one end of the third resistor, one end of the sixth resistor, the positive electrode of the electrolytic capacitor, and the non-inverting input end 3 pins of the voltage-stabilizing integrated circuit, the other end of the third resistor is connected to the negative electrode of the diode, the positive electrode of the diode is connected to the other end of the fourth resistor, and one end of the output end 1 pin of the comparator, and one end of the, the anode 2 pin of the voltage-stabilizing integrated circuit, the cathode of the electrolytic capacitor, the other end of the sixth resistor and the cathode power input end 4 pin of the comparator are grounded.

5. The ac voltage regulator for use in a bedsore-proof mattress controller according to claim 1, wherein the regulating circuit comprises an NPN transistor, a diode and a relay connected by wiring on a circuit board, wherein the collector of the NPN transistor is connected to the negative power input of the relay and the positive terminal of the diode, the positive power input of the relay is connected to the negative terminal of the diode, and the emitter of the NPN transistor is connected to ground.

6. An alternating current constant voltage device for use with an anti-bedsore mattress controller according to claim 1 wherein the voltage between one end of one of the set of output windings of the autotransformer and one end of the other of the input and output windings of the autotransformer is greater than twice the voltage between the other end of one of the set of output windings of the autotransformer and one end of the other of the input and output windings of the autotransformer.