Automatic switching dual-voltage input power supply for massage armchair

[0018] The embodiment of the present invention is used as the input power source of the massage chair, and can provide three-way AC power supply to the main control board that controls the operation of the massage chair to meet the working requirements of the main control board of the massage chair.

[0019] In order to adapt the main control board of the massage chair to two different mains power sources (such as 110VAC and 220VAC), and at the same time keep the three AC power supplies of the main control board stable and unchanging (such as 110VAC, 20.5VAC and 10.5VAC power supply) ), a corresponding power supply is needed to achieve this, and the present invention can meet the requirements. A detailed description will be given below in conjunction with the drawings.

[0020] See figure 1 , The embodiment of the present invention is provided with a high and low voltage automatic switching module 1 and a dual input transformer 2. The input terminal of the high and low voltage automatic switching module 1 is externally connected to the mains power supply, the output terminal of the high and low voltage automatic switching module 1 is connected to the primary winding of the dual input transformer 2, and the secondary winding of the dual input transformer 2 is externally connected to the control circuit of the massage chair body.

[0021] The high and low voltage automatic switching module 1 is provided with an input terminal J1 for external mains power supply, a DC voltage stabilizer circuit PART1 for providing a stable voltage for the high and low voltage automatic switching module 1, a collection circuit PART2 for collecting mains voltage signals The judgment switching circuit PART3 for judging the level of the mains voltage and switching the connection mode of the dual-input transformer, the output terminal J2 for the external dual-input transformer 2 and the printed circuit board. The input terminal J1 is respectively connected with the input terminal of the DC voltage stabilizer circuit PART1, the input terminal of the acquisition circuit PART2 and the input terminal of the judgment switching circuit PART3. The output terminal of the DC voltage stabilizer circuit PART1 is connected to the input terminal of the judgment switching circuit PART3, The output terminal is connected to the input terminal of the judgment switching circuit PART3, and the output terminal of the judgment switching circuit PART3 is connected to the primary winding of the dual-input transformer 2 through the output terminal J2. The primary winding is provided with two independent sets of windings N1 and N2 with equal turns, and the secondary The winding is provided with 3 sets of output windings S1, S2 and S3.

[0022] See figure 2 , The DC voltage stabilizer circuit PART1 is provided with a step-down capacitor C1, a discharge diode D1, a filter capacitor C3, a half-wave rectifier diode D2 and a voltage regulator tube (including three voltage regulator tubes D5, D6 and D7 connected in series). The 1 pin of the step-down capacitor C1 and R1 is connected to the live line L of the mains power supply; the anode of the discharge diode D1 is connected to the neutral line N of the power supply; the anode of the half-wave rectifier diode D2, the 2 pins of the step-down capacitors C1 and R1, and the discharge diode The cathode of D1 is connected together; the cathode of half-wave rectifier diode D2 and the anode of filter capacitor (C3) are connected with the cathode of voltage regulator (D5), namely Net5; the cathode of filter capacitor C3, voltage regulator ( The positive poles of D7) are connected to the neutral line N of the mains power supply. After the mains voltage is stepped down by the step-down capacitor C1, it is half-wave rectified by the half-wave rectifier diode D2, filtered by the filter capacitor C3, and stabilized by the regulator tubes D5, D6 and D7, and finally a DC is obtained at Net5 Regulated value, the DC voltage stabilizer circuit PART1 is connected to the input end of the judgment switching circuit PART3, and is used to drive the judgment switching circuit PART3.

[0023] The acquisition circuit PART2 is provided with a half-wave rectifier diode D3, a filter capacitor C2, and sampling resistors R2 and R4. After the mains power supply is turned on, the positive pole of the half-wave rectifier diode D3 is connected to the power line L, the negative pole is connected to the positive electrode of the filter capacitor C2 and the 1 pin of the sampling resistor R2, namely Net1; the negative electrode of the filter capacitor C2 is connected to the neutral line of the mains power supply N; Pin 2 of sampling resistor R2 is connected to pin 1 of sampling resistor R4, that is, point Net2; Pin 2 of sampling resistor R4 is connected to neutral line N of the mains power supply. The mains input voltage is half-wave rectified by the half-wave rectifier diode D3, filtered by the filter capacitor C2, and an output voltage signal is generated at the Net1 point. The output voltage signal is connected to the signal input terminal of the judgment switching circuit PART3.

[0024] The judgment switching circuit PART3 is provided with a freewheeling diode D4, a relay K1 (double-pole double-throw type), a comparison transistor Q1, a switching transistor Q2, a current limiting resistor R3, and a pull-up resistor R5. Pin 1 of the current-limiting resistor R3 is connected to the Net1 point, and pin 2 of the current-limiting resistor R3 is connected to the base Q1-B of the comparison transistor Q1. The emitter Q1-E of the comparison transistor Q1 is connected to the neutral line N of the mains power supply, and the collector Q1-C of the comparison transistor Q1 is connected to the base Q2-B of the switching transistor Q2 and the 2 pins of the pull-up resistor R5. The emitter Q2-E of the switching transistor Q2 is connected to the neutral line N of the mains power supply, and the collector Q2-C of the switching transistor Q2 is connected to the 8-pin K1-8 of the relay K1 and the anode of the freewheeling diode D4. The cathode of the freewheeling diode D4, the 1 pin of the pull-up resistor R5 and the 7 pins K1-7 of the relay K1 are all connected to the DC power supply VCC. The 6 pins K1-6 of relay K1 are connected to the live wire L of the mains power supply, the 5 pins K1-5 of the relay K1 are connected to the neutral wire N of the mains power supply, the 1 pin K1-1 of the relay K1 and the 4 pins K1-4 of the relay K1 Both are connected to pin 2 of output terminal J2, and pin 2 of relay K1 is connected to pin 3 of output terminal J2. Pin 1 of the output terminal J2 is connected to the live line L of the mains power supply, and pin 4 of the output terminal J2 is connected to the neutral line N of the mains power supply. The pin K1-1 of the relay K1 is connected to the lead 3Blu of the primary winding N1 of the dual-input transformer through the terminal J1, and the pin K1-2 is connected to the lead 2Brn of the primary winding N1 of the dual-input transformer through the terminal J1, and the pin K1 -5 is connected to the lead 1Blk of the primary winding N2 of the dual-input transformer through the terminal J1, and pins K1-6 are connected to the lead 4Red of the primary winding N1 of the dual-input transformer through the terminal J1.

[0025] The following specific analysis and calculations illustrate that as long as the connection mode (ie series or parallel) of the two sets of primary windings N1 and N2 of the dual-input transformer 2 in the embodiment of the present invention is changed, regardless of whether the input voltage is 110VAC or 220VAC, the embodiment of the present invention The output voltage of the dual-input transformer 2 can be kept unchanged, and both can provide a stable AC voltage to the main control board of the massage chair. The specific analysis and calculation are as follows:

[0026] In this embodiment, the voltages of the three AC output power supplies are set to 110, 20.5, and 10.5 VAC, respectively. The mains power supply is set to 110VAC or 220VAC. The turns ratio of the primary winding and the secondary winding of the dual-input transformer 2 is set as:

[0027] N1/N2=1/1 (1)

[0028] N1/S1=110/20.5 (2)

[0029] N1/S2=110/10.5 (3)

[0030] N1/S3=1/1 (4)

[0031] image 3 A schematic diagram of the initial parallel connection of two groups of primary windings N1 and N2 of the dual-input transformer 2 according to an embodiment of the present invention is given. That is, the ends of the two groups of primary windings N1 and N2 with the same name are connected, that is, the lead 1Blk of the primary winding N2 is connected to the lead 3Blu of the primary winding N1, and the lead 2Brn of the primary winding N2 is connected to the lead 4Red of the primary winding N1. The primary winding is connected in parallel. The number of turns is N in parallel, which can be seen from the characteristics of the transformer:

[0032] N in parallel =N1=N2 (5)

[0033] Set the input mains voltage as V IN , The three outputs of dual input transformer 2 are V S1 , V S2 , V S3 From the characteristics of the transformer, it can be known that the ratio of the input voltage to the output voltage of the transformer is equal to the ratio of the primary winding turns to the secondary winding turns ratio, namely:

[0034] V IN /V S1 =N in parallel /S1 (6)

[0035] Then the output voltage of the secondary winding S1 is:

[0036] V S1 =V IN *S1/N in parallel (7)

[0037] Substituting equations (2) and (5) into equation (7), we get:

[0038] V S1 =V IN *20.5/110 (8)

[0039] Substituting equations (3) and (5) into equation (7), we get:

[0040] V S2 =V IN *10.5/110 (9)

[0041] Substituting formula (4) and (5) into formula (7), we get:

[0042] V S3 =V IN (10)

[0043] Figure 4 A schematic diagram of the series connection mode of two sets of primary windings N1 and N2 of the dual-input transformer 2 according to an embodiment of the present invention is given. That is, the opposite ends of the two sets of primary windings are connected, that is, the lead 2Brn of the primary winding N2 is connected to the lead 3Blu of the primary winding N1, and the number of turns of the primary winding after the series connection is N Tandem , Known from the characteristics of the transformer:

[0044] N Tandem =N1+N2 (11)

[0045] It can be known from the characteristics of the transformer that the ratio of the input voltage to the output voltage of the transformer is equal to the ratio of the number of turns of the primary winding to the number of turns of the secondary winding, namely:

[0046] V IN /V S1 =N Tandem /S1 (12)

[0047] Then the output voltage of the secondary winding S1 is:

[0048] V S1 =(S1/N Tandem )VIN (13)

[0049] Substituting formula (2) and (11) into formula (13), we get:

[0050] V S1 =(20.5/220)V IN (14)

[0051] Substituting formulas (3) and (11) into formula (13), we get:

[0052] V S1 =V IN *20.5/220 (15)

[0053] Substituting formulas (4) and (11) into formula (13), we get:

[0054] V S1 =V IN *110/220 (16)

[0055] It can be seen from the above detailed analysis that the output voltage of the dual-input transformer 2 in the embodiment of the present invention can be obtained by changing the connection mode of the two primary windings N1 and N2 of the dual-input transformer 2 in the embodiment of the present invention, regardless of whether the input voltage is 110VAC or 220VAC. All remain unchanged.

[0056] Then, how to change the connection mode of the two primary windings N1 and N2 of the dual-input transformer 2 of the embodiment of the present invention at any time for the input voltage of 110VAC or 220VAC? This is achieved by the high and low voltage automatic switching module 1, which will be described in detail below.

[0057] Such as figure 2 As shown, when the mains power is turned on, set the power input voltage to V IN , After half-wave rectification by diode D3 and filtering by electrolytic capacitor C2, a voltage will be generated at point Net1:

[0058] V Net1 =1.414V IN (17)

[0059] After the sampling resistor R2 and R4 divide the voltage, a voltage will be generated at the Net2 point:

[0060] V Net2 =R4V Net1 /(R2+R4) (18)

[0061] Comprehensive formula (11) and formula (12) are:

[0062] V Net2 =1.414R4V IN /(R2+R4) (19)

[0063] Substituting R2=150kΩ and R4=510Ω into equation (13), we can get:

[0064] V Net2 =0.0048V IN (20)

[0065] It can be seen from equation (20) that V Net2 The size depends on the input mains voltage V IN the size of

[0066] figure 2 The function of the judgment switching circuit PART 3 in is based on the voltage V of the Net2 point Net2 The size of the input mains voltage V IN Is it 110VAC or 220VAC, and then automatically adjusts the connection mode of the two primary windings N1 and N2 of the dual-input transformer 2 according to the judgment result. The detailed working process is as follows:

[0067] When the mains power is connected, if the input voltage is 220VAC, that is, V IN =220V, change V IN =220V is substituted into formula 14, namely:

[0068] V Net2 =1.056V

[0069] According to the characteristics of the triode, when V Net20.7V, the current reaches the base Q1-B of the transistor Q1 through the current limiting resistor R3, the transistor Q1 is turned on, and the voltage at point Net3 is pulled down to the ground level, that is, the voltage at point Net3, V Net3 = 0V, the voltage of the base Q2-B of the transistor Q2 is V Q2-B =0V, so the transistor Q2 is cut off, no current flows through the wire package of the double-pole double-throw relay K1, the relay is in the normally closed state, the pin K1-1 of the relay K1 is connected to the pin K1-4, and the pin K1-2 Connected to pin K1-4, so the pin K1-1 of the relay K1 and the pin K1-2 are also connected, that is, the lead 2Brn of the primary winding N2 is connected to the lead 3Blu of the primary winding N1, so the dual-input transformer 2 The 2 sets of primary windings N1 and N2 are in the Figure 4 The series connection mode shown. From the above analysis, it can be seen that the corresponding formulas for the output voltages of the dual input transformer 2 and the three outputs in the series connection mode are formulas (14) ~ (16), and V IN =220V is substituted into equations (14)~(16) respectively, and then:

[0070] V S1 = 20.5V,

[0071] V S2 =10.5V,

[0072] V S3 =110V.

[0073] When the mains power is connected, if the input voltage is 110VAC, that is V IN =110V, change V IN =110V is substituted into equation (14), that is:

[0074] V Net2 =0.528V

[0075] According to the characteristics of the triode, when V Net2 When <0.7V, no current passes through the current limiting resistor R3 to the base Q1-B of the transistor Q1, and the transistor Q1 is cut off. Under the action of the pull-up resistor R5, the voltage at point Net3 rises, when V Net3 When ≥0.7V, there will be a current passing through R5 to the base Q2-B of the transistor to turn on the transistor Q2, driving the double-pole double-throw relay K1 to pull in, and the pin K1-1 of the relay K1 is connected to the pin K1-3 , The pin K1-2 is connected to the pin K1-6, that is, the lead 1Blk of the primary winding N2 is connected to the lead 3Blu of the primary winding N1, and the lead 2Brn of the primary winding N2 is connected to the lead 4Red of the primary winding N1, so the dual input transformer The two sets of primary windings are in such image 3 Parallel connection shown. It can be seen from the above analysis that the corresponding formulas for the output voltages of the dual input transformer 2 and the three outputs in the parallel connection mode are formulas (8)~(10), and V IN =110V are respectively substituted into equations (8)~(10), that is:

[0076] V S1 = 20.5V,

[0077] V S2 =10.5V,

[0078] V S3 =110V.

[0079] The complete working process is that after the mains power supply is turned on, the high and low voltage automatic switching module 1 of the present invention will first determine the mains voltage. If the mains voltage is 220V, the high and low voltage automatic switching module 1 will control the dual input transformer 2 The 2 groups of primary windings N1 and N2 are in such Figure 4 In the series connection mode shown, the output voltage of the dual-input transformer is V S1 = 20.5V, V S2 =10.5V, V S3 =110V; if the mains voltage is 110V, the high and low voltage automatic switching module 1 will control the two sets of primary windings N1 and N2 of the dual input transformer 2 in such a way image 3 In the parallel connection mode shown, the output voltage of the dual-input transformer 2 is also V S1 = 20.5V, V S2 =10.5V, V S3 =110V.

[0080] It can be seen that the high-low voltage automatic switching module 1 of the present invention can automatically change the primary winding connection mode of the dual input transformer 2 in the embodiment of the present invention for different mains voltage (110V or 220V), and finally realize the dual The three output voltages of the input transformer 2 remain unchanged, so as to ensure that the power supply of the main control board of the massage chair is stable, and it is realized that the present invention can work normally under the environment of 110V city power or 220V city power at the same time.

[0081] In addition, the primary winding of the dual-input transformer in this embodiment is set in 2 groups, or more than 2 sets can be set according to the above design principle; the secondary winding of the dual-input transformer is set in 3 sets of output, in actual application, it can also be set according to specific requirements Set 1 group, 2 groups or more than 3 groups of output.