Switching power supply self-adaptive to specific LED low-voltage lamp strip voltage

Abstract

The utility model discloses a switching power supply self-adaptive to specific LED low-voltage lamp strip voltage, which comprises a high-voltage rectification and control circuit (W1), an isolation transformer and low-voltage rectification circuit (W2) and an LED lamp strip voltage self-adaptive circuit (W3). The isolation transformer and low-voltage rectification circuit (W2) is connected to the high-voltage rectification and control circuit (W1), the LED lamp strip voltage self-adaptive circuit (W3) is connected to the isolation transformer and low-voltage rectification circuit (W2), and the LED lamp strip voltage self-adaptive circuit (W3) is connected with the high-voltage rectification and control circuit (W1). The utility model relates to the field of switching power supply design and LED application, in particular to a switching power supply self-adaptive to the voltage of a specific LED low-voltage lamp strip.

Description

Technical Field

[0001] The utility model relates to the fields of switching power supply design and LED application, and particularly refers to a switching power supply that adapts to the voltage of a specific LED low-voltage light strip. Background Art

[0002] LED low-voltage light strips are increasingly used in the fields of home decoration and industrial decoration due to their diverse types, flexible cutting, and low-voltage safety characteristics. The switching power supplies supporting the power supply of LED low-voltage light strips have also developed vigorously. In different usage scenarios, the series and parallel numbers of LED lamp beads are often different. The commonly used power supply voltages for LED low-voltage light strips in the market are DC12V, DC24V, and DC48V. Therefore, it is necessary to match the switching power supplies with corresponding voltages for LED low-voltage light strips with different power supply voltages. This undoubtedly increases the product categories for power supply manufacturers, and for distributors, they need to prepare inventories of multiple voltage specifications. For end-users, multiple voltage specifications increase the probability of errors. When we go to the site to handle customer complaints, we often find situations where the voltage of the switching power supply does not match the voltage of the LED low-voltage light strip: the LED low-voltage light strip with a high voltage is wrongly paired with a switching power supply with a low voltage - the light cannot be turned on; the LED low-voltage light strip with a low voltage is paired with a switching power supply with a high output voltage, which damages the light strip. The first situation is easy to detect and can be solved during the construction process; the second situation is not easy to detect. The wrongly paired light strip can also light up for a period of time, but this situation is very dangerous: the excessive voltage causes the light strip to generate a huge amount of heat, and there is a risk of fire in an enclosed space.

[0003] In the existing solutions, some manufacturers have added LED digital tubes or liquid crystal screens on the shell of the switching power supply to indicate its output voltage, and some manufacturers have added buttons on the basis of the display, allowing customers to use the buttons to switch different output voltages. These practices all require manual identification and intervention, increasing the workload of users and cannot fundamentally solve the problem of incorrect voltage connection. Even new risks may be introduced: if a customer connects a 12V light strip and accidentally adjusts the output voltage to 48V with a button, the light strip has a risk of being instantly burned out. Summary of the Utility Model

[0004] Aiming at the above problems, the utility model provides a switching power supply that adapts to the voltage of a specific LED low-voltage light strip.

[0005] The technical solution of the present utility model is as follows: The present utility model is a switching power supply that adapts to the voltage of a specific LED low-voltage light strip, including a high-voltage rectification and control circuit (W1), an isolation transformer and a low-voltage rectification circuit (W2), and an LED light strip voltage adaptation circuit (W3). The high-voltage rectification and control circuit (W1) is connected to the main line of the AC power supply. The isolation transformer and the low-voltage rectification circuit (W2) are connected to the high-voltage rectification and control circuit (W1). The LED light strip voltage adaptation circuit (W3) is connected to the isolation transformer and the low-voltage rectification circuit (W2), and the LED light strip voltage adaptation circuit (W3) is connected to the high-voltage rectification and control circuit (W1).

[0006] Further, the LED light strip voltage adaptation circuit (W3) includes an input positive electrode Vinput, a power supply negative electrode GND, a voltage sampling and LDO circuit (W301), an MCU control unit (W302), a current sampling circuit (W303), a programmable opto-isolation feedback circuit (W304), a PMOS line-changing circuit (W305), an FB signal, a high-voltage GND, a light strip interface LED+, and a light strip interface LED-.

[0007] Further, the MCU control unit (W302) is sequentially connected to the voltage sampling and LDO circuit (W301), the current sampling circuit (W303), the programmable opto-isolation feedback circuit (W304), and the PMOS line-changing circuit (W305). The current sampling circuit (W303) is connected to the light strip interface LED-. The programmable opto-isolation feedback circuit (W304) is connected to the high-voltage rectification and control circuit (W1). The PMOS line-changing circuit (W305) is connected to the light strip interface LED+. The voltage sampling and LDO circuit (W301), the programmable opto-isolation feedback circuit (W304), and the PMOS line-changing circuit (W305) are commonly connected to the input positive electrode Vinput. The voltage sampling and LDO circuit (W301), the MCU control unit (W302), the current sampling circuit (W303), the programmable opto-isolation feedback circuit (W304), and the PMOS line-changing circuit (W305) are commonly connected to the power supply negative electrode GND.

[0008] Further, the voltage sampling and LDO circuit (W301) includes an input positive terminal Vinput, a strip interface LED+, a power negative terminal GND, resistors R1, R2, R3, R4, R5, R27, R28, R29, ceramic capacitors C1, C2, C3, C4, C5, C6, C11, a sampling voltage port ADC1, a sampling voltage port ADC2, a DCDC circuit (W30101), an LDO voltage regulator U4, an electrolytic capacitor CE1, a microcontroller power positive terminal VCC, and an operational amplifier power positive terminal VDD. The first end of the resistor R1 and the Vin terminal of the DCDC circuit (W30101) are commonly connected to the input positive terminal Vinput. The second end of the resistor R1, the first end of the resistor R2, and the first end of the resistor R3 are connected. The second end of the resistor R2 and the first end of the capacitor C1 are commonly connected to the sampling voltage port ADC1. The Vo terminal of the DCDC circuit (W30101) is connected to the first end of the resistor R4. The second end of the resistor R4, the first end of the capacitor C2, and the first end of the capacitor C3 are commonly connected to the Vin terminal of the LDO voltage regulator U4. The Vo terminal of the LDO voltage regulator U4, the first end of the capacitor C4, the first end of the capacitor C5, and the first end of the resistor R5 are commonly connected to the microcontroller power positive terminal VCC. The second end of the resistor R5, the first end of the capacitor C6, and the positive electrode of the electrolytic capacitor CE1 are commonly connected to the operational amplifier power positive terminal VDD. The first end of the resistor R27 is connected to the strip interface LED+. The second end of the resistor R27, the first end of the resistor R28, and the first end of the resistor R29 are connected. The second end of the resistor R28 and the first end of the capacitor C11 are commonly connected to the sampling voltage port ADC2. The second ends of the resistors R3 and R29, the second ends of the capacitors C1, C2, C3, C4, C5, C6, C11, the Vss terminal of the DCDC circuit (W30101), the Vss terminal of the LDO voltage regulator U4, and the negative electrode of the electrolytic capacitor CE1 are commonly connected to the power negative terminal GND.

[0009] Further, the current sampling circuit (W303) includes the positive power supply terminal VDD of the operational amplifier, the negative power supply terminal GND, resistors R6, R7, R8, R9, operational amplifier U5, the LED strip interface LED-, and the sampling voltage port ADC3. The Vin+ of the operational amplifier U5 is sequentially connected to the first ends of the resistor R7 and the resistor R9. The Vin- of the operational amplifier U5 is sequentially connected to the first ends of the resistor R6 and the resistor R8. The second end of the resistor R9 and the first end of the sampling resistor Rcs1 are commonly connected to the LED strip interface LED-. The second end of the resistor R7 and the V+ terminal of the operational amplifier U5 are commonly connected to the positive power supply terminal VDD of the operational amplifier. The second end of the resistor R8, the second end of the sampling resistor Rcs1, and the V- terminal of the operational amplifier U5 are commonly connected to the negative power supply terminal GND. The second end of the resistor R6 and the Vo terminal of the operational amplifier U5 are commonly connected to the sampling voltage port ADC3.

[0010] Further, the programmed optoelectronic isolation feedback circuit (W304) includes an input positive terminal Vinput, a power negative terminal GND, a single-chip microcomputer port PWM, an operational amplifier power positive terminal VDD, an FB signal, a high-voltage GND, resistors R10, R11, R12, R13, R14, R15, R16, R17, R18, R19, R20, capacitors C7, C8, C9, C10, an operational amplifier U1, an NPN-type triode Q1, a resistor Rcs2, an optoelectronic isolator U2, and a reference source U3. The Vin+ terminal of the operational amplifier U1 is sequentially connected to the first terminal of the resistor R11, the first terminal of the resistor R12, and the first terminal of the capacitor C8. The Vin- terminal of the operational amplifier U1 is connected to the first terminal of the resistor R14. The Vo terminal of the operational amplifier U1 is connected to the first terminal of the resistor R13. The V+ terminal of the operational amplifier U1 is connected to the operational amplifier power positive terminal VDD. The base b terminal of the NPN-type triode Q1 is connected to the second terminal of the resistor R13. The collector c terminal of the NPN-type triode Q1 is sequentially connected to the first terminal of the resistor R15 and the first terminal of the resistor R18. The emitter e terminal of the NPN-type triode Q1 is sequentially connected to the second terminal of the resistor R14 and the first terminal of the resistor Rcs2. The 1 terminal of the optoelectronic isolator U2 is sequentially connected to the first terminal of the resistor R16 and the first terminal of the resistor R17. The 2 terminal of the optoelectronic isolator U2 is sequentially connected to the second terminal of the resistor R17, the first terminal of the resistor R19, the first terminal of the capacitor C10, and the K terminal of the reference source U3. The 3 terminal of the optoelectronic isolator U2 is connected to the high-voltage GND. The 4 terminal of the optoelectronic isolator U2 is connected to the FB signal. The Ref terminal of the reference source U3 is sequentially connected to the second terminal of the resistor R18, the first terminal of the resistor R20, the first terminal of the capacitor C9, and the second terminal of the capacitor C10. The second terminal of the resistor R19 is connected to the second terminal of the capacitor C9. The single-chip microcomputer port PWM is connected to the first terminal of the resistor R10. The second terminal of the resistor R10 is connected to the second terminal of the resistor R11 and the first terminal of the capacitor C7. The second terminal of the resistor R15 and the second terminal of the resistor R16 are commonly connected to the input positive terminal Vinput. The second terminal of the capacitor C7, the second terminal of the capacitor C8, the second terminal of the resistor R12, the V- terminal of the operational amplifier U1, the second terminal of the resistor Rcs2, the second terminal of the resistor R20, and the A terminal of the reference source U3 are commonly connected to the power negative terminal GND.

[0011] Further, the PMOS line change circuit (W305) includes an input PMOS channel 1 circuit (W30501), a PMOS channel 2 circuit (W30502), a wide-voltage and small-current constant-current circuit (W30503), an input positive electrode Vinput, a power supply negative electrode GND, a control port PG1, a control port PG2, and a light bar interface LED+. The input PMOS channel 1 circuit (W30501) and the PMOS channel 2 circuit (W30502) are commonly connected to the input positive electrode Vinput. The input PMOS channel 1 circuit (W30501) and the wide-voltage and small-current constant-current circuit (W30503) are commonly connected to the light bar interface LED+. The PMOS channel 2 circuit (W30502) is connected to the wide-voltage and small-current constant-current circuit (W30503). The control port PG1 is connected to the input PMOS channel 1 circuit (W30501). The control port PG2 is connected to the PMOS channel 2 circuit (W30502). The input PMOS channel 1 circuit (W30501), the PMOS channel 2 circuit (W30502), and the wide-voltage and small-current constant-current circuit (W30503) are commonly connected to the power supply negative electrode GND.

[0012] Further, the PMOS channel 1 circuit (W30501) includes an input positive electrode Vinput, a power supply negative electrode GND, resistors R21, R22, R23, a capacitor C11, a Zener diode D1, a PMOS transistor Q2, an NMOS transistor Q3, a control port PG1, and a light bar interface LED+. The first end of the resistor R21, the first end of the capacitor C11, the negative electrode of the Zener diode D1, and the S terminal of the PMOS transistor Q2 are commonly connected to the input positive electrode Vinput. The second end of the resistor R21, the second end of the capacitor C11, the positive electrode of the Zener diode, and the G terminal of the PMOS transistor Q2 are commonly connected to the first end of the resistor R22. The D terminal of the PMOS transistor Q2 is connected to the light bar interface LED+. The second end of the resistor R22 is connected to the D terminal of the NMOS transistor Q3. The G terminal of the NMOS transistor Q3 and the first end of the resistor R23 are commonly connected to the control port PG1. The S terminal of the NMOS transistor Q3 and the second end of the resistor R23 are commonly connected to the power supply negative electrode GND.

[0013] Furthermore, the PMOS channel 2 circuit (W30502) includes an input positive electrode Vinput, a power supply negative electrode GND, resistors R24, R25, R26, a Zener diode D2, a PMOS tube Q4, an NMOS tube Q5, a control port PG2 and a small current constant current circuit input port Pout, a first end of the resistor R24, a cathode of the Zener diode D2 and an S end of the PMOS tube Q4 are commonly connected to the input positive electrode Vinput, a second end of the resistor R24, the Zener diode D2 and the S end of the PMOS tube Q4 are commonly connected to the input positive electrode Vinput, The positive electrode of the pole tube D2 and the G end of the PMOS tube Q4 are commonly connected to the first end of the resistor R25, the D end of the PMOS tube Q4 is connected to the input port Pout of the small current constant current circuit, the second end of the resistor R25 is connected to the D end of the NMOS tube Q5, the G end of the NMOS tube Q5 and the first end of the resistor R26 are commonly connected to the control port PG2, and the S end of the NMOS tube Q5 and the second end of the resistor R26 are commonly connected to the negative electrode GND of the power supply.

[0014] The implementation process of the utility model using the above structure is as follows: the circuit parameters are adjusted so that the PMOS line switching circuit (W305) is initially in the disconnected state when powered on. After the switching power supply is powered on, the positive input Vinput has a voltage output, the voltage sampling and LDO circuit (W301) first starts to work and starts the MCU control unit (W302), the MCU control unit (302) controls PG1 to remain in the disconnected state, PG2 is turned on, so that the PMOS channel 2 circuit (W30502) works, so that Pout has an output, and the wide voltage and low current constant current circuit (W30503) starts to work. At this time, the light bar interface LED+ and LED- are output in the constant current mode, no matter how much the working voltage of the connected LED low-voltage light bar is, it will not be damaged, and then the MCU controls the single The source (W302) collects the voltage of the light bar interface LED+ through the ADC3 port of the current sampling circuit (W303), thereby calculating the low-current working voltage of the current LED low-voltage light bar. The MCU control unit (W302) can deduce the working voltage of the LED low-voltage light bar through algorithm comparison. The MCU control unit (W302) controls the programmable photoelectric isolation feedback circuit (W304) through the PWM port, so that the voltage of the input positive electrode Vinput is adjusted to this voltage, and then the MCU control unit (W302) controls PG2 to turn off and controls PG1 to turn on, so that the PMOS channel 1 circuit (W30501) works. At this point, the light bar interface LED+ and LED- are output in constant voltage mode, and their output voltage is the working voltage of this LED low-voltage light bar. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1Schematic diagram of the overall structure of a switching power supply for a specific LED low-voltage light strip that can adapt to voltage

[0016] Figure 2 Schematic diagram of the voltage sampling and LDO circuit (W301) of a switching power supply for a specific LED low-voltage light strip that can adapt to voltage

[0017] Figure 3 Schematic diagram of the current sampling circuit (W303) of a switching power supply for a specific LED low-voltage light strip that can adapt to voltage

[0018] Figure 4 Schematic diagram of the programmed opto-isolation feedback circuit (W304) of a switching power supply for a specific LED low-voltage light strip that can adapt to voltage

[0019] Figure 5 Schematic diagram of the PMOS wire-changing circuit (W305) of a switching power supply for a specific LED low-voltage light strip that can adapt to voltage

[0020] Figure 6 Schematic diagram of the PMOS channel 1 circuit (W30501) of a switching power supply for a specific LED low-voltage light strip that can adapt to voltage

[0021] Figure 7 Schematic diagram of the PMOS channel 2 circuit (W30502) of a switching power supply for a specific LED low-voltage light strip that can adapt to voltage Detailed implementation

[0022] The utility model is a switching power supply that can adapt to the voltage of a specific LED low-voltage light strip. Its implementation principle is as follows: The output characteristics of the switching power supply are controlled by a single-chip microcomputer. After the switching power supply is powered on, its output is in the small-current constant-current output mode. The V-A characteristics of the LED low-voltage light strip in this mode are measured, and the working voltage of this LED low-voltage light strip is deduced. Then, the feedback circuit is controlled by the single-chip microcomputer to adjust the output voltage of the switching power supply to this voltage, and then the power supply output is switched to the constant-voltage output mode.

[0023] Such as Figures 1-7As shown in the figure, the utility model is a switching power supply that adapts to the voltage of a specific LED low-voltage light strip, including a high-voltage rectification and control circuit (W1), an isolation transformer and a low-voltage rectification circuit (W2), and an LED light strip voltage adaptation circuit (W3). The high-voltage rectification and control circuit (W1) is connected to the main line of the AC input power supply. The isolation transformer and the low-voltage rectification circuit (W2) are connected to the high-voltage rectification and control circuit (W1). The LED light strip voltage adaptation circuit (W3) is connected to the isolation transformer and the low-voltage rectification circuit (W2). The LED light strip adaptation circuit (W3) is connected to the high-voltage rectification and control circuit (W1) through a programmed opto-isolation feedback circuit (W304) inside it. The LED light strip voltage adaptation circuit (W3) internally includes a voltage sampling and LDO circuit (W301), an MCU control unit (W302), a current sampling circuit (W303), a programmed opto-isolation feedback circuit (W304), and a PMOS wire-changing circuit (W305).

[0024] Further, the voltage sampling and LDO circuit (W301) internally includes an input positive terminal Vinput, a light strip interface LED+, a power supply negative terminal GND, resistors R1, R2, R3, R4, R5, R27, R28, R29, capacitors C1, C2, C3, C4, C5, C6, C11, sampling voltage ports ADC1, ADC2, a DCDC circuit (W30101), an LDO voltage regulator U4, an electrolytic capacitor CE1, a positive power supply terminal VCC for the single-chip microcomputer, and a positive power supply terminal VDD for the operational amplifier. In the voltage division circuit composed of the series connection of resistor R1 and resistor R3, the voltage U ADC1 of the sampling voltage port ADC1 and the voltage U Vinput of the input positive terminal Vinput satisfy the following relationship: U ADC1 = U Vinput ×R3 / (R1 + R3)

[0025] In the voltage division circuit composed of the series connection of resistor R27 and R29, the voltage U ADC2 of the sampling voltage port ADC2 and the voltage U LED+ of the light strip interface LED+ satisfy the following relationship: U ADC2 = U LED+ ×R29 / (R27 + R29)

[0026] Through this circuit, the MCU control unit (W302) can obtain the voltage of the input positive terminal Vinput and the LED strip interface LED+. In this circuit, the resistor R2 and the capacitor C1 form an RC filter circuit, which is used to filter out power interference and improve the recognition accuracy. The resistors R4, R5 and the capacitors C2, C3, C4, C5, C6 and the electrolytic capacitor CE1 also play a role in filtering. Since the present utility model has requirements for the response speed of the LDO power supply part, the capacitors C2, C3, C4, C5 should be MLCC capacitors with fast response speed. Such capacitors can enable the positive terminal VCC of the single-chip microcomputer power supply to provide the voltage for the MCU control unit (W302) to work in a short time after the switch lamp power supply is powered on. The positive terminal VDD of the operational amplifier power supply is specially used to supply power to the operational amplifier, and a low power supply ripple is required. Therefore, an MLCC capacitor C6 and an electrolytic capacitor CE1 are adopted. In this circuit, the resistance value of R5 should not be too large or too small. The empirical resistance value is 10 ohms.

[0027] Further, the current sampling circuit (W303) includes the positive terminal VDD of the operational amplifier power supply, the negative terminal GND of the power supply, the resistors R6, R7, R8, R9, the operational amplifier U5, the LED strip interface LED-, and the sampling voltage port ADC3. In the non-inverting proportional operational amplifier circuit composed of the resistors R6, R8 and the operational amplifier U5, the voltage U ADC3 of the sampling voltage port ADC3 and the input voltages U Vin- and U Vin+ of the Vin- port and the Vin+ port satisfy the following operational relationship:

[0028] U ADC3 = U Vin- × (1 + R6 / R8) = U Vin+ × (1 + R6 / R8)

[0029] Thus, on the premise that R6 and R8 are determined, we can calculate the voltage of the Vin+ port by collecting the voltage of the ADC3 port through the MCU control unit. In conventional analysis, when R7 is disconnected and R9 is 0 ohm, the voltage of Vin+ is equal to the voltage of the LED strip interface LED-. Thus, we can obtain the voltage of the LED strip interface LED-. Since the resistance value of Rcs1 is known, we can calculate the current flowing through Rcs1. In this circuit, R9 is a balancing resistor, and its value is generally R6 / / R8. R7 is used to provide a fixed positive bias voltage for Vin+ to improve the stability of the circuit. When the MCU control unit collects the voltage data, subtracting this bias voltage can obtain the actual voltage of the LED strip interface LED-.

[0030] Further, the programmed optoelectronic isolation feedback circuit (W304) includes an input positive terminal Vinput, a power negative terminal GND, a single-chip microcomputer port PWM, an operational amplifier power positive terminal VDD, an FB signal, a high-voltage GND, resistors R10, R11, R12, R13, R14, R15, R16, R17, R18, R19, R20, capacitors C7, C8, C9, C10, an operational amplifier U1, an NPN-type triode Q1, a resistor Rcs2, an optoelectronic isolator U2, and a reference source U3. In this circuit, the high-frequency PWM pulse of the single-chip microcomputer port PWM passes through resistors R10, R11 and capacitors C7, C8 to form a filtering circuit and then becomes a stable DC voltage signal. This voltage signal is divided by resistor R12 and then connected to the Vin+ port of the operational amplifier U1; this voltage is U A3 , here, the operational amplifier U1, resistors R13, R14, the NPN-type triode Q1, and the resistor Rcs2 form a voltage-controlled constant current system. According to the principle of "virtual short" and "virtual open" of the operational amplifier, the voltage U A2 at the Rcs2 terminal is equal to the voltage at the Vin+ port, that is, U A3 = U A2 .

[0031] makes the current I Rcs2 flowing through Rcs2 = U A2 / Rcs2 = U A3 / Rcs2. Therefore, by adjusting the input voltage U A3 of Vin+, I Rcs2 can be adjusted. Since I 1 = I 2 + I 3 , I 3 = I b + I Rcs2 , thus I 1 = I 2 + I b + I Rcs2 . By adjusting the parameters, the NPN-type triode is made to operate in the amplification region, and the magnitude of I b can be ignored in this scenario. I 3 is approximately equal to I Rcs2 . When I Rcs2 changes, the voltage U A1 at the first end of the resistor R18 also changes, and thus the current I 2 flowing through R18 also changes. According to the feedback characteristics of the reference source U3, the current I k flowing through the reference source U3 also changes. This change is fed back to the high-voltage and rectification control circuit (W1) through the optoelectronic isolator U2, and the voltage U Vinput of the input positive terminal Vinput can be changed.. In this circuit, by adjusting parameters such as resistor R12, resistor R13, resistor R15, resistor R20, etc., feedback data with different ratios can be obtained. Therefore, the voltage U of the input positive terminal Vinput can be controlled through the PWM port of the MCU control unit (W302). Vinput Change.

[0032] . Further, the PMOS wire-changing circuit (W305) includes an input PMOS channel 1 circuit (W30501), a PMOS channel 2 circuit (W30502), a wide-voltage and small-current constant-current circuit (W30503), an input positive terminal Vinput, a power supply negative terminal GND, a control port PG1, a control port PG2, and a light bar interface LED+. In this circuit, when the system is just powered on or the load is not connected, the MCU control unit (W302) controls the PMOS channel 1 circuit (W30501) to disconnect the connection between the input positive terminal Vinput and the light bar interface LED+ through PG1, and controls the PMOS channel 2 circuit (W30502) to connect the input positive terminal Vinput to the Pout port through PG2, so that the wide-voltage and small-current constant-current circuit (W30503) starts to work. At the same time, the MCU control unit (W302) judges whether there is a load connected through the current sampling circuit (W303). After determining that an LED light bar load is connected, the MCU control unit (W302) obtains the voltage of the light bar interface LED+ through the voltage sampling and LDO circuit (W301), and records the V-A characteristic of this light bar, and calculates the working voltage of this LED low-voltage light bar. After the calculation is completed, the MCU control unit (W302) promotes the high-voltage rectification and control circuit (W1) to adjust the isolation transformer and the low-voltage rectification circuit (W2) through the programmed optoelectronic isolation feedback circuit (W304), so that the voltage of the input positive terminal Vinput is adjusted to the working voltage of the LED low-voltage light bar. Then, the MCU control unit (W302) controls the PMOS channel 2 circuit (W30502) to close through PG2, and controls the PMOS channel 1 circuit (W30501) to open through PG1, so that the input positive terminal Vinput is conducted to LED+, thus realizing the self-adaptation of the voltage of the LED low-voltage light strip.

[0033] Further, the PMOS channel 1 circuit (W30501) includes a positive input terminal Vinput, a power negative terminal GND, resistors R21, R22, R23, a capacitor C11, a Zener diode D1, a PMOS transistor Q2, an NMOS transistor Q3, a control port PG1, and a strip interface LED+. In this circuit, the Zener diode D1 functions to clamp and protect the PMOS transistor Q2. The resistor R21 and the capacitor C11 form a soft-start circuit, enabling the PMOS transistor Q2 to turn on slowly and achieving the effect of the LED low-voltage strip lighting up slowly. The NMOS transistor Q3 is used to expand the voltage for PG1 of the MCU control unit (W302), allowing PG1 to control the PMOS transistor Q2 on the power supply side. The resistor R23 is essential as a discharge resistor.

[0034] Further, the PMOS channel 2 circuit (W30502) includes a positive input terminal Vinput, a power negative terminal GND, resistors R24, R25, R26, a Zener diode D2, a PMOS transistor Q4, an NMOS transistor Q5, a control port PG2, and a small-current constant-current circuit input port Pout. In this circuit, the functions of the Zener diode D2 and the NMOS transistor Q5 are the same as those in the PMOS channel 1 circuit (W30501). The only difference is that the Pout output needs to quickly start a wide-voltage small-current constant-current circuit (W30503), and a soft-start circuit cannot be used here.

[0035] It should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A switching power supply that is adaptive to a specific LED low-voltage lamp with voltage, characterized in that: The invention comprises a high-voltage rectification and control circuit (W1), an isolation transformer and a low-voltage rectification circuit (W2), and an LED light strip voltage adaptive circuit (W3); the high-voltage rectification and control circuit (W1) is connected to an AC power main line; the isolation transformer and the low-voltage rectification circuit (W2) are connected to the high-voltage rectification and control circuit (W1); the LED light strip voltage adaptive circuit (W3) is connected to the isolation transformer and the low-voltage rectification circuit (W2); and the LED light strip voltage adaptive circuit (W3) is connected to the high-voltage rectification and control circuit (W1).

2. The switching power supply according to claim 1, which is self-adaptive to a specific LED low-voltage lamp voltage, is characterized in that: The LED light strip voltage adaptive circuit (W3) comprises an input positive electrode Vinput, a power supply negative electrode GND, a voltage sampling and LDO circuit (W301), an MCU control unit (W302), a current sampling circuit (W303), a programmable photoelectric isolation feedback circuit (W304), a PMOS line switching circuit (W305), an FB signal, a high voltage GND, and a light bar interface LED+ and a light bar interface LED-. The MCU control unit (W302) is sequentially connected to the voltage sampling and LDO circuit (W301), the current sampling circuit (W303), the programmable photoelectric isolation feedback circuit (W304) and the PMOS line switching circuit (W305). The current sampling circuit (W303) is connected to the light bar interface. The programmable photoelectric isolation feedback circuit (W304) is connected to the high-voltage rectification and control circuit (W1), the PMOS line switching circuit (W305) is connected to the light bar interface LED+, the voltage sampling and LDO circuit (W301), the programmable photoelectric isolation feedback circuit (W304) and the PMOS line switching circuit (W305) are commonly connected to the input positive electrode Vinput, and the voltage sampling and LDO circuit (W301), the MCU control unit (W302), the current sampling circuit (W303), the programmable photoelectric isolation feedback circuit (W304) and the PMOS line switching circuit (W305) are commonly connected to the power supply negative electrode GND.

3. The switching power supply according to claim 2, which is self-adaptive to a specific LED low-voltage lamp voltage, is characterized in that: The program-controlled photoelectric isolation feedback circuit (W304) includes an input positive electrode Vinput, a power supply negative electrode GND, a single-chip microcomputer port PWM, an operational amplifier power supply positive electrode VDD, an FB signal, a high voltage GND, resistors R10, R11, R12, R13, R14, R15, R16, R17, R18, R19, R20, capacitors C7, C8, C9, C10, an operational amplifier U1, an NPN transistor Q1, a resistor Rcs2, a photoelectric isolator U2 and a reference source U3, wherein the Vin+ end of the operational amplifier U1 is sequentially connected to the first end of the resistor R11, the first end of the resistor R12 and the first end of the capacitor C8. The first end, the Vin- end of the operational amplifier U1 is connected to the first end of the resistor R14, the Vo end of the operational amplifier U1 is connected to the first end of the resistor R13, the V+ end of the operational amplifier U1 is connected to the positive electrode VDD of the operational amplifier power supply, the base b end of the NPN transistor Q1 is connected to the second end of the resistor R13, the collector c end of the NPN transistor Q1 is connected to the first end of the resistor R15 and the first end of the resistor R18 in sequence, the emitter e end of the NPN transistor Q1 is connected to the second end of the resistor R14 and the first end of the resistor Rcs2 in sequence, and the End 1 of the photoelectric isolator U2 is connected to the first end of the resistor R16 and the first end of the resistor R17 in sequence, end 2 of the photoelectric isolator U2 is connected to the second end of the resistor R17, the first end of the resistor R19, the first end of the capacitor C10 and the K end of the reference source U3 in sequence, end 3 of the photoelectric isolator U2 is connected to the high voltage GND, end 4 of the photoelectric isolator U2 is connected to the FB signal, and the Ref end of the reference source U3 is connected to the second end of the resistor R18, the first end of the resistor R20, the first end of the capacitor C9 and the second end of the capacitor C10, the resistor R1 The second end of the single-chip microcomputer port PWM is connected to the first end of the resistor R10, the second end of the resistor R10 is connected to the second end of the resistor R11 and the first end of the capacitor C7, the second end of the resistor R15 and the second end of the resistor R16 are commonly connected to the input positive electrode Vinput, the second end of the capacitor C7, the second end of the capacitor C8, the second end of the resistor R12, the V-end of the operational amplifier U1, the second end of the resistor Rcs2, the second end of the resistor R20 and the A end of the reference source U3 are commonly connected to the power supply negative electrode GND.

4. The switching power supply capable of adaptively adjusting the voltage of a specific LED low-voltage lamp according to claim 2, characterized in that: The PMOS line switching circuit (W305) includes an input PMOS channel 1 circuit (W30501), a PMOS channel 2 circuit (W30502), a wide voltage and small current constant current circuit (W30503), an input positive electrode Vinput, a power supply negative electrode GND, a control port PG1, a control port PG2 and a light bar interface LED+. The PMOS channel 1 circuit (W30501) and the PMOS channel 2 circuit (W30502) are connected to the input positive electrode Vinput. The PMOS channel 1 circuit (W30501) and the wide voltage and small current constant current circuit (W30503) are commonly connected to the light bar interface LED+, the PMOS channel 2 circuit (W30502) is connected to the wide voltage and small current constant current circuit (W30503), the control port PG1 is connected to the PMOS channel 1 circuit (W30501), the control port PG2 is connected to the PMOS channel 2 circuit (W30502), the PMOS channel 1 circuit (W30501), the PMOS channel 2 circuit (W30502) and the wide voltage and small current constant current circuit (W30503) are commonly connected to the negative pole of the power supply GND.

5. The switching power supply capable of adaptively adjusting the voltage of a specific LED low-voltage lamp according to claim 2, characterized in that: When the system is just powered on or the load is not connected, the MCU control unit (W302) controls the PMOS channel 1 circuit (W30501) through PG1 to disconnect the input positive electrode Vinput and the light bar interface LED+, and controls the PMOS channel 2 circuit (W30502) through PG2 to connect the input positive electrode Vinput and the Pout port, so that the wide voltage and small current constant current circuit (W30503) starts to work. At the same time, the MCU control unit (W302) determines whether there is a load connected through the current sampling circuit (W303). After determining that the LED light bar load is connected, the MCU control unit (W302) obtains the voltage of the light bar interface LED+ through voltage sampling and LDO circuit (W301). , and record the VA characteristics of this light strip, and calculate the working voltage of this LED low-voltage light strip. After the calculation is completed, the MCU control unit (W302) prompts the high-voltage rectification and control circuit (W1) to adjust the isolation transformer and the low-voltage rectification circuit (W2) through the programmable photoelectric isolation feedback circuit (W304), so that the input positive electrode Vinput voltage is adjusted to the working voltage of the LED low-voltage light strip. Then, the MCU control unit (W302) controls the PMOS channel 2 circuit (W30502) to be closed through PG2, and controls the PMOS channel 1 circuit (W30501) to be opened through PG1, so that the input positive electrode Vinput is transmitted to LED+, thereby realizing the self-adaptation of the LED low-voltage light strip voltage.

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