Signal conversion circuit, LED driving power supply and LED lamp

Abstract

The present invention discloses a signal conversion circuit, comprising an isolation conversion unit for receiving a PWM signal and isolating and transmitting the PWM signal to convert it into an output signal; a voltage stabilizing unit, the voltage stabilizing unit is connected to the isolation conversion unit and is used to provide a stable reference voltage for the conversion of the PWM signal; a voltage regulating unit, the voltage regulating unit is connected to the isolation conversion unit and the voltage stabilizing unit and is used to adjust and control the voltage amplitude of the output signal; a voltage following unit, the input end of the voltage following unit is connected to the voltage regulating unit, the output end is used to connect to a controller, and is used to stably output the output signal to the controller; a power supply unit, the power supply unit is connected to the voltage stabilizing unit and the voltage following unit, and is used to supply power to the voltage stabilizing unit and the voltage following unit. The implementation of the present invention can adjust the output signal, reduce interference, and improve the accuracy and stability of the output signal.

Description

Technical Field

[0001] The present invention relates to the technical field of switching power supplies, and in particular to a signal conversion circuit, an LED driving power supply and an LED lamp. Background Art

[0002] In the design of outdoor LED driver power supply, the signal conversion circuit is a very critical link. Figure 1 As shown, Figure 1 It is a traditional signal conversion circuit, where resistor R1 and capacitor C1 are filter circuits, and resistors R2 and R3 are voltage divider circuits. In traditional signal conversion circuits, the output signal follows the input signal, and the output signal is difficult to adjust. Moreover, the output signal is derived from the input signal, which is greatly affected by interference, and the control signal accuracy is poor, which is not suitable for high-precision signal control. In addition, when the input signal is delayed or there is no input signal, the output signal cannot effectively maintain a small voltage to achieve control of the controller. Summary of the invention

[0003] The present invention provides a signal conversion circuit, an LED driving power supply and an LED lamp, aiming to solve the problems in the related art that the output signal is difficult to adjust, the accuracy is poor, and when the input signal is delayed or there is no input signal, the output signal cannot effectively maintain a small voltage to achieve control of the controller.

[0004] In a first aspect, the present invention provides a signal conversion circuit, which includes: an isolation conversion unit, which is used to receive a PWM signal and isolate and transmit the PWM signal to convert it into an output signal; a voltage stabilizing unit, which is connected to the isolation conversion unit and is used to provide a stable reference voltage for the conversion of the PWM signal; a voltage regulating unit, which is connected to the isolation conversion unit and the voltage stabilizing unit and is used to adjust and control the voltage amplitude of the output signal; a voltage following unit, whose input end is connected to the voltage regulating unit and whose output end is used to connect to a controller and to stably output the output signal to the controller; a power supply unit, which is connected to the voltage stabilizing unit and the voltage following unit and is used to supply power to the voltage stabilizing unit and the voltage following unit; wherein the voltage regulating unit is also used to connect to the controller, and when the PWM signal is not input, the power supply unit outputs a control voltage signal through the voltage stabilizing unit and outputs it to the controller via the voltage regulating unit.

[0005] Further, the power supply unit includes a first resistor, a second resistor, a third resistor, a first diode, a second diode, a first voltage regulator and a first capacitor, the positive electrode of the first diode is connected to the first power supply, the negative electrode of the first diode is connected to one end of the third resistor, the other end of the third resistor is connected to the voltage regulator unit, one end of the first resistor is connected to the first power supply, the other end of the first resistor is connected to between the negative electrode of the first diode and the third resistor, the negative electrode of the first voltage regulator is connected to between the negative electrode of the first diode and the third resistor, the positive electrode of the first voltage regulator is grounded, the first capacitor is connected to the first voltage regulator in parallel, the positive electrode of the second diode is connected to the high-voltage starting circuit, the negative electrode of the second diode is connected to between the negative electrode of the first diode and the third resistor, one end of the second resistor is connected to between the negative electrode of the first diode and the third resistor, and the other end of the second resistor is connected to the voltage following unit.

[0006] Further, the voltage stabilizing unit includes a fourth resistor, a fifth resistor, a sixth resistor, a second capacitor, a third capacitor and a voltage stabilizing chip, one end of the sixth resistor is connected to the isolation conversion unit and the voltage regulating unit, the other end of the sixth resistor is connected to the third resistor, the output end of the voltage stabilizing chip is connected between the sixth resistor and the third resistor, the ground end of the voltage stabilizing chip is grounded, one end of the fourth resistor is connected to the input end of the voltage stabilizing chip, the other end of the fourth resistor is grounded, one end of the fifth resistor is connected to the sixth resistor and the third resistor, the other end of the fifth resistor is connected to the output end of the voltage stabilizing chip and to the voltage regulating unit, one end of the second capacitor is connected to the sixth resistor and the third resistor, the other end of the second capacitor is connected to the input end of the voltage stabilizing chip, one end of the third capacitor is connected to the sixth resistor and the third resistor, and the other end of the third capacitor is grounded.

[0007] Further, the isolation conversion unit includes a seventh resistor, a twenty-first resistor and an optocoupler, the positive electrode of the light-emitting diode of the optocoupler is connected to the second power supply, the negative electrode of the light-emitting diode is connected to one end of the twenty-first resistor, the other end of the twenty-first resistor is used to input the PWM signal, the emitter of the phototransistor of the optocoupler is grounded, the collector of the phototransistor is connected to one end of the seventh resistor, and the other end of the seventh resistor is connected to the other end of the sixth resistor and the voltage regulating unit.

[0008] Further, the voltage regulating unit includes an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor and an adjustable resistor, one end of the eighth resistor is connected between the sixth resistor and the seventh resistor, the other end of the eighth resistor is connected to the voltage following unit, one end of the ninth resistor is connected between the eighth resistor and the voltage following unit, the other end of the ninth resistor is connected to one end of the tenth resistor, the other end of the tenth resistor is grounded, one end of the eleventh resistor is grounded, the other end of the eleventh resistor is connected to one end of the adjustable resistor, the other end of the adjustable resistor is connected between the ninth resistor and the tenth resistor, one end of the twelfth resistor is connected between the eleventh resistor and the adjustable resistor, and the other end of the twelfth resistor is connected to the fifth resistor.

[0009] Further, the voltage follower unit includes a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a third diode and an operational amplifier, the power supply terminal of the operational amplifier is connected to the other end of the second resistor, the ground terminal of the operational amplifier is grounded, the output terminal of the operational amplifier is connected to the positive electrode of the third diode, the negative electrode of the third diode is used to be connected to the controller, the seventeenth resistor is connected in parallel with the third diode, the in-phase input terminal of the operational amplifier is connected to one end of the sixth capacitor, the other end of the sixth capacitor is grounded and connected to one end of the fourth capacitor, and the The other end of the four capacitors is connected to one end of the fourteenth resistor, the other end of the fourteenth resistor is used to connect to the controller, one end of the sixteenth resistor is connected between the non-inverting input terminal of the operational amplifier and the sixth capacitor, the other end of the sixteenth resistor is connected to one end of the fifth capacitor, the other end of the fifth capacitor is connected to one end of the fifteenth resistor, the other end of the fifteenth resistor is used to connect to the controller, one end of the thirteenth resistor is connected between the eighth resistor and the ninth resistor, the other end of the thirteenth resistor is connected between the fourth capacitor and the fourteenth resistor, and between the sixteenth resistor and the fifth capacitor.

[0010] Furthermore, it also includes an over-temperature protection unit, one end of which is connected to the power supply unit, and the other end is connected to the output end of the voltage follower unit and the voltage adjustment unit, and is used to lower the voltage of the output signal or the control voltage signal to reduce the temperature when over-temperature occurs.

[0011] Further, the over-temperature protection unit includes an eighteenth resistor, a nineteenth resistor, a twentieth resistor, a thermistor, a seventh capacitor, a second voltage-stabilizing diode, and a transistor, one end of the thermistor is connected between the positive electrode of the first diode and the first power supply, the other end of the thermistor is connected to the negative electrode of the second voltage-stabilizing diode, the positive electrode of the second voltage-stabilizing diode is connected to the base of the transistor, the collector of the transistor is connected to one end of the eighteenth resistor, the other end of the eighteenth resistor is connected between the fourteenth resistor and the controller, the emitter of the transistor is grounded, one end of the nineteenth resistor is connected between the base of the transistor and the positive electrode of the second voltage-stabilizing diode, the other end of the nineteenth resistor is grounded, the seventh capacitor is connected to the nineteenth resistor in parallel, one end of the twentieth resistor is connected between the negative electrode of the second voltage-stabilizing diode and the thermistor, and the other end of the twentieth resistor is grounded.

[0012] In a second aspect, the present invention further provides an LED driving power supply, which includes a signal conversion circuit, and the signal conversion circuit is the signal conversion circuit described in the first aspect above.

[0013] In a third aspect, the present invention further provides an LED lamp, comprising an LED driving power supply, wherein the LED driving power supply is the LED driving power supply described in the second aspect.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention isolates and transmits the PWM signal into an output signal through an isolation conversion unit, the voltage stabilization unit provides a reference voltage for the PWM signal conversion, the voltage adjustment unit can adjust the voltage amplitude of the output signal, and the output signal is output to the controller via the voltage follower unit to achieve control of the controller. The output signal can be adjusted to reduce interference and improve the accuracy and stability of the output signal. When the input signal is delayed or there is no input signal, the control voltage signal can effectively maintain a smaller voltage to achieve control of the controller and improve reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0016] Figure 1 A schematic diagram of a signal conversion circuit in the prior art is shown;

[0017] Figure 2 A schematic diagram of a signal conversion circuit provided by an embodiment of the present invention is shown;

[0018] Figure 3 A schematic diagram of a signal conversion circuit provided by another embodiment of the present invention is shown;

[0019] Figure 4 Shown Figure 3 A circuit diagram of a signal conversion circuit provided by the illustrated embodiment. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0022] It should also be understood that the terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0023] It should be further understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0024] Reference Figure 2-4, which shows an embodiment of the signal conversion circuit 100 provided by the present invention. The signal conversion circuit 100 includes: an isolation conversion unit 10, which is used to receive a PWM signal and isolate and transmit the PWM signal to convert it into an output signal; a voltage stabilizing unit 20, which is connected to the isolation conversion unit 10 and is used to provide a stable reference voltage for the conversion of the PWM signal; a voltage regulating unit 30, which is connected to the isolation conversion unit 10 and the voltage stabilizing unit 20 and is used to adjust and control the voltage amplitude of the output signal; a voltage following unit 40, whose input end is connected to the voltage regulating unit The voltage regulator 30 is connected to the controller 70, and the output end is used to connect to the controller 70, and is used to stably output the output signal to the controller 70; the power supply unit 50 is connected to the voltage regulator unit 20 and the voltage follower unit 40, and is used to supply power to the voltage regulator unit 20 and the voltage follower unit 40; wherein the voltage regulator unit 30 is also used to connect to the controller 70, and when the PWM signal is not input, the power supply unit 50 outputs the control voltage signal through the voltage regulator unit 20 and outputs it to the controller 70 via the voltage regulator unit 30. By implementing this embodiment, when the PWM signal is input, the input PWM signal is isolated and transmitted and converted into an output signal through the isolation conversion unit 10, and the voltage regulator unit 20 converts the PWM signal to increase the reference voltage. In addition, the voltage regulator unit 30 can adjust the voltage amplitude of the output signal, and the output signal is output to the controller 70 through the voltage follower unit 40 to control the controller 70, thereby realizing the adjustment of the output signal and improving the accuracy and stability of the output signal. When there is no PWM signal input, the power supply unit 50 provides power to the voltage stabilizing unit 20, and the voltage stabilizing unit 20 outputs a voltage control signal to the controller 70 via the voltage regulating unit 30. Therefore, even when the input signal is delayed or there is no input signal, a smaller voltage can be maintained to achieve control of the controller 70, thereby improving reliability.

[0025] In one embodiment, for example, in this embodiment, the power supply unit 50 includes a first resistor R1, a second resistor R2, a third resistor R3, a first diode D1, a second diode D2, a first voltage regulator ZD1 and a first capacitor C1, the positive electrode of the first diode D1 is connected to the first power supply, the negative electrode of the first diode D1 is connected to one end of the third resistor R3, the other end of the third resistor R3 is connected to the voltage regulator unit 20, one end of the first resistor R1 is connected to the first power supply, the other end of the first resistor R1 is connected to the negative electrode of the first diode D1 and the third resistor R3 The cathode of the first voltage regulator ZD1 is connected between the cathode of the first diode D1 and the third resistor R3, the anode of the first voltage regulator ZD1 is grounded, the first capacitor C1 is connected in parallel with the first voltage regulator ZD1, the anode of the second diode D2 is connected to the high-voltage startup circuit C, the cathode of the second diode D2 is connected between the cathode of the first diode D1 and the third resistor R3, one end of the second resistor R2 is connected between the cathode of the first diode D1 and the third resistor R3, and the other end of the second resistor R2 is connected to the voltage follower unit 40. In this embodiment, the first power supply is VCC. The high-voltage startup circuit C provides a start-up voltage for the voltage regulator chip U1 and the operational amplifier U3 through the second diode D2 and the first voltage regulator ZD1, and the power supply circuit is composed of the first diode D1, the first capacitor C1, the second resistor R2 and the third resistor R3 to provide a power supply voltage for the voltage regulator chip U1 and the operational amplifier U3.

[0026] In one embodiment, for example, in this embodiment, the voltage stabilizing unit 20 includes a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a second capacitor C2, a third capacitor C3 and a voltage stabilizing chip U1, one end of the sixth resistor R6 is connected to the isolation conversion unit 10 and the voltage regulating unit 30, the other end of the sixth resistor R6 is connected to the third resistor R3, the output end of the voltage stabilizing chip U1 is connected between the sixth resistor R6 and the third resistor R3, the ground end of the voltage stabilizing chip U1 is grounded, and one end of the fourth resistor R4 is connected to the input end of the voltage stabilizing chip U1. The fourth resistor R4 is connected to the ground, one end of the fifth resistor R5 is connected between the sixth resistor R6 and the third resistor R3, the other end of the fifth resistor R5 is connected to the output end of the voltage stabilizing chip U1 and the voltage regulating unit 30, one end of the second capacitor C2 is connected between the sixth resistor R6 and the third resistor R3, the other end of the second capacitor C2 is connected to the input end of the voltage stabilizing chip U1, one end of the third capacitor C3 is connected between the sixth resistor R6 and the third resistor R3, and the other end of the third capacitor C3 is grounded. The voltage stabilizing unit 20 in this embodiment provides a reference voltage when the PWM signal is converted, reduces interference, and improves signal accuracy.

[0027] In one embodiment, such as the present embodiment, the isolation conversion unit 10 includes a seventh resistor R7, a twenty-first resistor R21, and an optical coupler U2, the positive electrode of the light-emitting diode of the optical coupler U2 is connected to the second power supply, the negative electrode of the light-emitting diode is connected to one end of the twenty-first resistor R21, the other end of the twenty-first resistor R21 is used to input the PWM signal (ADJ), the emitter of the phototransistor of the optical coupler U2 is grounded, the collector of the phototransistor is connected to one end of the seventh resistor R7, the other end of the seventh resistor R7 is connected to the other end of the sixth resistor R6 and the voltage adjustment unit 30. In the present embodiment, the second power supply is a 5V power supply, and the isolation conversion unit 10 in the present embodiment electrically isolates the PWM signal, and can achieve efficient conversion of the isolated PWM signal.

[0028] In one embodiment, for example, in this embodiment, the voltage regulating unit 30 includes an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12 and an adjustable resistor VR1, one end of the eighth resistor R8 is connected between the sixth resistor R6 and the seventh resistor R7, the other end of the eighth resistor R8 is connected to the voltage following unit 40, one end of the ninth resistor R9 is connected between the eighth resistor R8 and the voltage following unit 40, the other end of the ninth resistor R9 is connected to one end of the tenth resistor R10, the other end of the tenth resistor R10 is grounded, one end of the eleventh resistor R11 is grounded, the other end of the eleventh resistor R11 is connected to one end of the adjustable resistor VR1, the other end of the adjustable resistor VR1 is connected between the ninth resistor R9 and the tenth resistor R10, one end of the twelfth resistor R12 is connected between the eleventh resistor R11 and the adjustable resistor VR1, and the other end of the twelfth resistor R12 is connected to the fifth resistor R5. The voltage regulating unit 30 in this embodiment can regulate the voltage of the transformed output signal when the PWM signal is input, thereby achieving the adjustable output signal.

[0029] In one embodiment, for example, in this embodiment, the voltage follower unit 40 includes a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a seventeenth resistor R17, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, a third diode D3 and an operational amplifier U3, the power supply end of the operational amplifier U3 is connected to the other end of the second resistor R2, the ground end of the operational amplifier U3 is grounded, the output end of the operational amplifier U3 is connected to the positive electrode of the third diode D3, the negative electrode of the third diode D3 is used to connect to the controller 70 (F), the seventeenth resistor R17 is connected in parallel with the third diode D3, the in-phase input end of the operational amplifier is connected to one end of the sixth capacitor C6, the other end of the sixth capacitor C6 is grounded and connected to one end of the fourth capacitor C4 , the other end of the fourth capacitor C4 is connected to one end of the fourteenth resistor R14, the other end of the fourteenth resistor R14 is used to connect to the controller 70 (F), one end of the sixteenth resistor R16 is connected between the non-inverting input terminal of the operational amplifier U3 and the sixth capacitor C6, the other end of the sixteenth resistor R16 is connected to one end of the fifth capacitor C5, the other end of the fifth capacitor C5 is connected to one end of the fifteenth resistor R15, the other end of the fifteenth resistor R15 is used to connect to the controller 70 (F), one end of the thirteenth resistor R13 is connected between the eighth resistor R8 and the ninth resistor R9, the other end of the thirteenth resistor R13 is connected between the fourth capacitor C4 and the fourteenth resistor R14, and between the sixteenth resistor R16 and the fifth capacitor C5. In this embodiment, the thirteenth resistor R13 and the fourth capacitor C4 form a filter to smooth the output signal; the fifth capacitor C5 and the fifteenth resistor R15 are used for fast conduction to prevent oscillation; the sixth capacitor C6 is used to filter the high-frequency signal at the input end of the operational amplifier U3 to reduce the risk of high-frequency self-excitation of the amplifier; the operational amplifier U3, the third diode D3, the sixteenth resistor R16 and the sixth capacitor C6 form a voltage follower to improve the accuracy and anti-interference of the output signal. The voltage follower unit 40 of this embodiment can stably output the output signal to the controller 70, ensuring the stability and reliability of the output signal.

[0030] In one embodiment, such as the present embodiment, the signal conversion circuit 100 also includes an over-temperature protection unit 60, one end of the over-temperature protection unit 60 is connected to the power supply unit 50, and the other end is connected to the output end of the voltage follower unit 40 and the voltage adjustment unit 30, and is used to lower the voltage of the output signal or the control voltage signal to reduce the temperature when over-temperature occurs.

[0031] In a specific implementation, the over-temperature protection unit 60 includes an eighteenth resistor R18, a nineteenth resistor R19, a twentieth resistor R20, a thermistor RT2, a seventh capacitor C7, a second voltage regulator ZD2, and a transistor Q1, one end of the thermistor RT2 is connected between the positive electrode of the first diode D1 and the first power supply, the other end of the thermistor RT2 is connected to the negative electrode of the second voltage regulator ZD2, the positive electrode of the second voltage regulator ZD2 is connected to the base of the transistor Q1, and the collector of the transistor Q1 is connected to one end of the eighteenth resistor R18 The other end of the eighteenth resistor R18 is connected between the fourteenth resistor R14 and the controller 70, the emitter of the transistor Q1 is grounded, one end of the nineteenth resistor R19 is connected between the base of the transistor Q1 and the positive electrode of the second voltage-stabilizing tube ZD2, the other end of the nineteenth resistor R19 is grounded, the seventh capacitor C7 is connected in parallel with the nineteenth resistor R19, one end of the twentieth resistor R20 is connected between the negative electrode of the second voltage-stabilizing tube ZD2 and the thermistor RT2, and the other end of the twentieth resistor R20 is grounded.

[0032] Specifically, when the temperature rises, the resistance of the thermistor RT2 decreases, and the voltage across the twentieth resistor R20 increases. When the increased voltage exceeds the voltage of the second voltage regulator tube ZD2, the transistor Q1 (NPN) is turned on, and the voltage of the output signal or the voltage of the control voltage signal is lowered through the eighteenth resistor R18, thereby achieving the effect of temperature protection by reducing the voltage to avoid overheating and damage to components.

[0033] In another embodiment, when there is no PWM signal input, the voltage stabilizing unit 20 composed of the first resistor R1, the third resistor R3, the fourth resistor R4, the second capacitor C2 and the voltage stabilizing chip U1 provides a stable reference voltage, and the sixth resistor R6, the eighth resistor R8, the ninth resistor R9, the twelfth resistor R12, the adjustable resistor VR1, the thirteenth resistor R13, the fourteenth resistor R14 and the fourth capacitor C4 form a voltage regulating unit 30 to adjust the control voltage signal. Therefore, when the input signal is delayed or there is no input signal, the reference voltage of the voltage stabilizing unit 20 is used to provide a control voltage signal, and the voltage regulating unit 30 is used to adjust and transmit the control voltage signal, and the control voltage signal is output to the controller 70, effectively maintaining a relatively low voltage to control the controller 70.

[0034] The embodiment of the signal conversion circuit 100 of the present invention isolates and transmits the PWM signal into an output signal through the isolation conversion unit 10, the voltage stabilization unit 20 provides a reference voltage for the PWM signal conversion, the voltage adjustment unit 30 can adjust the voltage amplitude of the output signal, and the output signal is output to the controller 70 via the voltage follower unit 40 to achieve control of the controller 70. The output signal can be adjusted to reduce interference and improve the accuracy and stability of the output signal. When the input signal is delayed or there is no input signal, the control voltage signal can effectively maintain a smaller voltage to achieve control of the controller 70 and improve reliability.

[0035] The present invention also shows an LED driving power supply, which includes a signal conversion circuit 100. The signal conversion circuit 100 is the signal conversion circuit 100 described in the above embodiment. Other circuit components included in the LED driving power supply are well known to ordinary technicians in the field and will not be repeated here.

[0036] The embodiment of the LED driving power supply of the present invention isolates and transmits the PWM signal into an output signal through the isolation conversion unit 10, the voltage stabilizing unit 20 provides a reference voltage for the PWM signal conversion, the voltage regulating unit 30 can adjust the voltage amplitude of the output signal, and the output signal is output to the controller 70 via the voltage following unit 40 to achieve control of the controller 70. The output signal can be adjusted to reduce interference and improve the accuracy and stability of the output signal. When the input signal is delayed or there is no input signal, the control voltage signal can effectively maintain a smaller voltage to achieve control of the controller 70 and improve reliability.

[0037] The present invention further shows an LED lamp, which includes an LED driving power supply. The LED driving power supply is the LED driving power supply described in the above embodiment, which will not be described in detail here.

[0038] The embodiment of the LED lamp of the present invention isolates and transmits the PWM signal into an output signal through the isolation conversion unit 10, the voltage stabilizing unit 20 provides a reference voltage for the PWM signal conversion, the voltage regulating unit 30 can adjust the voltage amplitude of the output signal, and the output signal is output to the controller 70 via the voltage following unit 40 to achieve control of the controller 70. The output signal can be adjusted to reduce interference and improve the accuracy and stability of the output signal. When the input signal is delayed or there is no input signal, the control voltage signal can effectively maintain a smaller voltage to achieve control of the controller 70 and improve reliability.

[0039] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A signal conversion circuit, characterized in that: include: An isolation conversion unit, used for receiving a PWM signal and isolating and transmitting the PWM signal to convert it into an output signal; A voltage stabilizing unit, the voltage stabilizing unit being connected to the isolation conversion unit and being used to provide a stable reference voltage for conversion of the PWM signal; A voltage regulating unit, the voltage regulating unit being connected to the isolation conversion unit and the voltage stabilizing unit and being used for regulating and controlling the voltage amplitude of the output signal; A voltage following unit, wherein the input end of the voltage following unit is connected to the voltage regulating unit, and the output end of the voltage following unit is used to be connected to the controller and is used to stably output the output signal to the controller; a power supply unit, the power supply unit being connected to the voltage stabilizing unit and the voltage following unit, and being used to supply power to the voltage stabilizing unit and the voltage following unit; The voltage regulating unit is also used to be connected to the controller. When the PWM signal is not input, the power supply unit outputs a control voltage signal through the voltage stabilizing unit and outputs the control voltage signal to the controller via the voltage regulating unit.

2. The signal conversion circuit according to claim 1, characterized in that: The power supply unit includes a first resistor, a second resistor, a third resistor, a first diode, a second diode, a first voltage regulator and a first capacitor, the positive electrode of the first diode is connected to the first power supply, the negative electrode of the first diode is connected to one end of the third resistor, the other end of the third resistor is connected to the voltage regulator unit, one end of the first resistor is connected to the first power supply, the other end of the first resistor is connected between the negative electrode of the first diode and the third resistor, the negative electrode of the first voltage regulator is connected between the negative electrode of the first diode and the third resistor, the positive electrode of the first voltage regulator is grounded, the first capacitor is connected to the first voltage regulator in parallel, the positive electrode of the second diode is connected to the high-voltage starting circuit, the negative electrode of the second diode is connected between the negative electrode of the first diode and the third resistor, one end of the second resistor is connected between the negative electrode of the first diode and the third resistor, and the other end of the second resistor is connected to the voltage follower unit.

3. The signal conversion circuit according to claim 2, characterized in that: The voltage stabilizing unit includes a fourth resistor, a fifth resistor, a sixth resistor, a second capacitor, a third capacitor and a voltage stabilizing chip, one end of the sixth resistor is connected to the isolation conversion unit and the voltage regulating unit, the other end of the sixth resistor is connected to the third resistor, the output end of the voltage stabilizing chip is connected between the sixth resistor and the third resistor, the ground end of the voltage stabilizing chip is grounded, one end of the fourth resistor is connected to the input end of the voltage stabilizing chip, the other end of the fourth resistor is grounded, one end of the fifth resistor is connected between the sixth resistor and the third resistor, the other end of the fifth resistor is connected to the output end of the voltage stabilizing chip and the voltage regulating unit, one end of the second capacitor is connected between the sixth resistor and the third resistor, the other end of the second capacitor is connected to the input end of the voltage stabilizing chip, one end of the third capacitor is connected between the sixth resistor and the third resistor, and the other end of the third capacitor is grounded.

4. The signal conversion circuit according to claim 3, characterized in that: The isolation conversion unit includes a seventh resistor, a twenty-first resistor and an optocoupler, the positive electrode of the light-emitting diode of the optocoupler is connected to the second power supply, the negative electrode of the light-emitting diode is connected to one end of the twenty-first resistor, the other end of the twenty-first resistor is used to input the PWM signal, the emitter of the phototransistor of the optocoupler is grounded, the collector of the phototransistor is connected to one end of the seventh resistor, and the other end of the seventh resistor is connected to the other end of the sixth resistor and the voltage regulation unit.

5. The signal conversion circuit according to claim 4, characterized in that: The voltage regulating unit includes an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor and an adjustable resistor, one end of the eighth resistor is connected between the sixth resistor and the seventh resistor, the other end of the eighth resistor is connected to the voltage following unit, one end of the ninth resistor is connected between the eighth resistor and the voltage following unit, the other end of the ninth resistor is connected to one end of the tenth resistor, the other end of the tenth resistor is grounded, one end of the eleventh resistor is grounded, the other end of the eleventh resistor is connected to one end of the adjustable resistor, the other end of the adjustable resistor is connected between the ninth resistor and the tenth resistor, one end of the twelfth resistor is connected between the eleventh resistor and the adjustable resistor, and the other end of the twelfth resistor is connected to the fifth resistor.

6. The signal conversion circuit according to claim 5, characterized in that: The voltage follower unit includes a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a third diode and an operational amplifier, the power supply terminal of the operational amplifier is connected to the other end of the second resistor, the ground terminal of the operational amplifier is grounded, the output terminal of the operational amplifier is connected to the positive electrode of the third diode, the negative electrode of the third diode is used to connect to the controller, the seventeenth resistor is connected in parallel with the third diode, the in-phase input terminal of the operational amplifier is connected to one end of the sixth capacitor, the other end of the sixth capacitor is grounded and connected to one end of the fourth capacitor, and the fourth The other end of the capacitor is connected to one end of the fourteenth resistor, the other end of the fourteenth resistor is used to be connected to the controller, one end of the sixteenth resistor is connected between the non-inverting input terminal of the operational amplifier and the sixth capacitor, the other end of the sixteenth resistor is connected to one end of the fifth capacitor, the other end of the fifth capacitor is connected to one end of the fifteenth resistor, the other end of the fifteenth resistor is used to be connected to the controller, one end of the thirteenth resistor is connected between the eighth resistor and the ninth resistor, the other end of the thirteenth resistor is connected between the fourth capacitor and the fourteenth resistor, and between the sixteenth resistor and the fifth capacitor.

7. The signal conversion circuit according to claim 6, characterized in that: It also includes an over-temperature protection unit, one end of which is connected to the power supply unit, and the other end is connected to the output end of the voltage follower unit and the voltage adjustment unit, and is used to lower the voltage of the output signal or the control voltage signal to reduce the temperature when over-temperature occurs.

8. The signal conversion circuit according to claim 7, characterized in that: The over-temperature protection unit includes an eighteenth resistor, a nineteenth resistor, a twentieth resistor, a thermistor, a seventh capacitor, a second voltage-stabilizing tube, and a transistor, one end of the thermistor is connected between the positive electrode of the first diode and the first power supply, the other end of the thermistor is connected to the negative electrode of the second voltage-stabilizing tube, the positive electrode of the second voltage-stabilizing tube is connected to the base of the transistor, the collector of the transistor is connected to one end of the eighteenth resistor, the other end of the eighteenth resistor is connected between the fourteenth resistor and the controller, the emitter of the transistor is grounded, one end of the nineteenth resistor is connected between the base of the transistor and the positive electrode of the second voltage-stabilizing tube, the other end of the nineteenth resistor is grounded, the seventh capacitor is connected to the nineteenth resistor in parallel, one end of the twentieth resistor is connected between the negative electrode of the second voltage-stabilizing tube and the thermistor, and the other end of the twentieth resistor is grounded.

9. An LED driving power supply, characterized in that: It comprises a signal conversion circuit, and the signal conversion circuit is the signal conversion circuit according to any one of claims 1 to 8.

10. An LED lamp, characterized in that: It comprises an LED driving power supply, and the LED driving power supply is the LED driving power supply according to claim 9.

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