A Feedback Circuit for Adaptive Output Voltage

Abstract

The present application relates to a feedback circuit with adaptive output voltage, including a power supply module, a rectifier filter module, a main control module, a voltage control module, a current control module and an optocoupler feedback module; the rectifier filter module is provided with a voltage sampling terminal and a current sampling terminal, the main control module is connected to the voltage sampling terminal to obtain the sampled voltage, the main control module is provided with a voltage reference terminal and a current reference terminal, the voltage control module is respectively connected to the voltage sampling terminal and the voltage reference terminal, the current control module is respectively connected to the current sampling terminal and the current reference terminal, and the optocoupler feedback module controls the output voltage of the power supply module after receiving the voltage signal of the voltage control module or the current signal of the current control module. The present application can realize that the LED driving power supply automatically outputs a matching voltage according to the specifications of the connected LED light strip without manual intervention, thereby improving the installation safety of the LED light strip.

Description

Technical Field

[0001] The present application relates to the field of power supply technology, and in particular to a feedback circuit for adaptive output voltage. Background Art

[0002] LED light strips are LEDs assembled on a strip-shaped FPC (flexible circuit board) or PCB hard board. LED light strips have a long service life and are very energy-saving and environmentally friendly, and are gradually emerging in various decoration industries.

[0003] LED light strips need to be driven by a constant current power supply, and most of the current driving power supplies commonly used in LED light strips in the industry use constant voltage power supplies, all of which have a fixed single voltage output. For example: a 12V light strip must use a 12V output driving power supply, and a 24V light strip must use a 24V output driving power supply. For LED light strips of different specifications, if the power supply voltage is different, it is likely to cause damage to the LED light strip after installation and use.

[0004] Regarding the above-mentioned related technologies, there is a defect that the compatibility between the LED light strip and the driving power supply is poor, and manual intervention of the driving power supply is required. Summary of the invention

[0005] In order to improve the compatibility between the LED light strip and the driving power supply, the present application provides a feedback circuit with adaptive output voltage.

[0006] The present application provides an adaptive output voltage feedback circuit, which adopts the following technical solution:

[0007] A feedback circuit for adaptive output voltage, comprising:

[0008] Power supply module;

[0009] A rectifier and filter module, the rectifier and filter module is connected to the power supply module, and is provided with a voltage sampling terminal and a current sampling terminal;

[0010] A main control module, the main control module is connected to the voltage sampling terminal to obtain a sampled voltage, and the main control module is provided with a voltage reference terminal and a current reference terminal;

[0011] A voltage control module, the voltage control module is connected to the voltage sampling terminal and the voltage reference terminal respectively, and the voltage control module outputs a voltage signal;

[0012] A current control module, the current control module is respectively connected to the current sampling terminal and the current reference terminal, and the current control module outputs a current signal;

[0013] An optocoupler feedback module, wherein the input end of the optocoupler feedback module is respectively connected to the rectifier filter, the voltage control module and the current control module, and the output end of the optocoupler feedback module is connected to the power supply module. After receiving the voltage signal of the voltage control module or the current signal of the current control module, the optocoupler feedback module controls the output voltage of the power supply module.

[0014] By adopting the above technical solution, a small current is output to the rectifier and filter module by using the power supply module. When the LED light strip is lit, if the power supply does not match, the LED light strip itself is clamped at a certain voltage value, and the current voltage and current are obtained through the voltage sampling terminal and the current sampling terminal on the rectifier and filter module, so as to facilitate the determination of the voltage value of the light strip; after the main control module obtains the voltage value and the current value, the voltage control module or the current control module controls the output according to the reference voltage or the reference current of the main control module, so as to control the output size of the optocoupler feedback module, so as to facilitate the power supply module to automatically adjust the voltage according to the output size of the optocoupler feedback module.

[0015] Optionally, the rectification and filtering module includes a rectification diode D1 and a filtering capacitor C1, and the rectification diode D1 and the filtering capacitor C1 are connected in series at the output end of the power supply module.

[0016] By adopting the above technical solution, the rectifier and filter module outputs relatively stable direct current, reducing the impact of voltage fluctuations on the LED light strip, thereby increasing the service life of the LED light strip.

[0017] Optionally, the rectification and filtering module also includes a first resistor R1, a second resistor R2 and a third resistor R3, the first resistor R1, the second resistor R2 and the third resistor R3 are connected in series, and the filter capacitor C1 and the first resistor R1, the second resistor R2 and the third resistor R3 are connected in parallel; the voltage sampling end is set between the first resistor R1 and the second resistor R2, and the current sampling end is set between the second resistor R2 and the third resistor R3.

[0018] By adopting the above technical solution, the voltage is sampled by means of resistance voltage division, and the current sampling is also converted into voltage collection, so the collection is more accurate.

[0019] Optionally, two ends of the first resistor R1 and the second resistor R2 connected in series are load output ends, and the load output ends are used to connect an LED light strip.

[0020] By adopting the above technical solution, when outputting voltage to the LED light strip, the voltage of the LED light strip can be more accurately known.

[0021] Optionally, the voltage control module includes a first operational amplifier U1, a first feedback capacitor C2, a first feedback resistor R4, a first output resistor R5 and a first diode D2; the first feedback capacitor C2 and the first feedback resistor R4 are connected in series between the inverting input and output ends of the first operational amplifier U1; the first output resistor R5 and the first diode D2 are connected in series and connected to the output end of the first operational amplifier U1; the inverting input end of the first operational amplifier U1 is connected to the voltage sampling end, and the non-inverting input end of the first operational amplifier is connected to the voltage reference end.

[0022] By adopting the above technical solution, the first operational amplifier U1 is used to compare and output the voltage. Since the in-phase input terminal of the first operational amplifier U1 is connected to the reference voltage terminal, when the sampled voltage and the reference voltage are different, the output terminal of the first operational amplifier U1 outputs a current, which is converted into a voltage through the first output resistor R5. The output voltage is high or low to make the optical coupling feedback module output signals of different strengths. And the first diode D2 is used to prevent the output current from being reversely conducted.

[0023] Optionally, the current control module includes a second operational amplifier U2, a second feedback capacitor C3, a second feedback resistor R7, a second output resistor R8 and a second diode D3; the second feedback capacitor C3 and the second feedback resistor R7 are connected in series between the inverting input and output terminals of the second operational amplifier U2; the second output resistor R8 and the second diode D3 are connected in series and connected to the output terminal of the second operational amplifier U2; the inverting input terminal of the second operational amplifier U2 is connected to the current sampling terminal, and the non-inverting input terminal of the second operational amplifier U2 is connected to the current reference terminal.

[0024] By adopting the above technical solution, the second operational amplifier also performs voltage comparison output. In fact, the current control module is eventually converted into voltage to continue control. For the voltage control module, it collects the voltage on the second resistor R2 and the third resistor R3, while the current control module samples the voltage on the third resistor R3. At the beginning of the adjustment, the rectifier and filter module outputs a smaller current. At this time, the sampling voltage of the voltage control module is small, and the output voltage cannot control the optocoupler feedback module. The current control module can be used to control the optocoupler feedback module. When the output voltage of the power supply module increases, the current control module cannot continue to control, but the current in the rectifier and filter module can be controlled by the main control module to increase the output current.

[0025] Optionally, the main control module includes a main control chip U3, a voltage stabilizing chip U4, a voltage reference resistor R6, a current reference resistor R9, a voltage reference capacitor C4 and a current reference capacitor C5; the output end of the voltage stabilizing chip U4 is connected to the power supply end of the main control chip U3, the voltage reference resistor R6 and the voltage reference capacitor C4 are connected in series between the main control chip U3 and the ground wire, and the voltage reference end is arranged between the voltage reference resistor R6 and the voltage reference capacitor; the current reference resistor R9 and the current reference capacitor C5 are connected in series between the main control chip U3 and the ground wire, and the current reference end is arranged between the current reference resistor R9 and the current reference capacitor C5.

[0026] By adopting the above technical solution, the main control chip is powered by the voltage stabilizing chip, and the reference voltage is formed by filtering and charging the voltage reference resistor and the voltage reference capacitor after the main control chip outputs the signal; similarly, the reference current is converted into voltage and formed by filtering and charging the current reference resistor and the current reference capacitor.

[0027] Optionally, the optocoupler feedback module is a linear optocoupler.

[0028] By adopting the above technical solution, the optocoupler feedback module can perform linear adjustment, so that the power supply module can adjust the output according to the signal size output by the optocoupler feedback module.

[0029] In summary, the present application includes at least one of the following beneficial technical effects:

[0030] 1. After the LED light strip is connected, the power supply output module can be adapted and adjusted according to the signal size fed back by the optocoupler feedback module, without manual intervention in the adjustment of the output voltage, thus improving the safety of the installation and use of the LED light strip;

[0031] 2. The power supply output is controllable and can be applied to LED light strips of various specifications, which is simple and convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of a feedback circuit for adaptive output voltage according to an embodiment of the present application.

[0033] Explanation of the accompanying drawings: 1. Power supply module; 2. Rectification and filtering module; 3. Main control module; 4. Voltage control module; 5. Current control module; 6. Optocoupler feedback module. DETAILED DESCRIPTION

[0034] The present application is further described in detail below in conjunction with the accompanying drawings.

[0035] The embodiment of the present application discloses a feedback circuit for adaptive output voltage. Figure 1The feedback circuit of the adaptive output voltage includes a power supply module 1, a rectifier and filter module 2, a main control module 3, a voltage control module 4, a current control module 5 and an optocoupler feedback module 6. The power supply module 1 is used to provide a variable working voltage. The rectifier and filter module 2 is connected to the power supply module 1 to rectify and filter the voltage for the use of the LED light strip. The rectifier and filter module 2 is provided with a voltage sampling terminal and a current sampling terminal.

[0036] Specifically, the power supply module 1 is a transformer T1, and the two ends of the secondary coil of the transformer T1 are the output ends of the power supply module 1. The rectifier and filter module 2 includes a rectifier diode D1, a filter capacitor C1, a first resistor R1, a second resistor R2, and a third resistor R3. The rectifier diode D1 and the filter capacitor C1 are connected in series, and the rectifier diode D1 and the filter capacitor C1 are commonly connected to the two ends of the secondary coil of the transformer.

[0037] The first resistor R1, the second resistor R2 and the third resistor R3 are connected in series, and the filter capacitor C1 is connected in parallel with the first resistor R1, the second resistor R2 and the third resistor R3. The two ends of the first resistor R1 and the second resistor R2 connected in series are load output ends, which are used to connect the LED light strip. Therefore, when the rectifier and filter module 2 is connected to the LED light strip, the voltage received by the LED light strip itself is not the full output voltage of the rectifier and filter, which reduces the risk of the LED light strip being burned by high voltage.

[0038] The voltage sampling terminal is arranged between the first resistor R1 and the second resistor R2, and the current sampling terminal is arranged between the second resistor R2 and the third resistor R3. In this embodiment, the third resistor R3 is used as a current sampling resistor to convert the current value into a voltage value. The resistance value of the third resistor R3 is very small and can be equivalent to a line resistance. Therefore, the voltage across the first resistor R1 and the second resistor R2 is the voltage across the LED light strip. At this time, the voltage of the LED light strip can be obtained by voltage division.

[0039] The main control module 3 is connected to the voltage sampling terminal to obtain the sampled voltage. The main control module 3 is the core of voltage regulation. A voltage reference terminal and a current reference terminal are provided on the main control module 3 to provide a reference for the voltage control module 4 and the current control module 5, so that the voltage control module 4 and the current control module 5 can sample and control the current voltage and current. The main control module 3 includes a main control chip U3, a voltage stabilizing chip U4, a voltage reference resistor R6, a current reference resistor R9, a voltage reference capacitor C4 and a current reference capacitor C5. The input end of the voltage stabilizing chip U4 is connected to the output end of the rectifier and filter module 2, and the output voltage of the rectifier and filter module 2 is used as the working voltage; and the output end of the voltage stabilizing chip U4 is connected to the power supply end of the main control chip U3, and the stabilized voltage is used as the working voltage of the main control chip.

[0040] The voltage reference resistor R6 and the voltage reference capacitor C4 are connected in series between the pin and the ground wire of the main control chip U3, and the voltage reference end is arranged between the voltage reference resistor R6 and the voltage reference capacitor C4. The pin of the main control chip U3 outputs a digital signal, specifically a PWM signal. Therefore, the voltage at the voltage reference end is formed by charging the voltage reference capacitor C4 with a PWM signal of different duty cycles. The current reference resistor R9 and the current reference capacitor C5 are connected in series between the pin and the ground wire of the main control chip U3, and the current reference end is arranged between the current reference resistor R9 and the current reference capacitor C5. The pin of the main control chip U3 also outputs a digital signal, which is also a PWM signal. Using the charging current of the current reference capacitor C5 as a reference value, the charging current of the current reference capacitor C5 is converted into the voltage on the current reference capacitor C5 at a fixed time.

[0041] The voltage control module 4 is connected to the voltage sampling terminal and the voltage reference terminal respectively, and the voltage control module 4 outputs a voltage signal. The voltage control module 4 includes a first operational amplifier U1, a first feedback capacitor C2, a first feedback resistor R4, a first output resistor R5 and a first diode D2. The first feedback capacitor C2 and the first feedback resistor R4 are connected in series between the inverting input terminal and the output terminal of the first operational amplifier U1. The first output resistor R5 and the first diode D2 are connected in series and connected to the output terminal of the first operational amplifier U1.

[0042] The inverting input terminal of the first operational amplifier U1 is connected to the voltage sampling terminal, and the output terminal of the first operational amplifier U1 is connected to the optocoupler feedback module 6 via the first output resistor R5 and the first diode D2, so the first operational amplifier U1, the first output resistor R5 and the first diode D2 together form a voltage control loop. The non-inverting input terminal of the first operational amplifier U1 is connected to the voltage reference terminal. Since the voltage of the non-inverting input terminal of the first operational amplifier U1 is determined by the main control chip, after the first operational amplifier U1 obtains the sampling voltage, the first operational amplifier U1 can perform a comparison output.

[0043] The current control module 5 is connected to the current sampling terminal and the current reference terminal respectively, and the current control module 5 outputs a current signal. The current control module 5 includes a second operational amplifier U2, a second feedback capacitor C3, a second feedback resistor R7, a second output resistor R8 and a second diode D3. The second feedback capacitor C3 and the second feedback resistor R7 are connected in series between the inverting input terminal and the output terminal of the second operational amplifier U2. The second output resistor R8 and the second diode D3 are connected in series and are commonly connected to the output terminal of the second operational amplifier U2.

[0044] The inverting input terminal of the second operational amplifier U2 is connected to the current sampling terminal, and the output terminal of the second operational amplifier U2 is connected via the second output resistor R8, the second diode D3 and the optical coupling feedback module 6, so that a current loop is formed between the second operational amplifier U2, the second output resistor R8 and the second diode D3. The non-inverting input terminal of the second operational amplifier U2 is connected to the current reference terminal, and in actual current control, the current signal is converted into a voltage signal, and the voltage formed by the current reference resistor R9 and the current reference capacitor C4 is compared with the voltage corresponding to the current sampling, thereby outputting a current signal.

[0045] In this embodiment, the anode of the first diode D2 and the anode of the second diode D3 are connected to each other, so that the signal output by the first operational amplifier U1 and the signal output by the second operational amplifier U2 do not affect each other.

[0046] In this embodiment, the optocoupler feedback module 6 is a linear optocoupler. One end of the input end of the optocoupler feedback module 6 is connected to the output end of the rectifier filter, and the other end is connected to the output end of the voltage control module 4 and the output end of the current control module 5, that is, the anode of the first diode D2 and the anode of the second diode D3. The output end of the optocoupler feedback module 6 is connected to the power supply module 1. When the optocoupler feedback module 6 receives the voltage signal of the voltage control module 4 or the current signal of the current control module 5, the optocoupler feedback module 6 outputs a control signal and controls the change of the output voltage of the power supply module 1.

[0047] Since the LED light strip is formed by LED lamp beads connected in series, and the LED lamp beads are basically semiconductor LED lamp beads, a constant current power supply is required to light up the LED lamp beads. And due to the characteristics of the LED lamp beads, when the LED lamp beads are lit, the voltage across the LED lamp beads is clamped to a specific range. The LED lamp beads require a constant current, and in terms of withstand voltage, they can temporarily withstand fluctuating voltages around the rated voltage.

[0048] In this embodiment, after the power supply module 1 starts to supply power, the main control chip U3 is powered on and starts to run, and an initial current value is output by the main control chip U3. At this time, there is current in the rectifier and filter module 2, which is converted into a voltage signal by the third resistor R3 and input to the reverse input terminal of the second operational amplifier U2. The initial current signal output by the main control chip U3 is converted into a voltage signal by the current reference resistor R9 and the current reference capacitor C5 and then input to the same direction input terminal of the second operational amplifier U2. The input signal of the reverse input terminal of the second operational amplifier U2 is greater than the same direction input terminal signal of the second operational amplifier U2, and the output negative voltage of the second operational amplifier U2 is fed back to the power supply module 1 through the optical coupling feedback module 6, so that the power supply module 1 outputs a low current and voltage that can light up the LED light strip. For example, the output voltage is 24V, and the current is small at this time, the LED can be lit, but it cannot be in normal operation.

[0049] At this time, due to the characteristics of the LED light strip, the voltage of the LED light strip is clamped. For LED light strips of different specifications, the voltage clamping values ​​are different. For example: the clamping voltage of a 12V LED light strip is between 6 and 9V, while the clamping voltage of a 24V LED light strip is between 14 and 21V. The clamping voltage when the low current is lit is obtained through the voltage sampling end to obtain the specifications of the LED light strip. After acquisition, the main control chip U3 outputs the operating voltage and operating current of the current specification of the LED light strip, and inputs information through the 6-phase power supply module 1 of the optocoupler feedback module, and adjusts the output current and output voltage of the power supply module 1 in turn, so as to achieve the adaptation of the LED light strip and the output voltage.

[0050] The implementation principle of the embodiment of the present application is as follows: when the primary end of the transformer T1 is initially powered on, the voltage and current transmitted to the secondary through the transformer T1 are supplied with power after rectification and filtering, and the main control chip U3 starts working immediately. A weak current signal is output through the pin of the main control chip U3, and the optocoupler feedback module 6 is driven by the current control loop to feed back the information to the power supply module 1, so that the current output by the rectifier and filter load is in a smaller range that can light up the LED light strip. The main control chip U3 then detects the voltage division value of the first resistor R1 and the second resistor R2 to determine the value of the output voltage. After the specifications of the LED light strip are determined, the optocoupler feedback module 6 is driven by the voltage control loop to feed back the information to the power supply module 1 to stabilize the main output voltage. At the same time, the main control chip U3 also outputs a normal current signal to control the current loop to output sufficient current.

[0051] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A feedback circuit for adaptive output voltage, characterized in that: include: Power supply module (1); A rectifier and filter module (2), the rectifier and filter module (2) being connected to the power supply module (1), and the rectifier and filter module (2) being provided with a voltage sampling terminal and a current sampling terminal; A main control module (3), the main control module (3) being connected to the voltage sampling terminal to obtain a sampled voltage, and the main control module (3) being provided with a voltage reference terminal and a current reference terminal; A voltage control module (4), the voltage control module (4) being connected to the voltage sampling terminal and the voltage reference terminal respectively, and the voltage control module (4) outputting a voltage signal; A current control module (5), the current control module (5) being connected to the current sampling end and the current reference end respectively, and the current control module (5) outputting a current signal; An optocoupler feedback module (6), wherein the input end of the optocoupler feedback module (6) is respectively connected to the rectifier filter module (2), the voltage control module (4) and the current control module (5), and the output end of the optocoupler feedback module (6) is connected to the power supply module (1). After receiving the voltage signal of the voltage control module (4) or the current signal of the current control module (5), the optocoupler feedback module (6) controls the level of the output voltage of the power supply module (1); the rectifier filter module (2) comprises a rectifier diode D1 and a filter capacitor C1, and the rectifier diode D1 and the filter capacitor C1 are connected in series to the output end of the power supply module (1); the rectifier filter module ( 2) also includes a first resistor R1, a second resistor R2 and a third resistor R3, the first resistor R1, the second resistor R2 and the third resistor R3 are connected in series, and the filter capacitor C1 and the first resistor R1, the second resistor R2 and the third resistor R3 connected in series are connected in parallel; the voltage sampling end is arranged between the first resistor R1 and the second resistor R2, and the current sampling end is arranged between the second resistor R2 and the third resistor R3; the two ends of the first resistor R1 and the second resistor R2 connected in series are load output ends, and the load output ends are used to connect the LED light strip; the voltage across the first resistor R1 and the second resistor R2 is the voltage across the LED light strip.

2. The adaptive output voltage feedback circuit according to claim 1, characterized in that: The voltage control module (4) comprises a first operational amplifier U1, a first feedback capacitor C2, a first feedback resistor R4, a first output resistor R5 and a first diode D2; the first feedback capacitor C2 and the first feedback resistor R4 are connected in series between the inverting input terminal and the output terminal of the first operational amplifier U1; the first output resistor R5 and the first diode D2 are connected in series and connected to the output terminal of the first operational amplifier U1; the inverting input terminal of the first operational amplifier U1 is connected to the voltage sampling terminal, and the non-inverting input terminal of the first operational amplifier is connected to the voltage reference terminal.

3. The adaptive output voltage feedback circuit according to claim 1, characterized in that: The current control module (5) comprises a second operational amplifier U2, a second feedback capacitor C3, a second feedback resistor R7, a second output resistor R8 and a second diode D3; the second feedback capacitor C3 and the second feedback resistor R7 are connected in series between the inverting input terminal and the output terminal of the second operational amplifier U2; the second output resistor R8 and the second diode D3 are connected in series and connected to the output terminal of the second operational amplifier U2; the inverting input terminal of the second operational amplifier U2 is connected to the current sampling terminal, and the non-inverting input terminal of the second operational amplifier U2 is connected to the current reference terminal.

4. The adaptive output voltage feedback circuit according to claim 1, characterized in that: The main control module (3) comprises a main control chip U3, a voltage stabilizing chip U4, a voltage reference resistor R6, a current reference resistor R9, a voltage reference capacitor C4 and a current reference capacitor C5; the output end of the voltage stabilizing chip U4 is connected to the power supply end of the main control chip U3, the voltage reference resistor R6 and the voltage reference capacitor C4 are connected in series between the main control chip U3 and a ground line, and the voltage reference end is arranged between the voltage reference resistor R6 and the voltage reference capacitor C4; the current reference resistor R9 and the current reference capacitor C5 are connected in series between the main control chip U3 and a ground line, and the current reference end is arranged between the current reference resistor R9 and the current reference capacitor C5.

5. The adaptive output voltage feedback circuit according to claim 1, characterized in that: The optical coupler feedback module (6) is a linear optical coupler.

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