CN111741569A - Circuit and method for constant power control of LED switching power supply - Google Patents

Abstract

The invention provides a circuit and a method for controlling constant power of an LED switch power supply, which comprises a power supply circuit module, a control module and an LED load, wherein the power supply circuit module is electrically connected with the LED load to form a main loop, one end of the control module is electrically connected with the LED load to read an input voltage signal of the LED load, the other end of the control module is electrically connected with the power supply circuit module, the output voltage change of the power supply circuit module is read, the PWM duty ratio is calculated, the power in the power supply circuit module is controlled and adjusted through the PWM duty ratio, the power is consistent with the LED power, the LED loads with different powers can be accessed into the power supply circuit module, the dial switch is set into a plurality of resistors, the effect of constant input power can be achieved by changing the resistance value of the resistors under the condition of constant voltage and current, the circuit is more stable and safe, and the trouble, and the adaptability of the switching power supply is greatly improved.

Description

Circuit and method for constant power control of LED switching power supply

technical field

The invention relates to the field of constant power control circuits, in particular to a circuit and a method for controlling constant power of an LED switching power supply.

Background technique

In the prior art, there are more and more types of LED lamps with different characteristics, and the power of LED lamps of different customers is also different. According to the standard of constant power, there are many types of power supply specifications. The same LED lamp, there are The voltage of LED lamps is very high, and some LED lamps have very low voltage. For lamps of different powers, it is usually necessary to manually adjust the input voltage of the power supply, and a power adapter can only be applied to LED lamps of one power, and the production cost is high.

SUMMARY OF THE INVENTION

In view of the shortcomings of the above technologies, the present invention provides a circuit and method for constant input power of an LED switching power supply, which can read the input voltage of the LED and the output voltage change in the power supply circuit module through the control module, and use the PWM duty cycle. The power in the power supply circuit module is controlled and adjusted so that the power is consistent with the LED power, so that the power supply circuit can be connected to LED loads of different powers, the circuit is simple, and the production cost is saved.

Specifically, the present invention provides a circuit for constant power control of an LED switching power supply, including a power supply circuit module, a control module and an LED load, the power supply circuit module is connected to the LED load, and the control module is connected to the power supply Between the circuit module and the LED load, the input power of the power supply circuit module is controlled;

The control module includes a DIP switch and a main control module, the DIP switch includes a plurality of power segments, the input terminal of the main control module reads the input voltage change of the power supply circuit module and controls the input power, and the output terminal outputs The PWM duty cycle adjusts and controls the power segment of the DIP switch, so that the input power of the power supply circuit module is consistent with the LED load power, and the other end of the DIP switch is electrically connected to the LED load, so that the switching power supply circuit is The input power is constant.

Preferably, the power supply circuit module and the LED load are electrically connected through an inductor, and the inductor is used to prevent the current of the LED load from flowing to the power supply circuit module at the moment when the switching power supply circuit is turned on.

Preferably, the DIP switch includes an electronic switch and a plurality of resistors connected in parallel, the main control module is connected to one resistor of the plurality of resistors, and the electronic switch is controlled by one of the plurality of resistors, The electronic switch is connected to one of the plurality of resistors, and the other end of the electronic switch is connected to the power supply circuit module.

Preferably, the DIP switch further includes an adjustable seventh resistor, and the main control module controls one end of the seventh resistor to be connected in series with one of the plurality of resistors, and the other end to be connected to the power supply voltage.

Preferably, the main control module includes a first port and a second port, the first port is electrically connected to the power supply circuit module, and is used for reading the reference point variation of the power supply circuit module, and according to the reference point The PWM duty ratio is calculated by the variation, the second port is electrically connected with the DIP switch, and the DIP switch is controlled to be adjusted to different power segments by adjusting the PWM duty ratio.

Preferably, the power supply circuit module includes a switching power supply input unit and a driving module, the switching power supply input unit rectifies the current in the circuit and provides a power supply voltage for the driving module, and one end of the driving module is connected to the switch The other end of the power input unit is electrically connected to the LED load and the control module, and provides driving for the LED load.

Preferably, it also includes an operational amplifier module, the operational amplifier module receives the electrical signal of the control module, performs operational amplification processing on the electrical signal of the control module, and feeds back the operational amplifier processed electrical signal to the power supply circuit module.

Preferably, the output voltage of the power supply circuit module is 31-81V.

The present invention also provides a method for controlling constant power of an LED switching power supply, comprising the following steps:

The control module reads the input voltage of the power circuit module;

The control module controls the input power and outputs the PWM duty cycle to the power supply circuit module;

The control module adjusts and controls the power of the power supply circuit module according to the PWM duty cycle, so that the LED load is consistent with the power of the power supply circuit module.

Preferably, the step of the control module adjusting and controlling the power of the power supply circuit module according to the PWM duty cycle includes:

The control module includes a main control module and a DIP switch, and the DIP switch includes a plurality of power segments,

The main control module controls the DIP switch to adjust to the same power segment as the LED load,

The other end of the DIP switch is connected to the power supply circuit module, so that the power of the power supply circuit module and the LED load power are constant.

The beneficial effects of the present invention are: compared with the prior art, the present invention provides a circuit and method for controlling constant power of an LED switching power supply, including a power supply circuit module, a control module and an LED load, and the power supply circuit module and the LED load electrical circuit The connection forms a main loop. One end of the control module is electrically connected to the LED load for reading the input voltage signal of the LED load, and the other end is electrically connected to the power supply circuit module to read the output voltage change of the power supply circuit module and calculate the PWM duty cycle. The PWM duty cycle control adjusts the power in the power supply circuit module to make the power consistent with the LED power, so that the power supply circuit module can be connected to LED loads of different powers. By setting the DIP switch to multiple resistors, the voltage and current Under constant conditions, the effect of constant input power can be achieved by changing the resistance value of the resistor, making the circuit more stable and safe, avoiding the trouble of manual adjustment, and greatly improving the adaptability of the switching power supply, greatly reducing the production cost.

Description of drawings

Fig. 1 is the overall circuit diagram of the present invention;

Fig. 2 is the circuit diagram of the control module of the present invention;

Fig. 3 is the specific circuit diagram of the dial switch of the present invention;

FIG. 4 is a specific circuit diagram of the connection between the LED load and the control module of the present invention;

FIG. 5 is a specific circuit diagram of the drive module of the present invention;

FIG. 6 is a specific circuit diagram of the operational amplifier module of the present invention.

The main component symbols are explained as follows:

1. Switching power input unit; 2. Drive module; 3. Control module; U5, main control module; 31. DIP switch; 4. Operational amplifier module; 6. LED load; 7. Power circuit module.

Detailed ways

In order to express the present invention more clearly, the present invention will be further described below with reference to the accompanying drawings.

Specifically, the present invention provides a circuit for constant power control of an LED switching power supply, please refer to FIG. 1 to FIG. 6 , including a power supply circuit module 7 , a control module 3 and an LED load 6 , and the power supply circuit module 7 and the LED load 6 are electrically connected to form In the main loop, one end of the control module 3 is electrically connected to the LED load 6 for reading the input voltage signal of the power supply circuit module 7, and the other end is electrically connected to the power supply circuit module 7 to read the input voltage change of the power supply circuit module 7 and calculate the PWM duty cycle. empty ratio;

The control module 3 includes a main control module U5 and a DIP switch 31. The DIP switch 31 includes a plurality of power segments. The main control module 3 can control the DIP switch 31 to adjust to the same power segment as the LED load 6 according to the duty cycle of the PWM. , the other end of the DIP switch 31 is connected to the power supply circuit module 7, so that the power of the power supply circuit module 7 is changed, so that the input power of the power supply circuit module 7 is consistent with the input power of the LED load 6, that is, the input power in the switching power supply circuit is constant.

In the present embodiment, the power supply circuit module 7 and the LED load 6 are connected through the inductor LF3. By arranging the inductor LF3 between the power supply circuit module 7 and the LED load 6, the connection between the LED load 6 and the power supply circuit module 7 can be prevented. Instantly, the current of the LED load 6 is blocked from flowing to the power supply circuit module 7, thereby preventing the LED load 6 from being damaged due to voltage inconsistency when the switching power supply circuit is turned on.

In this embodiment, please refer to FIG. 3 , the DIP switch 31 includes a plurality of resistors and an electronic switch SGND. One end of the plurality of resistors is connected to the power supply voltage, and the other end is connected to the main control module U5. One end of the electronic switch SGND is connected to one end of the plurality of resistors. One resistor is connected, and the other end is electrically connected to the power supply circuit module 7. The main control module U5 controls the electronic switch SGND through multiple resistors, so that the electronic switch SGND is connected to one resistor among the multiple resistors; The four resistors connected in parallel are the first resistor R51A with a power of 70W; the second resistor R51B with a power of 60W; the third resistor R51C with a power of 55W; the fourth resistor R51D with a power of 50W, the power in this embodiment The segment value is specially designed for the LED load 6 whose voltage in the switching power supply circuit is between 31-81V. Any LED load 6 whose voltage is between 31-81V is connected to this embodiment, and can be selected from the four power segments. One of the connections, and the control module 3 controls the connection and disconnection of the DIP switch 31; according to P=UI and U=IR, to ensure that the power is constant, it is necessary to ensure that the product value of the voltage and the current remains unchanged, that is, to ensure The product value of the current and the resistance remains unchanged. By setting multiple resistances, the main control module U5 can select different resistances for connection according to the power of the LED load 6 under the condition of constant voltage and current, that is, select the dial codes of different powers. Switch, that is, when selecting resistors with different resistance values, the current in the circuit will also change indirectly, so that the main control module does not need to use the PWM duty cycle to adjust the current in the circuit separately, which simplifies the circuit. In the state of constant voltage and constant current, only the resistance value of the resistor is changed, which makes the switching power supply circuit more stable. Of course, it can also be set to a power segment of other values, and the only setting is not made here.

In this embodiment, the DIP switch 31 further includes an adjustable seventh resistor R47D. The main control module U5 controls one end of the seventh resistor R47D to be connected in series with one of the plurality of resistors, and the other end is connected to the power supply voltage. It should be noted that , the seventh resistor R47D is an adjustable resistor with a resistance value of 10K. When the power supply voltage is constant, the main control module U5 can adjust the resistance of the seventh resistor R47D, so that the current value flowing through the power circuit module 7 is more accurate.

In this embodiment, - the main control module U5 includes the No. 14 pin of the first port and the No. 13 pin of the second port, and the No. 14 pin of the first port is electrically connected to the power supply circuit module 7 for reading the power supply circuit module 7, and calculate the PWM duty cycle according to the change of the reference point. Specifically, when the power circuit module 7 provides the drive for the LED load 6, the voltage of the LED load itself will cause the voltage of the power circuit module 7 to generate Toggle, the reference point is voltage, the main control module U5 calculates the PWM duty ratio of the input power and the input power through the change of the reference point, according to P=UI (where P is the power, U is the voltage, and I is the current) The main control module U5 can calculate the input power P and control the input power P to be constant. PWM is a method of digitally encoding the analog signal level. The space ratio is modulated to encode the level of a specific analog signal;

The No. 13 pin of the second port is electrically connected to the DIP switch 31. Specifically, the main control module U5 is connected to the DIP switch 31 through the No. 13 pin of the second port, so that the DIP switch can be controlled by adjusting the PWM duty cycle. The switch 31 is adjusted to different power segments, so that the switching power supply circuit can be connected to any LED load 6 without overloading.

In this embodiment, the power supply circuit module 7 includes a switching power supply input unit 1 and a driving module 2. The switching power supply input unit 1 rectifies the current in the circuit and provides a power supply voltage for the driving module 2, and one end of the driving module 2 is connected to the switching power supply The other end of the input unit 1 is electrically connected to the external LED load 6 and the control module 3 to provide driving for the external LED load 6 . By setting the switching power supply input unit 1 and the driving module 2, the control module 3 can read the power supply voltage of the driving module 2, and calculate the output power of the power supply circuit module 7 according to the power supply voltage. 2 is connected, so that the driving module 2 and the LED load 6 can generate a voltage variation, so that the control module 3 can read the variation, and then calculate the PWM duty ratio of the power of the power circuit module 7 .

In this embodiment, an operational amplifier module 4 is further included. The operational amplifier module 4 receives the electrical signal of the control module 3, performs operational amplification processing on the electrical signal of the control module 3, and feeds back the operational amplifier processed electrical signal to the power supply circuit Module 7, by setting the operational amplifier module 4, the operational amplifier module 4 can amplify the electrical signal of the main control module 3, so that the power supply circuit module 7 can more easily identify the electrical signal. Specifically, the electrical signal is a voltage signal, a current Signal, voltage and current change signal.

In this embodiment, the output voltage of the power supply circuit module 7 is 31-81V. Specifically, when the input voltage of the power supply circuit module 7 is 31V, the control module 3 detects the input voltage signal of the power supply circuit module 7, and according to The current in the circuit calculates the input power of the power supply circuit module at this time, the No. 14 pin of the first port of the control module 3 controls the input power of the power supply circuit module, the No. 8 pin of the control module 3 reads the input power of the LED load 6, And control the dial switch according to the PWM duty cycle to adjust the power of the power supply circuit module 7 to be consistent with the power of the LED load 6, so that the control power of the switching power supply is constant;

The present invention also provides a method for controlling constant power of an LED switching power supply, comprising the following steps:

The control module 3 reads the input voltage of the power supply circuit module 7;

The control module 3 controls the input power and outputs the PWM duty cycle to the power circuit module 7;

The control module 3 adjusts and controls the power of the power supply circuit module 7 according to the PWM duty cycle, so that the LED load is consistent with the power of the power supply circuit module;

The control module 3 includes a main control module U5 and a DIP switch 31, and the DIP switch 31 includes a plurality of power segments,

The main control module U5 controls the DIP switch 31 to adjust to the same power segment as the LED load 6 .

The advantages of the present invention are:

1) By setting the DIP switch in the control module, the control module can control the DIP switch to adjust to different power segments according to the calculated PWM duty cycle, the circuit is simple and the cost is low.

2) By connecting the main control module with the power supply circuit module, the main control module can read the reference point change of the input voltage of the power supply circuit module, and calculate the PWM duty cycle through the reference point voltage to control the power of the power supply circuit module. , so that the control power of the LED switching power supply is constant.

3) By setting the DIP switch as multiple resistors, under the condition of constant voltage and current, the effect of constant input power can be achieved by changing the resistance value of the resistor, making the circuit more stable and safe.

The above disclosures are only a few specific embodiments of the present invention, but the present invention is not limited thereto, and any changes that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims (10)

1. A circuit for a constant power control of an LED switching power supply, characterized in that it comprises a power supply circuit module, a control module and an LED load, the power supply circuit module is connected to the LED load, and the control module is connected to the power supply circuit Between the module and the LED load, the input power of the power supply circuit module is controlled; The control module includes a DIP switch and a main control module, the DIP switch includes a plurality of power segments, the input terminal of the main control module reads the input voltage change of the power supply circuit module and controls the input power, and the output terminal outputs The PWM duty cycle adjusts and controls the power segment of the DIP switch, so that the input power of the power supply circuit module is consistent with the LED load power, and the other end of the DIP switch is electrically connected to the LED load, so that the switching power supply circuit is The input power is constant. 2 . The circuit for controlling constant power of an LED switching power supply according to claim 1 , wherein the power supply circuit module and the LED load are electrically connected through an inductor, and the inductor is used for switching on the switching power supply circuit. 3 . The current of the LED load is momentarily blocked from flowing to the power circuit module. 3. The LED switching power supply control circuit with constant power according to claim 1, wherein the DIP switch comprises an electronic switch and a plurality of resistors connected in parallel, the main control module and one of the plurality of resistors Resistor connection, the electronic switch is controlled through one of the plurality of resistors, so that the electronic switch is connected to one of the plurality of resistors, and the other end of the electronic switch is connected to the power supply circuit module. 4 . The LED switching power supply control circuit with constant power according to claim 3 , wherein the DIP switch further comprises an adjustable seventh resistor, and the main control module controls one end of the seventh resistor to connect with the One of the plurality of resistors is connected in series, and the other end is connected to the supply voltage. 5 . The circuit for controlling constant power of an LED switching power supply according to claim 1 , wherein the main control module comprises a first port and a second port, and the first port is electrically connected to the power supply circuit module, 6 . It is used to read the reference point variation of the power supply circuit module, and calculate the PWM duty cycle according to the reference point variation. The second port is electrically connected to the DIP switch, and the PWM duty cycle is adjusted to control the DIP switch to adjust to different power segments. 6 . The circuit for constant power control of LED switching power supply according to claim 1 , wherein the power supply circuit module comprises a switching power supply input unit and a driving module, and the switching power supply input unit rectifies the current in the circuit, 7 . A power supply voltage is provided for the driving module. One end of the driving module is connected to the switching power supply input unit, and the other end is electrically connected to the LED load and the control module to provide driving for the LED load. 7 . The LED switching power supply control circuit with constant power according to claim 1 , further comprising an operational amplifier module, the operational amplifier module receives the electrical signal of the control module, and responds to the electrical signal of the control module. 8 . Operational amplification processing is performed, and the electrical signal after the operational amplification processing is fed back to the power supply circuit module. 8 . The circuit for controlling constant power of an LED switching power supply according to claim 1 , wherein the output voltage of the power supply circuit module is 31-81V. 9 . 9. A method for controlling constant power of an LED switching power supply, comprising the following steps: The control module reads the input voltage of the power circuit module; The control module controls the input power and outputs the PWM duty cycle to the power supply circuit module; The control module adjusts and controls the power of the power supply circuit module according to the PWM duty cycle, so that the LED load is consistent with the power of the power supply circuit module. 10 . The method for controlling constant power of an LED switching power supply according to claim 9 , wherein the step of the control module adjusting and controlling the power of the power supply circuit module according to the PWM duty cycle comprises: 10 . The control module includes a main control module and a DIP switch, and the DIP switch includes a plurality of power segments, The main control module controls the DIP switch to adjust to the same power segment as the LED load, The other end of the DIP switch is connected to the power supply circuit module, so that the power of the power supply circuit module and the LED load power are constant.

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