LED dimming drive circuit integrated with NFC control

Abstract

The utility model discloses an LED dimming drive circuit integrated with NFC control, which comprises a primary side control constant current chip U1 and an NFC module U2, the larger the direct current voltage formed by PWM pulse width of the NFC module U2 is injected into the ISEN pin of the primary side control constant current chip U1 through D1 and R2, the smaller the current injected into the voltage formed by R5 through primary side current through R4, and the smaller the current injected into the ISEN pin of the primary side control constant current chip U1 is. The smaller the voltage on the R5 is, the smaller the primary side current and the output current are, and the smaller the direct current voltage formed by the PWM pulse width of the NFC module U2 is injected into the ISEN pin of the primary side control constant current chip U1 through the D1 and the R2, and the larger the output current is. According to the utility model, the unique PWM conversion circuit is adopted, dimming can be realized without using a primary side constant current control chip with a PWM port, the dimming function of the circuit is simple to realize, the universality is improved, and the total cost is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of intelligent lighting, in particular to an LED dimming drive circuit integrated with NFC control. Background Art

[0002] In the prior art, a PWM pulse is generated by an NFC module U2, and the PWM1 port of U2 is connected to the PWM port of a primary side control constant current chip U1. U1 receives the PWM dimming signal and generates a proportional control signal to control the magnitude of the output current, thereby realizing dimming.

[0003] However, in the prior art, the circuit cost of the primary side control constant current chip with a PWM control port is much higher than that of the primary side control constant current chip without a PWM control port, and the selectable types are fewer.

[0004] Therefore, how to provide an LED dimming drive circuit integrated with NFC control is an urgent problem to be solved by those skilled in the art. Summary of the Utility Model

[0005] An object of the utility model is to provide an LED dimming drive circuit integrated with NFC control. The utility model adopts a unique PWM conversion circuit, which can realize dimming without using a primary side constant current control chip with a PWM port. The circuit dimming function is simply realized, the universality is improved, and the total cost is reduced.

[0006] An LED dimming drive circuit integrated with NFC control according to an embodiment of the utility model includes a rectifier bridge DB1, a field effect transistor Q1, a transformer T1, diodes D1, D2, resistors R1, R2, R3, R4, R5, R6, capacitors C1, C2, C3, C4, an NFC chip, a primary side control constant current chip U1, and an NFC module U2;

[0007] The DRV of the primary side control constant current chip U1 is connected to the gate of Q1 through R6, and the ISEN pin of U1 is connected to the upper end of R5 through R4. The 4th and 5th pins of the NFC module U2 are connected to C1 and the antenna. The PWM pin of U2 is connected to the upper end of C3 through R1. The upper end of C3 is connected to the ISEN pin of the primary side control constant current chip U1 through D1 and R2;

[0008] The NFC chip is provided with a PWM1 pin, the PWM pulse width of the NFC chip is adjustable, the PWM pulse width forms a DC voltage after being filtered by R1 and C3, and the DC voltage is injected into the ISEN pin of the primary side control constant current chip U1 through D1 and R2;

[0009] The greater the current injected into the ISEN pin of the primary-side control constant-current chip U1 through D1 and R2 by the DC voltage formed by the U2 PWM pulse width of the NFC module, the smaller the current injected through R4 by the voltage formed by the primary-side current through R5, the smaller the voltage on R5, and the smaller the primary-side current and output current. The smaller the current injected into the ISEN pin of the primary-side control constant-current chip U1 through D1 and R2 by the PWM pulse width of the NFC module U2, the greater its output current.

[0010] Optionally, the 2nd and 3rd pins of the rectifier bridge DB1 are connected to the mains power supply, the 1st pin is connected to the 2nd pin of T1, and the 4th pin is grounded.

[0011] Optionally, the primary-side control constant-current chip U1 is a commonly used primary-side control constant-current chip, and the primary-side current flowing through T1 and Q1 will form a voltage on R5.

[0012] Optionally, the 1st pin of T1 is connected to the drain of the field-effect transistor Q1, the 5th pin of T1 is connected to D2, D2 is connected to C2, and the other end of C2 is connected to the 6th pin of the transformer.

[0013] Optionally, the source of Q1 is grounded through the R5 resistor.

[0014] Optionally, the 4th and 5th pins of LA of the NFC chip are directly connected in parallel with an antenna and a capacitor C1, and the VCC and GND of the NFC chip are connected in parallel with a group of capacitors C4.

[0015] The beneficial effects of the present invention are as follows:

[0016] The present invention generates PWM pulses through the NFC control module U2, and then converts them into DC voltage through the PWM dimming circuit and injects them into the ISEN pin of the primary-side control constant-current chip U1. Since the internal reference voltage of the ISEN pin remains unchanged, the voltage formed by the primary-side current flowing through the sampling resistor will change with the change of the DC signal, thereby controlling the magnitude of the output current and achieving the purpose of dimming. The primary-side control constant-current chip U1 can achieve the dimming function without a PWM port, the circuit dimming function is simple to implement, the versatility is improved, and the total cost is reduced. Description of the Drawings

[0017] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In the drawings:

[0018] Figure 1 It is a circuit framework and flow structure schematic diagram of an LED dimming drive circuit integrating NFC control proposed by the present invention;

[0019] Figure 2 Schematic diagram of the specific circuit and working waveform structure of an LED dimming drive circuit integrating NFC control proposed by the present utility model. Specific embodiments

[0020] The present utility model will now be further described in detail with reference to the accompanying drawings. These drawings are all simplified schematic diagrams, only illustrating the basic structure of the present utility model in a schematic manner, so they only show the components related to the present utility model.

[0021] Reference Figure 1-2 , an LED dimming drive circuit integrating NFC control includes a rectifier bridge DB1, a field effect transistor Q1, a transformer T1, diodes D1, D2, resistors R1, R2, R3, R4, R5, R6, capacitors C1, C2, C3, C4, an NFC chip, a primary side control constant current chip U1, and an NFC module U2;

[0022] Pin 2 and pin 3 of the rectifier bridge DB1 are connected to the mains, pin 1 is connected to pin 2 of T1, and pin 4 is grounded;

[0023] Among them, pin 1 of T1 is connected to the drain of the field effect transistor Q1, pin 5 of T1 is connected to D2, D2 is connected to C2, and the other end of C2 is connected to pin 6 of the transformer;

[0024] In addition, the source of Q1 is grounded through the R5 resistor;

[0025] Secondly, the DRV of the primary side control constant current chip U1 is connected to the gate of Q1 through R6, and the ISEN is connected to the upper end of R5 through R4;

[0026] Pins 4 and 5 of the NFC module U2 are connected to C1 and the antenna, and the PWM pin of U2 is connected to the upper end of R1 and C3;

[0027] Among them, the upper end of C3 is connected to the ISEN pin of U1 through D1 and R2;

[0028] Specifically, the NFC module U2 is a module made of an NFC chip;

[0029] The LA4 pin and LA5 pin of the NFC chip are directly connected in parallel with an antenna and a capacitor C1;

[0030] The VCC and GND of the NFC chip are connected in parallel with a capacitor C4;

[0031] The NFC chip is provided with a PWM pin 1, and the PWM pulse width is adjusted through a mobile phone or a programmer with NFC function. According to the PWM pulse width, a DC voltage is formed after filtering by R1 and C3;

[0032] The DC voltage is injected into the ISEN pin of the primary side control constant current chip U1 through D1 and R2;

[0033] Specifically, the primary-side control constant-current chip U1 is a commonly used primary-side control constant-current chip;

[0034] Among them, the primary-side current flowing through T1 and Q1 will form a voltage across R5;

[0035] According to Kirchhoff's current law, at the ISEN pin node of the primary-side control constant-current chip U1, the sum of the currents flowing into the node is equal to the sum of the currents flowing out of the node;

[0036] Secondly, the larger the current injected into the ISEN pin through D1 and R2 by the DC voltage formed by the PWM pulse width of U2, the smaller the current injected through R4 by the voltage formed by the primary-side current across R5, the smaller the voltage across R5, the smaller the primary-side current, and the smaller the output current;

[0037] Conversely, the smaller the current injected into the ISEN pin through D1 and R2 by the DC voltage formed by the PWM pulse width of U2, the larger the output current, thereby realizing the control of the magnitude of the PWM-controlled output current;

[0038] In this embodiment, the NFC control module U2 generates PWM pulses, which are then converted into a DC voltage through the PWM dimming circuit and injected into the ISEN pin of the primary-side control constant-current chip U1. Since the internal reference voltage of the ISEN pin remains unchanged, the voltage formed across the sampling resistor by the primary-side current will change with the change of the DC signal, thereby controlling the magnitude of the output current and achieving the purpose of dimming. Moreover, the primary-side control constant-current chip U1 can achieve the dimming function without a PWM port, and the total cost of the circuit will be reduced.

[0039] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and the inventive concept of the present invention, makes equivalent substitutions or changes, and all should be covered within the protection scope of the present invention.

Claims

1. An LED dimming drive circuit integrated with NFC control, characterized in that, it includes a rectifier bridge DB1, a field effect transistor Q1, a transformer T1, diodes D1, D2, resistors R1, R2, R3, R4, R5, R6, capacitors C1, C2, C3, C4, an NFC chip, a primary side control constant current chip U1, and an NFC module U2; DRV of the primary side control constant current chip U1 is connected to the gate of Q1 through R6, and the ISEN pin of U1 is connected to the upper end of R5 through R4. The 4th and 5th pins of the NFC module U2 are connected to C1 and the antenna. The PWM pin of U2 is connected to the upper end of C3 through R1. The upper end of C3 is connected to the ISEN pin of the primary side control constant current chip U1 through D1 and R2; The NFC chip is provided with a PWM1 pin. The PWM pulse width of the NFC chip is adjustable. The PWM pulse width forms a DC voltage after being filtered by R1 and C3, and the DC voltage is injected into the ISEN pin of the primary side control constant current chip U1 through D1 and R2; The greater the current injected into the ISEN pin of the primary side control constant current chip U1 through D1 and R2 by the DC voltage formed by the PWM pulse width of the NFC module U2, the smaller the current injected through R4 by the voltage formed by the primary side current passing through R5, the smaller the voltage on R5, and the smaller the primary side current and the output current. The smaller the current injected into the ISEN pin of the primary side control constant current chip U1 through D1 and R2 by the DC voltage formed by the PWM pulse width of the NFC module U2, the greater the output current.

2. The LED dimming drive circuit integrated with NFC control according to claim 1, characterized in that, The 2nd and 3rd pins of the rectifier bridge DB1 are connected to the mains, and the 1st pin is connected to the 2nd pin of T1, and the 4th pin is grounded.

3. The LED dimming drive circuit integrated with NFC control according to claim 1, characterized in that, The primary side control constant current chip U1 is a common primary side control constant current chip. The primary side current flowing through T1 and Q1 will form a voltage on R5.

4. The LED dimming drive circuit integrated with NFC control according to claim 1, characterized in that, The 1st pin of T1 is connected to the drain of the field effect transistor Q1, the 5th pin of T1 is connected to D2, D2 is connected to C2, and the other end of C2 is connected to the 6th pin of the transformer.

5. The LED dimming drive circuit integrated with NFC control according to claim 1, characterized in that, The source of Q1 is grounded through the R5 resistor.

6. The LED dimming drive circuit integrated with NFC control according to claim 1, characterized in that, The 4th pin and 5th pin of LA of the NFC chip are directly connected in parallel with an antenna and a capacitor C1. The VCC and GND of the NFC chip are connected in parallel with a group of capacitors C4.

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