CN111182677B - LED control circuit - Google Patents

Abstract

The invention discloses an LED control circuit. The control circuit includes at least one drive circuit; each drive circuit controls one LED correspondingly; an input end of the drive circuit is used to receive a control signal, and an output of the drive circuit The terminal is used to connect the first terminal of the LED; the driving circuit includes a NOR gate, an OR gate, a first NOT gate, a second NOT gate, a first capacitor, a second capacitor, a first resistor and a second resistor. By adopting the technical scheme of the present invention, the LED can be stably controlled, and the anti-interference ability is strong and the reliability is good.

Description

A LED control circuit

technical field

The invention relates to the technical field of LED control, in particular to an LED control circuit.

Background technique

As a new type of energy-saving light source, LED lamps have been widely accepted and adopted due to their environmental protection, energy saving, long life and small size. Among them, the LED control circuit plays a very important role in making the LED in a stable and reliable working state.

In the traditional LED control circuit, the GPIO port of the control chip is generally configured by software to output the corresponding control signal to realize the flashing of the LED light. However, this method will have software problems such as driving errors, and is easily affected by the internal or external environment. interference, resulting in the inability to control the LED normally, and the reliability is poor.

SUMMARY OF THE INVENTION

The technical problem to be solved by the embodiments of the present invention is to provide an LED control circuit, which can stably control the LED, and has strong anti-interference ability and good reliability.

In order to solve the above technical problems, an embodiment of the present invention provides an LED control circuit, the control circuit includes at least one drive circuit; each drive circuit correspondingly controls one LED; the input end of the drive circuit is used to receive control signal, the output end of the drive circuit is used to connect the first end of the LED; the drive circuit includes a NOR gate, an OR gate, a first NOT gate, a second NOT gate, a first capacitor, a second capacitor, a first resistance and a second resistance; where,

The input terminal of the NOR gate is the input terminal of the driving circuit, the output terminal of the NOR gate is connected to the first input terminal of the OR gate, and the output terminal of the OR gate is connected to the first NOR gate. The input end of the gate is connected, the output end of the first NOT gate is connected with the first end of the first capacitor, the second end of the first capacitor is connected with the first end of the first resistor, the The second end of the first resistor is grounded, the input end of the second NOT gate is connected to the first end of the first resistor, and the output end of the second NOT gate is connected to the first end of the second capacitor , the second end of the second capacitor is connected to the second input end of the OR gate, the second end of the second capacitor is also connected to the first end of the second resistor, and the second end of the second resistor The second terminal is grounded, and the output terminal of the second NOT gate is the output terminal of the driving circuit.

Further, the driving circuit further includes a third capacitor; the first end of the third capacitor is connected to the output end of the NOR gate, and the second end of the third capacitor is grounded.

Further, the control circuit further includes a third resistor; the first end of the third resistor is used to connect the second end of the LED, and the second end of the third resistor is grounded.

Further, the number of the input terminals of the NOR gate is determined according to the number of the control signals.

Further, the capacitance value of the first capacitor is the same as the capacitance value of the second capacitor; the resistance value of the first resistor is the same as the resistance value of the second resistor.

Compared with the prior art, an embodiment of the present invention provides an LED control circuit, the control circuit includes at least one drive circuit, each drive circuit correspondingly controls one LED, and the input end of the drive circuit is used to receive a control signal, and the drive circuit The output end of the LED is used to connect the first end of the LED. The drive circuit is composed of a NOR gate, an OR gate, a first NOT gate, a second NOT gate, a first capacitor, a second capacitor, a first resistor, and a second resistor connection. The control circuit can stably control the LED, and has strong anti-interference ability and good reliability.

Description of drawings

1 is a schematic structural diagram of a preferred embodiment of an LED control circuit provided by the present invention;

FIG. 2 is a schematic structural diagram of another preferred embodiment of an LED control circuit provided by the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

An embodiment of the present invention provides an LED control circuit. Referring to FIG. 1, it is a schematic structural diagram of a preferred embodiment of an LED control circuit provided by the present invention. The control circuit includes at least one drive circuit; The drive circuit controls one LED correspondingly; the input end of the drive circuit is used to receive a control signal, and the output end of the drive circuit is used to connect the first end of the LED; the drive circuit includes a NOR gate G1, an OR gate G2 , the first NOT gate G3, the second NOT gate G4, the first capacitor C1, the second capacitor C2, the first resistor R1 and the second resistor R2; wherein,

The input end of the NOR gate G1 is the input end of the drive circuit, the output end of the NOR gate G1 is connected to the first input end of the OR gate G2, and the output end of the OR gate G2 is connected to the first input end of the OR gate G2. The input end of the first NOT gate G3 is connected, the output end of the first NOT gate G3 is connected with the first end of the first capacitor C1, and the second end of the first capacitor C1 is connected with the first resistor The first end of R1 is connected, the second end of the first resistor R1 is grounded, the input end of the second NOT gate G4 is connected to the first end of the first resistor R1, and the second NOT gate G4 is connected to the first end of the first resistor R1. The output terminal is connected to the first terminal of the second capacitor C2, the second terminal of the second capacitor C2 is connected to the second input terminal of the OR gate G2, and the second terminal of the second capacitor C2 is also connected to the second input terminal of the OR gate G2. The first end of the second resistor R2 is connected, the second end of the second resistor R2 is grounded, and the output end of the second NOT gate G4 is the output end of the driving circuit.

Specifically, the LED control circuit includes at least one drive circuit, each drive circuit correspondingly controls one LED, and the circuit topology of each drive circuit is the same; for any drive circuit, the NOR gate G1, the OR gate G2, the first The NOT gate G3, the second NOT gate G4, the first capacitor C1, the second capacitor C2, the first resistor R1 and the second resistor R2 are composed of, wherein, the input end of the NOR gate G1 is the input end of the driving circuit for receiving Control signal (Control), the output end of the second NOT gate G4 is the output end of the driving circuit, which is used to connect the first end of the LED (ie the anode of the LED), the second end of the LED (ie the cathode of the LED) is grounded, and the first end of the LED is connected to the ground. A capacitor C1 and a first resistor R1 form a first RC charge and discharge circuit, a second capacitor C2 and a second resistor R2 form a second RC charge and discharge circuit, and the first RC charge and discharge circuit and the second RC charge and discharge circuit are used for Control the frequency of LED flashing and the duration of each LED on and off; after the LED control circuit receives the control signal, through the logic operation of each logic gate device in the drive circuit and the charge and discharge process of the RC circuit, the output of the drive circuit The terminal will output the corresponding square wave signal to control the flashing of the LED.

It should be noted that the control signal (Control) can flexibly adopt the available signals sent by the chip in the device. For example, the PA enable signal and switch enable signal sent by the transceiver chip are all available signals, as long as they can be used as control signals. The signal of when the LED flashes and when it does not flash can be used as the control signal (Control) in the embodiment of the present invention.

Assuming that the LED control circuit receives two control signals, Control1 and Control2, respectively, when Control1 and Control2 are low, the output of the NOR gate G1 is high, and the output of the OR gate G2 is high, thus Limit the output of the first NOT gate G3 to a low level, and limit the output of the second NOT gate G4 to a high level, at this time the LED is always on; when Control1 or Control2 changes from a low level to a high level, The output terminal of the NOR gate G1 is low level, and the first input terminal of the OR gate G2 changes from high level to low level. With the continuous repetition of the charging and discharging process of the RC circuit, the first NOT gate G3 and the second The output terminals of the NOT gate G4 can output a square wave signal to control the flickering of the LED. The frequency of LED flickering and the duration of each LED on and off can be determined by the capacitance of the first capacitor C1 and the second capacitor C2. The resistance values of the first resistor R1 and the second resistor R2 are adjusted accordingly, that is, the charging and discharging time of the RC circuit is adjusted.

Referring to FIG. 2, it is a schematic structural diagram of another preferred embodiment of an LED control circuit provided by the present invention. In another preferred embodiment, the drive circuit further includes a third capacitor C3; the third capacitor The first end of C3 is connected to the output end of the NOR gate G1, and the second end of the third capacitor C3 is grounded.

Specifically, in combination with the above embodiment, the third capacitor C3 is connected to the output end of the NOR gate G1, and is used to filter the output signal of the NOR gate G1, so that the NOR gate G1 outputs a stable high level or low level .

It should be noted that the value of the third capacitor C3 can be set according to the actual signal to be filtered, for example, C3=22μF, and if the signal output by the NOR gate G1 is stable enough, the third capacitor C3 may not be added, so that Simplify circuit topology and reduce cost.

With reference to FIG. 2, in another preferred embodiment, the control circuit further includes a third resistor R3; the first end of the third resistor R3 is used to connect the second end of the LED, and the third resistor R3 The second terminal is grounded.

Specifically, in combination with the above embodiments, the third resistor R3 is connected to the second end of the LED (ie, the cathode of the LED), and the third resistor R3 is a current limiting resistor, used to control the current flowing through the LED and prevent the current flowing through the LED If it is too large or too small, the value of the third resistor R3 can be set according to the LED, and the brightness of the LED can also be adjusted by the value of the third resistor R3.

In yet another preferred embodiment, the number of input terminals of the NOR gate G1 is determined according to the number of the control signals.

Specifically, in conjunction with the above-mentioned embodiment, since the control signal (Control) can be one channel or any number of channels, correspondingly, the number of input terminals of the NOR gate G1 needs to be determined according to the number of specific control signals. For example, when the control signal only has In the case of one channel, one of the input terminals of the NOR gate G1 in Figures 1 and 2 is used to receive one channel control signal, and the other input terminal can be directly grounded (low level), or the OR in Figures 1 and 2 can be connected to The NOT gate G1 can be directly replaced with a NOT gate; when the control signal is n channels (n>1), the NOR gate G1 corresponds to a NOR gate with at least n channels of input terminals.

In yet another preferred embodiment, the capacitance value of the first capacitor C1 and the capacitance value of the second capacitor C2 are the same; the resistance value of the first resistor R1 and the resistance value of the second resistor R2 are the same.

Specifically, in combination with the above embodiments, the frequency of LED flashing and the duration of each LED on and off can be determined by the capacitance values of the first capacitor C1 and the second capacitor C2, and the resistance values of the first resistor R1 and the second resistor R2. Adjust accordingly, among them, C1 and R1 are used to control the time length of each time off when the LED is flashing (ie, the duty cycle of the low level of the square wave signal), and C2 and R2 are used to control the LED flashing. The length of time to light (that is, the duty cycle of the high level of the square wave signal), when C1=C2 and R1=R2, the duration of each LED on and off is the same (that is, the high level and low level of the square wave signal). The duty cycle of the level is the same); for example, assuming that C1=C2=1μF, R1=R2=118kΩ, the frequency of LED flashing is about 6Hz.

It can be understood that the values of C1, C2, R1 and R2 can be set according to actual needs, as long as the frequency of LED flashing can be controlled within the visible range of the human eye, and the values of C1 and C2 can be the same or Different, for the same reason, the values of R1 and R2 can be the same or different. It can be flexibly adjusted to adjust the time when the LED is on and off. When C1=C2 and R1=R2, the high value of the square wave signal output by the driving circuit The duty ratios of the level and the low level are the same. When C1≠C2 or/and R1≠R2, the duty ratios of the high level and the low level of the square wave signal output by the drive circuit are different.

To sum up, the LED control circuit provided by the embodiment of the present invention has the following beneficial effects:

(1) It can stably control the LED, and has strong anti-interference ability and good reliability;

(2) The design and operation of the LED control circuit are simple, and the flicker frequency of the LED is adjustable

(3) The components used in the LED control circuit are all standing materials, which are easy to use and low in cost.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the technical principle of the present invention, several improvements and modifications can also be made. These improvements and modifications It should also be regarded as the protection scope of the present invention.

Claims (5)

1. The LED control circuit is characterized by comprising at least one path of drive circuit; each path of the driving circuit correspondingly controls one path of the LED; the input end of the driving circuit is used for receiving a control signal, and the output end of the driving circuit is used for connecting the first end of the LED; the driving circuit comprises a NOR gate, an OR gate, a first NOT gate, a second NOT gate, a first capacitor, a second capacitor, a first resistor and a second resistor; wherein,

the input end of the NOR gate is the input end of the drive circuit, the output end of the NOR gate is connected with the first input end of the OR gate, the output end of the OR gate is connected with the input end of the first NOT gate, the output end of the first NOT gate is connected with the first end of the first capacitor, the second end of the first capacitor is connected with the first end of the first resistor, the second end of the first resistor is grounded, the input end of the second NOT gate is connected with the first end of the first resistor, the output end of the second NOT gate is connected with the first end of the second capacitor, the second end of the second capacitor is connected with the second input end of the OR gate, the second end of the second capacitor is also connected with the first end of the second resistor, the second end of the second resistor is grounded, and the output end of the second not gate is the output end of the driving circuit.

2. The LED control circuit of claim 1, wherein the driver circuit further comprises a third capacitor; and the first end of the third capacitor is connected with the output end of the NOR gate, and the second end of the third capacitor is grounded.

3. The LED control circuit of claim 1, wherein the control circuit further comprises a third resistor; the first end of the third resistor is used for being connected with the second end of the LED, and the second end of the third resistor is grounded.

4. The LED control circuit of claim 1, wherein the number of inputs of the nor gate is determined according to the number of the control signals.

5. The LED control circuit of claim 1, wherein the capacitance of the first capacitor is the same as the capacitance of the second capacitor; the resistance value of the first resistor is the same as that of the second resistor.

Images