CN218162935U

CN218162935U - LED drive circuit

Info

Publication number: CN218162935U
Application number: CN202221790437.6U
Authority: CN
Inventors: 鲍永
Original assignee: Yuyao Yuchang Electrical Appliance Co Ltd
Current assignee: Yuyao Yuchang Electrical Appliance Co Ltd
Priority date: 2022-07-08
Filing date: 2022-07-08
Publication date: 2022-12-27
Anticipated expiration: 2032-07-08

Abstract

The utility model relates to a LED drive circuit, include: a drive module; the method is characterized in that: further comprising: the control module comprises at least one output port for outputting high level and low level; the input end of each switch circuit is respectively connected with one output port corresponding to the control module; the output end of each switch circuit is respectively connected with one corresponding LED component, and each switch circuit is connected in parallel at two ends of the output pin of the driving module and the feedback pin of the driving module. Therefore, the circuit is simple, low in cost and capable of meeting the requirements of driving the LED assemblies with different powers.

Description

LED drive circuit

Technical Field

The utility model relates to a lighting apparatus technical field, in particular to LED (light emitting diode) drive circuit.

Background

As LED lighting becomes more intelligent, the need for light control and lighting of scenes becomes stronger, and more LED products are currently on the market.

The most common driving method of the LED lamp in the prior art is as follows: one LED driving circuit can only drive one power LED lamp, and the LED lamp has different power requirements in the actual use process. Therefore, the current same LED drive circuit cannot meet the drive requirements of LED lamps with different powers. Further improvements are needed for this purpose.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the technical problem that to above-mentioned prior art, a LED drive circuit that can drive a plurality of different power LED lamps is provided.

The utility model provides a technical scheme that above-mentioned technical problem adopted does: an LED driver circuit comprising:

a drive module;

the method is characterized in that: further comprising:

the control module comprises at least one output port for outputting high level and low level; and

the number of the switch circuits is matched with that of the output ports of the control module, and the input end of each switch circuit is connected with one output port corresponding to the control module; the output end of each switch circuit is respectively connected with one corresponding LED component, and each switch circuit is connected in parallel at two ends of the output pin of the driving module and the feedback pin of the driving module.

In this scheme, at least one of the switch circuits includes a first voltage-dividing circuit and an MOS transistor, a first end of the first voltage-dividing circuit is correspondingly connected to an output port of the control module, a second end of the first voltage-dividing circuit is connected to a source of the MOS transistor and then connected to a feedback pin of the driving module, an output end of the first voltage-dividing circuit is connected to a gate of the MOS transistor, a drain of the MOS transistor is correspondingly connected to one end of an LED module, and the other end of the LED module is connected to an output pin of the driving module.

Preferably, the MOS transistor is an NMOS transistor.

Preferably, the circuit of each switching circuit is the same.

In order to enable each LED component to be capable of conducting brightness adjustment, the LED brightness control circuit further comprises a brightness adjusting circuit, the control module further comprises a PWM output end used for outputting PWM pulse signals, the input end of the brightness adjusting circuit is connected with the PWM output end of the control module, and the output end of the brightness adjusting circuit is respectively connected between a feedback pin of the driving module and the switch circuit.

In order to obtain a stable current for each LED module, a current detection port is further disposed on a connection branch of each switching circuit and the brightness adjustment circuit, and the current detection port is connected to the control module and is used for enabling the control module to obtain a current output by each switching circuit.

In order to realize brightness adjustment of each LED component, in this scheme, the brightness adjustment circuit includes a filter circuit and a second voltage division circuit, the brightness adjustment circuit is connected to a PWM output end of the control module through an input end of the filter circuit, an output end of the filter circuit is connected to a first end of the second voltage division circuit, a second end of the second voltage division circuit is connected to the switch circuit, and an output end of the second voltage division circuit is connected to a feedback pin of the driving module.

In order to perform low-frequency filtering on the PWM pulse signal output by the first PWM output terminal, preferably, the filter circuit includes a first resistor and a first capacitor, one end of the first resistor is an input end of the filter circuit, the other end of the first resistor is connected to one end of the first capacitor and is an output end of the filter circuit, and the other end of the first capacitor is grounded.

Compared with the prior art, the utility model has the advantages of: the switch circuit for independently controlling each LED assembly is connected in parallel to the driving module, so that the driving of a plurality of LED assemblies can be realized by only one driving module, the cost is reduced, and each switch circuit outputs high and low levels through the output port of the control module so as to independently control the on or off of each switch circuit, and the use requirements of different LED assemblies can be met; therefore, the circuit is simple, low in cost and capable of meeting the requirements of driving the LED assemblies with different powers.

Drawings

Fig. 1 is a circuit diagram of an LED driving circuit according to an embodiment of the present invention (omitting a control module);

fig. 2 is a circuit diagram of a control module according to an embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the following embodiments.

As shown in fig. 1 and 2, the LED driving circuit in the present embodiment includes a driving module 1, a control module 2, at least one switching circuit 3, and a brightness adjusting circuit 4.

As shown in fig. 2, the control module 2 includes at least one output port for outputting a high level and a low level and a PWM output port PWM1 for outputting a PWM pulse signal, and an input terminal of each switch circuit 3 is connected to a corresponding output port of the control module 2; an output port correspondingly connected with the control module 2; the output end of each switch circuit 3 is connected with a corresponding LED component, and each switch circuit 3 is connected in parallel to the output pin SW of the driving module 1 and the feedback pin FB of the driving module 1.

The control module 2 is a common singlechip; as shown in fig. 1, the driving module 1 is a driving chip U3, the number of the LED assemblies is three, and the power of each LED assembly is different, namely, 10W of the first LED assembly COB1, 3W of the second LED assembly COB2, and 1W of the third LED assembly COB3; correspondingly, there are three switch circuits, which are respectively used for controlling the first switch circuit 31 of the first LED assembly COB1, the second switch circuit 32 of the second LED assembly COB2, and the third switch circuit 33 of the third LED assembly COB3; the output ports of the control module 2 are three, which are respectively a first output port A1, a second output port A2, and a third output port A3.

At least one of the switch circuits 3 includes a first voltage division circuit and an MOS transistor, a first end of the first voltage division circuit is correspondingly connected with an output port of the control module 2, a second end of the first voltage division circuit is connected with a feedback pin FB of the driving module 1 after being connected with a source electrode of the MOS transistor, an output end of the first voltage division circuit is connected with a gate electrode of the MOS transistor, a drain electrode of the MOS transistor is correspondingly connected with one end of an LED component, and the other end of the LED component is connected with an output pin SW of the driving module 1. The MOS tube is an NMOS tube. In this embodiment, the circuit of each switch circuit 3 is preferably the same, but of course, the circuit may be different. The first voltage divider circuit comprises at least two resistors connected in series. As shown in fig. 1, the first voltage dividing circuit in the first switch circuit 31 includes a resistor R12 and a resistor R19 connected in series, a connection between the resistor R12 and the resistor R19 is an output terminal of the first voltage dividing circuit in the first switch circuit 31, and the other ends of the resistor R12 and the resistor R19 are a first end and a second end of the first voltage dividing circuit in the first switch circuit 31, respectively; the first voltage dividing circuit in the second switch circuit 32 includes a resistor R13 and a resistor R20 connected in series, a connection between the resistor R13 and the resistor R20 is an output terminal of the first voltage dividing circuit in the second switch circuit 32, and the other ends of the resistor R13 and the resistor R20 are a first end and a second end of the first voltage dividing circuit in the second switch circuit 32, respectively; the first voltage dividing circuit in the third switching circuit 33 includes a resistor R14 and a resistor R21 connected in series, a connection between the resistor R14 and the resistor R2 is an output terminal of the first voltage dividing circuit in the third switching circuit 33, and the other ends of the resistor R14 and the resistor R2 are a first end and a second end of the first voltage dividing circuit in the third switching circuit 33, respectively.

The input end of the brightness adjusting circuit 4 is connected with the PWM output end PWM1 of the control module 2, and the output end of the brightness adjusting circuit 4 is respectively connected between the feedback pin FB of the driving module 1 and the switch circuit. And a current detection port LED _ OUT is also arranged on a connecting branch of each switching circuit and the brightness adjusting circuit 4, and the current detection port LED _ OUT is connected with the control module 2 and used for enabling the control module 2 to obtain the current output by each switching circuit. If the control module 2 detects that the current of the LED _ OUT terminal is greater than or less than a normal value (the normal value is a threshold range), the control module 2 automatically adjusts the duty ratio of the PWM output terminal PWM1 to achieve the purpose of stabilizing the output current.

As shown in fig. 1, the brightness adjusting circuit 4 includes a filter circuit 41 and a second voltage dividing circuit 42, the brightness adjusting circuit 4 is connected to the PWM output PWM1 of the control module 2 through an input terminal of the filter circuit 41, an output terminal of the filter circuit 41 is connected to a first terminal of the second voltage dividing circuit 42, a second terminal of the second voltage dividing circuit 42 is connected to the switch circuit 3, and an output terminal of the second voltage dividing circuit 42 is connected to the feedback pin FB of the driving module 1. The filter circuit 41 includes a first resistor R16 and a first capacitor C1, one end of the first resistor R16 is an input end of the filter circuit 41, the other end of the first resistor R16 is connected to one end of the first capacitor C1 and is an output end of the filter circuit 41, and the other end of the first capacitor C1 is grounded. The second voltage-dividing circuit 42 includes at least two resistors connected in series, as shown in fig. 1, in this embodiment, the second voltage-dividing resistor 42 includes a second resistor R17 and a third resistor R18 connected in series, and an output end of the second voltage-dividing circuit 42 is located between the second resistor R17 and the third resistor R18; the other end of the second resistor R17 and the other end of the third resistor R18 serve as a first end and a second end of the second voltage-dividing circuit 42, respectively.

The working principle of the LED driving circuit in this embodiment is as follows: the second LED modules COB2 and COB3 of the 10W and 1W first and third LED modules COB1 and 3W respectively cannot operate simultaneously, but only operate individually, and therefore, only one of the first output port A1, the second output port A2 and the third output port A3 in the control module 2 is at a high level, and the others are at a low level, for example:

1. when the first output port A1 is at a high level, and the second output port A2 and the third output port A3 are at a low level, the MOS transistor Q1 is turned on, the first LED assembly COB1 operates, the PWM output port PWM1 outputs a PWM pulse signal, and the driver chip U3 outputs a current, at this time, if the control module 2 detects that the current of the LED _ OUT port (i.e., corresponding to the first switch circuit 31) is greater than or less than a normal value, the control module 2 automatically adjusts the duty ratio of the PWM output port PWM1, and finally the driver chip U3 outputs a current for the first LED assembly COB1 to stably operate;

2. when the second output port A2 is at a high level and the first output port A1 and the third output port A3 are at a low level, the MOS transistor Q2 is turned on, the second LED module COB2 operates, the PWM output PWM1 outputs a PWM pulse signal, and the driver chip U3 outputs a current, at this time, if the control module 2 detects that the current of the LED _ OUT terminal (i.e., the current corresponding to the second switch circuit 32) is greater than or less than a normal value, the control module 2 automatically adjusts the duty ratio of the PWM output PWM1, and finally the driver chip U3 outputs a current for the second LED module COB2 to stably operate;

3. when the third output port A3 is at a high level and the first output port A1 and the second output port A2 are at a low level, the MOS transistor Q3 is turned on, the third LED module COB3 operates, the PWM output terminal PWM1 outputs a PWM pulse signal to drive the chip U3 to output a current, and at this time, if the control module 2 detects that the current at the LED _ OUT terminal (i.e., corresponding to the third switching circuit 33) is greater than or less than a normal value, the control module 2 automatically adjusts the duty ratio of the PWM output terminal PWM1, and finally the drive chip U3 outputs a current for the third LED module COB3 to stably operate.

Claims

1. An LED drive circuit comprises

A drive module (1);

the method is characterized in that: further comprising:

a control module (2) comprising at least one output port for outputting a high level and a low level; and

the number of the switch circuits is matched with that of the output ports of the control module (2), and the input end of each switch circuit is connected with one output port corresponding to the control module (2); the output end of each switch circuit is respectively connected with a corresponding LED component, and each switch circuit is connected in parallel at two ends of an output pin (SW) of the driving module (1) and a feedback pin (FB) of the driving module (1).

2. The LED driving circuit of claim 1, wherein: the at least one switch circuit comprises a first voltage division circuit and an MOS (metal oxide semiconductor) tube, a first end of the first voltage division circuit is correspondingly connected with one output port of the control module (2), a second end of the first voltage division circuit is connected with a feedback pin (FB) of the driving module (1) after being connected with a source electrode of the MOS tube, an output end of the first voltage division circuit is connected with a grid electrode of the MOS tube, a drain electrode of the MOS tube is correspondingly connected with one end of an LED component, and the other end of the LED component is connected with an output pin (SW) of the driving module (1).

3. The LED driving circuit according to claim 2, wherein: the MOS tube is an NMOS tube.

4. The LED driving circuit of claim 3, wherein: the circuit of each switching circuit is the same.

5. The LED driving circuit according to any of claims 1-4, wherein: the LED driving circuit is characterized by further comprising a brightness adjusting circuit (4), the control module (2) further comprises a PWM output end (PWM 1) used for outputting PWM pulse signals, the input end of the brightness adjusting circuit (4) is connected with the PWM output end (PWM 1) of the control module (2), and the output end of the brightness adjusting circuit (4) is respectively connected between a feedback pin (FB) of the driving module (1) and the switch circuit.

6. The LED driving circuit according to claim 5, wherein: and a current detection port (LED _ OUT) is also arranged on a connecting branch of each switching circuit and the brightness adjusting circuit (4), and the current detection port (LED _ OUT) is connected with the control module (2) and used for enabling the control module (2) to obtain the current output by each switching circuit.

7. The LED driving circuit according to claim 5, wherein: the brightness adjusting circuit (4) comprises a filter circuit (41) and a second voltage dividing circuit (42), the brightness adjusting circuit (4) is connected with a PWM output end (PWM 1) of the control module (2) through an input end of the filter circuit (41), an output end of the filter circuit (41) is connected with a first end of the second voltage dividing circuit (42), a second end of the second voltage dividing circuit (42) is connected with the switch circuit (3), and an output end of the second voltage dividing circuit (42) is connected with a feedback pin (FB) of the drive module (1).

8. The LED driving circuit of claim 7, wherein: the filter circuit (41) comprises a first resistor (R16) and a first capacitor (C12), one end of the first resistor (R16) is an input end of the filter circuit (41), the other end of the first resistor (R16) is connected with one end of the first capacitor (C12) and is an output end of the filter circuit (41), and the other end of the first capacitor (C12) is grounded.