CN108650755A - A kind of linear constant current driving chip and multi-chip parallel connection LED illumination driving circuit - Google Patents

Abstract

The invention discloses a kind of linear constant current driving chip and multi-chip parallel connection LED illumination driving circuits, are related to LED illumination driving circuit, and multi-chip parallel connection LED illumination driving circuit includes power supply unit, LED array, peripheral circuit, linear constant current driving chip；Linear constant current driving chip has current terminal pin, input pin and output pin；The input pin of linear constant current driving chip is sequentially connected the output pin of a linear constant current driving chip, and the input pin of first linear constant current driving chip connects peripheral circuit；Multi-chip parallel connection LED illumination driving circuit of the present invention only needs a set of various peripheral circuits, simplify structure, save cost, peripheral circuit signal is detected by first linear constant current chip, and signal is sent to the electric current for controlling the power conversion unit synchronous control in all linear constant current chips to all linear constant current chips and flowing through LED array.

Description

A linear constant current drive chip and a multi-chip parallel LED lighting drive circuit

technical field

The invention relates to an LED lighting driving circuit, in particular to a linear constant current driving chip and a multi-chip parallel LED lighting driving circuit.

Background technique

Chips and peripheral circuits are usually used in linear constant current LED lighting drive circuits. The chip includes a control circuit and a current source; there are various peripheral circuits, such as: current setting circuit, loop compensation circuit, filter circuit, detection circuit and abnormal protection circuit. At present, in applications with high power, it is often necessary to connect multiple chips in parallel to expand power and share power consumption. Correspondingly, the peripheral circuits corresponding to multiple groups of chips also need to be used together, which makes the peripheral circuits very complicated.

Fig. 1 is an existing LED lighting driving circuit with 3 chips connected in parallel, including a power supply unit, an LED array, 3 chips, and 3 peripheral circuits. Each chip includes a control circuit and a current source, one end of the control circuit is connected to one end of the current source, the other end of the control circuit is connected to the input pin MI, and the other end of the current source is connected to the current terminal pin MOUT. The three peripheral circuits are respectively connected to the input pins MI of the three chips, the current terminal pins MOUT of the three chips are all connected to the same end of the LED array, and the other end of the LED array is connected to the power supply unit.

In the existing multi-chip parallel LED lighting driving circuit, each chip needs to be connected to a corresponding peripheral circuit, so that there are many circuit components and the circuit connection is complicated.

Contents of the invention

The purpose of the present invention is to provide a linear constant current drive chip and a multi-chip parallel LED lighting drive circuit to solve the problems raised in the above background technology.

In order to achieve the above object, the present invention provides the following technical solutions: a linear constant current drive chip, which has a current terminal pin, an input pin, and an output pin; the linear constant current drive chip includes a power conversion unit, and the power conversion The unit controls the current flowing through the LED array through the current terminal pin; the input pin is used to detect various external signals and make it react to the output pin, and the state of the output pin is determined by the input pin control.

Further, the linear constant current drive chip also includes an input buffer circuit and an output buffer circuit; the output end of the output buffer circuit is connected to the output pin, and the output end of the input buffer circuit is connected to the output pin of the output buffer circuit. An input terminal, the input terminal of the input buffer circuit is connected to the input pin; the output terminal of the current conversion circuit is connected to the current terminal pin, and the input terminal is connected to the output terminal of the input buffer circuit.

Further, if the input pin is used to receive a current signal, the output pin generates a current signal with an equal value.

Further, if the input pin is used to receive a voltage signal, the output pin generates a voltage signal with an equal value.

Further, if the input pin is used to receive a logic signal, the output pin generates the same logic signal.

The present invention also proposes a multi-chip parallel LED lighting drive circuit, including a peripheral circuit, a power supply unit, an LED array, and several linear constant current drive chips as described in claim 1; the peripheral circuit is connected to one of the The input pin of the linear constant current driver chip, the output pin of the linear constant current driver chip is connected to the input pin of the next linear constant current driver chip in turn, and the last one of the linear constant current driver chip The output pin is vacant; one end of the LED array is connected to the power supply unit, and the other end is respectively connected to the current end pins of the linear constant current driver chip.

Further, the input pin of the first linear constant current drive chip detects the peripheral terminal signal of the peripheral circuit, and sends the signal to all the linear constant current chips to control all the linear constant current drivers. The power conversion unit in the constant current chip synchronously controls the current flowing through the LED array.

Further, the linear constant current driver chip has at least one input pin; the output pins of the linear constant current driver chip are sequentially connected to the corresponding input pins on the next linear constant current driver chip .

Further, part or all of the peripheral circuits are integrated into any one or more of the linear constant current drive chips.

Compared with the prior art, the beneficial effect of the present invention is that the multi-chip parallel LED lighting drive circuit of the present invention only needs a set of various peripheral circuits, which reduces the cost and simplifies the structure.

Description of drawings

FIG. 1 is a schematic structural diagram of an existing multi-chip parallel LED lighting drive circuit;

Fig. 2 is a structural schematic diagram of Embodiment 1 of a multi-chip parallel LED lighting driving circuit of the present invention;

Fig. 3 is a schematic structural diagram of Embodiment 2 of a multi-chip parallel LED lighting driving circuit of the present invention.

Among the reference signs: 1. Linear constant current drive chip; 2. Peripheral circuit; 21. Control circuit; 22. Detection circuit; 3. LED array; 31. First LED array; 32. Second LED array; 4. Power supply unit.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Embodiment one

As shown in FIG. 2 , the multi-chip parallel LED lighting drive circuit of this embodiment includes a peripheral circuit 2 , an LED array 3 , a power supply unit 4 and three linear constant current drive chips 1 .

The power supply unit 4 is connected to one end of the LED array 3 .

The peripheral circuit 2 has a peripheral terminal 1SEXT, including a current source 1IR and a resistor 1R. The negative electrode of the current source 1IR is grounded, and the positive electrode is connected to the peripheral terminal 1SEXT and one end of the resistor 1R. The other end of the resistor 1R is connected to the end of the LED array 3 not connected to the power supply unit 4 for detecting the voltage amplitude of the power supply unit 4 . The current source 1IR and the resistor 1R constitute a current reference affected by the voltage amplitude of the commercial power. The current reference is output through the peripheral terminal 1SEXT. When the commercial power rises, the current reference current decreases, and when the commercial power decreases, the current reference The current reference current increases.

The linear constant current driver chip 1 has an input pin SI, an output pin SO and a current terminal pin IO, including an input buffer circuit IA, an output buffer circuit IB and a current conversion circuit IC. The input buffer circuit IA, the output buffer circuit IB and the current conversion circuit IC are all current sources. The negative pole of the input buffer circuit IA is connected to the input pin SI; the negative pole of the output buffer circuit IB is connected to the ground, and the positive pole is connected to the output pin SO; the negative pole of the current conversion circuit IC is grounded, and the positive pole is connected to the current terminal pin IO. The input buffer circuit IA and the output buffer circuit IB constitute a current mirror; the input buffer circuit IA and the current conversion circuit IC constitute another current mirror. If the effective input signal of the input pin SI of the linear constant current driver chip 1 is a pull-down current, the output signal of the output pin SO is also a pull-down current, which is equal to the pull-down current amplitude of the input pin SI.

The linear constant current driver chips 1 are arranged in sequence, and the input pin SI of each linear constant current driver chip 1 is sequentially connected to the output pin SO of the last linear constant current driver chip 1, and the first linear constant current driver chip 1 The input pin SI is connected to the peripheral terminal 1SEXT of the peripheral circuit 2, and the output pin SO of the last linear constant current driver chip 1 is vacant. The current end pins IO of the linear constant current drive chip 1 are all connected to the end of the LED array 3 that is not connected to the power supply unit 4 .

The working principle of this embodiment is as follows:

The peripheral terminal 1SEXT of the peripheral circuit 2 sets an electrical signal at the input pin SI of the first linear constant current drive chip 1, and the electrical signal generates a set current through the input buffer circuit IA and the current conversion circuit IC on the one hand to drive the LED array 3 , and on the other hand output to the output pin SO through the output buffer circuit IB. The output pin SO of the linear constant current driver chip 1 sets the electrical signal at the input pin SI of the next linear constant current driver chip 1, and so on, so that the current terminal pins IO of the three linear constant current driver chips 1 all generate Set the current to drive the LED array 3 .

In this embodiment, the multi-chip parallel LED lighting driving circuit only needs one set of peripheral circuits 2, which reduces the cost and simplifies the structure. Moreover, the linear constant current driving chips in the multi-chip parallel LED lighting driving circuit of the present invention are connected sequentially, the structure is simple and easy to route, and the external circuit connections of the chips do not cross each other, which improves the stability of the circuit.

Embodiment two

As shown in FIG. 3 , the multi-chip parallel LED lighting drive circuit of this embodiment includes a peripheral circuit 2 , an LED array 3 , a power supply unit 4 and three linear constant current drive chips 1 . The LED array 3 includes a first LED array 31 and a second LED array 32 . The first LED array 31 and the second LED array 32 have two color temperatures of warm white and cool white respectively.

The output end of the power supply unit 4 is connected to one end of the first LED array 31 and the second LED array 32 .

The peripheral circuit 2 has a first peripheral terminal EXTA and a second peripheral terminal EXTB, and includes a control circuit 21 and a detection circuit 22 . One end of the detection circuit 22 is connected to the control circuit 21, and the other end is connected to the power supply unit 4 to detect the switching state of the power supply unit. After being processed by the control circuit, the state is fed to the peripheral terminals EXTA and EXTB as brightness control signals for LEDA and LEDB respectively. The two output terminals of the control circuit are respectively connected to the first peripheral terminal EXTA and the second peripheral terminal EXTB.

The linear constant current drive chip 1 has a first input pin SIA, a second input pin SIB, a first output pin SOA, a second output pin SOB, a first current terminal pin IOA and a second current terminal pin IOB , including a first input buffer circuit BIA, a second input buffer circuit BIB, a first output buffer circuit BOA, a second output buffer circuit BOB, a first current conversion circuit IA and a second current conversion circuit IB. The first input buffer circuit BIA, the second input buffer circuit BIB, the first output buffer circuit BOA, and the second output buffer circuit BOB are all voltage followers or logic followers, and the voltage followers or logic followers can make the follower The output terminal replicates the voltage signal or logic signal of the input terminal; the input terminal of the first input buffer circuit BIA is connected to the first input pin SIA, and the output terminal is connected to the input terminal of the first output buffer circuit BOA; the input terminal of the second input buffer circuit BIB Connect the second input pin SIB, the output end connects the input end of the second output buffer circuit BOB; the output end of the first output buffer circuit BOA connects the first output pin SOA; the output end of the second output buffer circuit BOB connects the second output pin SOB. Both the first current conversion circuit IA and the second current conversion circuit IB are adjustable constant current sources with a control terminal; the positive pole of the first current conversion circuit IA is connected to the first current terminal pin 10A, the negative pole is grounded, and the control terminal is connected to the first The output terminal of the input buffer circuit BIA; the positive pole of the second current conversion circuit IB is connected to the second current terminal pin IOB, the negative pole is grounded, and the control terminal is connected to the output terminal of the second input buffer circuit BIB.

The linear constant current drive chips 1 are arranged in sequence, the first input pin SIA of each linear constant current drive chip 1 is connected to the first output pin SOA of the previous linear constant current drive chip 1 in turn, and the second input pin SIB is sequentially connected It is connected with the second output pin SOB of the last linear constant current driver chip 1; and the first input pin SIA of the first linear constant current driver chip 1 is connected to the first peripheral terminal EXTA of the peripheral circuit 2, and the second input pin The pin SIB is connected to the second peripheral end EXTB of the peripheral circuit 2; the first output pin SOA and the second output pin SOB of the last linear constant current driver chip 1 are vacant. The first current terminal pins 10A of the three linear constant current drive chips 1 are all connected to one end of the first LED array 31 that is not connected to the power supply unit 4, and the second current terminal pins 10A are connected to the second LED array 32 that is not connected to the power supply unit. 4 connected ends.

The signals received by the first input pin SIA and the second input pin SIB of the linear constant current drive chip 1 are voltage signals or logic signals, so that the first output pin SOA and the second output pin of the linear constant current drive chip 1 The SOB outputs the same voltage signal or logic signal correspondingly.

The working principle of this embodiment is as follows:

The first peripheral terminal EXTA and the second peripheral terminal EXTB of the peripheral circuit 2 respectively set a group of electrical signals on the first input pin SIA and the second input pin SIB of the first linear constant current drive chip 1, the electrical signals After the signals respectively pass through the first input buffer circuit BIA and the second input buffer circuit BIB, on the one hand, the first current conversion circuit IA and the second current conversion circuit IB are controlled to generate a set of set currents to drive the first LED array 31 and the second LED array 31. On the other hand, the array 32 is output to the first output pin SOA and the second output pin SOB through the first output buffer circuit BOA and the second output buffer circuit BOB respectively. The first output pin SOA and the second output pin SOB of the linear constant current driver chip 1 set a group of electrical signals on the input terminals SIA and SIB of the next linear constant current driver chip 2, and so on, so that the three linear Both the first current terminal pin 10A and the second current terminal pin 10B of the constant current driver chip 1 generate a set of electrical signals to drive the first LED array 31 and the second LED array 32 .

In this embodiment, the multi-chip parallel LED lighting driving circuit only needs one set of peripheral circuit 2, which can simultaneously drive the first LED array 31 and the second LED array 32, which reduces the cost and simplifies the structure.

According to the design ideas of different technicians, the peripheral circuit 2 in the present invention can be partially or completely integrated into one or more linear constant current drive chips, so that one or more linear constant current drive chips can be integrated with other linear constant current drive chips. are different, but achieve the same technical effect.

Although the embodiments of the present invention have been shown and described, those skilled in the art can understand that various changes, modifications and substitutions can be made to these embodiments without departing from the principle and spirit of the present invention. and modifications, the scope of the invention is defined by the appended claims and their equivalents.

Claims (9)

1. A linear constant current drive chip, characterized in that: it has a current terminal pin, an input pin and an output pin; the linear constant current drive chip includes a power conversion unit, and the power conversion unit passes through the current terminal The pins control the current flowing through the LED array; the input pins are used to detect various external signals and make them react to the output pins, and the state of the output pins is controlled by the input pins. 2. A linear constant current driver chip according to claim 1, characterized in that: the linear constant current driver chip also includes an input buffer circuit and an output buffer circuit; the output end of the output buffer circuit is connected to the output pin, the output end of the input buffer circuit is connected to the input end of the output buffer circuit, the input end of the input buffer circuit is connected to the input pin; the output end of the current conversion circuit is connected to the current end lead pin, and the input end is connected to the output end of the input buffer circuit. 3 . The linear constant current drive chip according to claim 1 , wherein if the input pin is used to receive a current signal, the output pin generates a current signal with an equal value. 4 . 4 . The linear constant current driver chip according to claim 1 , wherein if the input pin is used to receive a voltage signal, the output pin generates a voltage signal with an equal value. 5. The linear constant current driver chip according to claim 1, wherein if the input pin is used to receive a logic signal, the output pin generates the same logic signal. 6. A multi-chip parallel LED lighting drive circuit, characterized in that it includes a peripheral circuit, a power supply unit, an LED array, and several linear constant current drive chips as claimed in claim 1; the peripheral circuit is connected to one of the The input pin of the linear constant current driver chip, the output pin of the linear constant current driver chip is sequentially connected to the input pin of the next linear constant current driver chip, and the last linear constant current driver chip The output pin of the LED array is vacant; one end of the LED array is connected to the power supply unit, and the other end is respectively connected to the current terminal pins of the linear constant current driver chip. 7. A multi-chip parallel LED lighting drive circuit according to claim 6, characterized in that: the input pin of the first linear constant current drive chip detects the peripheral terminal signal of the peripheral circuit, And send the signal to all the linear constant current chips, and control the power conversion units in all the linear constant current chips to synchronously control the current flowing through the LED array. 8. A multi-chip parallel LED lighting drive circuit according to claim 6, characterized in that: the linear constant current drive chip has at least one input pin; the output pin of the linear constant current drive chip The pins are sequentially connected to the corresponding input pins on the next linear constant current drive chip. 9. A multi-chip parallel LED lighting drive circuit according to claim 6, characterized in that: said peripheral circuits are partly or completely integrated into any one or more of said linear constant current drive chips.