CN115379616A

CN115379616A - Parallel sequenced light-emitting diode lamp string

Info

Publication number: CN115379616A
Application number: CN202110551027.XA
Authority: CN
Inventors: 彭文琦
Original assignee: Semisilicon Technology Corp
Current assignee: Semisilicon Technology Corp
Priority date: 2021-05-20
Filing date: 2021-05-20
Publication date: 2022-11-22

Abstract

The invention provides a parallel sequenced light-emitting diode lamp string which comprises a plurality of light-emitting diode modules. The light emitting diode modules are connected in parallel through a power line with a plurality of line resistors. Each LED module comprises an impedance element which can provide impedance characteristics. The LED modules connected in parallel receive a power supply, and the power supply makes the voltage generated on the LED modules different in magnitude through the wire resistors and the impedance elements, so as to sequence the LED modules.

Description

Parallel sequenced light-emitting diode lamp string

Technical Field

The present invention relates to a light emitting diode lamp string, and more particularly, to a parallel sequenced light emitting diode lamp string with impedance compensation.

Background

Because light-emitting diodes (LEDs) have the advantages of high light-emitting efficiency, low power consumption, long lifetime, fast response speed, high reliability …, etc., they are widely used in lighting lamps or decorative lighting, such as christmas tree lights, sports shoes lighting effects …, etc., in the form of series, parallel, or series-parallel connections of light bars (light bars) or light strings (light strings).

Taking festive lighting as an example, a complete led lamp basically comprises a led string (having a plurality of lamps) and a driving unit for driving the lamps. The driving unit is electrically connected with the lamp strings, and the lamps are controlled in a point control mode or a synchronous mode by providing required electric power and control signals with light-emitting data, so that diversified light output effects and changes of the light-emitting diode lamp are realized.

In the prior art, in order to drive each led of the led string to emit light in a diversified manner, each led has different address sequence data. Each light emitting diode receives a light emitting signal containing light emitting data and address data: if the address sequence data of the light emitting diode is the same as the address data of the light emitting signal, the light emitting diode emits light according to the light emitting data of the light emitting signal; if the address sequence data of the light emitting diode is not the same as the address data of the light emitting signal, the light emitting diode skips the light emitting data of the light emitting signal.

At present, the sequencing method of each light-emitting diode of the light-emitting diode string is mostly complex or difficult; for example, before the leds are combined into the led string, different address sequence data needs to be burned into each led. And then, the light-emitting diodes are sequentially placed according to address sequence data and combined into the light-emitting diode lamp string. If the light emitting diodes are not sequentially placed in the address order data, the diversified light emission of the light emitting diodes cannot be correctly achieved.

Disclosure of Invention

The invention aims to provide a parallel sequencing light-emitting diode lamp string which has an impedance compensation technology so as to solve the problem of sequencing light-emitting diodes by taking addresses as addresses in the prior art.

To achieve the foregoing objective, the led string with parallel sequencing according to the present invention includes a plurality of led modules. The light emitting diode modules are connected in parallel through a power line with a plurality of line resistors. Each LED module comprises an impedance element which can provide impedance characteristics. The LED modules connected in parallel receive a power supply, and the power supply makes the voltage generated on the LED modules different in magnitude through the wire resistors and the impedance elements, so as to sequence the LED modules.

In an embodiment, the generated voltages are compared with a plurality of voltage ranges to determine the sequence of the light emitting diode modules.

In one embodiment, each of the voltage ranges is established in a look-up table.

In an embodiment, each of the voltage ranges is determined according to a size of the power supply, a number of the light emitting diode modules, a size of the wire resistance, and a size of the impedance element.

In an embodiment, the power supply is a constant voltage source, each of the impedance elements is a controllable resistor with an adjustable resistance, and the resistance of the controllable resistor is designed to be reduced.

In one embodiment, the voltage generated by the front led module is greater than the voltage generated by the rear led module.

In an embodiment, the power supply is a constant current source, each of the impedance elements is a controllable resistor with an adjustable resistance, and the resistance of the controllable resistor is designed to be increased.

In one embodiment, the voltage generated by the front led module is less than the voltage generated by the rear led module.

In one embodiment, the parallel sequenced led light string further comprises a signal generating unit. The signal generating unit provides a sequence of signals; each impedance element is a controllable resistor with adjustable resistance.

In one embodiment, each of the led modules determines an order of the led modules according to a period order of the sequence signal; the power supply is a constant voltage source, and after sequencing of one light emitting diode module is completed, the corresponding impedance element is closed, and the resistance value of the impedance element corresponding to the light emitting diode module which is not sequenced is reduced.

In one embodiment, each of the led modules determines an order of the led modules according to a period order of the sequence signal; the power supply is a constant current source, and after sequencing of one light-emitting diode module is completed, the corresponding impedance element is closed, and the resistance value of the impedance element corresponding to the light-emitting diode module which is not sequenced is increased.

In one embodiment, the parallel sequenced led string further comprises a switch unit. The switch unit is connected in series with the controllable resistor.

In an embodiment, each of the led modules includes a plurality of resistors and a plurality of switch units. Each switch unit is correspondingly connected with each resistor in series.

In one embodiment, the parallel sequenced light emitting diode light string further comprises a compensation unit. The compensation unit is coupled in parallel with the last LED module. The compensation unit comprises a controllable resistor with adjustable resistance.

In one embodiment, the power supply is a constant voltage source; when the light emitting diode modules sequentially sequence, the resistance values of the controllable resistors are sequentially reduced.

In one embodiment, the power supply is a constant current source; when the light emitting diode modules sequentially sequence, the resistance values of the controllable resistors sequentially increase.

The light-emitting diode lamp string with the parallel sequencing provided provides corresponding lookup of the detected voltage through the voltage range information provided by the built-in lookup table, and determines the lamp sequence of the light-emitting diode module according to the difference of the voltage, so that the circuit design can be simplified, the sequencing of the light-emitting diode lamp string can be rapidly completed, and the accuracy of comparison, judgment and identification of the detected voltage and the voltage range of the lookup table can be improved through the controllable resistor with adjustable resistance value or the parallel design of a plurality of resistors or the resistance value adjustment of the compensation unit.

Drawings

FIG. 1A: a circuit diagram of a first embodiment of a parallel sequenced led light string supplying a constant voltage source according to the present invention.

FIG. 1B: a circuit diagram of a first embodiment of a parallel sequenced led light string supplying constant current sources in accordance with the present invention.

FIG. 2A: a circuit diagram of a second embodiment of a parallel sequenced led light string for supplying constant voltage source power in accordance with the present invention.

FIG. 2B: a circuit diagram of a second embodiment of a parallel sequenced led light string supplying constant current sources in accordance with the present invention.

FIG. 3A: a voltage schematic of a first embodiment of a parallel sequenced led light string in accordance with the present invention is shown.

FIG. 3B: a voltage schematic of a second embodiment of the parallel sequenced led light string of the present invention.

FIG. 4: a block diagram of a controllable resistance embodiment of the present invention is shown.

FIG. 5: a circuit block diagram of a multi-resistor embodiment of the present invention is shown.

FIG. 6: a block diagram of a counting operation of the present invention is shown.

In the figure:

10, a power line; 11,12, …,1N, a light emitting diode module;

R _L1 ,R _L2 ,…,R _LN ,R _L1’ ,R _L2’ ,…,R _LN’ wire resistance; r is ₁ ,R ₂ ,....,R _N A resistor;

C ₁ ,C ₂ ,....,C _N parasitic capacitance; v ₁ ,V ₂ ,…,V _N Voltage;

vdc is a power supply; idc is a power supply; r11, R21 and R22 are resistors; q11, Q21, Q22 switching units;

31, a voltage stabilizing unit; 32, an analog-digital conversion unit.

Detailed Description

The present invention is further described with reference to the following drawings and specific examples so that those skilled in the art can better understand the present invention and can practice the present invention, but the examples are not intended to limit the present invention.

FIG. 1A is a circuit diagram of a first embodiment of the constant voltage source powered parallel sequenced LED light string in accordance with the present invention. The parallel sequenced led light string comprises a plurality (N) of led

modules

11,12, …,1N. The

LED modules

11,12, … and 1N are connected in parallel through a power line 10. For the actual line, there is a wire resistance in the power line 10, so the power line 10 has a wire resistanceMain line resistor R _L1 ,R _L2 ,…,R _LN ,R _L1’ ,R _L2’ ,…,R _LN’ . Each

LED module

11,12, …,1N comprises a resistor R ₁ ,R ₂ ,....,R _N And equivalent and corresponding resistance R ₁ ,R ₂ ,....,R _N Parallel parasitic capacitance C ₁ ,C ₂ ,....,C _N That is, the first LED module 11 includes a first resistor R ₁ A first parasitic capacitance C connected in parallel ₁ The second LED module 12 includes a second resistor R ₂ A second parasitic capacitance C connected in parallel ₂ … the Nth LED module 1N includes an Nth resistor R _N With an Nth parasitic capacitance C in parallel _N 。

As shown in fig. 1A, each of the led

modules

11,12, …,1N connected in parallel receives a power supply Vdc. In the embodiment, the power supply Vdc is a constant voltage source (constant voltage source) for providing a voltage source with a constant voltage. The power supply Vdc is connected with the line resistor R through _L1 ,R _L2 ,…,R _LN ,R _L1’ ,R _L2’ ,…,R _LN’ And each resistor R in each

LED module

11,12, …,1N ₁ ,R ₂ ,....,R _N So that the voltage generated on each led

module

11,12, …,1N is different.

During power-up, since the circuits in the led

modules

11,12, …,1N are not yet activated and operated, the led

modules

11,12, …,1N can be equivalent to the corresponding resistors R ₁ ,R ₂ ,....,R _N . Furthermore, for convenience of explanation, the wire resistor R may be used _L1 And line resistance R _L1’ Wire resistance R equivalent to a single wire _L1 Likewise, line resistance R _L2 And line resistance R _L2’ Wire resistance R equivalent to a single wire _L2 … wire resistor R _LN And line resistance R _LN’ Wire resistance R equivalent to a single wire _LN 。

When the power supply is powered on, the power supply Vdc supplies power to the light emitting

diode modules

11,12, … and 1N, and current flows through the resistors R _L1 ,R _L2 ,…,R _LN The voltage difference is that, for the present embodiment, the power supply Vdc of the constant voltage source passes through each resistor R _L1 ,R _L2 ,…,R _LN The voltage difference is a voltage drop, and therefore, the voltage generated on each led

module

11,12, …,1N is different. Referring to FIG. 3A, which is a voltage diagram of the parallel sequenced LED light string according to the first embodiment of the present invention, a first voltage V is applied to the first LED module 11 ₁ Is greater than a second voltage V on the second LED module 12 ₂ The second voltage V ₂ Is greater than a third voltage V on the third LED module 13 ₃ …, and so on, meaning that the voltage generated by the front (upstream) led module is greater than the voltage (V) generated by the rear (downstream) led module ₁ >V ₂ >…>V _N ). Thereby, according to the generated voltage V ₁ ,V ₂ ,…,V _N The sizes of the LED modules are different, and the

LED modules

11,12, … and 1N are sequenced. The following is for the generated voltage V ₁ ,V ₂ ,…,V _N The different sizes and sequencing principles of the led

modules

11,12, …,1N are illustrated.

In one embodiment, the method can be implemented by building a corresponding lookup table (lookup table). For example, a circuit designer may select the number of the led

modules

11,12, …,1N, and the number of the wire resistors R according to the magnitude of the power supply Vdc _L1 ,R _L2 ,…,R _LN And each of the resistances R ₁ ,R ₂ ,....,R _N Pre-establishing said look-up table for the generated voltage V ₁ ,V ₂ ,…,V _N So as to sequence each of the led

modules

11,12, …,1N.

As shown below, an embodiment of the lookup table is described, in which 100 led

modules

11,12, …,1N are taken as an example.

Lamp sequence	Voltage range (volt)
		#1	5.10~4.90
#2	4.90~4.70
		#3	4.70~4.54
#4	4.54~4.38
		#5	4.38~4.26
#6	4.26~4.14
		…	…
#100	2.36~2.32

When the led light string is powered on, the power supply Vdc supplies power to each led

module

11,12, …,1N, so that a first voltage V is generated on the first led module 11 ₁ A second voltage V is generated on the second LED module 12 ₂ … generates the Nth voltage V on the Nth LED module 1N _N . For example, inWhen a certain LED module (e.g. the first LED module 11) obtains a voltage (e.g. the first voltage V) ₁ ) At 5.00 volts, the led modules can be sequenced as a first led module 11 because the voltage is within the voltage range (5.10 to 4.90 volts) of the first lamp (# 1). Similarly, the voltage (e.g. the second voltage V) obtained by a certain LED module (e.g. the second LED module 12) ₂ ) At 4.80 volts, the led modules can be sequenced as the second led module 12 because the voltage is within the voltage range (4.90-4.70 volts) of the second lamp (# 2). Similarly, the voltage (e.g. the sixth voltage V) obtained by a certain LED module (e.g. the sixth LED module 16) ₆ ) At 4.20 volts, the led modules can be sequenced as a sixth led module 16 because the voltage is within the voltage range (4.26-4.14 volts) of the sixth light sequence (# 6).

Therefore, after the LED lamp string is electrified, the voltage V generated by each

LED module

11,12, … and 1N can be detected ₁ ,V ₂ ,…,V _N The voltage range of the built-in lookup table is corresponded to obtain the lamp sequence of each

LED module

11,12, …,1N. The voltage range is not limited by the illustrated voltage value, and may be determined by the size of the power supply Vdc, the number of the led

modules

11,12, …,1N, and the number of the resistors R _L1 ,R _L2 ,…,R _LN Of (an estimated) magnitude of (a), each of the resistances R ₁ ,R ₂ ,....,R _N The size of the voltage range or other parameters of the pre-established lookup table, which can implement the correspondence of the detection voltage, should be included in the scope of the present invention.

FIG. 1B is a circuit diagram of a first embodiment of the constant current source parallel sequenced LED light string according to the present invention. The power supply Vdc may be implemented in a constant current source, that is, in this embodiment, the power supply Idc is a constant current sourcesource) for providing a current source of a constant current magnitude. The power supply Idc passes through each wire resistor R _L1 ,R _L2 ,…,R _LN ,R _L1’ ,R _L2’ ,…,R _LN’ And each resistor R in each

LED module

11,12, …,1N ₁ ,R ₂ ,....,R _N So that the voltage generated on each led

module

11,12, …,1N is different.

During power-up, since the circuits in the led

modules

11,12, …,1N are not yet activated and operated, the led

modules

When the power supply is powered on, the power supply Idc supplies power to each light-emitting

diode module

11,12, … and 1N, and current flows through each wire resistor R _L1 ,R _L2 ,…,R _LN The voltage difference caused is that, for the present embodiment, the power supply Idc of the constant current source passes through each resistor R _L1 ,R _L2 ,…,R _LN The resulting voltage difference is a voltage rise, and therefore, the magnitude of the voltage generated in each of the led

modules

11,12, …,1N is different. Referring to FIG. 3B, which is a voltage diagram of a second embodiment of the parallel sequenced LED light string of the present invention, a first voltage V is applied to the first LED module 11 ₁ Is less than a second voltage V on the second LED module 12 ₂ The second voltage V ₂ Is less than a third voltage V on the third LED module 13 ₃ …, and so on, meaning that the voltage generated by the front (upstream) led module is less than the voltage (V) generated by the rear (downstream) led module ₁ <V ₂ <…<V _N ). Thereby, according to the generated voltage V ₁ ,V ₂ ,…,V _N The

LED modules

11,12, … and 1N are sequenced in different sizes. The following is for the generated voltage V ₁ ,V ₂ ,…,V _N The difference in size and the sequencing principle of the led

modules

11,12, …,1N are illustrated.

modules

11,12, …,1N and the resistors R according to the size of the power supply Idc _L1 ,R _L2 ,…,R _LN And each of the resistances R ₁ ,R ₂ ,....,R _N Pre-establishing said look-up table for the generated voltage V ₁ ,V ₂ ,…,V _N So as to sequence each of the led

modules

11,12, …,1N.

modules

11,12, …,1N are taken as an example.

Lamp sequence	Voltage range (volt)
		#1	2.36~2.32
#2	2.40~2.36
		#3	2.46~2.40
#4	2.52~2.46
		#5	2.60~2.52
#6	2.68~2.60
		…	…
#100	5.10~4.90

When the led light string is powered on, the power supply Idc supplies power to each led

module

11,12, …,1N, so that a first voltage V is generated on the first led module 11 ₁ A second voltage V is generated on the second LED module 12 ₂ … generates the Nth voltage V on the Nth LED module 1N _N . For example, when a certain LED module (e.g. the first LED module 11) obtains a voltage (e.g. the first voltage V) ₁ ) At 2.34 volts, the led module can be sequenced as the first led module 11 because the voltage is within the voltage range (2.36-2.32 volts) of the first lamp (# 1). Similarly, the voltage (e.g. the second voltage V) obtained by a certain LED module (e.g. the second LED module 12) ₂ ) At 2.38 volts, the led modules can be sequenced as the second led module 12 because the voltage is within the voltage range (2.40-2.36 volts) of the second lamp (# 2). Similarly, the voltage (e.g. the sixth voltage V) obtained by a certain LED module (e.g. the sixth LED module 16) ₆ ) At 2.64 volts, the led modules can be sequenced as a sixth led module 16 because the voltage is within the voltage range (2.68-2.60 volts) of the sixth light sequence (# 6).

Therefore, after the LED lamp string is electrified, the voltage V generated by detecting each

LED module

11,12, …,1N. The voltage range is not limited by the illustrated voltage value, and may be determined according to the magnitude of the power supply Idc, the number of the led

modules

11,12, …,1N, and the number of the resistors R _L1 ,R _L2 ,…,R _LN Of the resistance R, the magnitude of each of the resistances R ₁ ,R ₂ ,....,R _N The size of the voltage range or other parameters of the pre-established lookup table, which can implement the correspondence of the detection voltage, should be included in the scope of the present invention.

In the first embodiment (i.e. the power supply manner of the constant voltage source) shown in fig. 1A, in order to improve the accuracy of comparing, determining and identifying the detected voltage with the voltage range of the lookup table, each resistor R in each led

module

11,12, …,1N is used ₁ ,R ₂ ,....,R _N Can be a controllable resistor with adjustable resistance. Moreover, when the

LED modules

11,12, … and 1N are sequenced during power-up, each controllable resistor (i.e. each resistor R) can be used ₁ ,R ₂ ,....,R _N ) Is designed to be the minimum value so as to flow through each of the resistors R ₁ ,R ₂ ,....,R _N So that the voltage V generated at each led

module

11,12, …,1N is the maximum ₁ ,V ₂ ,…,V _N The voltage range of the lookup table can be maximized, so that the comparison, judgment and identification accuracy of the detected voltage and the voltage range of the lookup table can be improved.

Furthermore, in circuit applications, due to the power supply Vdc providing a constant voltage source, and due to the equivalent resistance effect, the current flowing in the following direction is smaller, resulting in a smaller voltage difference between the two light emitting diode modules in the following direction. Referring to FIG. 3A, for example, a first voltage V is generated at a first LED module ₁ And a second voltage V generated on the second LED module ₂ Will be greater than the second voltage V ₂ And a third voltage V generated on the third LED module ₃ Voltage difference of (i.e., V) ₃ -V ₂ <V ₂ -V ₁ ) Moreover, the voltage difference between the two light emitting diode modules at the later stage is smaller. Incidentally, as shown in fig. 1B and fig. 3B, for the power supply Idc providing a constant current source, the circuit effect is similar to that of the power supply Vdc providing a constant voltage source, but the effect is opposite, so that the operation principle of the power supply Vdc providing a constant voltage source can be applied to the power supply Idc providing a constant current source, and will not be described again, and the operation principle of the power supply Vdc providing a constant voltage source is described below.

Therefore, in order to avoid the accuracy reduction of the comparison, judgment and identification of the detected voltage and the voltage range of the lookup table, which is caused by the smaller voltage difference between the light-emitting diode modules at the later stage, the light-emitting diode lamp string with the parallel sequencing of the invention adjusts the resistors R ₁ ,R ₂ ,....,R _N The resistance value of the light emitting diode module is kept consistent, so that the voltage difference between the Ren Liangfa light emitting diode modules is kept fixed, and the comparison, judgment and identification accuracy of the detected voltage and the voltage range of the lookup table is improved. The adopted mode is to adjust each resistor R in a matching way through a sequence of signals ₁ ,R ₂ ,....,R _N The resistance value of (2) is achieved. The concrete description is as follows.

The sequence signal is a pulse signal, i.e. a signal with alternating high and low levels, and each high level (or low level) can be used as the basis for the sequence. That is, the first cycle can be considered a first order, the second cycle can be considered a second order …, and so on.

Therefore, when first powered up, because each of the resistors R ₁ ,R ₂ ,....,R _N Since the resistance value is the smallest, the current flowing through the resistor is the largest. A first sequence in which said pulse signal is obtained(first period) corresponding first voltage V ₁ Size.

When the first power-on is finished, the first resistor R can be used ₁ Turning off, e.g. by turning off, said first resistor R ₁ Is adjusted to a relatively large value, like an open circuit, for the current flowing through the first resistor R ₁ Or by connecting said first resistor R in series ₁ Is turned off so as to flow through the first resistor R ₁ Is zero, and the second resistor R of the second LED module 12 is connected to the first resistor R ₂ The resistance of the resistor (e.g., the 100 th resistor) to the last led module, i.e., the remaining 99 resistors, is reduced, for example, but not limited to 1/100 of the original resistance. Therefore, the resistance values of the remaining resistors are all reduced, so that the equivalent resistance values after parallel connection are the same, and the flowing currents are the same. When the power is turned on again, a second voltage V corresponding to a second sequence (a second period) of the pulse signal can be obtained ₂ Size.

Similarly, when the second power-up is finished, the first resistor R can be used ₁ And a second resistor R ₂ Are all turned off, e.g. by turning off the first resistor R ₁ And a second resistor R ₂ Is adjusted to a relatively large value, like an open circuit, for the current flowing through the first resistor R ₁ And a second resistor R ₂ Is close to zero, and the third resistor R of the third led module 12 is connected to the first resistor R ₃ The resistance of the resistor (e.g., the 100 th resistor) to the last led module, i.e., the remaining 98 resistors, is reduced, for example, but not limited to 1/100 of the previous resistance. Therefore, the resistance values of the remaining resistors are all reduced, so that the equivalent resistance values after parallel connection are the same, and the flowing currents are the same. When the power is turned on again, a third voltage V corresponding to a third sequence (a third period) of the pulse signal can be obtained ₃ Size. Therefore, the current can be kept consistent by taking the sequence signal as the basis of the sequence and matching with the mode of adjusting (reducing) the resistance value of the residual resistor, so that the voltage difference between the Ren Liangfa photodiode modules is kept constant,so as to improve the accuracy of comparison, judgment and identification of the detected voltage and the voltage range of the lookup table.

Compared with the constant voltage power supply of fig. 1A, the impedance compensation of the constant current power supply of fig. 1B increases the resistance values of the remaining resistors, so that the equivalent resistance value after parallel connection is increased, and thus the flowing current is reduced. Therefore, the current can be kept consistent by taking the sequence signal as the basis of the sequence and matching with the mode of adjusting (increasing) the resistance value of the residual resistor, so that the voltage difference between the Ren Liangfa photodiode modules is kept fixed, and the accuracy of comparison, judgment and identification of the detected voltage and the voltage range of the lookup table is improved.

Fig. 2A and 2B are a circuit diagram of a second embodiment of the constant-voltage-source-powered parallel-sequenced led light string according to the present invention and a circuit diagram of a second embodiment of the constant-current-source-powered parallel-sequenced led light string according to the present invention, respectively. For convenience of description, fig. 2A and fig. 3A providing a constant voltage source are also taken as examples, and the power supply Idc providing a constant current source can be applied to fig. 2B, which will not be described again, and only the operation principle of the power supply Vdc providing a constant voltage source is described as follows.

The biggest difference between the led string shown in fig. 2A and the led string shown in fig. 1A is that: in the led string of fig. 2A, the resistance value of each led

module

11,12, …,1N does not have the controllable characteristic as in fig. 1A, i.e., to achieve the effect of resistance value compensation, the led string of fig. 2A further includes a compensation unit 20 for replacing the controllable adjustment of the resistance value of each led

module

11,12, …,1N in fig. 1A. In other words, the compensation method with adjustable resistance (i.e. controllable resistance) implemented in fig. 1A and 1B is implemented by the compensation unit 20, so that not only the circuit control is simplified, but also the circuit cost is saved. Wherein the compensation unit 20 is an Integrated Circuit (IC) having a counting function, or the compensation unit 20 is a circuit formed by a digital ratio circuit and a digital circuit having a counting function.

When first powered on, because ofThe resistor R ₁ ,R ₂ ,....,R _N Since the resistance value is the smallest, the current flowing through the resistor is the largest. The first voltage V corresponding to the first sequence (the first period) of the pulse signal can be obtained ₁ Size.

When the first power-on is finished, the first resistor R can be used ₁ And the impedance of the compensation unit 20 is reduced (i.e. the impedance compensation of the compensation unit 20) so that the equivalent resistance values after parallel connection are the same, and thus the currents flowing through the compensation unit are the same. When the power is turned on again, a second voltage V corresponding to a second sequence (a second period) of the pulse signal can be obtained ₂ Size.

Similarly, when the second power-up is finished, the first resistor R can be used ₁ And a second resistor R ₂ All are turned off, and the impedance of the compensation unit 20 is controlled to be reduced again so that the equivalent resistance values after being connected in parallel are the same, i.e. the first resistor R ₁ And a second resistor R ₂ The impedance of the compensation unit 20 is smaller than that of the first resistor R only when both are turned off ₁ The impedance at the time of turning off (i.e., the impedance compensation of the compensation unit 20) can be such that the same current flows. When the power is turned on again, a third voltage V corresponding to a third sequence (a third period) of the pulse signal can be obtained ₃ Size. Therefore, the current can be kept consistent by taking the sequence signal as the basis of the sequence and matching with the adjustment (reduction) of the impedance of the compensation unit 20, so that the voltage difference between the Ren Liangfa photodiode modules is kept constant, and the accuracy of the detected voltage identification is improved.

Compared to the constant voltage power supply of fig. 2A, the impedance compensation of the constant current power supply of fig. 2B is implemented by increasing the resistance of the compensation unit 20, so that the equivalent resistance after parallel connection is increased, and thus the flowing current is decreased. Therefore, the current can be maintained to be consistent by using the sequence signal as the basis of the sequence and matching with the way of adjusting (increasing) the resistance value of the compensation unit 20, so that the voltage difference between the Ren Liangfa photodiode modules is maintained to be fixed, and the accuracy of the detected voltage identification is improved.

Please refer to the drawingsFIG. 4 is a block diagram of a controllable resistance implementation of the present invention. The resistor R of each

LED module

11,12, … and 1N is used as the resistor ₁ ,R ₂ ,....,R _N May be a controllable resistor R11 with an adjustable resistance. Furthermore, the controllable resistor R11 is connected in series with a switching unit Q11, such as but not limited to a transistor switch. Therefore, by adjusting the resistance of the controllable resistor R11 to a reduced value, particularly when designed to be a minimum value, the current flowing through each controllable resistor R11 is maximized, so that the voltage V generated on each led

module

11,12, …,1N is increased ₁ ,V ₂ ,…,V _N The current can be the maximum value, so that the comparison, judgment and identification accuracy of the detected voltage and the voltage range of the lookup table can be improved, or the resistance value of the controllable resistor R11 can be adjusted to a large value, or the switch unit Q11 is turned off, so that the current flowing through the controllable resistor R11 approaches zero or equals zero, the current is kept consistent, the voltage difference between the Ren Liangfa optical diode modules is kept constant, and the comparison, judgment and identification accuracy of the detected voltage and the voltage range of the lookup table is improved.

Fig. 5 is a block diagram of a multi-resistor embodiment of the present invention. Compared with the controllable resistor with adjustable resistance shown in fig. 4, the present invention can also achieve different resistance designs by connecting two resistors (shown as two resistors R21, R22) in parallel. Each of the resistors R21 and R22 is connected in series with a corresponding one of the switching units Q21 and Q22, i.e., the resistor R21 is connected in series with the switching unit Q21, and the resistor R22 is connected in series with the switching unit Q22. Taking the two resistors R21, R22 and the two switch units Q21, Q22 as an example, if a smaller resistance value is to be generated, the resistors R21, R22 can be connected in parallel by turning on the switch units Q21, Q22. If a larger resistance is required, the open circuit state can be achieved by turning off at least one of the switching units Q21, Q22, or even both of the switching units Q21, Q22. Therefore, the comparison, judgment and identification accuracy of the detected voltage and the voltage range of the lookup table can be improved, the current is kept consistent, the voltage difference between the Ren Liangfa photodiode modules is kept fixed, and the comparison, judgment and identification accuracy of the detected voltage and the voltage range of the lookup table is improved. In addition, a voltage stabilizing unit 31 and an analog-to-digital conversion unit 32 are also included. The voltage stabilizing unit 31 is coupled in parallel to each of the resistors R21 and R22 and each of the switching units Q21 and Q22, and is used for providing a voltage stabilizing operation. The analog-to-digital conversion unit 32 is coupled to the voltage stabilization unit 31 for providing an operation of converting an analog signal into a digital signal.

Fig. 6 is a block diagram of a circuit for counting operation according to the present invention, and a block diagram of a compensation unit for implementing a compensation method with adjustable resistance (i.e. controllable resistance).

In summary, the present invention has the following features and advantages:

1. the voltage range information provided by the built-in lookup table provides corresponding lookup of the detection voltage, and the light sequence of the light-emitting diode module is determined according to the difference of the voltage, so that the circuit design can be simplified, and the sequencing of the light-emitting diode light string can be completed quickly.

2. By using the controllable resistor with adjustable resistance or the parallel design of several resistors or the resistance adjustment of the compensation unit 20, the accuracy of comparing, judging and identifying the detected voltage and the voltage range of the lookup table can be improved.

The above-mentioned embodiments are merely preferred embodiments for fully illustrating the present invention, and the scope of the present invention is not limited thereto. The equivalent substitution or change made by the technical personnel in the technical field on the basis of the invention is all within the protection scope of the invention. The protection scope of the invention is subject to the claims.

Claims

1. A parallel sequenced light emitting diode light string comprising:

the LED modules are connected in parallel through a power line with a plurality of line resistors, and each LED module comprises an impedance element capable of providing impedance characteristics;

the LED modules connected in parallel receive a power supply, and the power supply makes the voltages generated on the LED modules different in magnitude through the wire resistors and the impedance elements, so as to sequence the LED modules.

2. The parallel sequenced led light string of claim 1 wherein each of said generated voltage levels is compared to a plurality of voltage ranges to determine the sequence of each of said led modules.

3. The parallel sequenced led light string of claim 2 wherein each of said voltage ranges is established in a look-up table.

4. The parallel sequenced led light string of claim 2 wherein each of said voltage ranges is determined by the size of said power supply, the number of said led modules, the size of said wire resistors, and the size of said impedance elements.

5. The parallel sequenced led light string of claim 1 wherein said power supply is a constant voltage source;

each impedance element is a controllable resistor with adjustable resistance value, and the resistance value of the controllable resistor is designed in a reducing way.

6. The parallel sequenced led light string of claim 5 wherein the voltage generated by a preceding led module is greater than the voltage generated by a subsequent led module.

7. The parallel sequenced led light string of claim 1 wherein said power supply is a source of current;

each impedance element is a controllable resistor with adjustable resistance value, and the resistance value of the controllable resistor is designed to be increased.

8. The parallel sequenced led light string of claim 7 wherein the voltage generated by a preceding led module is less than the voltage generated by a following led module.

9. The parallel sequenced led light string as described in claim 1 further comprising:

a signal generating unit for providing a sequence signal;

wherein each impedance element is a controllable resistor with adjustable resistance.

10. The parallel sequenced led light string of claim 9 wherein each of said led modules sequences according to a periodic sequence of said sequence signal; the power supply is a certain voltage source, and when sequencing of one light-emitting diode module is completed, the corresponding impedance element is closed, and the resistance value of the impedance element corresponding to the light-emitting diode module which is not sequenced is reduced.

11. The parallel sequenced led light string of claim 9 wherein each of said led modules sequences according to a periodic sequence of said sequence signal; the power supply is a certain current source, and after sequencing of one light-emitting diode module is completed, the corresponding impedance element is closed, and the resistance value of the impedance element corresponding to the light-emitting diode module which is not sequenced is increased.

12. The parallel sequenced led light string of claim 9 further comprising:

and the switching unit is connected in series with the controllable resistor.

13. The parallel sequenced led light string of claim 1 wherein each of said led modules comprises:

a plurality of resistors; and

and the switch units are correspondingly connected in series with the resistors.

14. The parallel sequenced led light string as described in claim 1 further comprising:

a compensation unit coupled in parallel with the last LED module;

wherein, the compensation unit comprises a controllable resistor with adjustable resistance.

15. The parallel sequenced led light string of claim 14 wherein said power supply is a constant voltage source;

when the light emitting diode modules are sequenced in sequence, the resistance values of the controllable resistors are reduced in sequence.

16. The parallel sequenced light-emitting diode light string as described in claim 14 wherein said power supply is a constant current source;

when the light emitting diode modules are sequenced in sequence, the resistance value of the controllable resistor is increased in sequence.