Control circuit, multiple LED switching circuits and LED driver chips

Abstract

The present invention discloses a control circuit, a multi-group LED switching circuit, and an LED driver chip. The multi-group LED switching circuit includes a control circuit; M LED unit groups, each LED unit group including N LED segments connected in series: a first LED segment, ..., an N-1th LED segment, and an Nth LED segment, each LED unit group having a positive polarity terminal of the first LED segment and a negative polarity terminal of the Nth LED segment; and a switching circuit, wherein an AC signal is configured as an input between one end and the first end, and the other end can be selectively connected to the first end of one of the M LED unit groups. The present invention uses the switching circuit to enable multiple LED unit groups to share a single driver circuit, saving space, facilitating wiring, and reducing costs. A diode connected in series between the LED and a linear current source blocks the discharge circuit, achieving complete switching of multiple LED groups.

Description

[0001] This application claims priority to Chinese patent application CN201910832321.0, filed on September 4, 2019. Technical Field

[0002] The present invention belongs to the field of LED (light emitting diode) lighting, and in particular relates to a control circuit, multiple groups of LED switching circuits and an LED driver chip. Background Art

[0003] Multi-segment linear constant current drive solutions are widely used in LED lighting products. Typically, in linear constant current LED lighting devices, the linear constant current drive circuit components and grouped LEDs are soldered to an aluminum plate. Lamps with multiple color switching functions require separate drive circuits for each group of LEDs. This occupies a large area on the aluminum plate, greatly increases wiring complexity, and further increases circuit costs. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a multi-group LED switching circuit in order to overcome the defects of the prior art that one group of LED units requires one driving circuit, which causes large space occupation, great wiring difficulty and increased cost.

[0005] The present invention solves the above technical problems through the following technical solutions:

[0006] A control circuit for driving M LED unit groups, each LED unit group including N LED segments connected in series: a first LED segment, ..., an N-1th LED segment, and an Nth LED segment. Each LED unit group has a positive polarity terminal of the first LED segment at its first end and a negative polarity terminal of the Nth LED segment at its last end. The control circuit includes:

[0007] N linear current sources are provided corresponding to the N LED segments, namely: a first linear current source, ..., an N-1th linear current source, and an Nth linear current source, each linear current source having a first end and a second end, the first end of each linear current source being connected to each other, and the second end of the Nth linear current source being connected to the ends of the M LED unit groups; and

[0008] N-1 groups of diode groups correspond to the first linear current source, ..., the N-1th linear current source, each diode group includes M first diodes, the negative polarity ends of the M first diodes are connected to the second end of the linear current source corresponding to the diode group in which they are located, and the positive polarity ends of the M first diodes are configured to be respectively connected to the negative polarity ends of the M LED segments corresponding to the linear current source, where M and N are both integers, M≥2, N≥2.

[0009] A multi-group LED switching circuit, comprising the above-mentioned control circuit;

[0010] M LED unit groups, each LED unit group including N LED segments connected in series: a first LED segment, ..., an N-1th LED segment, and an Nth LED segment, with a first end of each LED unit group being the positive polarity end of the first LED segment and a terminal end being the negative polarity end of the Nth LED segment; and

[0011] The switch circuit has an AC signal configured as an input between one end and the first end, and the other end can be selectively connected to the first end of one of the M LED unit groups.

[0012] Optionally, the switch switching circuit includes:

[0013] a stationary contact, an AC signal being configured as an input between the stationary contact and the first end;

[0014] M moving contacts, connected to the head ends of the M LED unit groups respectively; and

[0015] The common terminal has one end connected to the static contact and the other end capable of being selectively connected to one of the M moving contacts.

[0016] Optionally, the switch switching circuit further includes:

[0017] A hybrid moving contact capable of selectively connecting to the stationary contact via a common terminal; and

[0018] The M second diodes have negative polarity ends connected to the hybrid movable contacts, and positive polarity ends connected to the M movable contacts respectively.

[0019] Optionally, it also includes:

[0020] The switch control logic circuit is connected to the switch switching circuit and is used to control the switching of the common end.

[0021] Optionally, the switch control logic circuit includes:

[0022] The signal generator has a single or multiple output terminals and is used to generate a signal for controlling the switch on time of the M LED unit groups.

[0023] Optionally, it further includes: a rectifier circuit for processing the AC signal into a DC signal and outputting it, the input end of the rectifier circuit is configured to receive the AC signal, and the output end of the rectifier circuit is respectively connected to the switch switching circuit and the common end.

[0024] Optionally, the switch switching circuit is any one of a mechanical switch, a remote control switch, and a touch switch, or a combination thereof.

[0025] The present invention also provides an LED driver chip integrated with the above control circuit.

[0026] On the basis of conforming to the common sense in this field, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0027] The positive and progressive effects of the present invention are as follows: the LED unit groups are switched through the switch switching circuit so that multiple LED unit groups share a driving circuit, which greatly saves the space occupied by the aluminum plate, reduces the wiring difficulty and the circuit cost; the diodes connected in series between the negative electrode of the LED in the LED unit group and the positive electrode of the linear current source block the discharge circuit, so that the LEDs in the LED unit group with the disconnected positive electrode have no current flowing through them and do not light up, thereby achieving complete switching of multiple groups of LEDs; further, multiple LED unit groups are connected by multiple diodes with a common anode connected by hybrid moving contacts, thereby achieving a mixed color light effect of the multiple LED unit groups, while not affecting the grouping control function of the multiple LED unit groups, thereby achieving multiple functional combinations of the multiple LED unit groups, while not affecting each other; further, the common end of the switch switching circuit is controlled by a switch control logic circuit, thereby achieving mixed color light effects of different proportions of the multiple LED unit groups. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0029] Figure 1 Schematic diagram of a circuit for switching multiple LED groups according to embodiment 1 of the present invention.

[0030] Figure 2 Schematic diagram of a circuit for switching multiple LED groups with light mixing effect according to embodiment 2 of the present invention.

[0031] Figure 3 2 is a circuit diagram of multiple groups of LED switching circuits with mixed color light effects in different proportions according to embodiment 3 of the present invention. DETAILED DESCRIPTION

[0032] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples.

[0033] Example 1

[0034] This embodiment provides a multi-group LED switching circuit powered by a rectifier circuit BD1, including three LED unit groups. The first LED unit group includes LED segments 11, 12, ..., and 1N. The second LED unit group includes LED segments 21, 22, ..., and 2N. The third LED unit group includes LED segments 31, 32, ..., and 3N.

[0035] The number of series-connected LEDs in each segment only needs to meet the design requirements of the LED driver chip IC1 (each vendor's LED driver chip has a recommended ratio for the LED segment string ratio used to meet parameters such as harmonics and surges).

[0036] A control circuit 01 is configured to drive three LED unit groups, and includes three linear current sources, each provided corresponding to the N LED segments, namely: a first linear current source I1, ..., an N-1th linear current source IN-1, and an Nth linear current source IN. Each linear current source has a first end and a second end, respectively. The first ends of each linear current source are connected to one another, and the second end of the Nth linear current source IN-1 is connected to terminals of the three LED unit groups.

[0037] N-1 diode groups, corresponding to the first linear current source I1, ..., and the N-1th linear current source IN-1, each diode group including three first diodes, the negative polarity ends of the three first diodes being connected to the second end of the linear current source corresponding to the diode group, and the positive polarity ends of the three first diodes being configured to be respectively connected to the negative polarity ends of the three LED segments corresponding to the linear current source; and

[0038] The switch circuit SW has an AC signal as an input configured between one end and the first end, and the other end can be selectively connected to the first end of one of the three LED unit groups.

[0039] Specifically, refer to Figure 1 The diode group corresponding to the first linear current source I1 includes a first diode D11, a first diode D12, and a first diode D13. The anodes of the diodes are connected to the negative terminals of LED segments 11, 21, and 31, respectively. The cathodes of the diodes D11, D12, and D13 are all connected to the positive terminal of the first linear current source I1. The diode group corresponding to the (N-1)th linear current source IN-1 includes a first diode DN-1,1, a first diode DN-1,2, and a first diode DN-1,3. The connection relationship between the diodes can be inferred from that of the diodes corresponding to the first linear current source I1 and is not further described here.

[0040] Wherein, N is an integer greater than 1.

[0041] It should be noted that, in this embodiment, three LED unit groups are used as an example. In other embodiments not shown, the LED unit groups may also be two groups, four groups, or more groups, which will not be repeated here.

[0042] The input of rectifier circuit BD1 is connected to a power supply, converting it into direct current. The positive output of rectifier circuit BD1 is connected to the common terminal of switching circuit SW. Switching circuit SW has several movable contacts connected to the positive terminals of each LED unit group, enabling switching between them.

[0043] like Figure 1 As shown, when the common terminal of the switching circuit SW is switched to be connected to the movable contact a, the first LED unit group is connected to the power supply, and LED segments 11, LED segments 12...LED segments 1N are controlled by linear current sources I1, I2...IN, respectively, and the LEDs in each LED segment in the first LED unit group are all illuminated. At this time, the first diodes D12, D22...DN-1,2 connected in series between the cathode of the last LED in each LED segment of the second LED unit group and the linear current source block the discharge circuit of each LED segment in the first LED unit group, so that the anode of the first LED in each LED segment of the second LED unit group has no voltage. Therefore, no current flows through the LEDs in each segment of the second LED unit group and they will not light up. Similarly, the LEDs in the third LED unit group will not light up either. Similarly, when the common end of the switch switching circuit SW1 is switched to be connected to the moving contact b, the LEDs in the second LED unit group are all lit, while the LEDs in the first LED unit group and the third LED unit group have no current flowing through them and will not light up. This enables multiple groups of LEDs to share one driver chip, while at the same time allowing each LED unit group to be completely switched without affecting each other, thereby enabling free switching of each group of monochromatic light.

[0044] This embodiment switches the LED unit groups through a switch switching circuit so that multiple LED unit groups share a driving circuit, which greatly saves the space occupied by the aluminum plate, reduces the wiring difficulty and circuit cost; the diode connected in series between the negative electrode of the LED in the LED unit group and the positive electrode of the linear current source blocks the discharge circuit, so that the LED in the LED unit group with the disconnected positive electrode has no current flowing through it and does not light up, thereby realizing complete switching of multiple LED unit groups.

[0045] This embodiment also provides an LED driver chip integrated with the above-mentioned control circuit 01.

[0046] Example 2

[0047] This embodiment is based on the embodiment 1, and adds a mixed color light lighting circuit. Figure 2 As shown, based on the circuit schematic diagram of Example 1, the switch switching circuit SW further includes a hybrid moving contact d and a plurality of second diodes (this embodiment is also exemplified by three groups of LED unit groups, so there are second diodes D1, D2 and D3), the anodes of the second diodes D1, D2 and D3 are connected together and connected to the hybrid moving contact d, and the cathodes of the second diodes D1, D2 and D3 are connected to the anodes of the first, second and third LED unit groups, respectively.

[0048] When the common end of the switch circuit SW is switched to be connected to the hybrid contact d, the first, second and third LED unit groups are connected to the power supply through the forward-conducting second diodes D1, D2 and D3. The linear current sources I1, I2...IN of the LED driver chip IC1 provide current to the LEDs of each segment. Current flows through each LED in the first, second and third LED unit groups and they are all illuminated. That is, LEDs of different color temperatures are illuminated together, producing a mixed-color light effect.

[0049] When the common terminal of the switch switching circuit SW is switched to another movable contact (such as a, b, or c, movable contact a is used as an example here), only the first LED unit group connected to movable contact a connected to the common terminal is connected to the power supply, lighting the LEDs in each segment of the first LED unit group, and emitting monochromatic light of a certain color temperature. At this time, although the second LED unit group is connected to the first LED unit group through the second diode D2, the second diode D2 is reverse-blocked relative to the second LED unit group. The current flowing through the first LED unit group cannot flow into the second LED unit group through the second diode D2. The LEDs in each segment of the second LED unit group have no current flowing through them and cannot be illuminated. Similarly, the LEDs in each segment of the third LED unit group cannot be illuminated. When the common terminal of the switch switching circuit SW is switched to another movable contact, the second diodes D1, D2, and D3 also play an isolating role, and the circuit presents a monochromatic light effect.

[0050] Based on Example 1, this embodiment realizes the mixed color light effect of multiple LED unit groups by connecting multiple diodes with common anodes through hybrid moving contacts, while not affecting the grouping control function of the multiple LED unit groups, and realizing multiple functional combinations of the multiple LED unit groups without affecting each other.

[0051] Example 3

[0052] This embodiment achieves mixed color light effects with different proportions based on the embodiment 1. Figure 3As shown, based on the circuit schematic diagram of Example 1, the multiple LED switching circuits further include a switch control logic circuit for controlling the switching of the common end of the switch switching circuit; the switch control logic circuit includes a single-channel or multi-channel output signal generator for generating a signal to control the switch on time of several LED unit groups.

[0053] The switch switching circuit here may include multiple common terminals, and the single-channel or multi-channel signal generator in the switch control logic circuit outputs a single-channel or multi-channel signal for controlling each common terminal of the switch switching circuit to switch between different moving contacts according to different time proportions. Within a certain period of time, the signal controls the switch on time of each group of LED units to be different, and the lighting time of each group of light colors is different, so that several groups of LED units obtain different proportions of power, thereby obtaining various random or manually set color temperatures, forming different light color mixtures, and producing mixed color light effects with different proportions.

[0054] Based on Example 1, this embodiment controls the common end of the switch switching circuit through a switch control logic circuit, controls the switch on time of each LED unit group so that the lighting time of each group of light color LEDs is different, and realizes the mixed color light effect of different proportions of multiple LED unit groups.

[0055] Although specific embodiments of the present invention have been described above, those skilled in the art will appreciate that these are merely illustrative and that the scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, and such changes and modifications are intended to fall within the scope of the present invention.

Claims

1. A control circuit for driving M LED unit groups, each LED unit group comprising N LED segments connected in series: a first LED segment, ..., an N-1th LED segment, and an Nth LED segment, wherein the first end of each LED unit group is the positive polarity end of the first LED segment, and the last end is the negative polarity end of the Nth LED segment, characterized in that: include: N linear current sources are provided corresponding to the N LED segments, namely: a first linear current source, ..., an N-1th linear current source, and an Nth linear current source, each linear current source having a first end and a second end, respectively, the first end of each linear current source being connected to each other, and the second end of the Nth linear current source being connected to the ends of the M LED unit groups; and N-1 groups of diode groups corresponding to the first linear current source, ..., and the N-1th linear current source, each diode group including M first diodes, the negative polarity ends of the M first diodes being connected to the second end of the linear current source corresponding to the diode group in which they are located, and the positive polarity ends of the M first diodes being configured to be respectively connected to the negative polarity ends of the M LED segments corresponding to the linear current source, M and N being integers, M ≥ 2, N ≥ 2, and the control circuit being configured to control the LED unit group whose head end is connected to the power supply to be illuminated.

2. A multi-group LED switching circuit, characterized in that: The control circuit of claim 1 comprises: M LED unit groups, each LED unit group comprising N LED segments connected in series: a first LED segment, ..., an N-1th LED segment, and an Nth LED segment; a first end of each LED unit group being a positive polarity end of the first LED segment, and a terminal end being a negative polarity end of the Nth LED segment; and a switch circuit, wherein an AC signal is configured as an input between one end and the first end, and the other end can be selectively connected to the head end of one of the M LED unit groups.

3. The multi-group LED switching circuit according to claim 2, wherein: The switch switching circuit includes: a static contact, an AC signal configured as an input between the static contact and the first end; M moving contacts, respectively connected to the head ends of the M LED unit groups; and a common end, one end of which is connected to the static contact and the other end can be selectively connected to one of the M moving contacts.

4. The multi-group LED switching circuit according to claim 3, wherein: The switch switching circuit also includes: a hybrid moving contact, which can be selectively connected to the static contact via the common end; and M second diodes, each having a negative polarity end connected to the hybrid moving contact and a positive polarity end connected to each of the M moving contacts.

5. The multi-group LED switching circuit according to claim 3, wherein: Also includes: A switch control logic circuit is connected to the switch switching circuit and is used to control the switching of the common end.

6. The multi-group LED switching circuit according to claim 5, wherein: The switch control logic circuit includes: a signal generator having a single-channel or multi-channel output terminal, which is used to generate a signal for controlling the switch on time of the M LED unit groups.

7. The multi-group LED switching circuit according to any one of claims 3 to 6, wherein: Also includes: The rectifier circuit is used to process the AC signal into a DC signal and output the DC signal. The input end of the rectifier circuit is configured to receive the AC signal, and the output end of the rectifier circuit is respectively connected to the switch circuit and the common end.

8. The multi-group LED switching circuit according to any one of claims 2 to 6, wherein: The switch switching circuit is any one of a mechanical switch, a remote control switch, and a touch switch, or a combination thereof.

9. An LED driver chip, characterized in that: The control circuit according to claim 1 is integrated.

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