DC-DC double-color-temperature driving circuit

Abstract

The utility model discloses a DC-DC double-color-temperature driving circuit which comprises three input interfaces V +, V1-and V2-, a first constant current circuit, a second constant current circuit, three output interfaces LED +, LED 1-and LED 2-, a first grounding point and a second grounding point. The interface V + is electrically connected with an interface LED +, the interface V1-is electrically connected with a first grounding point, the first grounding point is electrically connected with a first constant current circuit, and the first constant current circuit is electrically connected with an interface LED 1-; the interface V2-is electrically connected with a second grounding point, the second grounding point is electrically connected with a second constant current circuit, and the second constant current circuit is electrically connected with an interface LED2-; the first constant current circuit and the second constant current circuit are electrically connected with an interface V +. According to the DC-DC double-color-temperature driving circuit of the utility model, extra space required by dialing is avoided, the size is reduced, and the space is saved; and poor contact easily caused by dial-up is also avoided.

Description

Technical Field

[0001] This utility model relates to the field of LED driver circuit technology, and in particular to a DC-DC dual color temperature driver circuit. Background Technology

[0002] A dual-color temperature lamp is a type of lamp that can emit light with two different color temperatures; it has two different light emission modes and can switch between or emit warm and cool light simultaneously.

[0003] Most color temperature adjustment circuits use multi-switch circuits to light up two LEDs with different color temperatures. These circuits use many electrical components and are relatively large, which is not conducive to miniaturizing the driver. At the same time, direct color temperature adjustment at the circuit input is compared with using DIP switches, which requires DIP switches, takes up space, and are prone to poor contact. Utility Model Content

[0004] The purpose of this invention is to provide a DC-DC dual-color temperature driving circuit, which simplifies the LED switching circuit, uses fewer electronic components, is small in size, saves space, and is easy to carry; it is also easy to repair in case of functional failure.

[0005] The above-mentioned technical objective of this utility model is achieved through the following technical solution: a DC-DC dual-color temperature driving circuit, comprising: three input interfaces V+, V1- and V2-, a first constant current circuit, a second constant current circuit, and three output interfaces LED+, LED1- and LED2-, a first ground point and a second ground point; the V+ interface is electrically connected to the LED+ interface, the V1- interface is electrically connected to the first ground point, the first ground point is electrically connected to the first constant current circuit, and the first constant current circuit is electrically connected to the LED1- interface; the V2- interface is electrically connected to the second ground point, the second ground point is electrically connected to the second constant current circuit, and the second constant current circuit is electrically connected to the LED2- interface; the first constant current circuit and the second constant current circuit are respectively electrically connected to the V+ interface.

[0006] The present invention is further configured to include diodes D1 and D2, with the positive terminal of diode D1 connected to interface V+, the negative terminal of diode D1 connected to interface V2-, the positive terminal of diode D2 connected to interface V+, and the negative terminal of diode D2 connected to interface V1-.

[0007] A further feature of this invention is that it also includes an electrolytic capacitor CE1 and an electrolytic capacitor CE2, wherein the electrolytic capacitor CE1 is connected in parallel with the diode D2, and the electrolytic capacitor CE2 is connected in parallel with the diode D1.

[0008] A further feature of this invention is that the first constant current circuit includes a constant current driving chip U1, and the second constant current circuit includes a constant current driving chip U2.

[0009] A further feature of this invention is that the constant current drive chip U1 is model MT7201C or a chip with the same function or of the same type.

[0010] A further feature of this invention is that the constant current drive chip U2 is model MT7201C or a chip with the same function or of the same type.

[0011] The present invention is further configured such that: the first constant current circuit further includes resistors R1 and R2, inductor L1, capacitors C1 and C3 and diode D5; resistors R1 and R2 are connected in parallel to pins 5 and 4 of the constant current driver chip U1; capacitor C1 is connected to pin 5 of the constant current driver chip U1; capacitor C3 is connected to pin 3 of the constant current driver chip U1; inductor L1 is connected to pin 1 of the constant current driver chip U1; and diode D5 is connected to pin 1 of the constant current driver chip U1.

[0012] The present invention is further configured to include a capacitor C5, one end of which is connected to the LED+ interface and the other end is connected to pin 5 of the constant current drive chip U1. The positive terminal of the diode D5 is connected to the LED+ interface and the negative terminal of the diode D5 is connected to pin 1 of the constant current drive chip U1.

[0013] A further feature of this invention is that pin 5 of the constant current drive chip U1 is connected to the interface LED1-, pin 2 of the constant current drive chip U1 is connected to the first ground point, and capacitors C1 and C3 are connected to the first ground point.

[0014] A further feature of this invention is that the second constant current circuit is the same as the first constant current circuit.

[0015] Compared with the prior art, the present invention has the following advantages: the DC-DC dual color temperature drive circuit avoids the extra space required by using DIP switches, reduces the size, and saves space; it also avoids poor contact that is easily caused by using DIP switches. Attached Figure Description

[0016] Figure 1 This is a circuit diagram of the DC-DC dual-color temperature drive circuit in the embodiment.

[0017] Figure 2 This is the circuit schematic of the first constant current circuit in the embodiment.

[0018] Figure 3 This is the circuit schematic of the second constant current circuit in the embodiment.

[0019] Figure 4 This is an internal block diagram of the chip with model number MT7201C in the embodiment.

[0020] In the diagram: 100, first constant current circuit; 200, second constant current circuit; 300, first grounding point; 400, second grounding point. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the protection scope of the present utility model.

[0022] like Figure 1 As shown, this embodiment discloses a DC-DC dual-color temperature driving circuit, including three input interfaces V+, V1-, and V2-, diodes D1 and D2, a first constant current circuit 100, a second constant current circuit 200, and three output interfaces LED+, LED1-, and LED2-. Interface V+ is electrically connected to interface LED+, interface V1- is electrically connected to a first ground point 300, the first ground point 300 is electrically connected to the first constant current circuit 100, and the first constant current circuit 100 is electrically connected to interface LED1-. Interface V2- is electrically connected to a second ground point 400, the second ground point 400 is electrically connected to the second constant current circuit 200, and the second constant current circuit 200 is electrically connected to interface LED2-. The first constant current circuit 100 and the second constant current circuit 200 are respectively electrically connected to interface V+.

[0023] The V+ interface is connected to the positive terminal of the power supply, the V1- and V2- interfaces are connected to the negative terminal of the power supply, the LED+ interface is used as the common positive output terminal to connect two LED lights, the V1- interface is used as the negative terminal to connect one LED light, and the V2- interface is used as the negative terminal to connect the other LED light.

[0024] In this embodiment, diode D2 is connected to interface V+ and interface V1-. The positive terminal of diode D2 is electrically connected to interface V+, and the negative terminal of diode D2 is electrically connected to interface V1-.

[0025] In this embodiment, diode D1 is connected to interface V+ and interface V2-. The positive terminal of diode D1 is electrically connected to interface V+, and the negative terminal of diode D1 is electrically connected to interface V2-.

[0026] The dual-color temperature driving circuit in this embodiment also includes electrolytic capacitors CE1 and CE2. Electrolytic capacitor CE1 is connected in parallel with diode D2. The positive terminal of electrolytic capacitor CE1 is electrically connected to interface V+, and the negative terminal of electrolytic capacitor CE1 is electrically connected to the first ground point 300. Electrolytic capacitor CE2 is connected in parallel with diode D1. The positive terminal of electrolytic capacitor CE2 is electrically connected to interface V+, and the negative terminal of electrolytic capacitor CE2 is electrically connected to the second ground point 400.

[0027] In this embodiment, the first constant current circuit 100 includes a constant current driving chip U1, and the second constant current circuit 200 includes a constant current driving chip U2.

[0028] In this embodiment, the model of the constant current driving chip U1 is MT7201C. In some other embodiments, the constant current driving chip U1 can also be replaced by a chip with the same function or an equivalent model.

[0029] In this embodiment, the model of the constant current driving chip U2 is MT7201C. In some other embodiments, the constant current driving chip U2 can also be replaced by a chip with the same function or an equivalent model.

[0030] As Figure 4 shown, the chip MT7201C is a step-down constant current driving chip in continuous current mode. When the input voltage is higher than the LED voltage, it can be effectively used to drive one or more series-connected LEDs. The input voltage range is 6V to 40V, and the output current is adjustable.

[0031] MT7201C integrates a power switch and a high-side current detection circuit, uses an external resistor to set the average LED current, and receives analog dimming and PWM dimming through the ADJ pin. The chip contains a PWM filtering circuit, and the PWM filtering circuit realizes the function of soft start by controlling the rising edge of the current. The soft start time can be extended by adding an external capacitor between the ADJ pin and the ground. When the voltage of ADJ is lower than 0.2 volts, the power switch is turned off, and MT7201C enters the standby state with extremely low operating current.

[0032] As Figure 2 shown, pin 5 of the constant current driving chip U1 is the VIN pin, which is the power input terminal and is connected to a ceramic capacitor, and the ceramic capacitor is grounded; pin 4 is the ISENSE pin, which is the current sampling terminal, and the sampling resistor RS is connected between the ISENSE pin and the VIN pin to limit the magnitude of the output average current. The output average current satisfies: Ioutnom = 0.1 / RS; pin 3 is the ADJ pin, which is a multi-functional on / off and brightness control pin. When working normally, VADJ = 2.38V, and the output average current Ioutnom = 0.1 / RS. When VADJ < 0.235V, the output current is turned off, and the chip enters the small current off state. When 0.235V < VADJ < 1.6V, the output average current is adjusted to satisfy 20% to 100% of Ioutnom; when VADJ > 1.6V, the output average current is kept constant at 100% Ioutnom. Connecting a capacitor from the ADJ pin to the ground can increase the soft start time; pin 1 is the LX pin, which is the drain of the internal switching transistor, and pin 2 is the GND pin, which is the chip ground pin for grounding.

[0033] As Figure 2As shown, in this embodiment, the first constant current circuit 100 includes a constant current driver chip U1, resistors R1 and R2, inductor L1, capacitors C1, C3, and C5, and diode D5. One end of capacitor C1 is connected to the VIN pin of the constant current driver chip U1, and the other end is connected to the first ground point 300. Resistors R1 and R2 are connected in parallel between the VIN pin and the ISENSE pin as a sampling resistor. One end of capacitor C3 is connected to the ADJ pin of the constant current driver chip U1, and the other end is connected to the first ground point 300. Inductor L1 is connected to the LX pin and the ISENSE pin respectively. The LX pin is connected to the negative terminal of diode D5, and the positive terminal of diode D5 is connected to the positive terminal. At the same time, the VIN pin of the constant current driver chip U1 is connected to the interface LED1-.

[0034] In other embodiments, the ADJ pin can be connected to a PWM signal to adjust the output current. By adjusting the duty cycle of the PWM signal, the output current can be adjusted for dimming.

[0035] The first constant current circuit 100 also includes a capacitor C5, one end of which is connected to the interface V+, and the other end is connected to the VIN pin.

[0036] like Figure 3 As shown, in this embodiment, the second constant current circuit 200 is the same as the first constant current circuit 100, and the VIN pin of the constant current driver chip U2 is connected to the interface LED2-.

[0037] The driving circuit forms a loop to light up the LED. For example, if interface V+ is connected to the positive terminal and interface V1- is connected to the negative terminal, the current flows from interface V+ to LED+, then through the LED to LED1-, and then to the VIN pin of the constant current driver chip U1 to start the constant current driver chip U1. Finally, the current flows back to the negative terminal of the power supply through the ground point, forming a current path to light up the LED. The other path connects the negative terminal of the LED to interface V2-, and the principle is the same.

[0038] The driver circuit has three input and three output interfaces, with three wires leading out to connect to the positive and negative terminals. When the negative input is connected to V1-, LED1- lights up; when the negative input is connected to V2-, LED2- lights up; when the negative input is connected to both V1- and V2-, both outputs can work simultaneously, thus performing color switching.

[0039] The above description is only a preferred embodiment of the present utility model. Therefore, all equivalent changes or modifications made to the structure, features and principles described in the claims of the present utility model patent application are included in the scope of the present utility model patent application.

Claims

1. A DC-DC dual-color temperature driving circuit, characterized in that: include: The system includes three input interfaces V+, V1-, and V2-; a first constant current circuit (100) and a second constant current circuit (200); three output interfaces LED+, LED1-, and LED2-; a first ground point (300) and a second ground point (400); interface V+ is electrically connected to interface LED+; interface V1- is electrically connected to the first ground point (300); the first ground point (300) is electrically connected to the first constant current circuit (100); the first constant current circuit (100) is electrically connected to interface LED1-; interface V2- is electrically connected to the second ground point (400); the second ground point (400) is electrically connected to the second constant current circuit (200); the second constant current circuit (200) is electrically connected to interface LED2-; the first constant current circuit (100) and the second constant current circuit (200) are respectively electrically connected to interface V+.

2. The DC-DC dual-color temperature driving circuit according to claim 1, characterized in that: It also includes diodes D1 and D2. The positive terminal of diode D1 is electrically connected to interface V+, the negative terminal of diode D1 is electrically connected to interface V2-, the positive terminal of diode D2 is electrically connected to interface V+, and the negative terminal of diode D2 is electrically connected to interface V1-.

3. The DC-DC dual-color temperature driving circuit according to claim 2, characterized in that: It also includes electrolytic capacitor CE1 and electrolytic capacitor CE2. Electrolytic capacitor CE1 is connected in parallel with diode D2, and electrolytic capacitor CE2 is connected in parallel with diode D1.

4. The DC-DC dual-color temperature driving circuit according to claim 1, characterized in that: The first constant current circuit (100) includes a constant current driving chip U1, and the second constant current circuit (200) includes a constant current driving chip U2.

5. The DC-DC dual-color temperature driving circuit according to claim 4, characterized in that: The constant current drive chip U1 is model MT7201C or a chip with the same function or of the same type.

6. The DC-DC dual-color temperature driving circuit according to claim 4, characterized in that: The constant current driver chip U2 is model MT7201C or a chip with the same function or of the same type.

7. The DC-DC dual-color temperature driving circuit according to claim 5, characterized in that: The first constant current circuit (100) also includes resistors R1 and R2, inductor L1, capacitors C1 and C3 and diode D5. Resistor R1 and resistor R2 are connected in parallel to pins 5 and 4 of constant current drive chip U1. Capacitor C1 is connected to pin 5 of constant current drive chip U1. Capacitor C3 is connected to pin 3 of constant current drive chip U1. Inductor L1 is connected to pin 1 of constant current drive chip U1. Diode D5 is connected to pin 1 of constant current drive chip U1.

8. A DC-DC dual-color temperature driving circuit according to claim 7, characterized in that: It also includes capacitor C5, one end of which is connected to the LED+ interface, and the other end is connected to pin 5 of the constant current driver chip U1. The positive terminal of diode D5 is connected to the LED+ interface, and the negative terminal of diode D5 is connected to pin 1 of the constant current driver chip U1.

9. A DC-DC dual-color temperature driving circuit according to claim 8, characterized in that: Pin 5 of the constant current drive chip U1 is connected to the LED1- interface, pin 2 of the constant current drive chip U1 is connected to the first ground point (300), and capacitors C1 and C3 are connected to the first ground point (300).

10. A DC-DC dual-color temperature driving circuit according to any one of claims 4-9, characterized in that: The second constant current circuit (200) is the same as the first constant current circuit (100).

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