Double-color-temperature LED lamp bead driving circuit

Abstract

The utility model discloses a double color temperature LED lamp bead drive circuit, which comprises an LED control chip U1, two paths of LED lamp beads and an MOS tube group, the MOS tube group at least comprises two MOS tubes, the output end of the LED control chip used for outputting PWM signals is respectively connected with the grid electrodes of the two MOS tubes in the MOS tube group, the LED control chip is also respectively connected with the positive electrodes of the two paths of LED lamp beads, and the positive electrodes of the two paths of LED lamp beads are respectively connected with the positive electrodes of the two paths of LED lamp beads. The negative electrodes of the two paths of LED lamp beads are respectively connected with the drain electrodes of the corresponding MOS tubes in the MOS tube group, and the source electrodes of the MOS tubes are grounded. According to the utility model, only one path of PWM signal is needed to carry out color temperature control on two paths of LED lamp beads, which means that only one timer is needed to control the PWM signal, two paths of PWM control signals are not needed to carry out dimming traditionally, two timer resources are not needed, the structure is simpler, and the cost is lower.

Description

Technical Field

[0001] The utility model relates to the technical field of lamp bead color temperature driving circuits, in particular to a dual-color temperature LED lamp bead driving circuit. Background Art

[0002] The current two-color white flat panel lights generally require that the power of the LED lamp beads in the flat panel lights remain unchanged, but the color temperature is adjustable. In order to meet this requirement, the flat panel lights on the market generally use two PWM dimming signals and adopt a driving circuit with a constant current output function to drive the LED lamp beads to emit light. Under this circuit structure, it needs to occupy the timer resources of two single-chip microcomputers, one timer controls one PWM dimming signal, and the cost of such a driving circuit is twice that of a single-channel drive. In addition, due to the power limitation of the power supply, the LED lamp beads on both sides cannot be fully loaded at the same time, resulting in half of the LED driving capacity being idle, which is a waste in circuit design, resulting in insufficient utilization of circuit hardware resources and the disadvantage of resource limitation. Utility Model Content

[0003] In view of the deficiencies in the prior art, the purpose of the utility model is to provide a dual-color temperature LED lamp bead driving circuit, which can solve the problems described in the background technology.

[0004] The technical solution to achieve the purpose of the utility model is: a dual-color temperature LED lamp bead driving circuit, including an LED control chip U1, two LED lamp beads and a MOS tube group, the MOS tube group includes at least two MOS tubes,

[0005] The output end of the LED control chip for outputting PWM signals is respectively connected to the gates of the two MOS tubes in the MOS tube group. The LED control chip is also respectively connected to the positive electrodes of the two LED lamp beads. The negative electrodes of the two LED lamp beads are respectively connected to the drains of the corresponding MOS tubes in the MOS tube group, and the source of the MOS tube is grounded.

[0006] Furthermore, it also includes capacitor C1, capacitor C2, capacitor C3, capacitor C4, capacitor C5, capacitor C6, resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, resistor R6, resistor R7, resistor R8, resistor R9, resistor R10, resistor R11, diode D1, diode D2, MOS tube group includes MOS tube Q1, MOS tube Q2, MOS tube Q3, MOS tube Q4, MOS tube Q5, two LED lamp beads are defined as first LED lamp beads and second LED lamp beads respectively,

[0007] The input end of the LED control chip U1, the positive current sensing end, one end of the first parallel branch, and one end of the resistor R1 are connected together, and the connection node serves as the input end VIN of the dual-color temperature LED lamp bead driving circuit. The input end VIN is used to connect to the outside. The first parallel branch includes a capacitor C1 and a capacitor C2 in parallel. The other end of the first parallel branch is grounded.

[0008] The enable terminal of the LED control chip U1 is connected to one end of the resistor R3 and serves as the enable terminal EN of the dual-color temperature LED lamp bead driving circuit. The enable terminal EN is used to connect to the outside. The other end of the resistor R3 is grounded.

[0009] The dimming signal input terminal of the LED control chip U1 is connected to one end of the resistor R4 and serves as the PWM signal input terminal PWM of the dual-color temperature LED lamp bead driving circuit. The PWM signal input terminal PWM is used to connect to the outside. The other end of the resistor R4 is grounded.

[0010] The off time control end of the LED control chip U1 is respectively connected to one end of the capacitor C3 and one end of the resistor R6, the other end of the capacitor C3 is grounded, the other end of the resistor R6 is connected to one end of the inductor L1, the negative current sensing of the LED control chip U1 is respectively connected to the other end of the resistor R1 and the drain of the MOS tube Q1, the gate of the MOS tube Q1 is respectively connected to one end of the resistor R2 and one end of the resistor R5, the other end of the resistor R2 is connected to the power side switch gate end of the LED control chip U1, the other end of the resistor R5 is respectively connected to one end of the capacitor C4, the switch switching end of the LED control chip U1, the other end of the inductor L1, the cathode of the diode D2, and the source of the MOS tube Q1, the anode of the diode D2 is grounded, the other end of the capacitor C4 is respectively connected to the cathode of the diode D1 and the driving end of the LED control chip U1 for driving the power side switch gate, the anode of the diode D1 is respectively connected to one end of the capacitor C6 and the power end of the LED control chip U1 and then connected to an external power supply VCC, the other end of the capacitor C6 is grounded,

[0011] One end of the inductor L1 connected to the off time control end of the LED control chip U1 is also connected to one end of the capacitor C5 and one end of the two LED lamp beads, and the other end of the capacitor C5 is grounded.

[0012] One end of the inductor L1 is connected to the positive electrodes of two LED lamp beads. Each LED lamp bead includes a number of light-emitting diodes connected in series. The first LED lamp bead is connected to the drain of the MOS tube Q2, and the second LED lamp bead is connected to the drain of the MOS tube Q4. The source of the MOS tube Q2 is grounded.

[0013] The external Shunt switch driving signal output end of the LED control chip is respectively connected to one end of the resistor R7, one end of the resistor R10, the gate of the MOS tube Q3, and the gate of the MOS tube Q5. The source of the MOS tube Q5 is grounded. The other end of the resistor R7 is respectively connected to one end of the resistor R8 and the gate of the MOS tube Q2. The other end of the resistor R8 is grounded. The other end of the resistor R10 is connected to the source of the MOS tube Q3 and then connected to an external power supply VCC. The drain of the MOS tube Q3 is connected to the drain of the MOS tube D5 and then connected to one end of the resistor R9. The other end of the resistor R9 is respectively connected to the other end of the resistor R11 and the gate of the MOS tube Q4. The other end of the resistor R11 is grounded, and the source of the MOS tube Q4 is grounded.

[0014] Furthermore, the model of the LED control chip is MBI6672.

[0015] Furthermore, the capacitance values ​​of capacitor C1, capacitor C2, capacitor C3, capacitor C4, capacitor C5, and capacitor C6 are 47uF, 0.1uF, 470PF, 4.7uF, 104uF, and 4.7uF, respectively.

[0016] Furthermore, the resistance values ​​of resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, resistor R6, resistor R7, resistor R8, and resistor R9 are 0.05Ω, 10Ω, 10KΩ, 10KΩ, 10KΩ, 20KΩ, 10Ω, 10KΩ, 10Ω, 100KΩ, and 10KΩ respectively.

[0017] Furthermore, the inductance value of the inductor L1 is 22uH.

[0018] Furthermore, the first LED lamp beads include LEDs LED1 to LED4 connected in series, and the second LED lamp beads include LEDs LED5 to LED8 connected in series. The anode of the LED LED1 and the anode of the LED LED5 are connected to one end of the inductor L1.

[0019] Furthermore, the first LED lamp beads are warm white LED lamp strings, and the second LED lamp beads are natural white LED lamp strings.

[0020] The beneficial effects of the utility model are as follows: the utility model only needs one PWM signal to control the color temperature of two LED lamp beads, which means that only one timer is needed to control the PWM signal. There is no need for the traditional two-way PWM control signal for dimming, and thus no two timer resources are needed. The structure is simpler and the cost is lower. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a circuit diagram of the utility model. DETAILED DESCRIPTION

[0022] The present invention is further described below in conjunction with the accompanying drawings and specific implementation plans:

[0023] like Figure 1 As shown, a dual-color temperature LED lamp bead driving circuit includes an LED control chip U1, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a capacitor C6, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a resistor R11, a diode D1, a diode D2, a MOS tube Q1, a MOS tube Q1, a MOS tube Q2, a MOS tube Q3, a MOS tube Q4, a MOS tube Q5 and two LED lamp beads, the two LED lamp beads are defined as a first LED lamp bead and a second LED lamp bead respectively. The input end (i.e., VIN pin, pin 1) of the LED control chip U1, the positive current sensing end (i.e., CSP pin, pin 14), one end of the first parallel branch, and one end of the resistor R1 are connected together, and the connection node is used as the input end VIN of the dual-color temperature LED lamp bead driving circuit, and the input end VIN is used to connect to the outside (such as a controller, or a superior circuit). The first parallel branch includes a capacitor C1 and a capacitor C2 connected in parallel, and the other end of the first parallel branch is grounded.

[0024] The LED control chip U1 is a dimmable step-down external LED control chip.

[0025] The enable end (i.e., EN pin, pin 3) of the LED control chip U1 is connected to one end of the resistor R3 and serves as the enable end EN of the dual-color temperature LED lamp bead driving circuit. The enable end EN is used to connect to the outside, so that the outside can control the dual-color temperature LED lamp bead driving circuit by inputting an EN enable signal. The other end of the resistor R3 is grounded.

[0026] The dimming signal input terminal (i.e., SDIM pin, pin 4) of the LED control chip U1 is connected to one end of the resistor R4 and serves as the PWM signal input terminal PWM of the dual-color temperature LED lamp bead driving circuit. The PWM signal input terminal PWM is used to connect to the outside, so that the outside can input the PWM signal through the PWM signal input terminal PWM to input the PWM signal to the dual-color temperature LED lamp bead driving circuit. The other end of the resistor R4 is grounded.

[0027] The off time control end (i.e., COFF pin, pin 5) of the LED control chip U1 is respectively connected to one end of the capacitor C3 and one end of the resistor R6. The other end of the capacitor C3 is grounded, and the other end of the resistor R6 is connected to one end of the inductor L1. The negative current sensing of the LED control chip U1 is respectively connected to the other end of the resistor R1 and the drain of the MOS tube Q1, and the gate of the MOS tube Q1 is respectively connected to one end of the resistor R2 and one end of the resistor R5. The other end of the resistor R2 is connected to the power side switch gate end (i.e., HG pin, pin 11) of the LED control chip U1, and the other end of the resistor R5 is respectively connected to one end of the capacitor C4, the switch switching end (i.e., pin SW, pin 10) of the LED control chip U1, the other end of the inductor L1, the cathode of the diode D2, and the source of the MOS tube Q1. The anode of the diode D2 is grounded. The other end of the capacitor C4 is respectively connected to the cathode of the diode D1 and the driving end of the LED control chip U1 for driving the switch gate stage on the power side (i.e., the BOOT pin, pin 9). The anode of the diode D1 is respectively connected to one end of the capacitor C6 and the power end of the LED control chip U1 (i.e., the VCC pin, pin 8), and then connected to an external power supply VCC. The other end of the capacitor C6 is grounded.

[0028] One end of the inductor L1 connected to the off time control end of the LED control chip U1 is also connected to one end of the capacitor C5 and one end of the two LED lamp beads, that is, one end of the inductor L1 is connected to one end of the first LED lamp bead and one end of the second LED lamp bead. The other end of the capacitor C5 is grounded.

[0029] One end of the inductor L1 is connected to the positive poles of two LED lamp beads, and each LED lamp bead includes a plurality of light-emitting diodes connected in series. In this embodiment, the first LED lamp bead includes light-emitting diodes LED1-LED4 connected in series, and the second LED lamp bead includes light-emitting diodes LED5-LED8 connected in series, and the positive poles of the light-emitting diodes LED1 and LED5 are connected to one end of the inductor L1.

[0030] The first LED lamp bead is connected to the drain of the MOS tube Q2, the second LED lamp bead is connected to the drain of the MOS tube Q4, and the source of the MOS tube Q2 is grounded.

[0031] The external shunt switch drive signal output end of the LED control chip (i.e., SDRV pin, pin 7) is respectively connected to one end of resistor R7, one end of resistor R10, the gate of MOS tube Q3, and the gate of MOS tube Q5. The source of MOS tube Q5 is grounded. The other end of resistor R7 is respectively connected to one end of resistor R8 and the gate of MOS tube Q2. The other end of resistor R8 is grounded. The other end of resistor R10 is connected to the source of MOS tube Q3 and then connected to an external power supply VCC. The drain of MOS tube Q3 is connected to the drain of MOS tube D5 and then connected to one end of resistor R9. The other end of resistor R9 is respectively connected to the other end of resistor R11 and the gate of MOS tube Q4. The other end of resistor R11 is grounded. The source of MOS tube Q4 is grounded.

[0032] Among them, the model of the LED control chip is MBI6672.

[0033] The capacitance values ​​of capacitor C1, capacitor C2, capacitor C3, capacitor C4, capacitor C5, and capacitor C6 are 47uF, 0.1uF, 470PF, 4.7uF, 104uF, and 4.7uF, respectively. The resistance values ​​of resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, resistor R6, resistor R7, resistor R8, and resistor R9 are 0.05Ω (ohm), 10Ω, 10KΩ (i.e., 10000 ohms), 10KΩ, 10KΩ, 20KΩ, 10Ω, 10KΩ, 10Ω, 100KΩ, and 10KΩ, respectively. The inductance value of inductor L1 is 22uH (i.e., microhenry).

[0034] The first LED lamp beads are warm white LED lamp strings, and the second LED lamp beads are natural white LED lamp strings. Warm white, natural white or other color temperatures can be achieved by selecting different color temperatures, that is, the color temperatures of the two LED lamp beads are different.

[0035] The PWM signal as the dimming signal is sent to the LED control chip U1. The PWM signal is input through the SDIM pin of the LED control chip, amplified by the LED control chip U1, and then outputted through the SDRV pin of the LED control chip. The PWMOUT signal is input to the gate of the MOS tube Q2 after the current limiting effect of the resistor R7, so as to control the conduction and cutoff of the MOS tube Q2 and dim the first LED lamp bead. When the PWMOUT signal is a high voltage (i.e., the voltage is 1), the MOS tube Q2 is turned on, the first LED lamp bead emits light, and emits different degrees of brightness based on the voltage of the PWMOUT signal. Conversely, when the PWMOUT signal is a low voltage (i.e., the voltage is 0), the MOS tube Q2 is turned off, and the first LED lamp bead is turned off and does not emit light.

[0036] The output PWMOUT signal also flows into MOS tube Q3 and MOS tube Q5 at the same time, and the PWMOUT signal amplified by MOS tube Q3 and MOS tube Q5 is input to the gate of MOS tube Q4, thereby controlling the conduction and cutoff of MOS tube Q4, and dimming the second LED lamp bead. In addition, the first LED lamp bead and the second LED lamp bead are in a relationship of increase and decrease, that is, when the first LED lamp bead is lit, the second LED lamp bead is turned off; conversely, when the first LED lamp bead is turned off, the second LED lamp bead is lit, thereby realizing continuous adjustable color temperature and constant overall power, avoiding idle power waste.

[0037] The utility model only needs one PWM signal to control the color temperature of two LED lamp beads, which means that only one timer is needed to control the PWM signal. There is no need for the traditional two-way PWM control signal for dimming, and thus no need for two timer resources. The structure is simpler and the cost is lower.

[0038] The embodiment disclosed in this specification is only an example of the unilateral features of the utility model, and the protection scope of the utility model is not limited to this embodiment. Any other functionally equivalent embodiments fall within the protection scope of the utility model. For those skilled in the art, various other corresponding changes and deformations can be made according to the technical solutions and concepts described above, and all these changes and deformations should fall within the protection scope of the claims of the utility model.

Claims

1. A dual color temperature LED lamp bead driving circuit, characterized in that: It includes LED control chip U1, two-way LED lamp beads and MOS tube group, and the MOS tube group includes at least two MOS tubes. The output end of the LED control chip for outputting PWM signals is respectively connected to the gates of the two MOS tubes in the MOS tube group. The LED control chip is also respectively connected to the positive electrodes of the two LED lamp beads. The negative electrodes of the two LED lamp beads are respectively connected to the drains of the corresponding MOS tubes in the MOS tube group, and the source of the MOS tube is grounded.

2. The dual color temperature LED lamp bead driving circuit according to claim 1, characterized in that: It also includes capacitor C1, capacitor C2, capacitor C3, capacitor C4, capacitor C5, capacitor C6, resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, resistor R6, resistor R7, resistor R8, resistor R9, resistor R10, resistor R11, diode D1, diode D2, the MOS tube group includes MOS tube Q1, MOS tube Q1, MOS tube Q2, MOS tube Q3, MOS tube Q4, MOS tube Q5, and the two LED lamp beads are defined as the first LED lamp bead and the second LED lamp bead respectively. The input end of the LED control chip U1, the positive current sensing end, one end of the first parallel branch, and one end of the resistor R1 are connected together, and the connection node serves as the input end VIN of the dual-color temperature LED lamp bead driving circuit. The input end VIN is used to connect to the outside. The first parallel branch includes a capacitor C1 and a capacitor C2 in parallel. The other end of the first parallel branch is grounded. The enable terminal of the LED control chip U1 is connected to one end of the resistor R3 and serves as the enable terminal EN of the dual-color temperature LED lamp bead driving circuit. The enable terminal EN is used to connect to the outside. The other end of the resistor R3 is grounded. The dimming signal input terminal of the LED control chip U1 is connected to one end of the resistor R4 and serves as the PWM signal input terminal PWM of the dual-color temperature LED lamp bead driving circuit. The PWM signal input terminal PWM is used to connect to the outside. The other end of the resistor R4 is grounded. The off time control end of the LED control chip U1 is respectively connected to one end of the capacitor C3 and one end of the resistor R6, the other end of the capacitor C3 is grounded, the other end of the resistor R6 is connected to one end of the inductor L1, the negative current sensing of the LED control chip U1 is respectively connected to the other end of the resistor R1 and the drain of the MOS tube Q1, the gate of the MOS tube Q1 is respectively connected to one end of the resistor R2 and one end of the resistor R5, the other end of the resistor R2 is connected to the power side switch gate end of the LED control chip U1, the other end of the resistor R5 is respectively connected to one end of the capacitor C4, the switch switching end of the LED control chip U1, the other end of the inductor L1, the cathode of the diode D2, and the source of the MOS tube Q1, the anode of the diode D2 is grounded, the other end of the capacitor C4 is respectively connected to the cathode of the diode D1 and the driving end of the LED control chip U1 for driving the power side switch gate, the anode of the diode D1 is respectively connected to one end of the capacitor C6 and the power end of the LED control chip U1 and then connected to an external power supply VCC, the other end of the capacitor C6 is grounded, One end of the inductor L1 connected to the off time control end of the LED control chip U1 is also connected to one end of the capacitor C5 and one end of the two LED lamp beads, and the other end of the capacitor C5 is grounded. One end of the inductor L1 is connected to the positive electrodes of two LED lamp beads. Each LED lamp bead includes a number of light-emitting diodes connected in series. The first LED lamp bead is connected to the drain of the MOS tube Q2, and the second LED lamp bead is connected to the drain of the MOS tube Q4. The source of the MOS tube Q2 is grounded. The external Shunt switch driving signal output end of the LED control chip is respectively connected to one end of the resistor R7, one end of the resistor R10, the gate of the MOS tube Q3, and the gate of the MOS tube Q5. The source of the MOS tube Q5 is grounded. The other end of the resistor R7 is respectively connected to one end of the resistor R8 and the gate of the MOS tube Q2. The other end of the resistor R8 is grounded. The other end of the resistor R10 is connected to the source of the MOS tube Q3 and then connected to an external power supply VCC. The drain of the MOS tube Q3 is connected to the drain of the MOS tube D5 and then connected to one end of the resistor R9. The other end of the resistor R9 is respectively connected to the other end of the resistor R11 and the gate of the MOS tube Q4. The other end of the resistor R11 is grounded, and the source of the MOS tube Q4 is grounded.

3. The dual color temperature LED lamp bead driving circuit according to claim 2, characterized in that: The model of LED control chip is MBI6672.

4. The dual color temperature LED lamp bead driving circuit according to claim 2, characterized in that: The capacitance values ​​of capacitor C1, capacitor C2, capacitor C3, capacitor C4, capacitor C5, and capacitor C6 are 47uF, 0.1uF, 470PF, 4.7uF, 104uF, and 4.7uF respectively.

5. The dual color temperature LED lamp bead driving circuit according to claim 2, characterized in that: The resistance values ​​of resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, resistor R6, resistor R7, resistor R8, resistor R9, resistor R10, and resistor R11 are 0.05Ω, 10Ω, 10K Ω, 10K Ω, 10K Ω, 20K Ω, 10Ω, 10K Ω, 10Ω, 100K Ω, and 10K Ω respectively.

6. The dual color temperature LED lamp bead driving circuit according to claim 2, characterized in that: The inductance value of the inductor L1 is 22uH.

7. The dual color temperature LED lamp bead driving circuit according to claim 2, characterized in that: The first LED lamp beads include LEDs LED1 to LED4 connected in series, and the second LED lamp beads include LEDs LED5 to LED8 connected in series. The positive poles of the LEDs LED1 and LED5 are connected to one end of the inductor L1.

8. The dual color temperature LED lamp bead driving circuit according to claim 2, characterized in that: The first LED lamp string is a warm white LED lamp string, and the second LED lamp string is a natural white LED lamp string.

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