An LED lamp power supply

Abstract

The application provides an LED lamp power supply, which comprises a power conversion circuit, a constant current driving circuit, a color temperature adjusting circuit and an MCU, the power conversion circuit is used for converting alternating current power into constant voltage direct current and supplying power for the constant current driving circuit and the color temperature adjusting circuit, the constant current driving circuit is used for generating constant driving current for the color temperature adjusting circuit according to a first pulse control signal sent by the MCU, and the color temperature adjusting circuit is used for generating two complementary pulse driving currents to drive two LED lamp beads with different color temperatures according to the constant driving current provided by the constant current driving circuit and a second pulse control signal sent by the MCU. The LED lamp power supply has the advantages of fine dimming and color adjusting.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of LED lamps, in particular to a LED lamp power supply. BACKGROUND

[0002] Lighting lamps are daily necessities for people, with the gradual development of LED lighting technology, since the LED lamp has incomparable advantages over other lamps, the LED lamp is developing at a very fast speed and gradually replacing other lamps, and has been widely applied in various lighting fields.

[0003] The dimming and color control of the prior art LED lamp is usually 0-10V dimming, direct AC power output dimming control, and the dimming effect is not ideal, and the dimming depth is not good; the color temperature adopts hard cutting, color temperature fixed point, and generally only three color temperature switching, which cannot realize fine dimming, resulting in poor user experience. SUMMARY

[0004] The purpose of the present application is to provide a LED lamp power supply capable of fine dimming and color adjustment.

[0005] In the embodiment of the present application, a LED lamp power supply is provided, which comprises a power conversion circuit, a constant current driving circuit, a color temperature adjusting circuit and an MCU,

[0006] The power conversion circuit is used for converting alternating current power into constant voltage direct current, and supplying power for the constant current driving circuit and the color temperature adjusting circuit;

[0007] The constant current driving circuit is used for generating constant driving current to the color temperature adjusting circuit according to the first pulse control signal issued by the MCU;

[0008] The color temperature adjusting circuit is used for generating two complementary pulse driving currents to drive two LED lamp beads with different color temperatures according to the constant driving current provided by the constant current driving circuit and the second pulse control signal issued by the MCU;

[0009] The MCU is used for providing the first pulse control signal and the second pulse control signal, the first pulse control signal is used for controlling the current size output by the constant current driving circuit, and the second pulse control signal is used for controlling the duty cycle of the two pulse driving currents output by the color temperature adjusting circuit.

[0010] In the embodiment of the present application, the LED lamp power supply further comprises a wireless module connected with the MCU, the wireless module is used for connecting with a smart terminal, and transmitting the control command of the smart terminal to the MCU, so as to set the first pulse signal and the second pulse control signal.

[0011] The LED lamp power supply further comprises a voltage reduction circuit connected with the power conversion circuit, the MCU and the wireless module respectively, and the voltage reduction circuit is used for converting the constant voltage direct current provided by the power conversion circuit into low voltage direct current required by the MCU and the wireless module.

[0012] In the embodiment of the present application, the voltage reduction circuit comprises a voltage reduction chip U3, a diode D9, an inductor L5, resistors R28, R39, R40, capacitors C10, C19, C21, C22 and C23, wherein a pin VIN of the chip U3 is connected with a direct current power supply provided by the power conversion circuit, the pin VIN of the chip U3 is also connected with the ground through the capacitor C19, a pin GND of the chip U3 is connected with the ground, a pin EN of the chip U3 is connected with the pin VIN of the chip U3 through the resistor R28, a pin RST of the chip U3 is connected with a pin SW of the chip U3 through the capacitor C10, the pin SW of the chip U3 is connected with a voltage output end of the voltage reduction circuit through the inductor L5, the resistor R39 and the capacitor C21 are connected in parallel between a pin FB of the chip U3 and the voltage output end of the voltage reduction circuit, the pin FB of the chip U3 is also connected with the ground through the resistor R40, and the capacitors C22 and C23 are connected in parallel between the voltage output end of the voltage reduction circuit and the ground.

[0013] In the embodiment of the present application, the LED lamp power supply further comprises a dial switch connected with the MCU, and the dial switch is used for controlling the first pulse control signal.

[0014] In the embodiment of the present application, the power conversion circuit adopts the flyback constant voltage switching power controller chip MT7990 of the Meixinsheng Company.

[0015] In the embodiment of the present application, the constant current driving circuit comprises a current driving chip U2, an inductor L4, diodes D5 and D10, resistors R42, R43, R44, R46, R47 and R49, and capacitors C1, C25, C26, C27, C28 and C29; the capacitor C1 is connected between the voltage output end of the power conversion circuit and the ground; the resistors R43 and R44 are connected in parallel between the output end of the power conversion circuit and the pin VDD of the current driving chip U2; the capacitor C25 is connected between the pin VDD of the current driving chip U2 and the ground; the resistors R46 and R47 are connected in parallel between the pin CS of the current driving chip U2 and the ground; the first pulse control signal output pin PWM_P of the MCU is connected to the pin PWM of the current driving chip U2 through the resistor R42; the pin LD of the current driving chip U2 is connected to the ground through the capacitor C27; the anode of the diode D5 is connected to the pin D of the current driving chip U2, and the cathode is connected to the voltage output end of the power conversion circuit; the inductor L4 is connected between the pin D of the current driving chip U2 and the current output end of the constant current driving circuit; and the resistor R49, the capacitor C28 and the capacitor C29 are connected in parallel between the voltage output end of the power conversion circuit and the current output end of the constant current driving circuit.

[0016] In the embodiment of the present application, the color temperature adjusting circuit comprises a color adjusting control chip U4, a double N MOS tube U5 and a lamp holder J3; the pins 1 and 2 of the lamp holder J3 are respectively connected to one of the two lamp beads with different color temperatures, and the pin 3 is connected to the output voltage of the power conversion circuit; the two MOS tubes in the double N MOS tube U5 are respectively connected between the pins 1 and 2 of the lamp holder J3 and the current output end of the constant current driving circuit; the color adjusting control chip U4 is used for outputting two complementary PWM pulse signals according to the second pulse width control signal output by the MCU, and the two complementary PWM pulse signals are respectively used for controlling the on-off of the two MOS tubes in the double N MOS tube U5, so as to drive the two lamp beads with different color temperatures.

[0017] In the embodiment of the present application, the color adjusting control chip U4 is the electrodeless color adjusting control chip BP5929 of the Jiantong Company.

[0018] In the embodiment of the present application, the current driving chip U2 is the constant current driving chip HI7001 of the Zhixin Company.

[0019] Compared with the prior art, the LED lamp power supply of the present application adopts a three-stage light and color adjusting circuit structure, the first stage is to convert the commercial power into constant voltage output 50V or so DC, the second stage is to use high-depth million-level PWM signal light adjustment DC / DC step-down constant current drive, that is, to realize constant current drive, the first pulse width control signal output by the MCU can arbitrarily adjust the brightness of the lamp, the third stage is to divide the constant current output DC into two paths and drive two different color temperature lamp beads, and the second pulse width control signal is used to distribute the proportion of the two paths, so that the light emitted by the two color temperature lamp beads can be mixed according to different PWM signal duty cycles, and the light with different color temperature values presents different effects. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a structural schematic diagram of the LED lamp power supply of the embodiment of the present application.

[0021] Figure 2 is a circuit diagram of the power conversion circuit of the embodiment of the present application.

[0022] Figure 3 is a circuit diagram of the constant current drive circuit of the embodiment of the present application.

[0023] Figure 4 is a circuit diagram of the color temperature adjusting circuit of the embodiment of the present application.

[0024] Figure 5 is a circuit diagram of the step-down circuit of the embodiment of the present application. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0026] The implementation of the present application is described in detail below in combination with specific embodiments.

[0027] As shown in Figure 1 , in the embodiment of the present application, an LED lamp power supply is provided, which comprises a power conversion circuit, a constant current drive circuit, a color temperature adjusting circuit, an MCU, a wireless module, a step-down circuit and a dial switch. The following are described respectively.

[0028] The power conversion circuit is connected with the alternating current commercial power, the constant current drive circuit and the color temperature drive circuit respectively, and is used to convert the alternating current commercial power into constant voltage DC and supply power to the constant current drive circuit and the color temperature adjusting circuit.

[0029] The MCU is connected with the constant current driving circuit and the color temperature adjusting circuit respectively. The MCU is used for providing the first pulse control signal PWM_P to the constant current driving circuit and providing the second pulse control signal PWM_C to the color temperature adjusting circuit. The first pulse control signal PWM_P is used for controlling the current size output by the constant current driving circuit. The second pulse control signal PWM_C is used for controlling the duty cycle of the two pulse driving currents PWM1 and PWM2 output by the color temperature adjusting circuit. It should be noted that the MCU can also control the brightness to slowly change to a target value when the LED lamp is turned on and turned off, thereby improving the user experience.

[0030] The constant current driving circuit is connected with the color temperature adjusting circuit. The constant current driving circuit is used for generating a constant driving current to the color temperature adjusting circuit according to the first pulse control signal PWM_P sent by the MCU. The color temperature adjusting circuit is used for generating two complementary pulse driving currents PWM1 and PWM2 to drive two LED lamp beads with different color temperatures according to the constant driving current provided by the constant current driving circuit and the second pulse control signal PWM_C sent by the MCU. The signals of the pulse driving currents PWM1 and PWM2 are complementary, that is, when one of the signals is at a low level, the other signal is at a high level.

[0031] The wireless module is connected with the MCU. The wireless module is used for being connected with a smart terminal and transmitting a control command of the smart terminal to the MCU, so as to set the first pulse signal PWM_P and the second pulse control signal PWM_C.

[0032] The step-down circuit is connected with the power conversion circuit, the MCU and the wireless module respectively. The step-down circuit converts the constant voltage direct current provided by the power conversion circuit into 3.3V low voltage direct current required by the MCU and the wireless module. The LED lamp power supply further comprises a code switch connected with the MCU. The code switch is used for controlling the first pulse control signal.

[0033] As shown in Figure 2 The power conversion circuit in the embodiment of the application adopts a constant voltage control chip U1, specifically a flyback constant voltage switching power supply controller chip MT7990 of Meixinsheng Company. Specifically, the working principle of the power conversion circuit is as follows:

[0034] The power input terminal J1 is directly connected to the commercial 220V AC power, and passes through the fuse F1, which plays a role of overcurrent and short circuit protection, and then is connected to the voltage-dependent resistor RZ1, which plays a role of lightning protection. Then it is connected to L2 and L1, which are common-mode filters. RX1 and RX2 are bleeder resistors, which play a role of safety protection when there is no commercial power input into the power supply, and the voltage between the two terminals of J1 of the power supply is reduced to a safe voltage for human body in a very short time. Then the AC power is converted into pulsating DC power through the bridge rectifier, and then the π-type filter composed of C2, C3 and L3 is passed through, and then the current is limited through R4 and R6, and then the voltage starting circuit is supplied with power through C4 and C30. After starting, the auxiliary winding of the transformer T1 is half-wave rectified through D3, and then the current is limited through R17, and then the voltage starting circuit is supplied with power through C4 and C30. The voltage feedback to the constant voltage control chip U1 is obtained after R8 and R18 are divided and then filtered through C14, and the ratio of the division determines the size of the output voltage. R7 and C6 are the voltage compensation circuit of the constant voltage control chip U1, and C5 is the current compensation circuit of the constant voltage control chip U1. The output of the 5th pin of the constant voltage control chip is driven to the gate of Q1 through R19, D4, R20 and R21, so that Q1 works in the switching state. The 4th pin of the constant voltage control chip is a current detection pin, and the five resistors R23-R27 are current sampling resistors, and the size of the resistance value is used to adjust the output current. D2, R13, R14 and C13 are used to form an RCD snubber circuit. If the switch tube Q1 is disconnected, the energy accumulated in the parasitic inductance is charged through the parasitic capacitor of the switch, and the switching voltage rises, and when the voltage rises to the voltage of the snubber capacitor, the snubber diode is turned on, and the switching voltage is clamped by the snubber diode, which is about 1V. The energy accumulated in the parasitic inductance is also charged to the snubber capacitor. During the switch-on period of the switch, the snubber capacitor is discharged through the resistor. The secondary side of the transformer T1 is half-wave rectified through D6, and then filtered through C16, C17 and C18 to obtain a 50V output voltage. The output of the secondary side of the transformer T1 is also half-wave rectified through D10, and then filtered through C31, C32 and L6 to obtain a 50V output voltage and provide it to the step-down circuit.

[0035] As Figure 3As shown in the embodiment of the present invention, the constant current driving circuit includes a current driving chip U2, an inductor L4, diodes D5 and D10, resistors R42, R43, R44, R46, R47, and R49, and capacitors C1, C25, C26, C27, C28, and C29. Capacitor C1 is connected between the voltage output terminal V+ (50V) of the power conversion circuit and ground. Resistors R43 and R44 are connected in parallel between the output terminal of the power conversion circuit and the pin VDD of the current driving chip U2. Capacitor C25 is connected between the pin VDD of the current driving chip U2 and ground. Resistors R46 and R47 are connected in parallel to the current driving chip U2. Between pin CS of U2 and ground, the first pulse control signal output pin PWM_P of the MCU is connected to pin PWM of the current drive chip U2 through resistor R42. Pin LD of the current drive chip U2 is grounded through capacitor C27. The positive terminal of diode D5 is connected to pin D of the current drive chip U2, and the negative terminal is connected to the voltage output terminal V+ of the power conversion circuit. Inductor L4 is connected between pin D of the current drive chip U2 and the current output terminal V- of the constant current drive circuit. Resistor R49, capacitors C28 and C29 are connected in parallel between the voltage output terminal V+ of the power conversion circuit and the current output terminal V- of the constant current drive circuit. In this embodiment of the invention, the current drive chip U2 is the HI7001 constant current drive chip from Zhixin Company.

[0036] like Figure 4 As shown in the embodiment of the invention, the color temperature adjustment circuit includes a color control chip U4, a dual N MOS transistor U5, and a lamp holder J3. Pins 1 and 2 of the lamp holder J3 are respectively connected to a different color temperature LED, and pin 3 is connected to the output voltage of the power conversion circuit. The two MOS transistors in the dual N MOS transistor U5 are respectively connected between pins 1 and 2 of the lamp holder J3 and the current output terminal V- of the constant current drive circuit. The color control chip U4 outputs two complementary PWM pulse signals according to the second pulse width control signal output by the MCU. The two complementary PWM pulse signals are used to control the on / off state of the two MOS transistors in the dual N MOS transistor U5, thereby driving the two LEDs with different color temperatures. One of the two LEDs with different color temperatures is a warm white LED, and the other is a cool white LED. In this embodiment of the invention, the color control chip U4 uses the BP5929 stepless color control chip from Chipone Technology.

[0037] Specifically, the principle of the above color temperature driving circuit is as follows:

[0038] When the input of the 2-pin of the double N MOS tube U5 is high level, the 7-pin, 8-pin and 1-pin of U5 are conductive. The V+ voltage is connected in series with a positive white LED lamp, and the current flows from V+, through the white LED lamp, the 7-pin and 8-pin of U5, the 1-pin of U5, through LF1, L4, the 5-pin and 6-pin of U2, the 4-pin of U2, and then through R46 and R47 to the ground. This is the current flow path of the positive white LED lamp. When the input of the 4-pin of the double N MOS tube is high level, the 5-pin, 6-pin and 3-pin of U5 are conductive. The V+ voltage is connected in series with a warm white LED lamp, and the current flows from V+, through the warm white LED lamp, the 5-pin and 6-pin of U5, the 3-pin of U5, through LF1, L4, the 5-pin and 6-pin of U2, the 4-pin of U2, and then through R46 and R47 to the ground. This is the current flow path of the warm white LED lamp.

[0039] As shown in Figure 5 The step-down circuit comprises a step-down chip U3, a diode D9, an inductor L5, resistors R28, R39 and R40, and capacitors C10, C19, C21, C22 and C23. The pin VIN of the chip U3 is connected to a direct current power supply provided by the power conversion circuit, the pin VIN of the chip U3 is further connected to the ground through the capacitor C19, the pin GND of the chip U3 is connected to the ground, the pin EN of the chip U3 is connected to the pin VIN of the chip U3 through the resistor R28, the pin RST of the chip U3 is connected to the pin SW of the chip U3 through the capacitor C10, the pin SW of the chip U3 is connected to a voltage output end V+ of the step-down circuit through the inductor L5, the resistor R39 and the capacitor C21 are connected in parallel between the pin FB of the chip U3 and the voltage output end V+ of the step-down circuit, the pin FB of the chip U3 is further connected to the ground through the resistor R40, and the capacitors C22 and C23 are connected in parallel between the voltage output end V+ of the step-down circuit and the ground.

[0040] To sum up, the LED lamp power supply of the application adopts a three-stage light and color adjusting circuit structure. The first stage is to convert the commercial power into a constant voltage output of about 50V direct current. The second stage is to use a high-depth million-level PWM signal to light-adjust the 50V direct current DC / DC step-down constant current drive, so as to realize constant current drive. The first pulse width control signal output by the MCU can arbitrarily adjust the brightness of the lamp. The third stage is to divide the constant current output direct current into two paths and drive two paths of lamp beads with different color temperatures. The second pulse width control signal is used to distribute the proportion of the two output paths, so that the light emitted by the two color temperature lamp beads can be mixed according to different PWM signal duty cycles, and the mixed light with different color temperature values presents different effects.

[0041] The above only describes the preferred embodiments of the application and is not intended to limit the application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application shall be included in the protection scope of the application.

Claims

1. An LED luminaire power supply, characterized by, The power conversion circuit, the constant current drive circuit, the color temperature adjustment circuit and the MCU, The power conversion circuit is used for converting alternating current into constant voltage direct current and supplying power for the constant current drive circuit and the color temperature adjustment circuit. The constant current drive circuit is used for generating constant driving current for the color temperature adjustment circuit according to the first pulse control signal sent by the MCU; the color temperature adjustment circuit is used for generating two complementary pulse driving currents to drive two different color temperature LED lamp beads according to the constant driving current provided by the constant current drive circuit and the second pulse control signal sent by the MCU; the color temperature adjustment circuit comprises a color adjustment control chip U4, a double N MOS tube U5 and a lamp holder J3, the pins 1 and 2 of the lamp holder J3 are connected with one of the two different color temperature LED lamp beads respectively, the pin 3 is connected with the output voltage of the power conversion circuit, the two MOS tubes in the double N MOS tube U5 are connected between the pins 1 and 2 of the lamp holder J3 and the current output end of the constant current drive circuit respectively, the color adjustment control chip U4 is used for outputting two complementary PWM pulse signals according to the second pulse width control signal output by the MCU, the two complementary PWM pulse signals are used for controlling the on-off of the two MOS tubes in the double N MOS tube U5 respectively, thereby driving the two different color temperature LED lamp beads; The MCU is used for providing the first pulse control signal and the second pulse control signal, the first pulse control signal is used for controlling the current size output by the constant current drive circuit, and the second pulse control signal is used for controlling the duty cycle of the two pulse driving currents output by the color temperature adjustment circuit.

2. The LED luminaire power supply of claim 1, wherein, The wireless module connected with the MCU is further included, the wireless module is used for connecting with the intelligent terminal and transmitting the control command of the intelligent terminal to the MCU, thereby setting the first pulse control signal and the second pulse control signal.

3. The LED luminaire power supply of claim 2, wherein, The step-down circuit connected with the power conversion circuit, the MCU and the wireless module respectively is further included, the step-down circuit is used for converting the constant voltage direct current provided by the power conversion circuit into low voltage direct current required by the MCU and the wireless module.

4. The LED luminaire power supply of claim 3, wherein, The voltage reduction circuit includes voltage reduction chip U3, diode D9, inductor L5, resistor R28, R39, R40, capacitor C10, C19, C21, C22, C23, wherein the pin VIN of chip U3 is connected with the DC power provided by the power conversion circuit, the pin VIN of chip U3 is also grounded through capacitor C19, the pin GND of chip U3 is grounded, the pin EN of chip U3 is connected with the pin VIN of chip U3 through resistor R28, the pin RST of chip U3 is connected with the pin SW of chip U3 through capacitor C10, the pin SW of chip U3 is connected to the voltage output end of the voltage reduction circuit through inductor L5, resistor R39 and capacitor C21 are connected in parallel between the pin FB of chip U3 and the voltage output end of the voltage reduction circuit, the pin FB of chip U3 is also grounded through resistor R40, capacitor C22 and C23 are connected in parallel between the voltage output end of the voltage reduction circuit and the ground.

5. The LED luminaire power supply of claim 1, wherein, The dial switch connected with the MCU is further included, and the dial switch is used for controlling the first pulse control signal.

6. The LED luminaire power supply of claim 1, wherein, In the power conversion circuit, the flyback constant voltage switching power controller chip MT7990 of Meixi Sheng Company is adopted.

7. The LED luminaire power supply of claim 1, wherein, The constant current driving circuit includes current driving chip U2, inductor L4, diode D5, D10, resistor R42, R43, R44, R46, R47, R49, capacitor C1, C25, C26, C27, C28, C29, capacitor C1 is connected between the voltage output end of the power conversion circuit and the ground, resistor R43 and R44 are connected in parallel between the output end of the power conversion circuit and the pin VDD of current driving chip U2, capacitor C25 is connected between the pin VDD of current driving chip U2 and the ground, resistor R46 and R47 are connected in parallel between the pin CS of current driving chip U2 and the ground, the first pulse control signal output pin PWM_P of the MCU is connected with the pin PWM of current driving chip U2 through resistor R42, the pin LD of current driving chip U2 is grounded through capacitor C27, the anode of diode D5 is connected with the pin D of current driving chip U2, the cathode is connected with the voltage output end of the power conversion circuit, inductor L4 is connected between the pin D of current driving chip U2 and the current output end of the constant current driving circuit, resistor R49, capacitor C28 and C29 are connected in parallel between the voltage output end of the power conversion circuit and the current output end of the constant current driving circuit.

8. The LED luminaire power supply of claim 1, wherein, The dimming control chip U4 adopts the non-polar dimming control chip BP5929 of Jingfeng Company.

9. The LED luminaire power supply of claim 1, wherein, The current driving chip U2 adopts the constant current driving chip HI7001 of Zhixi Company.

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