DC-DC dimming circuit capable of adjusting output voltage and improving output voltage overshoot

Abstract

The utility model discloses a DC-DC dimming circuit capable of adjusting output voltage and improving output voltage overshoot. The DC-DC dimming circuit comprises a main circuit, a DC-DC circuit, an output voltage adjusting and anti-overshoot circuit, an MOS tube Q1 and an MCU control circuit. The main circuit is connected to a live wire L and a null line N; the input end of the DC-DC circuit is connected with the main circuit, the first output end of the DC-DC circuit is connected with the source electrode of the MOS tube Q1, the second output end of the DC-DC circuit is connected with one end of the lamp, and the other end of the lamp is connected with the drain electrode of the MOS tube Q1; the output voltage regulation and anti-overshoot circuit is connected among the feedback end of the DC-DC circuit, the second output end of the DC-DC circuit and the MCU control circuit, and is used for regulating the output voltage and buffering the rapid rise of the output voltage; the MCU control circuit is connected with the grid electrode of the MOS tube Q1 and is used for outputting a PWM signal to control the on-off of the MOS tube Q1 so as to adjust the brightness of the lamp; through the above structure, the output voltage can be adjusted and the rapid rise of the output voltage can be buffered at the same time, so that the overshoot of the output voltage is relatively low, and the practicability is very good.

Description

Technical Field

[0001] The utility model relates to the field of LED dimming power supply circuits and controllers, and particularly relates to a DC-DC dimming circuit with adjustable output voltage and improved output voltage overshoot. Background Art

[0002] With the booming development of the LED power lighting industry, LED driver power supplies have been installed in every household and outdoor lighting, which has also rapidly developed the LED power supply market. At the same time, customers' requirements for the performance of LED power supplies are getting higher and higher.

[0003] Currently, in practical applications, the output voltage range of power supplies is very wide. A single voltage output is difficult to meet customers' requirements or will cause customers to need to stock multiple models, which will undoubtedly increase the inventory. In addition, if the output voltage overshoot of the power supply is relatively large, it will undoubtedly reduce the service life of the powered device or even directly damage the device. Therefore, it is very necessary to develop a dimming circuit with adjustable output voltage and low overshoot. Summary of the Utility Model

[0004] The utility model aims to solve at least one of the technical problems existing in the prior art. For this purpose, the utility model provides a DC-DC dimming circuit with adjustable output voltage and improved output voltage overshoot.

[0005] An embodiment of the utility model adopts the following technical solution to solve its technical problems: A DC-DC dimming circuit with adjustable output voltage and improved output voltage overshoot includes a main circuit, a DC-DC circuit, an output voltage regulation and overshoot prevention circuit, an MOS transistor Q1, and an MCU control circuit;

[0006] The main circuit is connected to the live wire L and the neutral wire N;

[0007] The input end of the DC-DC circuit is connected to the main circuit, the first output end is connected to the source electrode of the MOS transistor Q1, the second output end is connected to one end of the lamp, and the other end of the lamp is connected to the drain electrode of the MOS transistor Q1;

[0008] The output voltage regulation and overshoot prevention circuit is connected between the feedback end of the DC-DC circuit, the second output end of the DC-DC circuit, and the MCU control circuit, and is used to regulate the output voltage and buffer the rapid rise of the output voltage;

[0009] The MCU control circuit is connected to the gate electrode of the MOS transistor Q1 and is used to output a PWM signal to control the on and off of the MOS transistor Q1 to adjust the brightness of the lamp.

[0010] As one of the preferred embodiments of the present utility model, the DC-DC circuit includes a power chip U1, resistors R4-7, electrolytic capacitors EC1-2, capacitors C1-2, an inductor L1, and diodes D1-2. The anode of diode D1 is connected to the first output terminal of the main circuit, and the cathode of diode D1 is respectively connected to one end of resistor R4, one end of electrolytic capacitor EC1, one end of resistor R5, one end of resistor R6, and the VIN terminal of power chip U1. The other end of resistor R5 is respectively connected to the CS terminal of power chip U1 and one end of capacitor C1. The other end of resistor R6 is connected to the EN terminal of power chip U1. The other end of capacitor C1 is respectively connected to the SW terminal of power chip U1, one end of inductor L1, one end of capacitor C2, and the cathode of diode D2. The other end of capacitor C2 is connected to the BST terminal of power chip U1 via resistor R7. The other end of inductor L1 is respectively connected to one end of electrolytic capacitor EC2 and one end of the lamp. The other end of electrolytic capacitor EC2, the anode of diode D2, the other end of resistor R4, the other end of electrolytic capacitor EC1, and the source electrode of MOS transistor Q1 are connected to the GND terminal.

[0011] As one of the preferred embodiments of the present utility model, the output voltage regulation and overshoot prevention circuit includes resistors R1-2, resistors R9-10, a variable resistor R3, and capacitors C3-4. One end of variable resistor R3 is respectively connected to the feedback terminal of the DC-DC circuit, one end of resistor R1, one end of capacitor C3, and one end of resistor R2. The other end of variable resistor R3 is connected to the GND terminal. The other end of resistor R1 is respectively connected to one end of resistor R9 and the second output terminal of the DC-DC circuit. The other end of capacitor C3 is connected to the other end of resistor R9. The other end of resistor R2 is respectively connected to one end of resistor R10 and one end of capacitor C4. The other end of capacitor C4 is connected to the GND terminal. The other end of resistor R10 is connected to the MCU control circuit.

[0012] As one of the preferred embodiments of the present utility model, a DC-DC dimming circuit with adjustable output voltage and improved output voltage overshoot further includes a wireless communication circuit connected to the MCU control circuit, which is used to communicate with a wireless communication device to obtain an output voltage regulation signal.

[0013] As one of the preferred embodiments of the present utility model, the wireless communication circuit is set as an NFC circuit.

[0014] As one of the preferred embodiments of the present utility model, the wireless communication circuit is set as a Bluetooth circuit.

[0015] Advantages of the present utility model: A DC-DC dimming circuit with adjustable output voltage and improved output voltage overshoot, comprising a main circuit, a DC-DC circuit, an output voltage regulation and overshoot prevention circuit, an MOS transistor Q1, and an MCU control circuit; the main circuit is connected to the live wire L and the neutral wire N; the input end of the DC-DC circuit is connected to the main circuit, the first output end is connected to the source electrode of the MOS transistor Q1, the second output end is connected to one end of the lamp, and the other end of the lamp is connected to the drain electrode of the MOS transistor Q1; the output voltage regulation and overshoot prevention circuit is connected between the feedback end of the DC-DC circuit, the second output end of the DC-DC circuit, and the MCU control circuit, and is used for regulating the output voltage and buffering the rapid rise of the output voltage; the MCU control circuit is connected to the gate electrode of the MOS transistor Q1 and is used for outputting a PWM signal to control the on and off of the MOS transistor Q1 so as to regulate the brightness of the lamp; through the above structure, while the output voltage can be regulated, the rapid rise of the output voltage can be buffered, thereby making the output voltage overshoot relatively low, and having very good practicability. Description of the Drawings

[0016] The above and / or additional aspects and advantages of the present utility model will become apparent and be readily understood from the following description of the embodiments in conjunction with the accompanying drawings, wherein:

[0017] Figure 1 It is a principle block diagram of a DC-DC dimming circuit with adjustable output voltage and improved output voltage overshoot;

[0018] Figure 2 It is a circuit diagram of a DC-DC dimming circuit with adjustable output voltage and improved output voltage overshoot. Detailed Embodiments

[0019] This part will describe in detail the specific embodiments of the present utility model. The preferred embodiments of the present utility model are shown in the accompanying drawings. The role of the drawings is to supplement the description of the text part of the specification, enabling people to intuitively and vividly understand each technical feature and the overall technical solution of the present utility model, but it cannot be construed as a limitation on the protection scope of the present utility model.

[0020] In the description of the present utility model, the meaning of "a plurality of" is two or more. Understandings such as "greater than", "less than", and "exceeding" do not include the present number, and understandings such as "above", "below", and "within" include the present number. If there is a description of "first" and "second", it is only for the purpose of distinguishing technical features and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0021] In the description of the present utility model, it should be understood that when it comes to orientation descriptions, such as the upper, lower, front, rear, left, right, etc., the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model.

[0022] In the present utility model, unless otherwise clearly defined, words such as "set", "installed", "connected", etc. should be understood in a broad sense. For example, they can be directly connected, or indirectly connected through an intermediate medium; they can be fixedly connected, or detachably connected, or integrally formed; they can be mechanically connected; they can be the communication inside two components or the interaction relationship between two components. Those skilled in the art can reasonably determine the specific meaning of the above words in the present utility model in combination with the specific content of the technical solution.

[0023] Refer to Figures 1 to 2 , a DC-DC dimming circuit with adjustable output voltage and improved output voltage overshoot, including a main circuit 10, a DC-DC circuit 20, an output voltage regulation and overshoot prevention circuit 30, a MOS transistor Q1, and an MCU control circuit 40;

[0024] The main circuit 10 is connected to the live wire L and the neutral wire N;

[0025] The input end of the DC-DC circuit 20 is connected to the main circuit 10, the first output end is connected to the source electrode of the MOS transistor Q1, the second output end is connected to one end of the lamp, and the other end of the lamp is connected to the drain electrode of the MOS transistor Q1;

[0026] The output voltage regulation and overshoot prevention circuit 30 is connected between the feedback end of the DC-DC circuit 20, the second output end of the DC-DC circuit 20, and the MCU control circuit 40, and is used to adjust the output voltage and buffer the rapid rise of the output voltage;

[0027] The MCU control circuit 40 is connected to the gate electrode of the MOS transistor Q1, and is used to output a PWM signal to control the on and off of the MOS transistor Q1 to adjust the brightness of the lamp.

[0028] In the present utility model, the working principle is as follows:

[0029] 1) When the power supply is energized, the L and N signals enter the main circuit 10 of the power supply after passing through the rectification circuit 60. At this time, when the main circuit 10 starts to work, a voltage signal VC, a voltage signal VB, and a ground signal GND are generated in the secondary. The voltage signal VB is used to supply power to the single-chip microcomputer U2 in the MCU control circuit 40. The voltage signal VB is connected to the ground through the resistor R11 and the capacitor C5. The midpoint of the resistor R11 and the capacitor C5 is connected to the 16th pin of the single-chip microcomputer U2 to play a reset role.

[0030] 2) In the DC-DC circuit 20, the DC-DC circuit 20 includes a power chip U1, resistors R4-7, electrolytic capacitors EC1-2, capacitors C1-2, an inductor L1, and diodes D1-2. The anode of the diode D1 is connected to the first output terminal of the main circuit 10. The cathode of the diode D1 is respectively connected to one end of the resistor R4, one end of the electrolytic capacitor EC1, one end of the resistor R5, one end of the resistor R6, and the VIN terminal of the power chip U1. The other end of the resistor R5 is respectively connected to the CS terminal of the power chip U1 and one end of the capacitor C1. The other end of the resistor R6 is connected to the EN terminal of the power chip U1. The other end of the capacitor C1 is respectively connected to the SW terminal of the power chip U1, one end of the inductor L1, one end of the capacitor C2, and the cathode of the diode D2. The other end of the capacitor C2 is connected to the BST terminal of the power chip U1 through the resistor R7. The other end of the inductor L1 is respectively connected to one end of the electrolytic capacitor EC2 and one end of the lamp. The other end of the electrolytic capacitor EC2, the anode of the diode D2, the other end of the resistor R4, the other end of the electrolytic capacitor EC1, and the source electrode of the MOS transistor Q1 are connected to the GND terminal.

[0031] Specifically, the voltage signal VC flows into the electrolytic capacitor EC1 through the diode D1 for filtering. After processing, a voltage signal V+ is generated. At the same time, the resistor R4 is connected in parallel across the electrolytic capacitor EC1 to maintain the voltage stability under no-load conditions. The voltage signal V+ is connected to the VIN terminal of the power chip U1 to supply power to the power chip U1. The voltage signal V+ is connected to the EN terminal of the power chip U1 through the resistor R6 to ensure the normal operation of the power chip U1. The voltage signal V+ is connected to the CS terminal of the power chip U1 through the resistor R5. By changing the resistance value of the resistor R5 through the voltage difference between the voltage signal V+ and the voltage at the CS terminal, the output current is controlled. The capacitor C1 is used to connect the 9th pin of the power chip U1 to the 7th and 8th pins of the power chip U1. The BST terminal of the power chip U1 is connected to the 7th and 8th pins of the power chip U1 through the resistor R7 and the capacitor C2. At this time, the signal output from the 7th and 8th pins of the power chip U1 passes through the inductor L1, and then after filtering by the electrolytic capacitor EC2 and the electrolytic capacitor EC3, a stepped-down and stable output voltage VOUT is obtained. The anode of the diode D2 is connected to the GND, and the cathode is connected to the 7th and 8th pins of the power chip U1 to play a freewheeling role.

[0032] 3) In the output voltage regulation and overshoot prevention circuit 30, the output voltage regulation and overshoot prevention circuit 30 includes resistors R1-2, R9-10, adjustable resistor R3, and capacitors C3-4. One end of the adjustable resistor R3 is connected to the feedback terminal of the DC-DC circuit 20, one end of the resistor R1, one end of the capacitor C3, and one end of the resistor R2 respectively. The other end of the adjustable resistor R3 is connected to the GND terminal. The other end of the resistor R1 is connected to one end of the resistor R9 and the second output terminal of the DC-DC circuit 20 respectively. The other end of the capacitor C3 is connected to the other end of the resistor R9. The other end of the resistor R2 is connected to one end of the resistor R10 and one end of the capacitor C4 respectively. The other end of the capacitor C4 is connected to the GND terminal. The other end of the resistor R10 is connected to the MCU control circuit 40.

[0033] Specifically, one end of the resistor R1 is connected to the VOUT signal of the output voltage, and the other end is connected to the FB terminal of the power supply chip U1. The resistor R3 is an adjustable resistor. One end of the resistor R3 is connected to the FB terminal of the power supply chip U1, and the other end is connected to GND. The FB terminal of the power supply chip U1 is the reference pin for output voltage regulation. The voltage value of the output voltage VOUT depends on the resistance values of the resistor R1 and the resistor R3. The voltage value of the output voltage VOUT can be adjusted by adjusting the resistance value of the adjustable resistor R3, so as to achieve the function of adjustable output voltage.

[0034] 4) As a second embodiment of the output voltage regulation, a DC-DC dimming circuit with adjustable output voltage and improved output voltage overshoot further includes a wireless communication circuit 50 connected to the MCU control circuit 40, which is used to communicate with a wireless communication device to obtain an output voltage regulation signal; in a further embodiment, the wireless communication circuit 50 is set as an NFC circuit or a Bluetooth circuit;

[0035] Specifically, the output voltage value is adjusted through a wireless communication device. The voltage signal VB generated by the main circuit 10 is used to supply power to the wireless communication ICU3. The voltage signal VB is connected to pin 3 of the wireless communication ICU3 through the resistor R12 and to pin 4 of the wireless communication ICU3 through the resistor R13 to ensure the normal operation of the wireless communication ICU3. The signal is transmitted to pins 7 and 8 of the wireless communication ICU3 through the wireless communication device. At this time, after the wireless communication ICU3 processes the signal, the signal is transmitted to pins 7 and 8 of the single-chip microcomputer U2 in the MCU control circuit 40 through pins 5 and 6 of the wireless communication ICU3. Then, according to the requirement, different PWMs are output from pin 2 of the single-chip microcomputer U2 to one end of the resistor R10. The PWM signal is filtered by the resistor R10 and the capacitor C4 to obtain a voltage signal VD. The output voltage signal VOUT is connected to the voltage signal VD after passing through the resistors R1 and R2. The voltage value of the output voltage signal VOUT depends on the resistance values of the resistors R1 and R2 and the PWM signal output from pin 2 of the single-chip microcomputer U2. When the PWM signal output from pin 2 of the single-chip microcomputer U2 changes, the voltage signal VD changes, resulting in the change of the output voltage signal VOUT, achieving the effect of adjustable output voltage. It can be applied to the situation where the product is installed outdoors and an external adjustable resistor cannot be connected to ensure waterproofness.

[0036] 5) In one embodiment, the resistor R9 and the capacitor C3 are connected in series. One end of the series connection is connected to one end of the resistor R1, and the other end is connected to the output voltage VOUT. On the one hand, it plays a filtering role, and on the other hand, it can buffer the rapid rise of the output voltage, thereby reducing the overshoot of the output voltage signal VOUT. In addition, the single-chip microcomputer U2 can also send different PWM signals to the MOS transistor Q1 through its pin 10, thereby achieving a dimming effect.

[0037] 6) The advantages of the present utility model are as follows: Through the above structure, the output voltage can be adjusted while buffering the rapid rise of the output voltage, so that the output voltage overshoot is relatively low, and it has very good practicability.

[0038] Of course, the present utility model is not limited to the above embodiments. Those skilled in the art can make equivalent deformations or substitutions without departing from the spirit of the present utility model, and these equivalent deformations and substitutions are all included in the scope defined by the claims of this application.

Claims

1. A DC-DC dimming circuit with adjustable output voltage and improved output voltage overshoot, characterized in that: It comprises a main circuit (10), a DC-DC circuit (20), an output voltage regulation and overshoot prevention circuit (30), a MOS tube Q1 and an MCU control circuit (40); The main circuit (10) is connected to a live wire L and a neutral wire N; The input end of the DC-DC circuit (20) is connected to the main circuit (10), the first output end is connected to the source of the MOS tube Q1, the second output end is connected to one end of the lamp, and the other end of the lamp is connected to the drain of the MOS tube Q1; The output voltage regulation and overshoot prevention circuit (30) is connected between the feedback end of the DC-DC circuit (20), the second output end of the DC-DC circuit (20) and the MCU control circuit (40), and is used for regulating the output voltage and buffering the rapid rise of the output voltage; The MCU control circuit (40) is connected to the gate of the MOS tube Q1 and is used to output a PWM signal to control the on and off of the MOS tube Q1 so as to adjust the brightness of the lamp.

2. A DC-DC dimming circuit with adjustable output voltage and improved output voltage overshoot according to claim 1, characterized in that: The DC-DC circuit (20) comprises a power chip U1, a resistor R4-7, an electrolytic capacitor EC1-2, a capacitor C1-2, an inductor L1 and a diode D1-2, wherein the anode of the diode D1 is connected to the first output end of the main circuit (10), the cathode of the diode D1 is respectively connected to one end of the resistor R4, one end of the electrolytic capacitor EC1, one end of the resistor R5, one end of the resistor R6 and the VIN end of the power chip U1, the other end of the resistor R5 is respectively connected to the CS end of the power chip U1 and one end of the capacitor C1, and the cathode of the resistor R6 is respectively connected to the CS end of the power chip U1 and one end of the capacitor C1. The other end is connected to the EN end of the power chip U1, the other end of the capacitor C1 is respectively connected to the SW end of the power chip U1, one end of the inductor L1, one end of the capacitor C2 and the cathode of the diode D2, the other end of the capacitor C2 is connected to the BST end of the power chip U1 via the resistor R7, the other end of the inductor L1 is respectively connected to one end of the electrolytic capacitor EC2 and one end of the lamp, the other end of the electrolytic capacitor EC2, the anode of the diode D2, the other end of the resistor R4, the other end of the electrolytic capacitor EC1 and the source of the MOS tube Q1 are connected to the GND end.

3. The DC-DC dimming circuit with adjustable output voltage and improved output voltage overshoot according to claim 1, characterized in that: The output voltage regulation and overshoot prevention circuit (30) comprises resistors R1-2, resistors R9-10, an adjustable resistor R3 and a capacitor C3-4, one end of the adjustable resistor R3 is respectively connected to the feedback end of the DC-DC circuit (20), one end of the resistor R1, one end of the capacitor C3 and one end of the resistor R2, the other end of the adjustable resistor R3 is connected to the GND end, the other end of the resistor R1 is respectively connected to one end of the resistor R9 and the second output end of the DC-DC circuit (20), the other end of the capacitor C3 is connected to the other end of the resistor R9, the other end of the resistor R2 is respectively connected to one end of the resistor R10 and one end of the capacitor C4, the other end of the capacitor C4 is connected to the GND end, and the other end of the resistor R10 is connected to the MCU control circuit (40).

4. The DC-DC dimming circuit with adjustable output voltage and improved output voltage overshoot according to claim 1, characterized in that: It also includes a wireless communication circuit (50) connected to the MCU control circuit (40) and used for communicating with a wireless communication device to obtain an output voltage adjustment signal.

5. A DC-DC dimming circuit with adjustable output voltage and improved output voltage overshoot according to claim 4, characterized in that: The wireless communication circuit (50) is configured as an NFC circuit.

6. The DC-DC dimming circuit with adjustable output voltage and improved output voltage overshoot according to claim 4, characterized in that: The wireless communication circuit (50) is configured as a Bluetooth circuit.

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