Constant-voltage constant-current dual-mode LED driving power automatic switching circuit

Abstract

This utility model discloses a constant voltage and constant current dual-mode LED driver power supply automatic switching circuit, including an LED lamp. One side of the LED lamp has an LED driver circuit, and the other side of the LED driver circuit has a first conversion circuit, a first switch S, a second conversion circuit, a second switch S, a third conversion circuit, and a third switch S. One end of the first switch S is connected to one end of the first conversion circuit. This constant voltage and constant current dual-mode LED driver power supply automatic switching circuit activates the third conversion circuit when the main and auxiliary input voltages are required to be equal, the output voltage is also the same, and there cannot be a large voltage drop. When the main and auxiliary input voltages are required to be equal, the output voltages are different, and there cannot be a large voltage drop, the second conversion circuit is activated. The first conversion circuit is activated in simple switching environments, allowing the circuit to freely switch between different environments, thus demonstrating high practicality.

Description

Technical Field

[0001] This utility model relates to the field of power supply switching circuit technology, specifically a constant voltage and constant current dual-mode LED driver power supply automatic switching circuit. Background Technology

[0002] Power switching circuits automatically switch to backup power when the main power supply fails, ensuring continuous system operation and improving system stability and reliability. Through automatic switching mechanisms, power switching circuits can achieve smooth power switching without interrupting power supply, reducing system downtime caused by power failures. Power switching circuits typically prioritize higher voltage power supplies to ensure optimal power supply to the system, thereby optimizing energy efficiency. Some well-designed power switching circuits feature low static losses, which helps reduce overall system energy consumption.

[0003] However, traditional power switch circuits have the following drawbacks:

[0004] Currently, power supply switching circuits can only switch power supplies using a single MOSFET, which cannot meet the requirement of switching between dual power supplies in complex working environments. Utility Model Content

[0005] The purpose of this invention is to provide a constant voltage and constant current dual-mode LED driver power supply automatic switching circuit to solve the problem mentioned in the background art that the current power supply switching circuit can only switch the power supply with a single MOS transistor, which cannot meet the requirement of completing dual power supply switching in complex working environments.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a constant voltage and constant current dual-mode LED driver power supply automatic switching circuit, including an LED lamp. An LED driver circuit is provided on one side of the LED lamp. A first conversion circuit, a first switch S, a second conversion circuit, a second switch S, a third conversion circuit, and a third switch S are provided on one side of the LED driver circuit. One end of the first switch S is connected to one end of the first conversion circuit. One end of the second switch S is connected to one end of the second conversion circuit. One end of the third switch S is connected to one end of the third conversion circuit. The other ends of the first conversion circuit, the second conversion circuit, and the third conversion circuit are all connected to one end of the LED driver circuit. The other end of the LED driver circuit is connected to one end of the LED lamp.

[0007] Preferably, the first conversion circuit includes a resistor R1, a diode D1, and a MOSFET Q1. One pin of the MOSFET Q1 is connected to one end of the diode D1, and the other pin of the MOSFET Q1 is connected to one end of the resistor R1. The other end of the resistor R1 is grounded.

[0008] Preferably, pin 2 of the MOS transistor Q2 is connected to the first switch S.

[0009] Preferably, the second conversion circuit includes resistors R2 and R3, MOSFETs Q2, Q3, and Q4. One pin of MOSFET Q2 is connected to one pin of MOSFET Q4 and one end of resistor R3. The other end of resistor R3 is connected to one pin of MOSFET Q3. One pin of MOSFET Q3 is connected to one end of resistor R2 and one pin of MOSFET Q4. The second pin of MOSFET Q4 is connected to one pin of MOSFET Q2. The other end of resistor R2 and one pin of MOSFET Q2 are both grounded.

[0010] Preferably, pin 3 of the MOS transistor Q3 is connected to the second switch S.

[0011] Preferably, the third conversion circuit includes MOSFETs Q5, Q6, and Q7, resistors R4 and R5. One pin of MOSFET Q5 is connected to one pin of MOSFET Q6 and one end of resistor R5. The other end of resistor R5 and pin 2 of MOSFET Q6 are both connected to one pin of MOSFET Q7. Pin 2 of MOSFET Q7 and pin 2 of MOSFET Q5 are both connected to one end of resistor R4. The other end of resistor R4 and pin 3 of MOSFET Q5 are both grounded.

[0012] Preferably, pin 3 of the MOS transistor Q7 is connected to the third switch S.

[0013] Compared with the prior art, the beneficial effects of this utility model are: when the main and auxiliary input voltages are required to be equal, and the output voltage is also the same, and there cannot be too large a voltage drop, the third conversion circuit is activated; when the main and auxiliary input voltages are required to be equal, and the output voltages are also different, and there cannot be too large a voltage drop, the second conversion circuit is activated; and the first conversion circuit is activated in a simple switching environment, so that the circuit can freely switch in complex environments and has high practicality. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the architecture of this utility model;

[0015] Figure 2 This is a circuit diagram of the first conversion circuit of this utility model;

[0016] Figure 3 This is a circuit diagram of the second conversion circuit of this utility model;

[0017] Figure 4 This is a circuit diagram of the third conversion circuit of this utility model. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0019] Please see Figure 1-4 This utility model provides a constant voltage and constant current dual-mode LED driver power supply automatic switching circuit, including an LED lamp. An LED driver circuit is provided on one side of the LED lamp. A first conversion circuit, a first switch S, a second conversion circuit, a second switch S, a third conversion circuit, and a third switch S are provided on one side of the LED driver circuit. One end of the first switch S is connected to one end of the first conversion circuit, one end of the second switch S is connected to one end of the second conversion circuit, and one end of the third switch S is connected to one end of the third conversion circuit. The other ends of the first conversion circuit, the second conversion circuit, and the third conversion circuit are all connected to one end of the LED driver circuit, and the other end of the LED driver circuit is connected to one end of the LED lamp.

[0020] The first conversion circuit includes a resistor R1, a diode D1, and a MOSFET Q1. One pin of the MOSFET Q1 is connected to one end of the diode D1, and the other pin of the MOSFET Q2 is connected to one end of the resistor R1. The other end of the resistor R1 is grounded.

[0021] Pin 2 of MOSFET Q2 is connected to the first switch S.

[0022] The second conversion circuit includes resistors R2 and R3, MOSFETs Q2, Q3, and Q4. Pin 1 of MOSFET Q2 is connected to pin 1 of MOSFET Q4 and one end of resistor R3. The other end of resistor R3 is connected to pin 1 of MOSFET Q3. Pin 2 of MOSFET Q3 is connected to one end of resistor R2 and pin 2 of MOSFET Q4. Pin 2 of MOSFET Q4 is connected to pin 2 of MOSFET Q2. The other end of resistor R2 and pin 3 of MOSFET Q2 are both grounded.

[0023] Pin 3 of MOSFET Q3 is connected to the second switch S.

[0024] The third conversion circuit includes MOSFETs Q5, Q6, and Q7, resistors R4 and R5. Pin 1 of MOSFET Q5 is connected to pin 1 of MOSFET Q6 and one end of resistor R5. The other end of resistor R5 and pin 2 of MOSFET Q6 are both connected to pin 1 of MOSFET Q7. Pin 2 of MOSFET Q7 and pin 2 of MOSFET Q5 are both connected to one end of resistor R4. The other end of resistor R4 and pin 3 of MOSFET Q5 are both grounded.

[0025] Pin 3 of MOSFET Q7 is connected to the third switch S.

[0026] In this embodiment, when VIN1 (main power supply) is 3.3V, the NMOS transistor Q1 is turned on, which then pulls down the gate of the PMOS transistor Q3, causing Q3 to turn on. At this time, the voltage between the gate and source gates of the Q2 MOS transistor is equal to the on-state voltage drop of the Q3 PMOS transistor, which is approximately tens of mV. Therefore, the Q2 MOS transistor is turned off, the external power supply to VIN2 is disconnected, and VOUT is powered by VIN1. At this time, VOUT = 3.3V. When the main power supply to VIN1 is disconnected, the NMOS transistor Q1 is turned off, the gate of the Q2 PMOS transistor is pulled down through R1, and Q2 turns on; the gate of the Q3 PMOS transistor is pulled up through R2, and Q3 is turned off. At this time, both Q1 and Q3 are turned off, and VOUT is powered by VIN2 at 3.3V. The static power consumption of the circuit is I1 + I2 = 20uA. When VUSB is disconnected, the voltage 5V at the gate of the PMOS is pulled down to GND by resistor R1. At this time, the PMOS is turned on, and VCC is powered by VBAT to supply power to the lithium battery. When both Vin1 and Vin2 are powered, Vin1 will be used. As long as Vin1 is present, Q5 is turned on, grounding the gate of Q6, and Q6 is also turned on. The gate of Q7 is connected to Vin1, and the source is also Vin1. Then Q7 is turned off, and Vout comes from Vin1. That is to say, when Vin1 = 3.3V, regardless of whether Vin2 has voltage, the voltage is output from Vin1 through Q7. When Vin1 is disconnected, the voltage is output from Vin through Q6. Since the Rds of the MOS transistor is very small, the voltage drop is also very small, so Vout is basically equal to Vin.

[0027] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A constant voltage and constant current dual-mode LED driver power supply automatic switching circuit, comprising an LED lamp, characterized in that: One side of the LED lamp is provided with an LED driving circuit. The other side of the LED driving circuit is provided with a first conversion circuit, a first switch S, a second conversion circuit, a second switch S, a third conversion circuit, and a third switch S. One end of the first switch S is connected to one end of the first conversion circuit, one end of the second switch S is connected to one end of the second conversion circuit, and one end of the third switch S is connected to one end of the third conversion circuit. The other ends of the first conversion circuit, the second conversion circuit, and the third conversion circuit are all connected to one end of the LED driving circuit. The other end of the LED driving circuit is connected to one end of the LED lamp.

2. The constant voltage and constant current dual-mode LED driver power supply automatic switching circuit according to claim 1, characterized in that: The first conversion circuit includes a resistor R1, a diode D1, and a MOSFET Q1. One pin of the MOSFET Q1 is connected to one end of the diode D1, and the other pin of the MOSFET Q1 is connected to one end of the resistor R1. The other end of the resistor R1 is grounded.

3. The constant voltage and constant current dual-mode LED driver power supply automatic switching circuit according to claim 2, characterized in that: Pin 2 of the MOS transistor Q2 is connected to the first switch S.

4. The constant voltage and constant current dual-mode LED driver power supply automatic switching circuit according to claim 1, characterized in that: The second conversion circuit includes resistors R2 and R3, MOSFETs Q2, Q3, and Q4. One pin of MOSFET Q2 is connected to one pin of MOSFET Q4 and one end of resistor R3. The other end of resistor R3 is connected to one pin of MOSFET Q3. One pin of MOSFET Q3 is connected to one end of resistor R2 and one pin of MOSFET Q4. The second pin of MOSFET Q4 is connected to one pin of MOSFET Q2. The other end of resistor R2 and one pin of MOSFET Q2 are both grounded.

5. The constant voltage and constant current dual-mode LED driver power supply automatic switching circuit according to claim 4, characterized in that: The third pin of the MOS transistor Q3 is connected to the second switch S.

6. The constant voltage and constant current dual-mode LED driver power supply automatic switching circuit according to claim 1, characterized in that: The third conversion circuit includes MOSFETs Q5, Q6, and Q7, resistors R4 and R5. One pin of MOSFET Q5 is connected to one pin of MOSFET Q6 and one end of resistor R5. The other end of resistor R5 and pin 2 of MOSFET Q6 are both connected to one pin of MOSFET Q7. Pin 2 of MOSFET Q7 and pin 2 of MOSFET Q5 are both connected to one end of resistor R4. The other end of resistor R4 and pin 3 of MOSFET Q5 are both grounded.

7. The constant voltage and constant current dual-mode LED driver power supply automatic switching circuit according to claim 6, characterized in that: The third pin of the MOS transistor Q7 is connected to the third switch S.

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