Unloaded detection line

Abstract

This application discloses an unloaded detection circuit, relating to the field of circuit technology. The unloaded detection circuit includes: a microcontroller unit, a first detection unit, and a drive control unit; the drive control unit is used to control the LED power output; the first detection unit is used to detect the LED power output signal and generate a first detection signal accordingly; the second terminal of the microcontroller unit is connected to the drive control unit, and the microcontroller unit outputs a PWM waveform to the drive control unit, which then drives the LED power supply to output a PWM waveform accordingly; the first terminal of the microcontroller unit is connected to the first detection unit, and the microcontroller unit receives the first detection signal and determines whether the power supply is unloaded based on the first detection signal. This application can realize the unloaded detection function, and at the same time, it has fewer components than existing solutions, simplifies the circuit, and can further reduce the size of the LED power supply and reduce material costs.

Claims

1. An unloaded detection line, comprising: The system comprises a microcontroller unit, a first detection unit, and a drive control unit; wherein the drive control unit controls the output of an LED power supply; the first detection unit detects the output signal of the LED power supply and generates a first detection signal accordingly; the second terminal of the microcontroller unit is connected to the drive control unit, and the microcontroller unit outputs a PWM waveform to the drive control unit, which then drives the output PWM waveform of the LED power supply accordingly; the first terminal of the microcontroller unit is connected to the first detection unit, and the microcontroller unit receives the first detection signal and determines whether the power supply is unloaded based on the first detection signal; the first detection unit includes a first resistor, a first capacitor, a second capacitor, and a detection MOSFET; the first terminal of the first resistor and the first terminal of the microcontroller unit are connected to the source of the detection MOSFET, and the second terminal of the first resistor is connected to a set voltage; the drain of the detection MOSFET and the first terminal of the second capacitor are connected to a reference ground; the gate of the detection MOSFET and the second terminal of the second capacitor are connected to the first terminal of the first capacitor; and the second terminal of the first capacitor is connected to the V0 terminal of the LED power supply.

2. The no-load detection line as described in claim 1, wherein, The drive control unit includes a drive IC and a drive NMOS transistor; the first terminal of the drive IC is connected to the second terminal of the microcontroller, and the second terminal of the drive IC is connected to the gate of the drive NMOS transistor; the drain of the drive NMOS transistor is connected to the second terminal of the first capacitor; the source of the drive NMOS transistor is connected to the reference ground of the LED power supply.

3. The no-load detection circuit as described in claim 1 further includes a second detection unit; the second detection unit is connected to the third terminal of the microcontroller; when the PWM output is 100% duty or under heavy load, the output signal of the LED power supply is detected by the second detection unit, and a second detection signal is generated and transmitted to the microcontroller, and the microcontroller determines whether the power supply is no-load based on the second detection signal.

4. The no-load detection line as described in claim 3, wherein, The second detection unit includes: a second resistor and a comparator; the output terminal of the comparator is connected to the third terminal of the microcontroller unit; the second resistor is disposed in the LED power supply and acts as a sampling resistor; the first terminal of the second resistor is connected to the first terminal of the third resistor; the second terminal of the third resistor and the first terminal of the fourth resistor are connected to the negative input terminal of the comparator; the second terminal of the fourth resistor is connected to a reference voltage; the second terminal of the second resistor is connected to the first terminal of the fifth resistor; the second terminal of the fifth resistor is connected to the positive input terminal of the comparator.

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