Non-Isolated LED Driver Chip Power Supply via Flywheel Diode
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Solution Overview
Problem
Existing LED drive circuits using non-isolated constant-current driver chips have low driving efficiency, which fails to meet the requirement of high light efficiency in lighting products.
Innovation Solution
The proposed LED drive circuit includes a first voltage input sub-circuit, a non-isolated LED constant-current driver chip, a first inductor, and a fly-wheel diode, where power is supplied through the LED string light's positive or negative electrode, reducing losses and improving efficiency by omitting the power supply resistor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a non-isolated constant-current driver chip directly supplies power through a resistor, then the circuit structure is simple, but the driving efficiency is low
Solution Approach 1:
The patent extracts and removes the power supply resistor from the traditional circuit configuration. By connecting the power supply directly to the driver chip without an intermediate resistor, the energy loss caused by the resistor is eliminated, thereby improving driving efficiency while maintaining circuit simplicity
Solution Approach 2:
The patent introduces an intermediary capacitor connected between the power supply and the driver chip. This capacitor serves as a mediator that provides stable power supply and filtering, enabling direct power connection without resistors while maintaining signal integrity and reducing energy loss
2Loss of energy
If power is supplied through a resistor to the driver chip, then the circuit is easy to implement, but power loss increases
Solution Approach 1:
The power supply resistor is extracted and removed from the circuit. The driver chip is powered directly from the power supply through a capacitor, eliminating the I²R losses that occur with resistive power supply and significantly reducing overall power loss
Solution Approach 2:
The patent changes the power supply method from resistive to capacitive coupling. By using a capacitor instead of a resistor for power supply, the circuit maintains ease of implementation while dramatically reducing power loss through reactive rather than resistive power delivery
3Use of energy by moving object
If a traditional power supply method is used with a resistor, then the circuit design is straightforward, but light efficiency requirement is not met
Solution Approach 1:
The resistor is extracted from the power supply path, eliminating unnecessary energy conversion steps. Direct power delivery to the driver chip reduces energy loss and improves the overall light efficiency of the LED system
Solution Approach 2:
The capacitor enables continuous and stable power delivery to the driver chip without the interruptions and losses associated with resistive power supply. This continuous useful action ensures maximum energy is converted to light rather than heat in the resistor
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively reduces losses and enhances driving efficiency, improving the overall performance of the lighting apparatus, particularly evident in lower power consumption scenarios.
Implementation Method 1
a first inductor and a first fly-wheel diode... A second end of the first inductor is in connection with an anode of the first fly-wheel diode
Implementation Method 2
a first fly-wheel diode... A cathode of the first fly-wheel diode is in connection with a power-supply pin of the first non-isolated LED constant-current driver chip
Implementation Method 3
The first output filter sub-circuit includes: a first capacitor and a first resistor... A first end of the first capacitor is in connection with a first end of the first resistor
Data Source
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AI summary
The present invention is applicable to the field of lighting technology, and provides an LED drive circuit and a lighting apparatus. The LED drive circuit includes a first voltage input sub-circuit (11), a first non-isolated LED constant-current driver chip (U1), a first inductor (L1) and a first fly-wheel diode (D1). An input of the first voltage input sub-circuit (11) is configured to be connected with an external power supply, an output of the first voltage input sub-circuit (11) is in connection with a first end of the first inductor (L1), and the output of the first voltage input sub-circuit (11) is also configured to be connected with a negative electrode of the LED string light. A second end of the first inductor (L1) is in connection with an anode of the first fly-wheel diode (D1) and a drain of an internal MOSFET of the first non-isolated LED constant-current driver chip (U1). A cathode of the first fly-wheel diode (D1) is in connection with a power-supply pin of the first non-isolated LED constant-current driver chip (U1), and the cathode of the first fly-wheel diode (D1) is also configured to be connected with a positive electrode of the LED string light. In the present invention, power is supplied to the driver chip through the positive electrode or negative electrode of the LED string light, such that the loss of the drive circuit is effectively reduced, and the drive efficiency of the drive circuit is improved.