An LED power supply is a power converter that converts the mains power supply into a specific voltage and current to drive the LEDs. Its operating principle is as follows:
Input Section
The AC input (usually 220V or 110V) first passes through a filtering circuit. This filtering circuit, composed of capacitors and inductors, filters out noise and interference from the input power, preventing any adverse effects on subsequent circuits and providing relatively clean AC power to the rectifier circuit.
Filtering Section (Second Filtering)
The rectified DC voltage contains significant ripple and needs to be further smoothed by a filtering circuit. This step typically uses components such as large-capacity electrolytic capacitors. Capacitors store charge in a circuit. When the voltage increases, the capacitor charges; when the voltage decreases, the capacitor discharges, thus making the output DC voltage more stable. Furthermore, the filtering circuit may include components such as inductors. Inductors act to block current fluctuations and, in conjunction with capacitors, further reduce output voltage fluctuations.
DC-DC Conversion Section
After the previous processing, a relatively stable DC voltage is generated, but this voltage may not fully meet the specific voltage and current requirements for LED operation. Therefore, a DC-DC converter circuit is required to regulate voltage and current. DC-DC converter circuits come in a variety of topologies, including buck, boost, and buck-boost. The basic principle is to control the on and off times of switching elements (such as MOSFETs) to alter the charge and discharge states of energy storage components like inductors and capacitors, thereby regulating the output voltage and current.
Protection: LED power supplies are typically equipped with various protection features to ensure safe and reliable operation of the power supply and LEDs. Common protection features include overvoltage protection, overcurrent protection, short-circuit protection, and overtemperature protection.
