LED power supplies play a central role in LED lighting products. There are many types of LED power supplies on the market, with significant differences in quality, performance, and price. These differences directly impact the overall performance and cost of LED lighting products. Generally, LED driver power supplies can be categorized into three main types: switching constant current sources, linear IC power supplies, and RC step-down power supplies.
Switching Constant Current Source
Switching constant current sources convert high voltage to low voltage using a transformer, then undergo rectification and filtering to output stable low-voltage DC power. This type of power supply is further categorized as isolated or non-isolated. Isolated power supplies offer superior safety, as they isolate the output voltage between high and low, significantly improving safety while reducing the need for enclosure insulation. Non-isolated power supplies, while less safe, are relatively cost-effective. Traditional energy-saving lamps utilize these non-isolated power supplies, which are equipped with insulating plastic enclosures for enhanced protection.
Switching power supplies are renowned for their excellent safety and stable performance, despite their more complex circuitry and relatively high price. However, thanks to their mature technology and stable performance, switching power supplies have become the mainstream choice in the current LED lighting market.
Linear IC Power Supplies
Linear IC power supplies use one or more ICs to distribute voltage, reducing the number of electronic components and offering high power factor and efficiency. Furthermore, they eliminate the need for electrolytic capacitors, extending service life and reducing costs. However, it's important to note that their high-voltage output is not fully isolated, resulting in flickering, which requires protective enclosures to protect against electric shock. Currently, products marketed as electrolytic-capacitor-free and boasting exceptionally long lifespans mostly utilize linear IC power supply technology.
Due to their high reliability, high efficiency, and low cost, linear IC power supplies are expected to become an ideal choice for future LED driver power supplies.
RC Step-Down Power Supplies
RC step-down power supplies use the charging and discharging of a capacitor to provide drive current. Their circuit design is relatively simple and their cost is relatively low. However, their performance and stability are poor, making them susceptible to damage to LEDs when the grid voltage fluctuates. Furthermore, their high-voltage output is not fully isolated, requiring an insulating protective enclosure. RC step-down power supplies have a low power factor and a relatively short lifespan, making them typically only suitable for economical, low-power products, typically within the 5W power range.
For higher-power products, the output current is high, and the capacitors cannot provide sufficient current, making them prone to burnout. Furthermore, China has clear power factor requirements for high-power lamps, requiring products over 7W to have a power factor greater than 0.7. However, the power factor of RC step-down power supplies is typically low, typically between 0.2 and 0.3, making them unsuitable for high-power products.
