Solar LED street lights

The LED driver detailed in DER-340 uses Power Integrations’ Link Switch-PH family of power conversion ICs which combine single-stage PFC and accurate CC output control. Single-stage LED driver architectures typically yield up to 5% higher efficiency than two-stage designs, which led light bulbs combine losses from separate PFC and constant-current circuits. High-voltage aluminum electrolytic bulk capacitors - the least reliable component in traditional lighting power supply circuits - are not required in the single-stage approach, making 50,000-hour lifetimes attainable. In addition to providing a very effective solution for standard lighting applications in benign environments, DER-340 copes with conditions of poor ventilation and high temperatures in industrial applications through the use of ceramic output capacitors and an accurate hysteretic thermal shutdown feature included in the Link Switch-PH IC.

Comments Andrew Smith, product marketing manager for Power Integrations: “Power supplies are often the weak link in Solar LED street lights. This is especially true for industrial and infrastructure lighting applications where difficult operating conditions can quickly cause traditional power supplies to fail. This reduces the cost-effectiveness of solid-state lighting and conflicts with fixture lifetime expectations built on the basis of the longevity of Solar LED garden lights alone. With high power conversion efficiency and no high-voltage aluminum electrolytic bulk capacitors, DER-340 provides an architecture that avoids this problem and delivers on the long-lifetime promise.”

The single-stage topology also reduces component count, allowing developers to use single-sided boards and smaller enclosures. DER-340 is highly energy-efficient – above 88% at 230 VAC and over 87% at 120 VAC. Output current tolerance is less than 5% across line, load and temperature. Power Integrations’ Link Switch-PH ICs feature comprehensive integrated protection and reliability features including: output open circuit / output short-circuit protection with auto-recovery; line input overvoltage shutdown which extends voltage withstand during line faults; and auto-recovering thermal shutdown with large hysteresis that protects both components and the PCB.