A Switch Mode Power Supply (SMPS) is often used to provide regulated power to load devices. SMPSs are designed to transfer electrical power from a power source, such as a mains supply, to a load, such as a lighting fixture. SMPSs that are rated under 200 W are generally widely available. However, such SMPSs tend to be prone to failure due to line surges and transients, particularly in outdoor applications. In many applications that use SMPSs, an external surge suppressor module is installed at the input of an SMPS to provide additional protection. External surge suppression modules can add a significant cost to a system and do not necessarily guarantee full protection against surges and transients. Further, SMPSs require a power factor correction stage to improve the power factor from a typical value of 0.5 to desirable values of greater than 0.9.
SMPSs that are rated for greater than 300 W are generally expensive and require relatively larger surge suppression modules, and the availability of such SMPSs is generally limited. Although SMPSs that support AC input range of 120V-277V are commonly available, large wattage SMPSs, i.e., SMPSs with larger input voltages, are not easily available off-the-shelf. In general, SMPSs with relatively larger AC input (e.g., 347V, 480V, 600V) are virtually nonexistent and are also challenging to implement. A common approach used to overcome the challenges of acquiring large wattage SMPSs is to use a linear step-down transformer at the input of a lower rated SMPS to lower the input voltage from 600V to the universal input voltage range of 120V-277V. Thus, a solution that eliminates the need for an external surge suppression module by providing surge suppression and that provides a high power factor, and that can be readily implemented for relatively high AC input voltages is desirable.
USPTO Backgrounds
USPTO Backgrounds