The STMicroelectronics peak current mode PFC controller is suitable for boost converters with proprietary multiplier emulators

     The L4985A/B and L4986A/B quad device series of STMicroelectronics are peak current mode PFC controllers for boost converters, with proprietary multiplier emulators. In addition to the innovative THD optimizer, they also guarantee extremely low total harmonic distortion (THD) performance under all operating conditions. These devices provide a high-performance low component count solution for CCM operated boost PFC pre regulators in EN61000-3-2 and JEIDA-MITI compatible applications, with power ranges from hundreds of watts to thousands of watts. These devices benefit from proprietary off time modulators that operate at quasi fixed frequencies under all operating conditions. A 65 kHz option and B 130 kHz option are available.

     The 800 V high-voltage starting block includes a circuit to discharge the X capacitor of the EMI filter to a safe level. This allows the device to meet safety regulations such as IEC 61010-1 or IEC 62368-1 without using traditional discharge resistors in parallel with the X capacitor. These devices have low power consumption and disabling functions, and are suitable for applications that must comply with the latest energy conservation requirements issued by Energy Star (the joint program of the U.S. Environmental Protection Agency (EPA) and the Department of Energy (DoE)), the European Code of Conduct, the EU Ecological Design Directive and other guidelines. L4985A/B adopts SO8 package, while L4986A/B adopts SSOP10.

     In addition to controlling the over-voltage protection of the output voltage under transient conditions, the IC can also prevent feedback loop failures or incorrect settings, and improve the inductance saturation. The power down protection function allows the design of medical devices according to the latest IEC 60601-1-2 regulation, which requires a stable output in the event of power dips lasting up to 500 milliseconds. Soft start limits the peak current. For L4986A/B only, PG_ IN is an adjustable input comparator, which is suitable for monitoring PFC output voltage, and the corresponding drive is from PG_ Logic signal output by OUT pin