ST L4984DTR

The L4984D is a current-mode PFC controller operating with line-modulated fixed-off-time. It can be used in boost PFC converters as long as they are operated in CCM (continuous conduction mode). The chip comes in a 10-pin SO package and offers a low-cost solution. It allows wide-range-mains operation with a reasonably low THD (1% at Tj = 25 °C). The output voltage is controlled by means of a voltage-mode error amplifier and an accurate (1% at Tj = 25 °C) internal voltage reference. Loop stability is optimized by the voltage feedforward function, which also significantly improves the transient response in the case of line drops and surges. The device features low consumption and includes a disable function suitable for applications complying with the latest energy saving requirements. In addition to overvoltage protection, the IC is also provided with protection against feedback loop failures or erroneous settings.

• Line-modulated fixed-off-time (LM-FOT) control of CCM operation
• Proprietary LM-FOT modulator for nearly fixed frequency operation
• Proprietary multiplier design for minimum THD of 1/V² input current
• Fast "bi-directional" input voltage feedforward (1/V correction)
• Accurate adjustable output overvoltage protection
• Protection against feedback loop failure
• 1% (at Tj = 25 °C) internal reference voltage
• 600 / +800 mA active pull-down
• SSOP10 package

• Pre-regulators for IEC61000 - 3 - 2 and JEIDA - MITI