Overview
The L4984DTR is a current-mode Power Factor Correction (PFC) controller produced by STMicroelectronics. It operates using line-modulated fixed-off-time (LM-FOT) control, enabling fixed-frequency operation for boost PFC converters in continuous conduction mode (CCM). This IC is packaged in a 10-pin SSOP package and is designed to provide a low-cost solution for CCM-operated boost PFC pre-regulators. It is compliant with EN61000-3-2 and JEIDA-MITI standards and is suitable for power ranges from a few hundred watts to over 1 kW.
The L4984DTR features a highly linear multiplier that reduces crossover distortion of the AC input current, allowing for wide-range mains operation with low Total Harmonic Distortion (THD). The output voltage is controlled by a voltage-mode error amplifier and an accurate internal voltage reference. The device also includes various protection features and a disable function for remote on/off control, making it compliant with the latest energy-saving requirements such as Blue Angel, ENERGY STAR, and Energy 2000.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Supply Voltage (VCC) | 10.3 | - | 22.5 | V |
| Turn-on Threshold (VCCOn) | 11 | 12 | 13 | V |
| Turn-off Threshold (VCCOff) | 8.7 | 9.5 | 10.3 | V |
| Internal Reference Voltage | - | 2.5 | - | V |
| Gate Driver Output Current | - | - | 600 mA (source), 800 mA (sink) | mA |
| Junction Temperature Range | -40 | - | 150 | °C |
| Storage Temperature Range | -55 | - | 150 | °C |
Key Features
- Line-modulated fixed-off-time (LM-FOT) control of CCM-operated PFC pre-regulators
- Proprietary LM-FOT modulator for nearly fixed-frequency operation
- Proprietary multiplier design for minimum THD of AC input current
- Fast “bi-directional” input voltage feedforward (1/V2 correction)
- Accurate adjustable output overvoltage protection
- Protection against feedback loop failure (latched shutdown)
- Inductor saturation protection
- AC brownout detection
- Digital leading-edge blanking on current sense
- Soft-start to limit peak current and prevent flux runaway
- 1% (at Tj = 25 °C) internal reference voltage
- Totem pole gate driver with active pull-down during UVLO and voltage clamp
- SSOP10 package
Applications
The L4984DTR is suitable for various applications, including:
- PFC pre-regulators for IEC61000-3-2 and JEIDA-MITI compliant Switch-Mode Power Supplies (SMPS) in excess of 1 kW
- Desktop PCs, servers, and web servers
- Compliance with energy-saving standards such as Blue Angel, ENERGY STAR, and Energy 2000
Q & A
- What is the primary function of the L4984DTR?
The L4984DTR is a current-mode Power Factor Correction (PFC) controller designed for boost PFC converters operating in continuous conduction mode (CCM).
- What package type does the L4984DTR come in?
The L4984DTR comes in a 10-pin SSOP package.
- What is the operating voltage range of the L4984DTR?
The operating voltage range is from 10.3 V to 22.5 V.
- What protection features does the L4984DTR include?
The L4984DTR includes overvoltage protection, protection against feedback loop failure, inductor saturation protection, and AC brownout detection.
- How does the L4984DTR improve line transient response?
The device uses a proprietary “bi-directional” input voltage feedforward (1/V2 correction) to significantly improve line transient response during mains drops and surges.
- What is the purpose of the soft-start feature in the L4984DTR?
The soft-start feature limits peak current and extends off-time to prevent flux runaway in the initial cycles.
- What is the capability of the gate driver output stage?
The totem pole output stage is capable of 600 mA source current and 800 mA sink current.
- Is the L4984DTR compliant with energy-saving standards?
Yes, the L4984DTR is compliant with standards such as Blue Angel, ENERGY STAR, and Energy 2000.
- What is the junction temperature operating range of the L4984DTR?
The junction temperature operating range is from -40 °C to 150 °C.
- What is the storage temperature range for the L4984DTR?
The storage temperature range is from -55 °C to 150 °C.
