L4981A

Product Overview

Category: Integrated Circuit (IC)
Use: Power Factor Correction (PFC) controller
Characteristics: High efficiency, low standby power consumption
Package: DIP-16, SO-16, TSSOP-16
Essence: Regulates the input current to achieve high power factor and improve energy efficiency
Packaging/Quantity: Available in reels or tubes, quantity depends on manufacturer

Specifications

Input Voltage Range: 85V - 265V AC
Output Voltage Range: 10V - 20V DC
Maximum Output Current: 2A
Switching Frequency: 65kHz - 115kHz
Operating Temperature Range: -40°C to +125°C

Detailed Pin Configuration

The L4981A has a total of 16 pins. The pin configuration is as follows:

VCC: Power supply voltage input
GND: Ground reference
COMP: Compensation pin for feedback loop
CS: Current sense input
INV: Inverting input of error amplifier
NONINV: Non-inverting input of error amplifier
FB: Feedback voltage input
RT/CT: Timing capacitor and resistor connection
SS/TR: Soft-start and tracking pin
OSC: Oscillator frequency setting
SYNC: Synchronization input
OUT: Output voltage
VREF: Reference voltage output
UVLO: Under-voltage lockout
SD: Shutdown control
NC: No connection

Functional Features

Power factor correction with high efficiency
Low standby power consumption
Overvoltage protection
Overcurrent protection
Soft-start function for smooth startup
Synchronization capability for multi-phase operation

Advantages and Disadvantages

Advantages: - High power factor and energy efficiency - Wide input voltage range - Compact package options for flexibility in design - Comprehensive protection features

Disadvantages: - Limited maximum output current (2A) - Requires external components for complete PFC implementation

Working Principles

The L4981A is a power factor correction controller that regulates the input current to achieve a high power factor. It operates by controlling the switching of an external power MOSFET to shape the input current waveform. By ensuring the input current follows the shape of the input voltage, the power factor is improved, reducing harmonics and improving energy efficiency.

Detailed Application Field Plans

The L4981A is commonly used in various applications where power factor correction is required. Some typical application fields include:

Switched-mode power supplies (SMPS)
LED lighting systems
Motor drives
Industrial equipment
Home appliances

Detailed and Complete Alternative Models

L4981AD: Similar specifications, but with additional features like adjustable overvoltage protection
L4981B: Improved version with higher maximum output current (up to 4A)
L4981C: Enhanced version with integrated power MOSFET driver

These alternative models offer similar functionality and can be considered based on specific requirements and design constraints.

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Seznam 10 běžných otázek a odpovědí souvisejících s aplikací L4981A v technických řešeních

Sure! Here are 10 common questions and answers related to the application of L4981A in technical solutions:

Q1: What is the L4981A? A1: The L4981A is a high-voltage resonant mode controller designed for offline power supplies.

Q2: What are the key features of the L4981A? A2: The key features of the L4981A include wide input voltage range, adjustable switching frequency, soft-start function, and protection features like overvoltage and overcurrent protection.

Q3: How does the L4981A help in improving power supply efficiency? A3: The L4981A operates in resonant mode, which reduces switching losses and improves overall power supply efficiency.

Q4: Can the L4981A be used in both flyback and forward converter topologies? A4: Yes, the L4981A can be used in both flyback and forward converter topologies, making it versatile for various applications.

Q5: What is the maximum output power that the L4981A can handle? A5: The L4981A can handle output powers up to several hundred watts, depending on the specific design and operating conditions.

Q6: Does the L4981A have built-in protection features? A6: Yes, the L4981A has built-in protection features such as overvoltage protection, overcurrent protection, and thermal shutdown.

Q7: Can the switching frequency of the L4981A be adjusted? A7: Yes, the switching frequency of the L4981A can be adjusted using external components to meet specific design requirements.

Q8: Is the L4981A suitable for high-voltage applications? A8: Yes, the L4981A is designed for high-voltage applications, typically up to 600V.

Q9: What is the purpose of the soft-start function in the L4981A? A9: The soft-start function gradually ramps up the output voltage during startup, reducing stress on components and preventing excessive inrush current.

Q10: Are there any application notes or reference designs available for the L4981A? A10: Yes, STMicroelectronics provides application notes and reference designs that can help engineers in implementing the L4981A in their technical solutions.

Please note that these answers are general and may vary depending on specific design requirements and application scenarios.