UC3843B 고성능 PWM 컨트롤러 - 텍사스 인스트루먼트

  • Precision Control: The UC3843B offers a fixed frequency current-mode PWM control that ensures fast response and excellent stability in switching power supplies.
  • High Output Drive: With a totem-pole output stage capable of sourcing 1A and sinking 1.2A, it efficiently drives power MOSFETs and reduces switching losses.
  • Low Start-Up Current: The 0.5 mA start-up current improves energy efficiency in standby mode and reduces stress on auxiliary power sources.
  • Undervoltage Lockout (UVLO): Prevents premature MOSFET turn-on, protecting circuits during brownout or startup.
  • Industrial Application Ready: Commonly used in AC/DC power supplies, motor control, and telecom systems, ensuring robust and reliable performance.
텍사스 인스트루먼트 로고
产品上方询盘

Product Overview

그리고 Texas Instruments UC3843B is a fixed-frequency PWM controller optimized for off-line and DC-DC converter applications.
Featuring low start-up and operating current, precision voltage reference, and fast transient response, this controller is widely used
in current-mode control topologies, particularly for switched-mode power supplies (SMPS). Its internal oscillator, undervoltage
lockout, and fault protection make it ideal for robust designs.

Technical Highlights and Comparison Advantages

When comparing the UC3843B to other PWM controllers, its key strengths lie in its ultra-fast response time, energy efficiency, and
high-current output drive. This allows engineers to reduce external components, optimize thermal design, and extend operational
longevity. Compared to traditional voltage-mode controllers, the current-mode approach of the UC3843B provides superior line and
load regulation and inherent cycle-by-cycle current limiting. It is well-regarded in industrial design forums for its reliability
in field-deployed systems.

Technical Parameters

  • Input Voltage Range: 7.6V to 30V
  • Start-Up Current: 0.5 mA (typ)
  • Operating Supply Current: 17 mA (typ)
  • Reference Voltage: 5V ±2%
  • Output Current (Source): 1.0 A
  • Output Current (Sink): 1.2 A
  • Oscillator Frequency: Up to 500 kHz
  • Undervoltage Lockout: 8.4V ON, 7.6V OFF (typ)

Parameter Table

매개변수가치
Start-Up Current0.5 mA
Operating Current17 mA
Reference Voltage5V ±2%
출력 드라이브1A Source / 1.2A Sink
발진기 주파수Up to 500 kHz

일반적인 애플리케이션

  • AC/DC power supplies
  • Motor drive control
  • Telecom and networking power systems
  • Battery-powered industrial instruments
  • Isolated flyback and forward converter designs

자주 묻는 질문(FAQ)

What is the typical use of the UC3843B controller?

The UC3843B is widely used in offline switch-mode power supplies, particularly in current-mode architectures such as flyback or buck converters. It provides fast response and high efficiency, making it ideal for industrial and telecom systems.

How does the UC3843B improve energy efficiency?

With its low 0.5 mA start-up current and efficient totem-pole driver, the UC3843B minimizes standby power consumption and switching losses, improving overall energy performance.

Can this PWM controller drive high-power MOSFETs?

Yes, the UC3843B includes a robust output stage capable of sourcing 1A and sinking 1.2A, suitable for directly driving power MOSFETs in medium- to high-power applications.

Is undervoltage protection integrated?

Yes, the integrated UVLO (undervoltage lockout) prevents operation below the minimum voltage threshold, thereby protecting the system from unstable input conditions.

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产品中间询盘

How does it compare with other controllers?

Compared to older voltage-mode PWM controllers, the UC3843B’s current-mode operation offers enhanced loop stability, easier compensation, and built-in current limiting. These factors reduce BOM cost and simplify design.

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