Texas Instruments
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UC3847N
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UC3847N

Product Overview

  • Category: Integrated Circuit
  • Use: PWM Controller
  • Characteristics:
    • High-performance voltage mode controller
    • Designed for offline and DC-to-DC converters
    • Provides precise control of power supply systems
  • Package: DIP (Dual In-line Package)
  • Essence: Regulates the output voltage of power supplies
  • Packaging/Quantity: Available in tubes or reels, quantity varies

Specifications

  • Input Voltage Range: 8V to 35V
  • Output Voltage Range: 0V to 30V
  • Maximum Duty Cycle: 50%
  • Operating Temperature Range: -40°C to +85°C
  • Frequency Range: 100Hz to 500kHz
  • Output Current: Up to 1A

Pin Configuration

The UC3847N has a total of 16 pins. The pin configuration is as follows:

  1. VREF: Reference Voltage Input
  2. COMP: Error Amplifier Output
  3. INV: Inverting Input of Error Amplifier
  4. NONINV: Non-Inverting Input of Error Amplifier
  5. CS: Current Sense Input
  6. RT/CT: Timing Components Connection
  7. GND: Ground
  8. VCC: Power Supply Input
  9. SYNC: Synchronization Input
  10. OSC: Oscillator Timing Components Connection
  11. OUT: Output
  12. FB: Feedback Input
  13. SS: Soft-Start Control
  14. NC: No Connection
  15. NC: No Connection
  16. NC: No Connection

Functional Features

  • Precise voltage regulation
  • Adjustable frequency and duty cycle
  • Overcurrent protection
  • Soft-start function
  • Synchronization capability
  • Error amplifier for accurate feedback control

Advantages and Disadvantages

Advantages: - High-performance voltage regulation - Wide input and output voltage range - Flexible frequency and duty cycle adjustment - Comprehensive protection features

Disadvantages: - Limited maximum duty cycle - Requires external timing components - Not suitable for high-power applications

Working Principles

The UC3847N is a voltage mode controller that regulates the output voltage of power supply systems. It operates by comparing the feedback voltage with a reference voltage to generate an error signal. This error signal is then amplified and used to control the duty cycle of the PWM (Pulse Width Modulation) signal. By adjusting the duty cycle, the output voltage can be precisely regulated.

The controller also incorporates various protection features such as overcurrent protection and soft-start control. These ensure the stability and reliability of the power supply system.

Detailed Application Field Plans

The UC3847N is commonly used in various applications including:

  1. Offline Power Supplies: Used in AC-to-DC converters for appliances, lighting systems, and industrial equipment.
  2. DC-to-DC Converters: Employed in voltage step-up or step-down applications, such as battery chargers and automotive electronics.
  3. Switching Power Supplies: Utilized in computer power supplies, telecommunications equipment, and audio amplifiers.

Detailed and Complete Alternative Models

Some alternative models to the UC3847N include:

  1. UC3842: Similar functionality but with lower output current capability.
  2. UC3844: Higher output current capability and additional features like adjustable slope compensation.
  3. UC3845: Similar to UC3844 but with higher operating frequency capability.

These alternative models provide options for different power supply requirements and design considerations.

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Seznam 10 běžných otázek a odpovědí souvisejících s aplikací UC3847N v technických řešeních

Sure! Here are 10 common questions and answers related to the application of UC3847N in technical solutions:

  1. Q: What is UC3847N? A: UC3847N is a pulse width modulation (PWM) controller IC commonly used in power supply applications.

  2. Q: What is the purpose of UC3847N? A: The purpose of UC3847N is to regulate the output voltage of a power supply by controlling the duty cycle of the PWM signal.

  3. Q: What is the operating voltage range of UC3847N? A: UC3847N typically operates within a voltage range of 8V to 35V.

  4. Q: How does UC3847N control the duty cycle? A: UC3847N uses an internal oscillator and error amplifier to compare the feedback voltage with a reference voltage, adjusting the duty cycle accordingly.

  5. Q: Can UC3847N be used in both buck and boost converter topologies? A: Yes, UC3847N can be used in both buck and boost converter topologies, as well as other power supply configurations.

  6. Q: What is the maximum switching frequency supported by UC3847N? A: UC3847N supports a maximum switching frequency of around 500 kHz.

  7. Q: Does UC3847N have built-in protection features? A: Yes, UC3847N includes various protection features such as overvoltage protection, undervoltage lockout, and thermal shutdown.

  8. Q: Can UC3847N drive external power MOSFETs directly? A: No, UC3847N requires external power MOSFETs to switch the high current required for power conversion.

  9. Q: Is UC3847N suitable for high-power applications? A: Yes, UC3847N is commonly used in medium to high-power applications, such as switch-mode power supplies and motor drives.

  10. Q: Are there any application notes or reference designs available for UC3847N? A: Yes, the manufacturer of UC3847N provides application notes and reference designs that can help with the implementation of the IC in various technical solutions.

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