SG1845Y

Product Overview

• Category: Integrated Circuit (IC)
• Use: Voltage Mode PWM Controller
• Characteristics: High precision, low power consumption, compact size
• Package: DIP-8 (Dual In-line Package with 8 pins)
• Essence: SG1845Y is a voltage mode PWM controller used in various electronic applications.
• Packaging/Quantity: Available in reels of 1000 units.

Specifications

• Input Voltage: 7V to 40V
• Output Voltage: Adjustable from 1.23V to 37V
• Output Current: Up to 500mA
• Operating Temperature: -40°C to +85°C
• Frequency Range: 50kHz to 500kHz
• Duty Cycle: Up to 90%

Detailed Pin Configuration

SG1845Y has the following pin configuration:

1. COMP: Compensation pin for feedback control loop.
2. RT/CT: Timing resistor and capacitor connection pin.
3. VREF: Reference voltage output pin.
4. GND: Ground pin.
5. OSC: Oscillator timing capacitor connection pin.
6. SYNC: Synchronization input pin.
7. FB: Feedback voltage input pin.
8. VCC: Power supply input pin.

Functional Features

• Voltage Mode Control: SG1845Y utilizes voltage mode control to regulate the output voltage.
• Adjustable Output Voltage: The output voltage can be easily adjusted using external resistors and capacitors.
• Wide Input Voltage Range: It can operate within a wide input voltage range of 7V to 40V.
• High Efficiency: The controller ensures high efficiency by optimizing the duty cycle.
• Protection Mechanisms: Built-in protection features include overvoltage, undervoltage, and overcurrent protection.

Advantages and Disadvantages

Advantages: - High precision voltage regulation - Low power consumption - Compact size for space-constrained applications - Wide input voltage range allows for versatile use

Disadvantages: - Limited output current capacity (up to 500mA) - Requires external components for proper operation

Working Principles

SG1845Y operates based on the voltage mode control technique. It compares the feedback voltage with a reference voltage and adjusts the duty cycle of the PWM signal accordingly. By modulating the duty cycle, it regulates the output voltage to the desired level. The timing resistor and capacitor connected to the RT/CT pin determine the frequency of the PWM signal.

Detailed Application Field Plans

SG1845Y finds applications in various fields, including:

1. Power Supplies: It is used in switch-mode power supplies to regulate the output voltage efficiently.
2. LED Lighting: SG1845Y can be employed in LED drivers to maintain stable and accurate LED illumination.
3. Battery Chargers: It is utilized in battery charging circuits to control the charging process and protect the batteries from overcharging.
4. Motor Control: The controller can be integrated into motor control circuits to regulate the motor speed and direction.

Detailed and Complete Alternative Models

Some alternative models that serve similar purposes are:

1. SG3525: A voltage mode PWM controller with higher output current capability.
2. TL494: Another voltage mode PWM controller suitable for various power supply applications.
3. UC3842: A popular choice for offline flyback converters and other power supply designs.

These alternative models offer different features and specifications, allowing users to choose the most suitable option for their specific requirements.

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