Overview
The UC2843N is a current-mode PWM controller from Texas Instruments, designed for use in off-line and DC-to-DC converters. This integrated circuit is part of the UCx84x family and is optimized for fixed-frequency current-mode control schemes. It features a minimal number of external components, making it a versatile choice for various power supply applications. The UC2843N operates over a temperature range of -40°C to 85°C and is available in an 8-pin PDIP (P) package.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Operating Temperature Range | -40 to 85 | °C |
| Package Type | PDIP (P) | |
| Number of Pins | 8 | |
| Maximum Switching Frequency | Up to 500 kHz | |
| Start-Up Current | < 1 mA | |
| Output Current (Totem-Pole) | Up to 1 A | |
| Undervoltage Lockout (UVLO) Start Threshold | 7.8 to 9 V | |
| UVLO Minimum Operation Voltage After Turn-On | 7 to 8.2 V | |
| Maximum Duty Cycle | Up to 100% |
Key Features
- Optimized for off-line and DC-to-DC converters
- Low start-up current (< 1 mA)
- Automatic feedforward compensation
- Pulse-by-pulse current limiting
- Enhanced load-response characteristics
- Undervoltage lockout with hysteresis
- Double-pulse suppression
- High-current totem-pole output
- Internally trimmed bandgap reference
- Error amplifier with low output resistance
Applications
- Switch mode power supplies (SMPS)
- DC-DC converters
- Power modules
- Industrial power supplies
- Battery-operated power supplies
Q & A
- What is the operating temperature range of the UC2843N?
The UC2843N operates over a temperature range of -40°C to 85°C.
- What is the maximum switching frequency of the UC2843N?
The UC2843N can operate at switching frequencies up to 500 kHz.
- What is the start-up current of the UC2843N?
The start-up current of the UC2843N is less than 1 mA.
- What type of output stage does the UC2843N have?
The UC2843N has a high-current totem-pole output stage capable of sourcing or sinking up to 1 A of gate driver current.
- What is the purpose of the undervoltage lockout (UVLO) feature?
The UVLO feature prevents the power MOSFET from turning on during power-up and power-down sequences, ensuring controlled operation and protecting the device from undervoltage conditions.
- What are the typical applications of the UC2843N?
The UC2843N is typically used in switch mode power supplies (SMPS), DC-DC converters, power modules, industrial power supplies, and battery-operated power supplies.
- How does the pulse-by-pulse current limiting work in the UC2843N?
The pulse-by-pulse current limiting is inherent in the current mode control scheme, allowing an upper limit on the peak current to be established by clamping the error voltage.
- What is the role of the error amplifier in the UC2843N?
The error amplifier is used to control the power converter's output voltage and feedback loop, and it can source up to 0.8 mA and sink up to 6 mA.
- How does the UC2843N handle double-pulse suppression?
The UC2843N features double-pulse suppression to prevent unwanted pulses during operation.
- What is the significance of the internally trimmed bandgap reference in the UC2843N?
The internally trimmed bandgap reference provides a precise voltage reference for the device, ensuring accurate operation and stability.
