Overview
The UC2844BD1, part of the UC284xB family of control ICs from STMicroelectronics, is a high-performance current mode PWM controller. This device is designed to implement off-line or DC to DC fixed frequency current mode control schemes with a minimal external parts count. It features a trimmed oscillator for precise duty cycle control, an internally trimmed reference with undervoltage lockout, and a high current totem pole output stage suitable for driving N-Channel MOSFETs. The UC2844BD1 is particularly suited for off-line applications due to its under-voltage lockout thresholds and adjustable duty cycle ranges.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Supply Voltage (Vi) | - | - | 30 | V |
| Reference Output Voltage (Vref) | 4.95 | 5.00 | 5.05 | V |
| Oscillator Frequency | - | 250 | - | kHz |
| Output Current (IO) | - | - | ±1 | A |
| Output Energy (EO) | - | - | 5 | µJ |
| Power Dissipation at Tamb ≤ 25 °C (SO8) | - | - | 800 | mW |
| Storage Temperature Range | -65 | - | 150 | °C |
| Junction Operating Temperature | -40 | - | 150 | °C |
| Under-Voltage Lockout Thresholds (On/Off) | 16/10 | - | - | V |
Key Features
- Trimmed Oscillator for Precise Frequency Control: Ensures accurate duty cycle control with an oscillator frequency guaranteed at 250 kHz.
- Internally Trimmed Reference with Undervoltage Lockout: Provides a precision reference voltage and protects against undervoltage conditions.
- Current Mode Operation to 500 kHz: Supports high-frequency current mode operation.
- Latching PWM for Cycle-by-Cycle Current Limiting: Offers cycle-by-cycle current limiting for enhanced safety and reliability.
- High Current Totem Pole Output: Designed to source or sink high peak current, suitable for driving N-Channel MOSFETs.
- Automatic Feed Forward Compensation: Enhances the stability and performance of the control loop.
- Undervoltage Lockout with Hysteresis: Protects the device from operating under low voltage conditions with hysteresis for stability.
- Low Start-Up and Operating Current: Minimizes power consumption during start-up and operation).
Applications
The UC2844BD1 is ideally suited for various power management applications, including:
- Off-Line Power Supplies: Due to its under-voltage lockout thresholds and robust design, it is well-suited for off-line power supply applications).
- DC to DC Converters: The device supports fixed frequency current mode control, making it suitable for DC to DC converter applications).
- High-Frequency Switching Applications: With its ability to operate up to 500 kHz, it is suitable for high-frequency switching applications).
Q & A
- What is the primary function of the UC2844BD1?
The UC2844BD1 is a high-performance current mode PWM controller designed for off-line or DC to DC fixed frequency current mode control schemes).
- What is the oscillator frequency of the UC2844BD1?
The oscillator frequency is guaranteed at 250 kHz).
- What are the under-voltage lockout thresholds for the UC2844BD1?
The under-voltage lockout thresholds are 16V (on) and 10V (off)).
- What type of output stage does the UC2844BD1 have?
The UC2844BD1 has a high current totem pole output stage suitable for driving N-Channel MOSFETs).
- What is the maximum operating temperature of the UC2844BD1?
The maximum operating temperature is 150 °C).
- Does the UC2844BD1 have cycle-by-cycle current limiting?
Yes, it features latching PWM for cycle-by-cycle current limiting).
- What is the typical start-up current of the UC2844BD1?
The start-up current is less than 0.5 mA).
- Is the UC2844BD1 RoHS compliant?
Yes, the UC2844BD1 is RoHS compliant with an Ecopack2 grade).
- What are the common applications of the UC2844BD1?
Common applications include off-line power supplies, DC to DC converters, and high-frequency switching applications).
- What package types are available for the UC2844BD1?
The UC2844BD1 is available in SO-8 and DIP-8 packages).
