Overview
The UC3844BD1 is a high-performance current mode PWM (Pulse Width Modulation) controller produced by STMicroelectronics. This integrated circuit is part of the UC384xB family, designed to implement off-line or DC to DC fixed frequency current mode control schemes with a minimal number of external components. It features a trimmed oscillator for precise frequency control, automatic feed-forward compensation, and latching PWM for cycle-by-cycle current limiting. The device is suitable for a wide range of power supply applications, including switch-mode power supplies and DC-DC converters.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Supply Voltage (low impedance source) | 30 | V |
| Output Current | ±1 | A |
| Oscillator Frequency | 250 kHz (guaranteed) | kHz |
| Maximum Duty Cycle | 47-50% | % |
| Under-Voltage Lockout (UVLO) Start Threshold | 16 V (on), 10 V (off) | V |
| Minimum Operating Voltage After Turn-on | 9-11 V | V |
| Start-up Current | 0.3-0.5 mA | mA |
| Operating Supply Current | 12-17 mA | mA |
| Storage Temperature Range | -65 to 150 °C | °C |
| Junction Operating Temperature | -40 to 150 °C | °C |
Key Features
- Trimmed Oscillator: Provides precise frequency control up to 500 kHz.
- Current Mode Operation: Supports current mode control with automatic feed-forward compensation.
- Latching PWM: Ensures cycle-by-cycle current limiting.
- Internally Trimmed Reference: With under-voltage lockout and hysteresis.
- High Current Totem Pole Output: Capable of sourcing or sinking high peak currents, suitable for driving N-Channel MOSFETs.
- Low Start-up and Operating Current: Start-up current less than 0.5 mA and operating current of 12-17 mA.
Applications
The UC3844BD1 is widely used in various power supply applications, including:
- Switch-Mode Power Supplies: For efficient power conversion in off-line and DC-DC converters.
- DC-DC Converters: In fixed frequency current mode control schemes.
- Power Management Systems: Where precise control over output voltage and current is required.
Q & A
- What is the UC3844BD1 used for?
The UC3844BD1 is used for implementing off-line or DC to DC fixed frequency current mode control schemes in power supply applications.
- What is the oscillator frequency of the UC3844BD1?
The oscillator frequency is guaranteed at 250 kHz and can operate up to 500 kHz.
- What are the under-voltage lockout thresholds for the UC3844BD1?
The under-voltage lockout start threshold is 16 V (on) and 10 V (off).
- What is the maximum duty cycle of the UC3844BD1?
The maximum duty cycle is between 47% and 50%.
- What is the start-up current of the UC3844BD1?
The start-up current is less than 0.5 mA.
- What is the operating supply current of the UC3844BD1?
The operating supply current is between 12 mA and 17 mA.
- What is the storage temperature range for the UC3844BD1?
The storage temperature range is from -65 °C to 150 °C.
- What is the junction operating temperature range for the UC3844BD1?
The junction operating temperature range is from -40 °C to 150 °C.
- Can the UC3844BD1 drive N-Channel MOSFETs?
Yes, the UC3844BD1 has a high current totem pole output stage suitable for driving N-Channel MOSFETs.
- What are some common applications of the UC3844BD1?
Common applications include switch-mode power supplies, DC-DC converters, and power management systems.
