Overview
The UCC2894DRG4 is a Current Mode Active Clamp PWM Controller produced by Texas Instruments. This component is part of the UCC289x family, designed to simplify the implementation of various active clamp/reset switching power topologies. It is particularly useful in high-performance power conversion applications, offering advanced features such as high-voltage start-up, undervoltage lockout, and overvoltage protection.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Line Input Voltage, VIN | 18 | - | 110 | V |
| Supply Voltage, VDD | 8.5 | 12.0 | 16.0 | V |
| Operating Junction Temperature, TJ | -40 | - | 125 | °C |
| Start-up Current, ISTARTUP | 300 | 500 | - | µA |
| Operating Supply Current, IDD | -11 | -8 | - | mA |
| Oscillator Frequency, fOSC | 237 | 250 | 263 | kHz |
| Maximum Duty Cycle | 66% | 70% | 74% | % |
| Current Sense Threshold (UCC2894) | 1.23 | 1.27 | 1.31 | V |
Key Features
- High-Voltage Start-Up: The UCC2894DRG4 includes a high-voltage start-up device for applications where the input voltage does not exceed 110 V, though in this specific model, it uses a different function for overvoltage protection.
- Undervoltage Lockout (UVLO): Features a user-programmable UVLO with hysteresis to ensure reliable start-up and operation.
- Overvoltage Protection: Provides accurate overvoltage protection with user-programmable hysteresis, implemented using a single pin.
- Internal 5-V Bias Regulator: Includes an internal 5-V bias regulator with a bypass capacitor for noise filtering and stability.
- Soft Start Capability: Allows for soft start of the power converter using an external capacitor connected to the SS/SD pin).
- High-Current Gate Drivers: Equipped with high-current gate drivers for driving external N-channel MOSFETs, ensuring high-speed and high-drive current capability).
Applications
The UCC2894DRG4 is suitable for a variety of high-performance power conversion applications, including:
- Active Clamp Reset Converters: Ideal for active clamp/reset switching power topologies, enhancing efficiency and reliability in power conversion systems).
- DC-DC Converters: Used in DC-DC conversion applications requiring high accuracy and control over output voltage and current).
- Power Supplies: Applicable in power supply designs that require advanced features such as UVLO, overvoltage protection, and soft start capabilities).
Q & A
- What is the operating junction temperature range of the UCC2894DRG4?
The operating junction temperature range is -40°C to 125°C).
- What is the typical oscillator frequency of the UCC2894DRG4?
The typical oscillator frequency is 250 kHz).
- How is the undervoltage lockout (UVLO) implemented in the UCC2894DRG4?
The UVLO is implemented using a single pin with user-programmable hysteresis).
- What is the purpose of the internal 5-V bias regulator in the UCC2894DRG4?
The internal 5-V bias regulator provides a stable voltage supply for internal logic and can supply up to 5 mA to external circuits).
- How does the soft start capability work in the UCC2894DRG4?
The soft start is achieved using an external capacitor connected to the SS/SD pin, which is charged by an internal DC current source).
- What type of gate drivers does the UCC2894DRG4 have?
The UCC2894DRG4 is equipped with high-current gate drivers for driving external N-channel MOSFETs).
- What is the maximum duty cycle of the UCC2894DRG4?
The maximum duty cycle is up to 74%).
- How is overvoltage protection implemented in the UCC2894DRG4?
Overvoltage protection is implemented using a single pin with user-programmable hysteresis, similar to the UVLO function).
- What is the recommended bypass capacitance for the VDD pin?
A minimum of 1-µF ceramic capacitor is recommended for the VDD pin, with a larger energy storage capacitor in parallel for steady-state operation).
- Can the UCC2894DRG4 be used in high-voltage applications?
Yes, the UCC2894DRG4 can be used in applications where the input voltage does not exceed 110 V, but it does not utilize the high-voltage start-up device; instead, it monitors for overvoltage protection).
