| Topology | Active-Clamp Forward, |
| Duty cycle (Max) (%) | 74 |
| Vin (Max) (V) | 16 |
| UVLO thresholds on/off (V) | 12.7/~8 |
| Features | HV Start-up, Input Line Monitor, Programmable Slope Compensation, Soft Start, Soft Switching, Supports PFET Clamp |
| Operating temperature range (C) | -40 to 125 |
| Switching frequency (Max) (kHz) | 1000 |
| Rating | Catalog |
| Gate drive (Typ) (A) | 2 |
- Low-output jitter
- Soft-stop shutdown of MAIN and AUX
- 110-V input startup function
- Ideal for active-clamp, reset-forward, flyback and synchronous rectifier uses
- Provides complementary auxiliary driver with programmable dead time (Turn-On Delay) between AUX and MAIN switches
- Peak current-mode control with 0.5-V cycle-by-cycle current limiting
- TrueDrive? 2-A Sink, 2-A source outputs
- Trimmed internal-bandgap reference for accurate line UV and line OV threshold
- Programmable slope compensation
- High-performance 1-MHz synchronizable oscillator with internal timing capacitor
- Precise programmable maximum duty cycle
- PB-free lead finish package
The UCC2897A PWM controller simplifies implementation of the various active clamp or reset and synchronous rectifier switching power topologies.
The UCC2897A is a peak current-mode fixed-frequency high-performance pulse-width modulator. The controller includes the logic and the drive capability for the P-channel auxiliary switch along with a simple method of programming the critical delays for proper active-clamp operation.
Features include an internal programmable slope compensation circuit, precise DMAX limit, and a synchronizable oscillator with an internal-timing capacitor. An accurate line-monitoring function also programs the ON and OFF transitions of the converter with regard to the bulk input voltage, VIN.
The UCC2897A adds a second-level hiccup-mode current-sense threshold, bi-directional synchronization and input-overvoltage protection functionalities. The UCC2897A is offered in 20-pin TSSOP (PW) and 20-pin QFN (RGP) packages.
