The UCC28951-Q1 controller is an enhanced version of the UCC28950-Q1. It is a fully compatible drop-in replacement for the UCC28950-Q1. Refer to application note Making the Correct Choice: UCC28950-Q1 or UCC28951-Q1 to determine which controller to use.The UCC28951-Q1 uses advanced control of the full-bridge in addition to active control of the synchronous rectifier (SR) output stage.Programmable delays ensure ZVS operation over a wide range of operating conditions, while the load current naturally tunes the switching delays of the secondary-side synchronous rectifiers(SR). This functionality maximizes overall system efficiency.The 24-pin, TSSOP package complies with RoHS requirements.
- Qualified for automotive applications
- AEC-Q100 qualified with the following results:
- Device temperature grade 1: –40°C to +125°C ambient operating temperature range
- Device HBM ESD classification level H2
- Device CDM ESD classification level C3B
- Enhanced zero-voltage switching (ZVS) range
- Direct synchronous rectifier (SR) control
- Light-load efficiency management including:
- Burst mode operation
- Discontinuous conduction mode (DCM), dynamic SR on/off control with programmable threshold
- Programmable adaptive delay
- Average- or peak-current mode control with programmable slope compensation and voltage-mode control
- Closed-loop soft-start and enable function
- Programmable switching frequency up to 1 MHz with bidirectional synchronization
- (±3%) cycle-by-cycle current limit protection with hiccup mode support
- 150-µA start-up current
- VDD undervoltage lockout
- Wide temperature range: –40°C to +125°C
| Topology | Phase-shifted full bridge |
| Control mode | Current |
| Duty cycle (max) (%) | 97 |
| Switching frequency (max) (kHz) | 1000 |
| Features | Adjustable switching frequency, Current limiting, Enable/Shutdown, Error amplifier, Green mode, Light-load efficiency, Programmable slope compensation, SR logic, Soft start, Soft switching, Synchronization pin, Thermal shutdown |
| UVLO thresholds on/off (V) | 7.3/6.7 |
| Operating temperature range (°C) | -40 to 125 |
| Rating | Automotive |
| Gate drive (typ) (A) | 0.2 |
| Vin (max) (V) | 17 |