| Topology | Active-Clamp Forward, Forward |
| Duty cycle (Max) (%) | 73 |
| Vin (Max) (V) | 15 |
| UVLO thresholds on/off (V) | Programmable/2.5V |
| Features | Current Limiting, HV Start-up, Leading Edge Blanking, Soft Start, Supports NFET Clamp, Supports PFET Clamp, Thermal Shutdown |
| Operating temperature range (C) | -40 to 125 |
| Switching frequency (Max) (kHz) | 1000 |
| Rating | Catalog |
| Gate drive (Typ) (A) | 3 |
- Internal Start-Up Bias Regulator
- 3A Compound Main Gate Driver
- Programmable Line Under-Voltage Lockout (UVLO) with Adjustable Hysteresis
- Voltage Mode Control with Feed-Forward
- Adjustable Dual Mode Over-Current Protection
- Programmable Overlap or Deadtime between the Main and Active Clamp Outputs
- Volt x Second Maximum Duty Cycle Clamp
- Programmable Soft-Start
- Current Sense Leading Edge Blanking
- Single Resistor Programmable Oscillator
- Oscillator Up / Down Sync Capability
- Precision 5V Reference
- Thermal Shutdown
Packages
- TSSOP-16
- WSON-16 (5x5 mm) Thermally Enhanced
All trademarks are the property of their respective owners.
The LM5025B is a functional variant of the LM5025 active clamp PWM controller. The functional differences of the LM5025B are as follows:
- The maximum PWM duty cycle is limited to less than 75% to reduce voltage stress on the power MOSFETs.
- The CS2 hiccup mode threshold is increased to 0.5V
- The CS2 filter discharge device is disabled
- The VCC regulator continues to operate when the line UVLO is below the threshold of normal operation
- The VREF regulator is switched off when the line UVLO input falls below the operating threshold
- The internal 5k? COMP pin pull-up resistor is removed
The LM5025B PWM controller contains all of the features necessary to implement power converters utilizing the Active Clamp / Reset technique. With the active clamp technique, higher efficiencies and greater power densities can be realized compared to conventional catch winding or RDC clamp / reset techniques. Two control outputs are provided, the main power switch control (OUT_A) and the active clamp switch control (OUT_B). The two internal compound gate drivers parallel both MOS and Bipolar devices, providing superior gate drive characteristics. This controller is designed for high-speed operation including an oscillator frequency range up to 1MHz and total PWM and current sense propagation delays less than 100ns.
The LM5025B includes a high-voltage start-up regulator that operates over a wide input range of 13V to 100V. Additional features include: Line Under Voltage Lockout (UVLO), softstart, oscillator UP/DOWN sync capability, precision reference and thermal shutdown.
