The TPS40009DGQ is a Buck Controller for low-voltage non-isolated synchronous buck regulators. It drives an N-channel MOSFET for the primary buck switch and an N-channel MOSFET for the synchronous rectifier switch, thereby achieving very high-efficiency power conversion. In addition, the device controls the delays from main switch off to rectifier turn-on and from rectifier turn-off to main switch turn-on in such a way as to minimize diode losses (both conduction and recovery) in the synchronous rectifier with TI"s proprietary Predictive Gate Drive™ technology. The reduction in these losses is significant and increases efficiency. For a given converter power level, smaller FETs can be used, or heat sinking can be reduced or even eliminated. The current-limit threshold is adjustable with a single resistor connected to the device. The TPS4000x controllers implement a closed-loop soft start function. Startup ramp time is set by a single external capacitor connected to the SS/SD pin.
1% Internal 0.7V reference
Predictive Gate Drive™ N-channel MOSFET drivers for higher efficiency
Externally adjustable soft-start and overcurrent limit
Fixed-frequency voltage-mode control
Source/sink with VOUT pre-bias
Internal bootstrap diode the SS/SD pin is also used for shutdown
