The LM25116 is a synchronous step-down controller for step-down regulator applications with high voltage or wide range of input power changes. The control method is based on current mode control, using a simulated current ramp. The device comes in a power-enhanced 20-pin HTSSOP package with exposed die attachment pads to aid in heat dissipation. Current mode control provides inherent line feedforward, cycle current limiting and easy loop compensation.
Typical Application
The use of simulation control ramps reduces the noise sensitivity of pulse width modulation circuits, allowing reliable control of very small duty ratios in high input voltage applications. Operating frequency can be programmed from 50 KHZ to 1 MHZ. The LM25116 drives external high side and low side NMOS power switches with adaptive dead zone control. A user selectable diode simulation mode enables discontinuous mode operation to improve efficiency under light load conditions.
Functional block diagram
Low static current turns off the controller, consuming less than 10 μA of total input current. Other features include a high voltage bias regulator, automatic switch to external bias for increased efficiency, thermal shutdown, frequency synchronization, cycle term flow and adjustable line undervoltage locking.
