The LM34930 constant On-Time Step Down Switching Regulator
features all the functions needed to implement a low
cost, efficient, buck bias regulator capable of supplying in excess
of 1A load current. This high voltage regulator contains
an N-Channel Buck Switch, and is available in a μSMD
bumped package. The constant on-time regulation principle
requires no loop compensation, results in fast load transient
response, and simplifies circuit implementation. The operating
frequency remains constant with line and load. The valley
current limit results in a smooth transition from constant voltage
to constant current mode when current limit is detected
without the use of current limit foldback. To reduce the possibility
of saturating the inductor the valley current limit threshold
reduces as the input voltage increases, and the on-time
is reduced when current limit is detected. Additional features
include: Over-voltage indicator, Input over-voltage shutdown,
Vcc under-voltage lock-out, thermal shutdown, and maximum
duty cycle limiting.