peculiarity
8V to 40V Input Voltage Range:
Integrated N-channel buck switch
The valley current limit varies with V IN and V OUT to reduce excessive inductor current
Time reduction on current limit
Integrated start-up regulator
No loop compensation is required
Ultra-fast transient response
Maximum switching frequency: 1.3 MHz
The operating frequency remains almost constant, with changes in load current and input voltage
Programmable soft-start
Precision internal reference
Adjustable output voltage
Thermal shutdown
illustrate
The LM34914 buck switching regulator has all the features needed to implement a low-cost, high-efficiency, buck bias regulator capable of delivering at least 1.25A load. To reduce excessive switching current due to the possibility of saturation inductance, valley current limiting with changes in input and output voltage thresholds, and when current limiting is detected, time on time decreases. This buck regulator contains a 44V N-channel buck switch in a thermally enhanced 3 mm x 3 mm LLP-10 package. The feedback regulation mechanism requires no loop compensation, fast load transient response, and results in simplified circuit implementation. Changes in operating frequency, line and load remain unchanged due to the inverse relationship between input voltage and time. From constant voltage constant current mode, when current limiting is detected in a smooth transition, the valley current limit results in reducing frequency and output voltage without the use of foldback. Other features include VCC undervoltage lockout, thermal shutdown, gate drive at lockout voltage, and maximum duty cycle limit.