Analog Devices
A 2-phase nonsynchronous boost controller that drives two stages of external N-channel power MOSFETs has been released by Analog Devices, with the Power by Linear LTC7840. It is configurable as single or dual output boost regulator or for higher voltages, the output of the first channel can feed the input of second channel allowing an output voltage which exceeds several hundred volts.
A typical LTC7840 application is for a 12V input voltage to be boosted to 48V with the first channel and the second channel boosting the 48V to 240V with an output current of up to 700mA, making it ideal for automotive, industrial and medical applications.
The LTC7840 operates over an input voltage ranging from 5.5 to 60V and regulates output voltages that are limited by the choice of external components. Up to four power stages can be clocked out-of-phase to minimize input and output filtering requirements. External MOSFETs switch at a fixed frequency programmable from 50 to 425kHz and can be synchronized to an external clock.
Each channel of the LTC7840 can also be configured as a SEPIC or flyback topology making it highly flexible. Additional features include adjustable maximum duty cycle, adjustable minimum on-time, overload and overvoltage protection along with peak current mode control.
The LTC7840 is available from stock in two thermally enhanced 28 lead packages: a low profile four to five millimeters QFN and TSSOP packages. E and I grades are specified over an operating junction temperature range of -40 to +125°C, and the H grade features operation from -40 to +150°C.
