advertisement 80µA Quiescent Current Synchronous Step-Down Controller Extends Battery Life in Automotive Applications – Design Note 1014
Julian Zhu Introduction
Battery powered applications that have a significant
amount of time in standby mode, require electrical circuits
to operate with a low quiescent current to preserve battery life. The LTC3835 synchronous step-down controller
is an excellent solution with its ultralow quiescent current (80µA). Other features make it uniquely qualified to
satisfy the needs of automotive applications. A wide 4V
to 36V input voltage range protects the supply against
high input voltage transients and is compatible with low
voltage cold crank conditions. The constant frequency
current-mode architecture with high-side inductor current sensing provides excellent line and load regulation
and reliable current limiting and sharing. The 0.8V to
10V output voltage range provides flexibility for a variety
of applications. Solution size is small due to the 650kHz
switching frequency, which reduces external component
sizes, and the integrated synchronous FET driver, which
keeps component count low. Furthermore, the LTC3835
provides high efficiency over a wide load range up to 20A.
Other important features include:
CLKOUT The output voltage can be ramped during start-up with
an adjustable soft-start or it can track an external ramp
signal. The controller can be synchronized to an external clock
via a phase-locked loop. The CLKOUT pin and current mode control allow interleaved operation of multiple parallel controllers for …