ZHCSIH0B December 2017 – July 2019 LP87702-Q1
The LP87702-Q1 includes two high-efficiency step-down DC/DC converters. The buck converters deliver 0.7-V to 3.36-V regulated voltage rails from 2.8-V to 5.5-V input-supply voltage. The converters are designed for flexibility; most of the functions are programmable, thus optimizing the converter operation for each application:
Some of the key parameters that can be programmed via registers (with default values set by OTP bits):
There are two modes of operation for the buck converters, depending on the output current required: pulse width modulation (PWM) and pulse-frequency modulation (PFM). The converter operates in PWM mode at high load currents of approximately 520 mA or higher. Lighter output current loads will cause the converter to automatically switch into PFM mode for reduced current consumption when forced PWM mode is disabled. The forced PWM mode can be selected to maintain fixed switching frequency at all load currents. When buck is disabled, buck output is isolated from the input voltage rail. Output has an optional pulldown resistor.
A block diagram of a single buck converter is shown in Figure 7.