EA

REF

EN/SYNC

SW

BOOT

VCC

Internal

SS

OV/UV

Detector

Oscillator

Precision

Enable

LDO

PFM

Detector

Slope

Comp

PWM CONTROL LOGIC

UVLO

TSD

Freq

Foldback

Zero

Cross

HICCUP

Detector

VIN

Rc

Cc

PGND

FB

LS I Sense

HS I Sense

FB

VCC

Enable

SYNC

Detector

SYNC Signal

SYNC Signal

AGND

11

LMR23625

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SNVSAH3B – DECEMBER 2015 – REVISED APRIL 2017

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7.2 Functional Block Diagram

7.3 Feature Description

7.3.1 Fixed Frequency Peak Current Mode Control

The following operating description of the LMR23625 will refer to the Functional Block Diagram and to the

waveforms in Figure 13. LMR23625 is a step-down synchronous buck regulator with integrated high-side (HS)

and low-side (LS) switches (synchronous rectifier). The LMR23625 supplies a regulated output voltage by turning

on the HS and LS NMOS switches with controlled duty cycle. During high-side switch ON time, the SW pin

When the HS switch is turned off by the control logic, the LS switch is turned on after an anti-shoot-through dead

switching period. The regulator control loop maintains a constant output voltage by adjusting the duty cycle D. In

an ideal buck converter, where losses are ignored, D is proportional to the output voltage and inversely