Control Logic

Soft Start

Thermal

Shutdown

UVLO

Gate

Drive

GND

FB

EN

SW

Modulator

GND

Zero Current Detect

Peak Current Detect

+

_

+

±

GND

VIN

PG

Power Good feature is only available in TLV62568P

Copyright Ú 2016, Texas Instruments Incorporated

7

TLV62568, TLV62568P

www.ti.com

SLVSD89A – NOVEMBER 2016 – REVISED APRIL 2017

Product Folder Links: TLV62568 TLV62568P

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Copyright © 2016–2017, Texas Instruments Incorporated

7 Detailed Description

7.1 Overview

The TLV62568 is a high-efficiency synchronous step-down converter. The device operates with an adaptive off-

time with peak current control scheme. The device operates at typically 1.5-MHz frequency pulse width

required off time for the low-side MOSFET. It makes the switching frequency relatively constant regardless of the

variation of input voltage, output voltage, and load current.

7.2 Functional Block Diagram

Figure 4. TLV62568 Functional Block Diagram

7.3 Feature Description

7.3.1 Power Save Mode

The device automatically enters Power Save Mode to improve efficiency at light load when the inductor current

becomes discontinuous. In Power Save Mode, the converter reduces switching frequency and minimizes current

consumption. In Power Save Mode, the output voltage rises slightly above the nominal output voltage. This effect

is minimized by increasing the output capacitor.

7.3.2 100% Duty Cycle Low Dropout Operation

The device offers a low input-to-output voltage differential by entering 100% duty cycle mode. In this mode, the

high-side MOSFET switch is constantly turned on and the low-side MOSFET is switched off. The minimum input

voltage to maintain output regulation, depending on the load current and output voltage, is calculated as:

where

•

•

(1)

7.3.3 Soft Startup

After enabling the device, internal soft startup circuitry ramps up the output voltage which reaches nominal output

voltage during a startup time. This avoids excessive inrush current and creates a smooth output voltage rise

slope. It also prevents excessive voltage drops of primary cells and rechargeable batteries with high internal

impedance.