8 Detailed Description

8.1 Overview

The TPS62830x is a family of low-voltage step-down converters available in 1-, 2-, 3- and 4-A versions. These

devices use a DCS-Control scheme which transitions seamlessly from pulse-width modulation (PWM) at medium

and high output currents to pulsed-frequency modulation (PFM) at low output currents. During PWM operation,

the devices switch at 2 MHz; during PFM operation, the switching frequency varies with the load current and

reduces as the load current decreases. For applications that require the lowest possible output voltage ripple

and/or a constant switching frequency, a high logic level on the MODE pin forces the devices to use PWM under

all load conditions (at the expense of lower efficiency at low output currents). An external resistor-divider sets

the output voltage anywhere from 0.5 V to 4.5 V and the nominal switching frequency is 2 MHz with a controlled

variation over the input voltage range.

Device variants are available that support both hiccup and latch-off protection behavior.

The TPS62830x devices offer two significant advantages compared to previous devices in this series: Transient

performance is much better, due to the quick reaction of a fast comperator in both PFM and PWM modes, and

EMI is much lower, thanks to an on-chip decoupling capacitor and an optimized gate driver.

8.2 Functional Block Diagram

Gate

Drivers

Output

Discharge

Zero Current

Detector

Peak Current

Detector

Modulator

Hiccup /

Latch-Off

ton

Timer

+

–

Vref

(0.5V)

Ramp

Generator

VSW

VIN

VOS

Soft-Start

UVLO

Thermal

Shutdown

Control Logic

SW

EN

MODE

VOS

FB

PG

VIN

Vref

V(FB,INT)

V(FB,INT)

Cff

EA

GND

To all blocks

8.3 Feature Description

8.3.1 Pulse Width Modulation (PWM) Operation

If the MODE pin is LOW and at load currents larger than half the inductor ripple current, the device operates in

pulse width modulation in continuous conduction mode (CCM) as shown in Figure 8-1. The PWM operation is

based on an adaptive constant on-time control with stabilized switching frequency. To achieve a stable switching

frequency in a steady state condition, the on-time is calculated as:

TON=VOUTVIN×500ns

(1)

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TPS628301, TPS628302, TPS628303, TPS628304

SLVSG98A – FEBRUARY 2023 – REVISED OCTOBER 2023

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Product Folder Links: TPS628301 TPS628302 TPS628303 TPS628304