L

V

V

t

I

OUT

IN

ON

L

-

´

=

D

IN

OUT

ON

V

V

ns

420

t

´

=

VOUT

FB

GND

Output Discharge

Logic

Direct Control

and

Compensation

Timer

ton

Comparator

Ramp

Error Amplifier

DCS - Control

TM

MOSFET Driver

Control Logic

High Side

Current Sense

Hiccup

Counter

VIN

EN

Bandgap

Undervoltage Lockout

Thermal Shutdown

EN

PG

V

FB

V

REF

V

REF

(1)

Note:

(1) When the device is enabled, the 400 k

resistor is disconnected.

(2) The integrated inductor in the module, L = 0.47µH.

L

(2)

TPS82084

www.ti.com

SLVSD11A – JUNE 2015 – REVISED SEPTEMBER 2015

8 Detailed Description

8.1 Overview

The TPS82084 synchronous step-down converter power module is based on DCS-Control™ (Direct Control with

Seamless transition into Power Save Mode). This is an advanced regulation topology that combines the

advantages of hysteretic, voltage and current mode control.

The DCS-Control™ topology operates in PWM (Pulse Width Modulation) mode for medium to heavy load

conditions and in PSM (Power Save Mode) at light load currents. In PWM, the converter operates with its

nominal switching frequency of 2.4 MHz having a controlled frequency variation over the input voltage range. As

the load current decreases, the converter enters Power Save Mode, reducing the switching frequency and

minimizing the IC's quiescent current to achieve high efficiency over the entire load current range. DCS-Control™

supports both operation modes using a single building block and therefore has a seamless transition from PWM

to PSM without effects on the output voltage. The TPS82084 offers excellent DC voltage regulation and load

transient regulation, combined with low output voltage ripple, minimizing interference with RF circuits.

8.2 Functional Block Diagram

8.3 Feature Description

8.3.1 PWM and PSM Operation

modes, is estimated as:

(1)

In PWM mode, the TPS82084 operates with pulse width modulation in continuous conduction mode (CCM) with

half the inductor's ripple current estimated by Equation 2.

(2)

To maintain high efficiency at light loads, the device enters Power Save Mode seamlessly when the load current

decreases. This happens when the load current becomes smaller than half the inductor's ripple current. In PSM,

the converter operates with a reduced switching frequency and with a minimum quiescent current to maintain

estimated as:

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