Charge Pump

Power Stage

C1

C1−

C1+

IN

PGND

C2

C2−

C2+

IN

OUT

PGND

Oscillator

Control

Circuit

ENABLE

Shutdown/

Start-up Control

_

+

+

−

VREF

_

+

+

−

0.8 × VI

GND

FB

_

+

+

−

VREF

LBI

LBO

TPS60140

TPS60140, TPS60141

www.ti.com

SLVS273A – FEBRUARY 2000 – REVISED NOVEMBER 2015

9 Detailed Description

9.1 Overview

The TPS6014x devices regulate the output voltage using an improved pulse-skip topology. In pulse-skip mode

the error amplifier disables switching of the power stages when it detects an output voltage higher than 5 V. The

oscillator halts and the controller skips switching cycles. The error amplifier reactivates the oscillator and starts

switching of the power stages again when the output voltage drops below 5 V. The output resistance of the

charge pump is controlled to improve the ripple performance. This limits the output current to the minimum that is

necessary to sustain a regulated output voltage. The benefit is that the ripple performance is nearly as good as

with a linear-regulation topology.

At light loads a conventional pulse-skip regulation mode is used, but the charge pump output resistance is held

at a high level. The pulse-skip regulation minimizes the operating current because the charge pump does not

switch continuously and hence the gate-charge losses of the MOSFETs are reduced. Additionally, all functions

except voltage reference, error amplifier, and low-battery or power-good comparator are deactivated when the

output is higher than 5 V. When switching is disabled by the error amplifier, the load is also isolated from the

input. This improved pulse-skip control topology is also referred to as active-cycle control.

9.2 Functional Block Diagrams

Figure 3. TPS60140 Functional Block Diagram

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