Outputvoltage

Vout (PWM)

Vout +1%

PFMComparator

threshold

VoltagePositioning

Lightload

PFMMode

moderatetoheavyload

PWMMode

TPS62060

www.ti.com

SLVSA95 – MARCH 2010

Figure 22. Power Save Mode Operation with automatic Mode transition

100% Duty Cycle Low Dropout Operation

The device starts to enter 100% duty cycle mode as the input voltage comes close to the nominal output voltage.

In order to maintain the output voltage, the High-Side MOSFET switch is turned on 100% for one or more cycles.

With further decreasing VIN the High-Side MOSFET switch is turned on completely. In this case the converter

offers a low input-to-output voltage difference. This is particularly useful in battery-powered applications to

achieve longest operation time by taking full advantage of the whole battery voltage range.

The minimum input voltage to maintain regulation depends on the load current and output voltage, and can be

calculated as:

With:

Undervoltage Lockout

The under voltage lockout circuit prevents the device from malfunctioning at low input voltages and from

excessive discharge of the battery. It disables the output stage of the converter once the falling VIN trips the

typically 1.95V.

Output Capacitor Discharge.

With EN = GND, the devices enter shutdown mode and all internal circuits are disabled. The SW pin is

connected to PGND via an internal resistor to discharge the output capacitor.

MODE SELECTION

The MODE pin allows mode selection between forced PWM mode and Power Save Mode.

Connecting this pin to GND enables the Power Save Mode with automatic transition between PWM and PFM

mode. Pulling the MODE pin high forces the converter to operate in fixed frequency PWM mode even at light

load currents. This allows simple filtering of the switching frequency for noise sensitive applications. In this mode,

the efficiency is lower compared to the power save mode during light loads.

Copyright © 2010, Texas Instruments Incorporated

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