IN,MIN

OUT

OUT,MAX

DS(on)

L

V

V

I

(R

+ R )

=

+

´

TPS62080, TPS62080A

TPS62081, TPS62082

www.ti.com

SLVSAE8D – SEPTEMBER 2011 – REVISED JULY 2013

DETAILED DESCRIPTION

DEVICE OPERATION

The TPS6208x synchronous switched mode converters are 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 and voltage mode control.

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

conditions and in Power Save Mode at light load currents. In PWM the converter operates with its nominal

switching frequency of 2MHz 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 quiescent current to achieve high efficiency over the entire load current range. DCS™ Control supports both

operation modes (PWM and PFM) using a single building block having a seamless transition from PWM to Power

Save Mode without effects on the output voltage. Fixed output voltage versions provide smallest solution size

combined with lowest quiescent current. The TPS6208x offers both excellent DC voltage and superior load

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

The device is equipped with the Snooze Mode functionality, which is enabled with the Mode pin. The Snooze

Mode supports high efficiency conversion at lowest output currents below 2mA. If no load current is drawn, the

ultra low quiescent current of 6.5uA is sufficient to maintain the output voltage. This extends battery run time by

reducing the quiescent current during lowest or no load conditions in battery driven applications. For mains-

operated voltage supplies, the Snooze Mode reduces the system's stand-by energy consumption. During

shutdown (EN = LOW), the device reduces energy consumption to less than 1uA.

POWER SAVE MODE

As the load current decreases the TPS6208x will enter the Power Save Mode operation. During Power Save

Mode the converter operates with reduced switching frequency in PFM mode and with a minimum quiescent

current maintaining high efficiency. The power save mode occurs when the inductor current becomes

The switching frequency over the whole load current range is shown in Figure 21 and Figure 22.

SNOOZE MODE

The TPS6208x offers a Snooze Mode function. If the Snooze Mode is enabled by an external logic signal setting

the MODE pin to HIGH, the device's quiescent current consumption is reduced to typically 6.5µA. As a result, the

high efficiency range is extended towards the range of lowest output currents below 2mA, see the typical

characteristics efficiency figures.

If the device is operating in Snooze Mode, a dedicated, low power consuming block monitors the output voltage.

All other control blocks are snoozing during that time. If the output voltage falls below the programmed output

voltage by 3.5% (typ), the control blocks wake up, regulates the output voltage and allow themselves to snooze

again until the output voltage drops again. The Snooze Mode operation provides a clear efficiency improvement

at lowest output currents. If the load current increases, the advantage of efficiency in Snooze mode will be

deprived. Since the dynamic load regulation operates best if the Snooze Mode is disabled, it is recommended to

turn off the Snooze Mode by external logic signal if the load current exceeds 2mA, like a micro controller to

operate the MODE pin.

100% DUTY CYCLE LOW DROPOUT OPERATION

The device offers low input to output voltage difference 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. 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 switching regulation, depending on the load current and

output voltage can be calculated as:

(1)

With:

Copyright © 2011–2013, Texas Instruments Incorporated

Submit Documentation Feedback

13

Product Folder Links: TPS62080 TPS62080A TPS62081 TPS62082