L

peak(typ)

LIMF

PD

V

I

I

t

L

=

+

´

(

)

IN(min)

OUT(min)

OUT

DS(on)

L

V

V

I

R

R

=

+

+

(

)

OUT

LPSM(pea

IN

ON

k)

V

V

t

L

I

-

´

=

10

TPS62160-Q1, TPS62162-Q1

SLVSCK6A – DECEMBER 2014 – REVISED NOVEMBER 2016

www.ti.com

Product Folder Links: TPS62160-Q1 TPS62162-Q1

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Copyright © 2014–2016, Texas Instruments Incorporated

Device Functional Modes (continued)

space

The peak inductor current in PSM can be approximated by:

space

(2)

space

regardless of the load current. The device maintains output regulation in PWM mode.

9.4.3 100% Duty-Cycle Operation

The duty cycle of the buck converter is given by D = Vout/Vin and increases as the input voltage comes close to

the output voltage. In this case, the device starts 100% duty cycle operation turning on the high-side switch

100% of the time. The high-side switch stays turned on as long as the output voltage is below the internal set

point. This allows the conversion of small input to output voltage differences, e.g. for longest operation time of

battery-powered applications. In 100% duty cycle mode, the low-side FET is switched off.

The minimum input voltage to maintain output voltage regulation, depending on the load current and the output

voltage level, can be calculated as:

space

(3)

space

where

space

9.4.4 Current Limit and Short Circuit Protection

The TPS6216x-Q1 is protected against heavy load and short circuit events. At heavy loads, the current limit

determines the maximum output current. If the current limit is reached, the high-side FET will be turned off.

Avoiding shoot through current, the low-side FET is then switched on to allow the inductor current to decrease.

The high-side FET will turn on again, only if the current in the low-side FET has decreased below the low side

current limit threshold.

The output current of the device is limited by the current limit (see Electrical Characteristics). Due to internal

propagation delay, the actual current can exceed the static current limit during that time.

space

The dynamic current limit can be calculated as follows:

space

(4)

space

where

L is the inductor value,