IN,MIN

OUT

OUT,MAX

DS(on)

L

V

V

I

(R

+ R )

=

+

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TLV62080

www.ti.com

SLVSAK9A

– OCTOBER 2011 – REVISED NOVEMBER 2011

DETAILED DESCRIPTION

DEVICE OPERATION

The TLV62080 synchronous switched mode converter 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 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. The TLV62080 offers both excellent DC voltage and superior

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

POWER SAVE MODE

As the load current decreases the TLV62080 enters 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 discontinuous. It is

frequency over the whole load current range is shown in Figure 10.

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:

ENABLING / DISABLING THE DEVICE

The device is enabled by setting the EN input to a logic HIGH. Accordingly, a logic LOW disables the device. If

the device is enabled, the internal power stage will start switching and regulate the output voltage to the

programmed threshold. The EN input must be terminated with a resistance less than 1M

Ω pulled to VIN or GND.

OUTPUT DISCHARGE

down. This is the case when the device gets disabled by enable, thermal shutdown trigger, and undervoltage

lockout trigger.

SOFT START

After enabling the device, an internal soft-start circuitry monotonically ramps up the output voltage and reaches

the nominal output voltage during a soft start time (100

µs, typical). This avoids excessive inrush current and

creates a smooth output voltage rise slope. It also prevents excessive voltage drops of primary cells and

rechargeable batteries with high internal impedance.

Copyright

© 2011, Texas Instruments Incorporated

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Product Folder Link(s): TLV62080