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TPS62180, TPS62182

www.ti.com

SLVSBB8A – AUGUST 2014 – REVISED AUGUST 2014

Device Functional Modes (continued)

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This allows the conversion of small input to output voltage differences, for example for lthe ongest operation time

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

While the maximum ON-time is not limited, the AEE feature, explained in the next section, secures a minimum

ON-time of about 100 ns.

9.4.4 Automatic Efficiency Enhancement (AEE)

AEE provides highest efficiency over the entire input voltage and output voltage range by automatically adjusting

the converter's switching frequency. This is achieved by setting the predictive off-time of the converter.

The efficiency of a switched mode converter is determined by the power losses during the conversion. The

following equation shows the relation between the inductor ripple current, switching frequency and duty cycle.

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(7)

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Efficiency increases by decreasing switching losses, preserving high efficiency for varying duty cycles, while the

ripple current amplitude remains low enough to deliver the full output current without reaching current limit. The

AEE feature provides an efficiency enhancement for various duty cycles, especially for lower Vout values, where

fixed frequency converters suffer from a significant efficiency drop. Furthermore, this feature compensates for the

Figure 9 shows the typical switching frequency over the input voltage range.

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Figure 9. Typical Switching Frequency vs Input Voltage

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