Вот выдержка из DS по TPS61220:
The device is enabled when EN is set high and shut down when EN is low. During shutdown, the converter stops
switching and all internal control circuitry is turned off. In this case the input voltage is connected to the output
through the back-gate diode of the rectifying MOSFET. This means that there always will be voltage at the output
which can be as high as the input voltage or lower depending on the load.

Для TPS61070 всё по-другому:
A special circuit is applied to disconnect the load from the input
during shutdown of the converter. In conventional synchronous rectifier circuits, the backgate diode of the
high-side PMOS is forward biased in shutdown and allows current flowing from the battery to the output.
However, this device uses a special circuit which takes the cathode of the backgate diode of the high-side PMOS
and disconnects it from the source when the regulator is not enabled (EN = low).
The benefit of this feature for the system design engineer is that the battery is not depleted during shutdown of
the converter. No additional components must be added to the design to make sure that the battery is
disconnected from the output of the converter.

Замечу, что и там, и там синхронный выпрямитель.