The LM62440-Q1 features
selectable operating modes through the MODE/SYNC input pin. The LM62440-Q1 can operate in
one of three selectable modes:
- Auto Mode: Pulse frequency modulation (PFM) operation is
enabled during light load and diode emulation prevents reverse current
through the inductor. See Section 9.4.3.2 for more details.
- FPWM Mode: In FPWM mode, diode emulation is disabled,
allowing current to flow backwards through the inductor. This allows
operation at full frequency even without load current. See Section 9.4.3.3 for more details.
- SYNC Mode: The LM62440-Q1 clock
locks to an external signal applied to the MODE/SYNC pin. As long as output
voltage can be regulated at full frequency and is not limited by minimum
off-time or minimum on-time, clock frequency is matched to the frequency of
the signal applied to the MODE/SYNC pin. While the LM62440-Q1 is in
SYNC mode, it operates as though in FPWM mode: diode emulation is disabled
allowing the frequency applied to the MODE/SYNC pin to be matched without a
load.
In addition, the
MODE/SYNC pin can be used to activate or deactivate the spread spectrum feature of
the LM6243540-Q1. The MODE/SYNC
pin can be configured in two ways: level dependent MODE/SYNC control (see Section 9.3.2.1) or pulse dependent MODE/SYNC pin control (see Section 9.3.2.2).