Device description L5962
16/24 Doc ID 16819 Rev 3
VLR1 (5.0 V /8.5 V) and VLR2 (3.3 V, 5.0 V, 5.5 V, 6.0 V, 7.0 V, 7.5 V, 8.0 V, 10.0 V)
The output of these two regulators can be selected through the I
2
C bus.
When the dropout voltage of the regulator cannot be maintained, the output tracks the VBAT
input voltage less the saturation voltage of the regulator pass element.
This regulator has a short circuit protection consisting of current limit and thermal shutdown.
If the local die temperature exceeds the thermal shutdown detection threshold, the output is
disabled. The thermal shutdown circuitry has hysteresis such that the output is enabled only
after the die temperature falls below the thermal shutdown disable threshold. Thermal
shutdown on this output doesn't directly disable any other circuitry.
VLR2 has its own power supply (VINLR2) because of its high current capability.
4.1.2 Switching regulator
The IC contains an independent, step-down, synchronous switching regulator, which is used
to produce an output voltage that is adjustable in the system by means of an external
resistor divider.
The switching regulator functionality is guaranteed in the 1.2-8.0 V output voltage range.
The switching frequency is externally synchronizable. The switcher has its own supply input
pin (VINSW) and is enabled by the EN input.
The regulator contains soft-start control to protect external devices from excessive in-rush
currents. This control is independent of the presence of a synchronizing signal on the
SYNCH input.
The switching cycle is synchronized to the internal oscillator unless a signal is present on
the SYNC input. The signal present on the SYNCH input overrides the internal oscillator to
control the switching of the regulator if its frequency gets inside the allowed range (220-
400 kHz). The IC detects a small number of edges (e.g. 2-5) prior to recognize a valid input
signal and synchronizing internal operation to the external signal.
It is designed to operate in continuous conduction mode (CCM), where the inductor current
remains continuous throughout the entire load range of the output. It can also work in DCM
mode.
This regulator has short circuit protection consisting of cycle-by-cycle duty-cycle limitation.
Upon return from over-voltage shutdown this regulator employs the soft-start.
An external bootstrap capacitor must be connected between the output (PH, phase output
pin) and the CBS pin.
The switching regulator output slew rate can be controlled with an external capacitor on the
SOST (soft start) pin. This protects the device against excessive dV/dt transients, lowering
the stress of the internal components. A maximum slews rate of 10 V/ms is suggested.
Two separate current limits for the switching regulator can be chosen in order to guarantee a
proper protection for the device at the desired load current rating. The CLIM pin should be
tied to ground for the low limit (max 3 A) or to 5.0 V for the high limit (max 6 A).
The VFB pin is the voltage feedback from the regulated output for the switching regulator;
the VCMP one is the compensation feedback for the switching regulator.
