Datasheet

Detailed description STOD1317B
12/22 DocID022607 Rev 2
6.2 Enable pin
The device operates when the EN pin is set high. If the EN pin is set low, the device stops
switching, all the internal blocks are turned off. In this condition the current drawn from V
IN
is
below 1 µA in the whole temperature range. In addition, the internal switches are in OFF
state so the load is electrically disconnected from the input, this avoids unwanted current
leakage from the input to the load.
6.3 Soft-start and inrush current limiting
After the EN pin is pulled high, or after a suitable voltage is applied to V
IN
and EN, the
device initiates the startup phase.
As a first step, the C
MID
capacitor is charged, the P1 switch implements a current limiting
technique in order to keep the charge current below 400 mA. This avoids battery
overloading during startup.
After V
MID
reaches the V
IN
voltage level, the P1 switch is fully turned on and the soft-start
procedure for the step-up is started. V
OUT
starts to softly increase until it reaches the
regulation value.
6.4 Undervoltage lockout
The undervoltage lockout function avoids improper operation of the STOD1317B when the
input voltage is not high enough. When the input voltage is below the UVLO threshold the
device is in shutdown mode. The hysteresis of 100 mV avoids unstable operation when the
input voltage is close to the UVLO threshold.
6.5 Overtemperature protection
An internal temperature sensor continuously monitors the IC junction temperature. If the IC
temperature exceeds 150 °C, typical, the device stops operating. As soon as the
temperature falls below 135 °C, typical, normal operation is restored.
6.6 Digital low power function
The digital low power (DLP) function allows physical disconnection of the load from the
device.