STOD1317B datasheet(12/22 Pages) STMICROELECTRONICS

12 / 22 page

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 VIN 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 VIN and EN, the

device initiates the startup phase.

As a first step, the CMID 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 VMID reaches the VIN voltage level, the P1 switch is fully turned on and the soft-start

procedure for the step-up is started. VOUT 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.

STOD1317B Datasheet(PDF) 12 Page - STMicroelectronics