STUSBCD01B datasheet(6/19 Pages) STMICROELECTRONICS

6 / 19 page

Functional description

STUSBCD01B

6/19

3.4

Detection triggering

USB Charger detection automatically starts when VBUS voltage is over VTH_VBUS threshold

and shutdown input is low.

If VBUS drops under VTH_VBUS threshold or shutdown input is pulled high, the charger

detection is immediately terminated.

If no charger is detected (DETECT = 0 and /OE = 0), VBUS voltage is kept over VTH_VBUS

threshold and VIO is not present then a new detection is started every 1 s.

If a charger is detected, detect and status pins are kept high until VBUS drops under

VTH_VBUS threshold or a new detection is started.

Any hardware detection (VIO not present) is terminated as soon as VIO voltage rises above

VTH_IO threshold.

3.5

VBUS clamping

The STUSBCD01B features a built in over voltage protection circuit which prevents VBUS

voltage from going over 6 V. The device is able to withstand continuous voltages of up to

10 V applied to VBUS pin through an external resistor; in this case the clamping circuit limits

the voltage to 6 V within 1 µs. A 470

Ω resistor in series between VBUS voltage and VBUS pin

is required. Any external device needing VBUS over-voltage protection must be connected to

STUSBCD01B's VBUS pin.

Minimum input resistance for VBUS pin in normal operating conditions (up to ~ 5.3 V) is

400 k

Ω.

3.6

Internal regulator

The STUSBCD01B has an internal regulator which outputs 1.8 V (nominal) to supply

internal blocks. The regulator does not require any bypass capacitor for stability.

STUSBCD01B Datasheet(PDF) 6 Page - STMicroelectronics