STCC5011 Datasheet, PDF (21/37 Pages) STMicroelectronics – Constant current mode overcurrent protection

STCC5011, STCC5021
Application information
FAULT functionality
The FAULT open drain active low output is asserted during overcurrent or overtemperature
conditions. Signal is asserted until the fault is removed.
For overcurrent conditions, the STCC50x1 device is designed to eliminate false FAULT
reporting, by using an internal deglitch delay (9 ms typ.).
In the case of overtemperature, there is no deglitch delay and the FAULT signal is asserted
immediately. It is deasserted with delay after the device has cooled down and begins to turn
on. This unidirectional glitch immunity prevents FAULT oscillation during an
overtemperature event.
In the case of fault condition, the host may disable the power switch by toggling EN input to
logic low (see Figure 10).
Current limit programming
Current limit can be adjusted by an external resistor in the range 500 mA to 2.8 A (typ.). The
programming resistor may be calculated using Equation 1 to Equation 3:
Equation 1
I_OS(typ)=
48000
-_R-----_I--_L---_I-_M----
(
m
A,
kΩ)
Equation 2
I_OS(min)=
48000
R^-----_I^--_L^---_I^-_M^{----1---.-0---3---7-}
(
m
A,
kΩ)
Equation 3
I_OS(max)=
48000
R^-----_I^--_L^---_I^-_M^{----0---.-9---6---2-}
(
m
A,
kΩ)
Equation 2 and Equation 3 allow the minimum and maximum variation to be estimated
around the typical value predefined by the external resistor, R_ILIM, given in Equation 1.
Equation 2 and Equation 3 do not take into consideration external resistor variations.
5.8
EN functionality
The enable input (EN, active high) serves to turn off the STCC50x1 device and achieve the
lowest current consumption.
The behavior of the STCC50x1 device in disabled state (EN = 0) is as follows:
• Power switch, USB data switch and emulation profiles are turned off
• The FAULT and CHARGING/ATTACH flags are cleared (the FAULT and
CHARGING/ATTACH outputs are set to Hi-Z mode)
• If ATTACH_EN = 0, permanent output discharge is turned on
• If ATTACH_EN = 1, the device turns into the attach detection mode.
DocID024660 Rev 6
21/37
37