Rohm BD93F10MWV, Application Note

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Application Note BD93F10MWV Function Description
© 2021 ROHM Co., Ltd. No. 64AN078E Rev.002
Nov.2021
VBUS Over Voltage Protection / Short
Circuit Protection Function
This product has an overvoltage protection function for the VB
pin voltage (VBUS voltage). When an overvoltage is detected,
the Nch-MOS switch on the VBUS power line is turned off to
isolate the system from Type-C receptacle safely.
The SCP (Short Circuit Protection) can only be used on the
source mode, therefore the SCP is disabled.
Please refer to Table 9 regarding the behavior after these
detections, the releasing voltage, or something for more detail.
Over Current Protection Function
Please remove 10 m
Ω
resistor for current sensing then short
CSP and CSN each other if this feature is NOT required.
By using current sensing external shunt resistor of 10 m
Ω
,
which connected with this product GND side, load current is
detected by monitoring the voltage difference between CSP
and CSN. Current to detect OCP is detected through the
shunt resistor. The error of ±1% can be acceptable for the RS
resistance, so please select the appropriate resistor within
the range.
This over current protection is being enabled during plugged
condition, Active (Type-C) and Active (USBPD) state. The
OCP is triggered whenever the over current condition is
ongoing above the threshold for the specific mask duration (It
is 200ms fixed). As well as the OVP, the Nch-MOS switch on
the VBUS power line is turned off to isolate the system from
Type-C receptacle safely.
Depending on the noise situation on the actual applications,
the OCP cannot detect the current correctly. In case of the
situation, it is recommended that the capacitor (“CS” in
Figure
17
) is connected between CSP /CSN terminals to stabilize the
voltage ( ΔV ) of the voltage on both terminal.
C
SP
C
SN
10m
Ω
RS
CS
System GND
USB Type-C
Receptacle GND
Δ
V
13 12
IL
Figure 6. Current Detection Resistor
As shown in Table 4. The threshold of the OCP is depending
on the connected source device.
Table 4. Source Device and its VB OCP threshold
Connected
Source Device VBUS OCP
Threshold Note
Type-C
Default*/1.5A Fixed 1.95A
Type-C 3.0A Fixed 3.9A
Type-C USB PD Contracted
Current
×
1.3
Contracted
current is
depending on the
GPIO
configuration,
VMAX / VMIN /
PMIN features.
*The current of “Type-C Default” is according to the definition in USB version.
The OCP threshold is set to 1.3 times the contracted current
when the source device has supported the USB PD. The
contracted current means the maximum current that can be
supplied by the source and also the maximum current that
the sink device can consume. Please see VMAX / VMIN /
PMIN features in the GPIO clause for more detail regarding
the contracted currents.
Over Temperature Protection Function
using external thermistor
Please remove RTHU in Figure 7 between ADCVREF
terminal and ADCIN terminal and remove RTHD from ADCIN
terminal then short ADCIN terminal to GND directly if the
feature is NOT required.
This product can provide the over-temperature protection
function (OTP function: Over Temperature Protection) in the
system by using an external thermistor RTHD (PTC
Thermistor). For example, the system can monitor the
thermal condition via the OTP by implementing a PTC