ST X-NUCLEO-SRC1M1, Руководство пользователя

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1.2.7 Consumer and provider path
The provider path can be connected to V
BUS
thanks to two dual STL40DN3LLH5 N-MOSFETs (Q2) controlled by
the TCPP02-M18 gate driver (SRC and GATE pins).
Figure 11. Provider path
Provider
GND
SOURCE
R22
4k
D7
LED5 blue
GND
GND
GND
ADC_Prov
SOURCE
FLGN
D9
NM
R10
47K
R3
200k
C8
NM
Q2B
D 5
G
4
3 S
R4
40.2k
R5
0.007
G
A
T
E
6
S
R
C
7
ISENSE
9
VBUSc
8
C9
NM
Q2A
STL40DN3LLH5
D
7
G
2
1
S
CN3
1725656
1
2
Isense
The blue LED (D7) signals the voltage presence on the provider path. This LED does not indicate the N-MOSFET
state. In fact, the source LED D7 can be on to indicate the voltage presence on the provider path but, at the same
time, Q2 can be off (no connection of the provider path on the V
BUS
).
The CN3 screw connector allows accessing the consumer path. You can add additional protections (transient
or free-wheel diodes) on the D9 footprint that is compatible with the ESDAP series (
ESDA7P120-1U1M up to
ESDA25P35-1U1M ).
The output current of the TCPP02-M18 gate driver charge pump manages the inrush current. It is associated with
the STL40DN3LLH5 drain to the gate MOSFET capacitance (also called Miller capacitance or reverse transfer
capacitance). This association avoids any potential parasitic OCP triggering due to the inrush current generated
by cSnkBulk (between 1 µF and 10 µF), as defined by the USB Power Delivery standard at attach.
When using another MOSFET reference, the C8 external capacitor can be implemented to another MOS
reference. This implementation avoids the OCP triggering due to the inrush current, in case the drain-to-gate
capacitance is too low. The effective drain-to-gate capacitance including C8 must be higher than 20 pF.
When using a higher cSnkBulk capacitance, close Q2 slower. Then, mount the C8 capacitor, choosing 100 pF for
every additional 10 µF on the cSnkBulk terminal.
1.2.8 Overcurrent protection for V
BUS
and CC lines
The R5 terminal voltage (voltage between the TCPP02-M18 VBUSc and ISENSE pins) protects the TCPP02-M18
from overcurrent on the V
BUS
. When this voltage is higher than 0.042 V, the overcurrent protection turns on and
opens the provider path.
Table 1. V
BUS
currents according to the R5 shunt resistor values
Max. nominal current Overcurrent protection threshold R5 shunt resistor
0.5 A 0.9 A 47 mΩ
1.5 A 1.9 A 22 mΩ
3.0 A 4.2 A 10 mΩ
5.0 A 6.0 A 7 mΩ (default value)
When the overcurrent fault is detected:
•
FLGN falls;
• the register 2 is updated;
UM2973
Hardware architecture
UM2973 - Rev 1
page 9/25