
The STPD01PUR programmable buck converters (U400 and U600) constitute the core of these blocks. These
devices, controlled by the STM32G071RBT6 microcontroller through I2C communication and GPIOs, set the
correct level of voltage and current every time a new power negotiation is accomplished with a Sink platform
connected to a port Type-C connector (P0 or P1).
The figure below shows the STPD01PUR setup for port P0 (for analogy, the stage is repeated for port P1).
Figure 10. STPD01 USBPD programmable buck converter (U400, for port P0)
VOUT
1^,6
VIN_24V 1^,2
I2C_SDA
1^,3,5,6,7
I2C_SCL
1^,3,5,6,7
ADD_STPD01_Px
1^
GND_Sign1^
GND_Pwr1^
GND
GND
GND
R400
25mOhms
TP401
5001
U400
STPD01
VDRIVEH 6
PVIN8
8
PVIN9
9
VCC
7
ADD
3
PGND10
10
PGND11
11
SGND
24
ISNS+ 19
ISNS- 20
LX13 13
LX14 14
BOOT 16
INT
4
EN
5
CDC
22
SDA
1SCL
2
VSNS 21
VREG
18
LX15 15
Pon
17
NC 23
PGND12
12 EXP_PAD
25
C415
10uF
N.M.
TP402
5001
TP403
5001
R403
24k
C400
1uF
C405
10uF
C403
68uF
C407
47uF
C411
10000pF
C409
1uF
TP404
5001
C402
0.1uF
C401
0.1uF
C414
10uF
TP400
5001
L400
10uH
1 2
C404
68uF
N.M.
C408
0.1uF
C406
68uF
N.M.
R402
10k
R401
0
C410
1uF
TP405
5001
Pon_STPD01_Px
ENB_STPD01_Px
I2C_SCL
I2C_SDA
ALT_STPD01_Px
ADR_STPD01_Px
ISNS-_x
PHASE_x
ISNS+_x
ISNS+_x
ISNS-_x
VBUS_PxVA_x
CDC_STPD01_Px
24V_Input
The STPD01PUR ENABLE pin (EN) is driven by the microcontroller to enable the device startup and,
consequently, its I2C communication interface. The microcontroller sets the STPD01PUR registers via I2C
commands and, at startup, the VOUT level to the default voltage value.
After startup, the Power-on (Pon) pin is high if the value is within ±5% of the regulation point. This event on Pon
pin is also monitored by the microcontroller.
The STPD01PUR Interrupt pin (INT) triggers the STM32 microcontroller providing notifications related to the
watchdog functionalities (OVP, OTP, SCP,etc.). These notifications shall be read by the microcontroller through
I2C communication as well.
The output voltage on the STPD01PUR CDC pin is managed by the conditioning stage (shown in Figure 11),
before being acquired by the microcontroller to monitor the output current.
Figure 11. STPD01PUR CDC conditioning stage
CSENS_STPD01_Px1^
A_VDD
1^,3
GND
GND
GND
TP407
5001
-
+
U401
TSV991AILT
3
4
1
52
R411
100K
R412
100K
C412
0.1uF
C413
0.22uF
R407
0
CDC_STPD01_Px
For each USBPD power block, two LEDs mounted on the expansion board top side provide clear information on
the STPD01PUR status as shown in Figure 12:
•when the microcontroller sets high the STPD01PUR EN pins, the associated device immediately switches
on after the startup sequence, turning on D400 (EN0) and D600 (EN1) green LEDs, respectively;
• when the STPD01PUR Pon pin is high, D401 (PWR0) and D601 (PWR1) blue LEDs turn on, indicating the
device is providing the right value of output voltage (within ±5% of the regulation point).
UM2880
System architecture
UM2880 - Rev 1 page 8/41