Tool/software:
Hi Sir,
please help confirm if the schematic requires modification.
VSYS=3.3~4.2V and Vf of D40=0.4V
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Tool/software:
Hi Sir,
please help confirm if the schematic requires modification.
VSYS=3.3~4.2V and Vf of D40=0.4V
Hi,
1. Is VSYS the VBUS on the type-C port? VBUS_DET needs to be pulled up directly to the Type-C VBUS. VBUS should be at least 4V, not 3.3V.
2. Make sure the 3V3 rail rises after VSYS is stable. This is because VDD needs to rise before any of the open drain outputs to prevent back-driving of the TUSB320.
Best,
Shane
Hi Shane,
Pls check schematic, thanks.
SDA1、SCL1、Int1_2 link to MCU (3.3V system)
The specifies that Int (Pin 6) needs to be pulled up to Vbus. Can Vbus be connected to 3.3V instead?
Hi,
Can Vbus be connected to 3.3V instead?
1. Pin 6 doesn't need to be pulled up to VBUS. This is an open drain output that can be pulled up to a 3.3V rail if desired.
2. The VBUS_DET pin looks correct now.
3. My only comment is to be sure that VSYS rises before the 3V3 rail so the I2C lines do not back-drive the TUSB320. One way to ensure this is to pull up the I2C lines to VSYS.
Best,
Shane
Hi Shane,
Since the system voltage is 3.3V, the I2C pull-up needs to be connected to 3.3V.
The power sequence is as follows: Vsys ready → Buck DC/DC at 3.3V.
That should work fine.