Diodes AP33772S I2C - Chapter 7. Protection; Overvoltage Protection (OVP); Overcurrent Protection (OCP); Undervoltage Protection (UVP)

AP33772S I2C USB PD Sink Controller
EVB User Guide
AP33772S EVB User Guide
Rev. 2.0
26 of 34
www.diodes.com
July 2024
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Chapter 7. Protection
7.1 Overvoltage Protection (OVP)
The AP33772S triggers OVP protection when the VBUS voltage is higher than the OVP Threshold Voltage. Th table below summarizes the
correspondence between VREQ, OVPTHR, and OVP Threshold Voltage.
Mode
Criteria
OVP Threshold Voltage
SPR Mode
(V
VREQ
+ V
OVPTHR
) ≤ 20V
V
VREQ
+ V
OVPTHR
(V
VREQ
+ V
OVPTHR
) > 20V
V
VREQ
* 110%
EPR Mode
(V
VREQ
+ V
OVPTHR
) ≤ 40V
V
VREQ
+ V
OVPTHR
(V
VREQ
+ V
OVPTHR
) > 40V
V
VREQ
* 110%
The OVP debounce time mechanism is to prevent false triggering caused by various spurious noises. The OVP debounce time is preset to
30ms. If the VBUS voltage is greater than the OVP threshold voltage after the debounce time (30ms), the STATUS.OVP will be set to 1 and the
associated VOUT MOS switches are turned off. The host MCU will need to load a new PD_CMDMSG to start the PD negotiation process,
resuming quick-charging operation.
7.2 Overcurrent Protection (OCP)
The AP33772S triggers OCP protection when the charging current is larger than OCP Threshold Current. The table below shows the
correspondence between OCPTHR and OCP Threshold Current. The default value of the OCPTHR register is 00h.
If the OCPTHR value is still 00h after successful negotiation with the PD source, the OCP Threshold Current should be updated to 110% of the
maximum current (I
MAX
) of the selected PDO/APDO.
If the OCPTHR value has been updated through I2C interface, the OCP Threshold Current should be updated to 110% of the OCPTHR value.
OCPTHR
OCP Threshold Current
OCPTHR = 0
I
MAX
* 110%
(Note)
OCPTHR != 0
I
OCPTHR
* 110%
Note: I
MAX
: The Maximum Current of PDO/APDO
The default OCP debounce time is 30ms. If the charging current is larger than OCP Threshold Current after debounce time (30ms), the
STATUS.OCP will be set to 1 and the associated VOUT MOS switches are turned off. The host MCU will need to load a new PD_CMDMSG to
start the PD negotiation process, resuming quick-charging operation.
7.3 Undervoltage Protection (UVP)
The AP33772S triggers UVP protection when VBUS voltage is lower than UVP Threshold Voltage. The table below shows the correspondence
between the UVPTHR and UVP Threshold Voltage.
The default value of the Undervoltage Protection Threshold (UVPTHR) is 80%, which can be modified by writing the UVPTHR command.
UVPTHR
UVP Threshold Voltage
1
V
VREQ
* 80%
2
V
VREQ
* 75%
3
V
VREQ
* 70%
The default UVP debounce time is 30ms. If VBUS voltage is lower than UVP Threshold Voltage after debounce time (30ms), the STATUS.UVP
will be set to 1 and the associated VOUT MOS switches are turned off. The host MCU will need to load a new PD_CMDMSG to start the PD
negotiation process, resuming quick-charging operation.