HUSB238A

Datasheet

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Page 14 of 22

If both the conditions above are satisfied, then HUSB238A sends a request for this source PDO with operating current

set to the RDO current value.

If either one of the condition is not satisfied, the HUSB238A continues to compare with the second highest voltage

source PDO or requests 5V source PDO directly, depending on the RDO_VOLTAGE_SELECT.

When the actual requested RDO is less than target RDO, the Cap Mismatch bit is sent in the actual requested RDO.

The RDO results are also suitable for legacy charging protocol request. When performing the legacy charging protocol

detection, the request voltage is also determined by this RDO results.

RDO IN I2C MODE

Additionally, in I2C mode, HUSB238A can access the internal registers to dynamic change the RDO by I2C bus. After

initialization, the HUSB238A may receive the Source Capabilities message from the PD source adapter and the

HUSB238A saves the source capability information in registers SRC_PDO_5V to SRC_PDO_20V. The I2C master can

visit the HUSB238A registers through the I2C bus and select a proper PDO by setting SRC_PDO register and then

writing 0x01 to GO_COMMAND register.

The I2C has the highest priority. If using I2C to select a source PDO, it over writes the internal RDO which is created by

SNK_VSET, SNK_ISET pins and internal factory fuse option, and the HUSB238A requests the I2C selected source PDO

once the I2C commands are written.

LEGACY CHARGER DETECTION

After the power on reset, the HUSB238A runs the PD PE or Apple Divider 3 and BC1.2 detections simultaneously when

PD_PRIOR=1. If PD_PRIOR =0, the PD PE is enabled 3s late after the connection is established.

For BC1.2 detection, the HUSB238A detects SDP (Standard Data Port), CDP (Charging Data Port) and DCP (Dedicated

Charging Port) sequentially.

If DCP is detected and HVDCP is enable, the HUSB238A performs HVDCP detection further.

EMARKER EMULATION

The HUSB238A is able to respond a Discover Identity message in SOP’ format anytime. No additional analog circuit is

needed. The HUSB238A also can be configured to only respond the Discover Identity SOP’ message when a PD

contract is established. This function can be enabled or disabled by internal effuse option.

FAULT RESPONSE

The HUSB238A implements multiple protections to prevent any damage from failure. CCOV, OVP, UV, TSD, UVLO are

all involved.

CC OVER VOLTAGE PROTECTION

Since CC1 and CC2 in Type-C connector is very close to VBUS pin, it is possible that the CC1 and CC2 pins are shorted

to VBUS pin in some unexpected cases. It is important to guarantee that the CC1 and CC2 pins can be survived under

such accidents. When the CC over-voltage condition occurs, the HUSB238A enters fault mode, If the fault is removed,

the device enters into unattached mode after 50ms.

OVER VOLTAGE PROTECTION

The HUSB238A detects the VBUS pin voltage to achieve over-voltage protection function. The OVP threshold is

changed with the Requested Voltage. When the over-voltage condition occurs, the HUSB238A enters fault Mode, the

HUSB238A turns off the external PMOS, the internal 5.1k Rd resistor is also disconnected during fault mode. If the fault

is removed, the device enters into unattached mode after 50ms.

The VBUS OV threshold is shown in Table 13.

Table 13. Over-voltage Protection Threshold

Requested Voltage (V)

Over-voltage Threshold

5 V and less

6 V

5 V to 26 V

120% of Requested Voltage

Higher than 26 V

31 V