Data Sheet

HUSB251

©2023 Hynetek Semiconductor Co., Ltd. All rights reserved.

Page 13 of 21

80uA

CC Logic

Control

330uA

180uA

VCONN

Rd

CC1

80uA

330uA

180uA

VCONN

Rd

CC1

Figure 4. CCx Hardware Diagram

BMC DRIVER

Through the Type-C detection, one of the CC pins will be connected to the internal BMC block to achieve PD

communication.

VBUS PIN

This pin is used to sense VBUS presence and discharge VBUS voltage on USB Type-C receptacle side.

The VBUS pin is also connected to an internal MOSFET and discharging circuitry, which is used as a bleeder to help

dissipate the energy stored in the VBUS capacitor. With this bleeder, VBUS is discharged to vSafe0V upon the

detachment of a connected device, or to a lower desired output voltage level upon a request command received from

the Sink, such as from 20 V to 5 V.

GATE PIN

The GATE pin of the HUSB251 is designed to drive an external N-MOSFET. When the HUSB251 is attached and is

ready to enable VBUS. The GATE pin outputs a voltage to turn on the external N-MOSFET. The turn on time of the

external N-MOSFET may impacted by the external N-MOSFET’s characteristics.

OVER VOLTAGE PROTECTION

The HUSB251 detects the VIN pin voltage to achieve over-voltage protection function. The threshold to trigger over-

voltage protection can be configured as 4 options. When the over-voltage condition occurs, the firmware is notified to

handle this fault.

OVER CURRENT PROTECTION

When the current sensed by the sense resistor exceeds the pre-set threshold in firmware. The threshold to trigger

over-current protection can be configured by firmware. When the over-current condition occurs, the firmware is

notified to handle this fault.

SHORT CIRCUIT PROTECTION

The HUSB251 integrates SCP protection function. When the VBUS is hard shorted to GND by fault, the output current

increases sharply. When the output current reaches the SCP threshold, the firmware is notified to handle this fault.

OVER TEMPERATURE PROTECTION

The HUSB251 integrates a current source at OTP pin. When the OTP function is preferred, a NTC thermistor is

recommended to be place at OTP pin. In addition, the internal current source outputs the current to the GND through

the external thermistor. The voltage at the OTP pin can be sampled by ADC to identify the actual temperature.