Data Sheet

HUSB238

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Page 9 of 17

THEORY OF OPERATION

OVERVIEW

The HUSB238 is a highly integrated USB Power Delivery (PD) controller as sink role. It’s compatible with PD3.0 and

Type-C V1.4. It can also support Apple Divider 3, BC1.2 SDP, DCP and CDP while source is attached. When

HUSB238 is connected to power source, it applies Rd to both CC lines, trying to establish USB Type-C connection.

After the USB Type-C connection is established, it monitors the CC lines to get source capabilities pack from USB PD

source. If there is valid source capabilities pack before time out, the HUSB238 policy engine requests a power supply

with voltage no greater than the programmed request voltage. If there is no valid source capabilities pack after time

out, the HUSB238 switches to Apple divider 3 or BC1.2 mode trying to determine corresponding charging protocol.

VIN PIN

VIN pin is the power supply input of the HUSB238, which is derived from the output of the PD source. Connect a 1µF

decoupling MLCC between VIN pin and GND pin as closer as possible.

The VIN pin is also connected to an internal MOSFET and 500Ohm discharging resistor, which is used as a bleeder to

help discharge the output capacitor to vSafe5V upon the hard reset, over-voltage fault, over-temperature fault or

detachment of a connected device.

GATE PIN

The GATE pin is open–drain output which allows to drive an external PMOS load switch directly. The GATE pin can be

programmed to turn on after POR or after the explicit contract. The default option is to turn on after POR. Please

contact local Hynetek sales for a device with options other than the default option.

CC1 AND CC2 PINS

CC1 and CC2 are the Configuration Channel pins used for connection and attachment detection, plug orientation

determination and system configuration management across USB Type-C cable. CC1 and CC2 pins can support as

high as 25V voltage, which is used for protection when CC1 or CC2 is shorted to VBUS pin on the connector.

Through the Type-C detection, one of the CC pin is connected to the internal BMC block to achieve PD

communication.

VSET PIN

A fixed 100μA current source is applied on VSET pin. Connect a resister between VSET and GND to indicate the

VSET_VOLTAGE value as shown in Table 6.

Table 6. VSET_VOLTAGE Setting

RVSET (kΩ)

VSET_VOLTAGE (V)

0

5

6.04

9

10

12

14

15

17.8

18

Open

20

The RDO voltage of the HUSB238 is determined by the lower value between VSET_VOLTAGE and

SNK_PDO2_VOLTAGE. SNK_PDO2_VOLTAGE is programmable by internal fuse options and the default value is

20V. The requested voltage value can be changed dynamically with the resistance value change.