The HUSB238 chip from Hynetek is a PD trigger chip (an integrated circuit that will auto-negotiate a PD profile over the CC lines in an USB-C connector) - it can be used to set voltages higher than the default USB voltage of 5 V. The voltage and current can be set using two resistors. The chip also drives a PMOS transistor to switch the power rail itself after successful negotiation. It also integrates an I2C interface (for microcontroller control) and some protection circuitry. This chip, unlike most others, has been tested by the USB-IF to be actually compliant. It has a DFN-10 package with a thermal pad, so it is not nearly as easy to solder as SOIC packages.
This chip exists in several variations. The variant shown here is HUSB238_002DD (no SOP', 150/130°C OTP, if a PD profile with enough voltage is not found, then one with the nearest lowest voltage and enough current is selected).
The development board shown here exposes the output voltage on a terminal block connector and some extra inputs/outputs, including the I2C interface, on a pin header.
Populated circuit board (click for full resolution)
Schematic diagram (click for full resolution)
Diodes D1, D3-D6 are used for ESD protection. A suitable type is mentioned in the comments in the schematic.
Resistors R3/R4 (0-ohm jumpers) can be omitted to disable functions related to the USB data lines (D+/D-).
The gate driver seems to drive the pin to ground, which could potentially cause gate overvoltage if the selected voltage exceeds the source-gate maximum voltage. To mitigate this, a Zener diode is used (D2). The gate drive resistors (R2, R5) and capacitor (C2) can be adjusted as necessary (e.g. for soft-start purposes). A HY19P03 MOSFET was used in the prototype, but it is unnecessarily overdimensioned. A logic-level PMOS should be used.
The switched output is connected to the terminal block (J8).
Output voltage and current are set using R6 (VSET) and R7 (ISET). If the resistors are omitted, external resistors can be connected to the pin header J2. The I2C interface is also connected to J2, as well as the output of the voltage divider formed by R8/R9. Some data lines are broken out onto test pads (J3-J7).
(default values from the datasheet)
| RVSET [kΩ] | 0 | 6.04 | 10 | 14 | 17.8 | ∞ (open) |
| Voltage [V] | 5 | 9 | 12 | 15 | 18 | 20 |
| RISET [kΩ] | 0 | 4.53 | 7.5 | 10.5 | 13.7 | 16.5 | 19.6 | 22.6 | ∞ |
| Current [A] | 1.25 | 1.5 | 1.75 | 2 | 2.25 | 2.5 | 2.75 | 3 | 3.25 |
The I2C interface was not tested, only the PD trigger functions set by resistors. The product page contains only a data brief, the datasheet is available through a direct link here. Additional information is on the manufacturers website and in Chinese datasheets (avaliable e.g. on LCSC).
Design files (KiCad, gerbers) can be downloaded here.