65W 2C1A Step-Down Fast Charging Solution for GaN Adapters

As consumers own an increasing number of electronic gadgets, demand for multi-port fast chargers has surged, making multi-port power adapters mainstream across the market.

Nevertheless, conventional multi-port fast charging designs face three core pain points: complex inter-chip communication leading to lengthy debugging cycles, forced 5V fallback and lost fast-charging performance when multiple ports are occupied simultaneously, and excessive peripheral components that block ultra-compact miniaturization.

To resolve these industry challenges and help OEM/ODM vendors rapidly develop high-integration, compact multi-port chargers, Hynetek Semiconductor releases a 65W 2C1A step-down fast charging reference design built around HUSB380B + HUSB382D. This complete chipset can be directly integrated into multi-port GaN adapters and desktop chargers to optimize total BOM cost.

Core Solution Advantages

This single-buck architecture based on HUSB380B and HUSB382D addresses all three prevailing design headaches:

1. Simplified Single-Line Inter-Chip Communication The two protocol ICs interconnect via a dedicated FC pin, eliminating complicated external detection circuits and cumbersome timing management. This drastically shortens software development and product validation cycles.

2. Intelligent Dynamic Power Sharing for Concurrent Fast Charging No more mandatory 5V downgrade when multiple devices plug in. The system auto-distributes available power according to the number of connected ports, sustaining full fast-charging speeds even when a laptop and smartphone charge at the same time. Built-in NTC thermal sensing further adjusts output power intelligently to guarantee safe operation under high temperatures.

3. Ultra-High Integration Minimizes Peripheral Count Both HUSB380B and HUSB382D integrate internal VBUS power switches and current-sense resistors, delivering a "zero extra component" design for the USB PD protocol section. A shared ground topology further streamlines PCB routing, slashing overall BOM cost and enabling ultra-small form factors for GaN chargers.

Demo Board Overview

This 2C1A step-down fast charging reference design adopts a compact green PCB layout with optimized component placement to maximize space utilization.

• Front side: Two USB-C female ports, one USB-A female port, two solid-state capacitors and one alloy inductor arranged in staggered layout.

• Back side: Three core ICs mounted, including the step-down converter and dual protocol chips. Each protocol IC only requires one decoupling capacitor as external component.

The finished demo board achieves an extremely small footprint when compared to a standard one-yuan coin.

Lab Test Results

We validated real-world charging performance with POWER-Z KM003C power analyzer to verify the elimination of multi-port fast charging drop-off.

When USB-C1 negotiates 12V/3A full power, USB-C2 can stably run at 9V/2.22A fast charging.

PDO reading on USB-C2 confirms complete power profiles: fixed 5V/3A, 9V/2.22A, 12V/1.67A plus 5–11V 2A PPS programmable voltage range.

NTC thermal throttling test: When over-temperature protection triggers, the system redistributes power. With USB-C1 locked at 9V/3A, USB-C2 maintains stable 5V/3A output to avoid overheating risks.

Component Deep Dive

HP2010 Synchronous Step-Down Converter

HP2010 is a 30V/5A synchronous buck IC housed in eSOP-8L packaging:

• Wide input voltage range: 4V to 30V

• Integrates dual 25mΩ internal power MOSFETs

• Constant On-Time (COT) control for ultra-fast transient response

• Fixed 250kHz switching frequency compatible with miniature inductors

• Maintains high conversion efficiency across full load range; switches to low-loss PFM mode under light load

• Comprehensive built-in protection circuitry Ideal for fast chargers, network power supplies and distributed power systems.

HUSB380B Multi-Port PD Protocol Controller

HUSB380B is a high-integration fast charging protocol IC in ESSOP-10L packaging, rated for up to 65W maximum output:

• Embedded VBUS switch and integrated current-sense resistor to cut peripheral count, optimized for wall chargers and car adapters

• Compliant with USB PD 3.2 standard; supports 5 fixed PDOs and 2 configurable APDOs

• Full legacy protocol compatibility: BC 1.2, DCP, Apple 5V/2.4A, QC 2.0/3.0/3+, AFC, FCP, SCP, PE 1.1+/2.0 and UFCS

• Complete protection suite: OVP, UVP, UVLO, fast OCP and thermal shutdown.

HUSB382D Dual-Port Type-C+Type-A Protocol IC

HUSB382D is a highly integrated dual-port (USB-C + USB-A) controller in DFN3×3-12L packaging, supporting peak 45W output:

• Onboard VBUS switches and current-sense resistors reduce PCB footprint and BOM expenses for chargers and car power supplies

• Compliant with USB PD 3.1, featuring 5 fixed PDOs and 2 programmable APDOs

• Universal cross-brand fast charging compatibility matching HUSB380B’s protocol coverage

• Full set of hardware safeguards including overvoltage, undervoltage, overcurrent and thermal protection.

Hynetek’s complete 2C1A step-down fast charging chipset demonstrates  deep technical expertise in multi-port GaN charger solutions. Thanks to fully integrated VBUS switches and current sampling resistors inside HUSB380B and HUSB382D, the reference design drastically cuts peripheral component quantity, shrinks PCB size and lowers total material costs.

The platform delivers broad cross-device compatibility, supporting mainstream standards including USB PD 3.2/3.1, QC, AFC, FCP, SCP and UFCS. Equipped with full-cycle electrical protection, the HUSB380B+HUSB382D solution can be directly deployed on mass-production multi-port GaN adapters and desktop chargers, shortening OEM evaluation and development lead times to capture fast-charging market opportunities faster.

For complete datasheets, engineering samples and dedicated technical support, contact Hynetek’s global sales team: Tel: +86-0755-8656 4099 / +86-021-5035 0688 Email: sales@hynetek.com Website: www.hynetek.com