Page 7 - PEN eBook October2023

Cover Story — Design

like smart speakers, the USB-C port takes on a dual-role functionality, capable of recharging the
device’s battery through a USB-C charger while also serving as a charging point for other devices,
such as phones.

Empowered by the USB Type-C and Power Delivery (PD) 2.0 specification, USB-C connectors can
now deliver an impressive 100 W (20 V at 5 A) through the interface. The latest advancement, USB
PD Specification 3.1, has further elevated USB-C power adapters, enabling them to provide 240 W
(48 V at 5 A) via the Type-C connector. This standardized USB-C framework has not only fueled
the adoption of USB-C as the go-to charging connector for notebooks and mobile phones but has
also contributed to sustainability efforts by reducing electronic waste and promoting the reuse of
USB-C power adapters.

This article targets embedded firmware engineers and system designers exploring the integration
of USB-C into their embedded applications, spanning smart speakers, IoT hubs, home appliances,
internet gateways, and power and garden tools. It intends to provide a comprehensive overview
of the USB-C PD system, shedding light on the evolving system architecture specifically suited
for battery-powered applications transitioning to USB-C. Additionally, the article offers insights
into the Infineon EZ-PD™ PMG1-B1, an innovative, high-voltage microcontroller (MCU). It is the
industry’s first high-voltage MCU that seamlessly integrates a USB-C PD controller, a buck-boost

battery-charge controller and high-voltage protection circuits, leading to a reduction in overall
system complexity and efficient utilization of the system bill of materials (BOM).

TRADITIONAL BATTERY-CHARGING SYSTEM ARCHITECTURE

Traditionally, battery-powered electronics were typically shipped with their proprietary AC/DC
power adapters. These specialized chargers featured a distinctive barrel connector that frequently
lacked compatibility with other adapters, rendering them unsuitable for sharing or repurposing.
This practice not only hindered charger versatility but also increased the overall production costs
of the product and e-waste.

These battery-charger systems typically included the following components:
▶ A buck-boost or a battery-charger IC to enable charging of the battery packs. These
battery-charging ICs typically support various modes, such as trickle charging,
pre-charging, constant-current (CC) and constant-voltage (CV), required to charge the
battery packs. The battery-charging IC also supports safety timers for protection against
prolonged battery charging.

▶ A battery management MCU to monitor and cut off charging in case the primary
battery-charging IC fails.
▶ Sensors to monitor system temperature and battery temperature.
▶ Battery protection and individual cell-monitoring circuits to ensure each cell voltage
doesn’t exceed safe limits.

OCTOBER 2023 | www.powerelectronicsnews.com 7