USB Type-C Power Management for Portable Devices

Energy consumption is one of the biggest challenges for the mobile technology sector. USB-C was supposed to be primarily a connectivity option, but it is increasingly finding favor because it is also a useful means of managing power in portable devices. 

In this ever-evolving mobile ecosystem, devices become more and more intelligent and powerful, which means that they all require more energy to work. Although manufacturers strive to reduce battery consumption, the common problem with smartphones, wearable devices, fitness bracelets, tablets, and laptops is the high energy consumption after a couple of hours of use at full capacity, necessitating a session with power supply to recharge the battery. Therefore, one of the many challenges for designers is assessing the energy factor, estimating the energy needed, and designing very efficient power management configuration.

In the design of a wireless charging system, a fundamental parameter is represented by the amount of charging power required to replenish the battery. The received power depends on innumerable factors, including the level of the transmitted power, the distance, and the alignment between the transmitting winding and the receiver, otherwise defined as “coupling” and, finally, the tolerance of the components of the transmitter and of the receiver. Nobody has time to wait for a battery to be recharged: the shorter the time to recharge the battery, the better the user experience. This is well understood in the consumer electronics market and all the major brands are trying to reduce charge times.

Devices with a USB-C port recharge quickly and offer ultra-fast transfer speeds for connection to peripherals and external devices. USB-C also supports audio and video output and is compatible with HDMI, VGA, and DisplayPort displays. USB-C is on track to become the industry standard for manufacturers of all types of devices.

But while USB-C simplifies things for end-users, it increases complexity from the design and engineering point of view. There are substantial design and test challenges that designers have to face with the creation of a USB Type-C power connector that allows compatibility and reversible use with all other types. The USB port has evolved from its initial use mainly as a data interface, subsequently becoming the main means of charging portable electronic devices.

Silicon Mitus has four lines of products that address the mobile device and consumer electronics market, LCD and OLED display market, and the charging accessory market. The main applications are power management integrated circuits (PMIC) for smartphone applications such as IF PMIC/Battery management with Quick charging, complete USB Type-C solutions, and wireless chargers; PMIC solutions for LCD and OLED displays for smartphones, monitors and large TVs; Audio products for boosted Class-D amplifiers, high-performance audio codec, and surface sound for flat panel displays; PMIC solutions for computing applications and USB Type-C battery chargers.

“We have shipped over 3.5 billion ICs in these markets to date,” said Youm Huh, CEO of Silicon Mitus, a South Korean company based in Pangyo (Seoul) specializing in analog IC products. “Automotive is another market we are addressing with PMIC, as well as audio products for automotive infotainment and display modules. Silicon Mitus provides Power management ICs to module manufacturers of rear-view cameras of the latest generation of cars (replacing the glass mirrors).”

Silicon Mitus recently announced the SM58IP04: a single-chip buck-boost USB Type-C Narrow VDC (NVDC) charger targeting 2S/3S and 4S battery applications. It achieves up to 95% efficiency while in both buck- or boost-mode charging the battery up to 6 A due to advanced thermal management (Figure 1).

Figure 1: circuit layout for the SM58IP04 single-chip

“We are extremely satisfied with the performances of SM58IP04: it has been quickly adopted in computing applications where the product has been very effective in delivering great performance, with a small PCB solution size and cost-saving,” said Gianfranco Scherini, the company’s VP of business development. “This product combines the features of a multi-cell battery charger with the full support of the USB Type-C and PD specification.”

The USB Type-C standard meets the needs of the market in terms of power delivery and data rate, but above all, in terms of the ever-increasing quantity of devices able to interconnect. It is a reversible connector, meaning you don’t need to know the connection direction. The USB Type-C standard adapts to be a perfect connection for accessories and external peripherals, but also for powering laptops and other devices. Indeed, the USB Type-C Power Delivery (PD) standard supports currents up to 5A and 20V, making it possible to deliver up to 100Watts of power. Given the current levels, the standard requires appropriate protections, without which it could damage the device.

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