98% Efficient Switched-Capacitor DC-DC for Fast Charging Applications

Silicon Mitus has announced the SM5428, a switched-capacitor battery charger. The dc-dc converter has been highly optimized to meet the demands of the emerging fast charging applications in the USB Type-C market, offering a higher efficiency that allows for a reduced time to charge the battery and better management of the thermal dissipation during the recharging cycle of the device.

It is tailored specifically for smartphones, tablets and any other battery powered consumer devices. The SM5428 offers the highest figures in efficiency and output current while guaranteeing safety

The SM5428 integrates the company's most efficient converter with the highest output charger current to date. It reaches a peak efficiency of 98 percent and a maximum output current of 8A to support 35W of charging power. It also integrates 10-bit ADC to measure the VBUS input voltage, VBAT output voltage, current and die temperature.

Furthermore, the serial I2C interface and numerous battery protection schemes help minimize heat dissipation while doubling the power, thereby reducing costs for designers. This allows for an efficient, safe and cost-effective solution for fast charging in consumer applications that are taking full advantage of the latest USB Type-C PD3.0 standard.

Typical application schematic for the SM5428 (click on schematic to enlarge)

"The introduction of SM5428 underscores Silicon Mitus's long term commitment to delivering innovation in the computing and consumer applications within the USB Type-C ecosystem," said Gianfranco Scherini, VP of Business Development of Silicon Mitus based in Cupertino, California.

"The device is a recent addition to our current line of USB Type-C compatible products, which also include Type-C CC controllers, OVP protections and eMarker ICs," concluded Scherini.

Summary of SM5428 features:

• Maximum 8A output current
• 6V to 10.5V Vbus input range
• 10-bit AC for Vbus, Vbat, Vout, Ibus, Ibat, Ithem_bus, Vthem_bus, and die temperature
• Programmable protections via I2C
  • Vbus OVP threshold
  • Vbat OVP threshold with alarm
  • Vout OVP threshold with alarm
  • Ibus OCP threshold with alarm
  • Ibat OCP threshold with alarm
  • THEM_BUS OTP threshold
  • THEM_BAT OTP threshold
  • Die thermal alarm threshold
• Protections
  • Vbus, Vout, Vbat OVP
  • Ibus, Ibat OCP
  • THEM_BUS, THEM_BAT OTP
  • Reverse blocking
  • Flying capacitor SCP
  • Die thermal shutdown
  • Watchdog timer
• Up to 34MHz high-speed I2C interface
• 56-bump, 3.01mm x 3.21mm WLCSP package