Energy-harvesting IC combines energy collection and battery charger

December 11, 2013 // By Graham Prophet
STMicroelectronics' SPV1050 is suitable for applications using either a solar cell or Thermo-Electric Generator (TEG) with power requirements from a few microwatts to several milliwatts, and is equally suitable for both indoor and outdoor consumer and industrial applications using either solar or thermal energy.

The ultra low-power energy-harvesting IC also includes 1.8V and 3.3V regulators to power a companion microcontroller or wireless transmitter directly without requiring additional components. Maximum Power-Point Tracking (MPPT) continuously optimises energy harvesting, or can be disabled. The battery-charging circuitry supports a wide variety of battery types including lithium-ion and lithium-polymer, lithium thin-film solid state, NiMH and NiCd, as well as supercapacitors.

Inside the SPV1050, a buck-boost converter allows the device to connect to either TEG or indoor/outdoor solar-energy harvesting modules by providing a wide input-voltage range from 180 mV to 8V. Average operating efficiency of 90% allows fast battery charging even at low input power levels, while minimum MPPT accuracy of 90% maximises energy extraction from solar or TEG sources. In addition, the integrated battery-charging controller uses highly accurate under-voltage and end-of-charge thresholds, and provides safe control logic to prevent excessive discharging for longer battery life.

The SPV1050 is available in a 20-lead QFN 3x3x1mm package or in 20-bump WLCSP tested and unsawn wafers, at $1.15 (1,000).