November 21, 2013 – TI Korea (CEO Kent Jeon) has launched five new next-generation power management integrated circuits (ICs) that efficiently harvest and manage power ranging from microwatts (uW) to milliwatts (mW) from light, thermal, or mechanical energy sources. The bq25570, bq25505, TPS62740, TPS62737, and TPS62736 enable battery-free operation in wireless sensor networks, monitoring systems, wearable medical devices, mobile accessories, and other applications with limited power access, while managing the industry's lowest active standby current. (For sample and development kit orders, please visit www.ti.com/energyharvesting-pr )

Nano power harvesting

TI's latest bq25570 boost charger, featuring an integrated buck converter, consumes an extremely low standby current of 488nA and maintains high efficiency even at the lowest available power levels, achieving over 90% efficiency at output currents of less than 10uA. This device features maximum power point tracking (MPPT) to extract and manage power from photovoltaic and thermoelectric generators, and supports all energy storage elements such as rechargeable lithium-ion batteries, thin-film batteries, supercapacitors, or conventional capacitors. For long storage times, the "ship mode" function can cut off power to the bq25505, allowing the device to consume less than 5nA.

The bq25505 boost charger is similar to the bq25570 but achieves a lower active standby current of 325nA. The bq25505 incorporates a unique auto-power multiplexer gate drive to ensure seamless system operation from the energy harvesting source and the primary battery, thereby guaranteeing that constant power is available when system operation is required, even when there is no available energy from the harvester.

Ultra-low power DC/DC converter

In addition to battery management circuits, TI has released the TPS62740, an ultra-compact, lowest-power buck converter for 300mA output current designs. This device provides 360nA during active operation and 70nA in standby mode, achieving over 90% efficiency down to as low as 10uA. The total solution size is only 31mm², and it powers microcontrollers such as TI's ultra-low-power MSP430FR59xx and Bluetooth® Low Energy solutions like the SimpleLink™ CC2541 wireless MCU using programmable output voltage and DCS-Control™ functions. It also conserves power for components such as LEDs or sensors that are used temporarily via an integrated load switch.

In addition to this, new devices for lower current designs have also been released. The TPS62737 converter for 200mA designs and the TPS62736 for 50mA designs provide a very low standby current of 370nA during active operation and 15nA in sleep mode, while achieving 90% efficiency at an output current of less than 15uA.

Energy Harvesting Design Implementation

TI is a leading supplier of power management ICs and MCUs that is leading next-generation ultra-low power designs by successively launching innovative devices that extract and manage ambient energy with high efficiency and lowest power consumption. In 2011, TI released the bq25504 boost charger circuit with a low standby current of 330nA, and also supplies boost converters, buck converters, and battery chargers that support all low-voltage, low-power design requirements.

Supply timing and price

All products are supplied in large-volume production and are available for purchase through TI's distributors worldwide. The bq25570 and bq25505 are available in 3.5mm x 3.5mm QFN packages at $3.20 and $2.40, respectively, in 1,000-unit quantities. The TPS62740 is available in an ultra-small 2mm x 3mm SON package at $1.10, in 1,000-unit quantities, while the TPS62737 and TPS62736, available in 3.5mm x 3.5mm QFN packages, are also priced at $1 and $0.80, respectively, in 1,000-unit quantities.

More detailed information on TI's nano-power power management portfolio

• Order evaluation modules for bq25570EVM-206 and bq25505EVM-218 and download PSpice transient model simulation software for bq25570 and bq25505 to simplify design and reduce development time
• Evaluation modules for low-power DC/DC converters including TPS62740EVM-186, TPS62737EVM-560, and TPS62736EVM-205
• Search for solutions, Q&A, and knowledge sharing in the TI E2E™ community's power management forum