The bq25570, bq25505, TPS62740, TPS62737 and TPS62736 claim to maintain the industry’s lowest levels of active quiescent current and enable battery-free operation to wireless sensor networks, monitoring systems, wearable medical devices, mobile accessories and other applications with limited access to power.
TI’s new bq25570 boost charger with integrated buck converter consumes a miniscule 488 nA of quiescent current and achieves greater than 90-percent efficiency at output currents lower than 10 uA, maintaining high efficiency even at the lowest amount of available power. The device features maximum power point tracking (MPPT) to extract and manage power from photovoltaic cells and thermoelectric generators, and supports any energy storage element, such as a rechargeable Li-Ion battery, thin film battery, super-capacitor or conventional capacitor. During long periods of storage, power to the bq25570 can be disabled through a ‘ship mode’ feature, which allows the device to consume less than 5 nA.
The bq25505 boost charger is similar to the bq25570, but achieves an even lower active quiescent current of 325 nA. The bq25505 features an autonomous power multiplexor gate drive that enables seamless system operation from energy harvesting sources and the primary battery, ensuring constant power is available when the system needs to operate, even when no energy is available from the harvester.
In addition to the battery management circuits, TI introduced the TPS62740, the smallest and lowest power buck converter for 300-mA output current designs, providing 360 nA of quiescent current during active operation and 70 nA during standby. The converter achieves greater than 90-percent efficiency down to 10 uA. Achieving a total solution size of 31 mm2, the converter uses a programmable output voltage feature and DCS-Control functionality to power microcontrollers, such as TI’s ultra-low power MSP430FR59xx microcontrollers (MCUs) and Bluetooth low energy solutions, such as the SimpleLink CC2541 wireless MCU. The TPS62740’s integrated load switch also conserves the power of components like LEDs or sensors that are used temporarily.
For lower current designs, TI’s new TPS62737 converter for 200-mA designs and TPS62736 for 50-mA designs provide an ultra-low 370 nA quiescent current during active operation and 15 nA during sleep, while achieving 90 percent efficiency at output currents lower than 15 uA.
Availability and Pricing
All products are shipping in volume production and are available through TI’s worldwide distributor network. The bq25570 and bq25505 come in a 3.5-mm by 3.5-mm QFN package, and are priced at $3.20 and $2.40, respectively, in 1,000-unit quantities. The TPS62740 comes in a tiny 2-mm by 3-mm SON package, and is priced at $1.10 in 1,000-unit quantities. The TPS62737 and TPS62736 are available in a 3.5-mm by 3.5-mm QFN package, and are priced at $1.00 and $0.80, respectively, in 1,000-unit quantities.
More information about the PMICs at www.ti.com/energyharvesting-pr