Design and Construction
The BQ25790 and BQ25792 are fully integrated 1-cell to 4-cell switch mode buck-boost battery chargers. It consists of 4 MOSFETs (Q1, Q2, Q3, Q4) switches, current-sensing circuits for charging and dual input selector, the battery field-effect transistor (FET) and all the loop compensation of the buck-boost converter.
The devices have flexible designs to charge batteries across the full input voltage range (3.6V to 24V) for USB Type-C and USB power delivery (USB-PD) applications, such as those relevant to smartphones, tablets, and other portable devices with up to 5A charging current, along with the provision of maximum power density.
The BQ25790 and BQ25792 charger ICs have less than 1µA quiescent current, which provides up to 5 times longer shelf life than other competitive devices, which also deliver ten times lower quiescent current. The BQ25790 and BQ25792 charger ICs are available in a 56-pin (2.9 mm by 3.3 mm) wafer-level chip-scale package and 29-pin (4mm × 4mm) quad-flat no-leads packages.
Buck-boost charger integrated circuits for USB Type-C and USB power delivery ports. Image Credit: Texas Instruments.
Features and Specifications
The BQ25790 and BQ25792 feature NVDC (narrow volt direct current) power path management to reduce power loss by decreasing the voltage range, while not dropping below the minimum system voltage. The system doesn’t stop operating even if the battery is completely discharged or removed. The technology helps to keep the system from crashing and stops the input source from being overloaded when load power passes by the input source rating.
The devices use legacy USB adapters, high-voltage USB-PD adapters, and traditional barrel adapters to charge a battery.
The BQ25790 and BQ25792 provide a D+/D− handshake using an adjustable high voltage adapter (i.e. high-voltage dedicated charging ports, or HVDCP) to support fast charging. They can accommodate both the USB 2.0 and USB 3.0 power delivery specification with input current and voltage regulation. The input current optimiser also enables the detection of the maximum power point of an unknown input source.
Greater Power Density
The buck-boost chargers have the ability to charge a battery from almost any input source, regardless of whether the input voltage is higher or lower than the battery voltage.
The technology provides 97% efficiency at 30W with charging current up to 5A. It maximises battery life for applications that require long periods of operations with ultra-low power consumption: this is by working in combination with an extremely low-battery FET resistance of 8ohm.
Package and Availability
Texas Instruments are providing newly-launched BQ25790 and BQ25792 buck-boost charger ICs available in a 56-pin (2.9 mm by 3.3 mm) wafer-level chip-scale package and a 29-pin (4 mm × 4 mm) quad flat no-lead package respectively.
Applications for Engineers
The BQ25790 and BQ25792 charger ICs assist engineers in reducing solution size and bill of materials, which are features that are certainly in demand for applications such as smart speakers, smartphones, tablets, digital cameras, and other portable devices. This reduction of size and cost increase product market demands and adoption.
Engineers benefit from using adjustable high voltage HVDCP adapters, such as those relevant to the BQ25790 and BQ25792: this is to support fast charging while completing a charging cycle without any software engagement.
The technology is escorting a new level of flexibility and convenience to portable medical devices, such as blood pressure monitors and power continuous positive airway pressure machines.
Ultimately, the newly-introduced buck-boost BQ25790 and BQ25792 charger ICs are helping engineers by reducing production cost and solution sizes, as well as providing maximum power density and greater efficiency. The devices are beneficial in portable devices with high accuracy. The technology is altogether efficient, reliable and affordable due to the products’ compactness and convenience—and this provides much ease to engineers.