We use more and more portable devices in our daily lives, from consumer electronics to industrial equipment. Looking at battery configuration and charging requirements in more detail, you’ll find major differences between consumer electronics and industrial equipment.
In industrial applications such as drones and robots, batteries configured with high cell counts (more than two battery cells in series achieve higher power. Configuration usually requires a higher input voltage from the adapter to charge the battery more efficiently. In consumer electronics, 5V USB power source are widely used to charge single cell battery.
Besides the basic charging current, voltage and efficiency, when selecting a battery charger for an industrial application you should also consider solution size and cost. These factors lead to different charger configuration and charging topologies to balance between performance and cost. Higher performance is also associated with higher cost.
Should I select stand-alone or host-controlled chargers
Most industrial applications require a stand-alone charger to reduce software overhead and stabilize operation. Stand-alone chargers use different pins with different voltage levels to set the charging parameters. You can set the different voltage levels with a resistor divider or pull up/pull downs. With a fixed resistor-divider value, the charger can run by itself and the host can handle other important tasks. There is no software effort involved and no communication interface (such as I2C or SMBus) needed, preventing any charging parameter changes during operation, however. The bq2417x and bq2461x charger families are stand-alone chargers.
In other cases, the host microcontroller needs to change the charger-register setting at the beginning (or during the charging cycle) based on system and environment conditions. The charger must have a dedicated communication interface. The host microcontroller can adjust charge voltages, current limits or timer settings on the fly with communication interface and automatically adapt to different cell types or application needs. The communication interface will also allow for more detailed read-back of fault conditions (over temperature, timer limit, input voltage, etc.). The bq24770 (SMBus), bq24773 (I2C) and bq24780S (SMBus) are among host controlled charger category.
Should I select external or integrated switching MOSFET charger
In industrial applications, charging current can be very high; sometimes up to 10A. To achieve high efficiency and low solution cost, designers tend to select a switching MOSFET based on system requirements and overall performance. A system with an external MOSFET can provide better thermal performance when the charging current is high.
Figure 1: Charger with an integrated MOSFET
On the other hand, when the charging current is low, a switching MOSFET integrated into the charger IC can reduce total solution cost (Figure 1), such as the bq24133 and bq2417x. A charger with integrated MOSFETs is carefully designed to achieve high charging efficiency while meeting budgets.
To select the right charger, the overall system requirements need to be considered along with the solution cost. The different charger configuration and topology can provide optimized charging design for various industrial applications. Learn more about TI’s battery charger ICs and start designing today!