For engineers, designing applications that use rechargeable batteries and provide a superior charging experience for consumers can be challenging, especially when different projects have varying battery charging requirements. Using a dedicated battery charger for each application increases design time because you have to redesign, debug, and requalify each new circuit.
Imagine if you could minimize development time by choosing a battery charger suitable for a variety of projects? Single-cell charger integrated circuits (ICs) with wide input voltage (VIN) and output voltage (VOUT) ranges enable you to use the same charger in a variety of applications with different input adapters and battery configurations, thus helping to shorten development time.
In addition to helping shorten design time, using wide VIN and VOUT chargers allows you to explore new technologies such as solar power and bidirectional charging, thereby optimizing the charging experience for consumers. This article will introduce the advantages of wide VIN and VOUT buck/boost battery chargers.
Supporting a variety of designs using a single battery charger IC.
The design of an e-bike battery charging system is an example of an application that benefits from using the same battery charger IC across different e-bike models. This involves a new USB Power Delivery (PD) standard called Extended Power Range (EPR), offering output power up to 240W and VIN up to 48V. Given the higher EPR power and the convenience of using standard USB Type-C® adapters, designers are seeking to implement USB PD EPR charging for e-bikes, which requires integrating the battery charger IC into the e-bike battery pack.
However, e-bike companies offer different models, and their battery chemistry and charging voltages vary. It's more convenient to use the same battery charger for both models compared to using one charger for 36V batteries and another for 48V batteries. Supporting the full voltage range of the USB PD EPR adapter also helps minimize the design changes required between different models. For universality, the battery charger must have wide VIN and VOUT ranges to support USB PD EPR input and battery voltages from 36V to 48V, respectively.
Bidirectional charging, related to USB PD EPR charging, is a new feature supported by wide VIN and VOUT battery chargers. When the battery charger is in forward mode, it can charge batteries such as those used in e-bikes, while in reverse mode, it discharges the battery from the same USB Type-C port. The application also features a new function: in addition to its regular operation, it can also function as a power bank, benefiting consumers. To support power bank functionality, the battery charger needs a wide VIN and VOUT range and bidirectional charging capability to support various input and output voltage combinations in both forward and reverse modes.
Solar charging under different solar radiation intensities
Solar panels provide consumers with a way to charge their products when there is no grid power outlet nearby. Since the output of the solar panel serves as the input to the battery charger, it is crucial to determine the solar panel's maximum power point (MPP). Lower input power to the battery charger results in lower charging current, leading to longer charging times. Battery chargers with maximum power point tracking (MPPT) algorithms autonomously determine the solar panel's MPP under varying sunlight conditions. Using wide VIN and VOUT buck/boost battery chargers helps support the range of possible output voltage values from the solar panel.
Mobile power stations will also benefit from chargers with MPPT algorithms. For solar charging applications, designing charging systems using battery chargers with proprietary MPPT algorithms helps to fully utilize solar panels and reduce charging time.
Wide VIN and VOUT battery charger
The BQ25756 buck/boost battery charger supports a 70V operating voltage and up to 20A charging current at both input and output, meeting a maximum USB PD EPR power of 240W. In addition to its wide VIN and VOUT ranges, the BQ25756 is also a bidirectional battery charger, supporting charging and discharging from the same USB Type-C port. The device employs an advanced MPPT algorithm for solar charging, capable of determining the MPPT of multiple series or parallel solar panels even under various sunlight conditions, including partial shade. With its wide VIN and VOUT ranges, bidirectional charging, and MPPT functionality, the BQ25756 can be used in a wide range of designs.
Conclusion
Using a charger with a wide VIN and VOUT range in the design allows the same circuit to be reused in multiple applications, helping to reduce engineers' development time. Suppose you need to design a completely new product line of power tools; selecting different battery chargers for drills, heat guns, and blowers would increase workload because you would need to understand three different chargers. Using the same charger for these power tools helps to shorten the understanding and development time compared to using multiple different chargers.
Furthermore, wide VIN and VOUT chargers enable engineers to adopt new technologies such as USB Type-C power delivery and solar charging. With wide VIN and VOUT chargers like the BQ25756, which features MPPT algorithms, engineers can design products that can be charged anytime, anywhere using solar panels, while simultaneously providing consumers with a fast-charging experience. Combining the BQ25756 with a Texas Instruments USB-C PD controller eliminates the hassle of an adapter only working with one type of device. This combination allows consumers to utilize bidirectional charging capabilities and charge a wide range of applications using a universal USB-C adapter, including power tools, e-bikes, and mobile power stations. Wide VIN and VOUT chargers optimize the customer charging experience and reduce development time.
