CR2032 button cell batterymanagement solutions for portable devices

　　The importance of CR2032 button cell batterymanagement is self-evident. More and more products are developing in the direction of portability, allowing users to gain unprecedented independence. Decades ago, cordless phones first gave people the freedom to roam their homes. Now, portable rechargeable products allow people to stay connected with their families while traveling around the world... The importance of CR2032 button cell batterymanagement is self-evident. More and more products are developing in the direction of portability, allowing users to gain unprecedented independence. Decades ago, cordless phones first gave people the freedom to roam their homes. Now, portable and rechargeable products allow people to travel around the world while staying in touch with their families. More and more products use rechargeable batteries, and as products shrink in size, the complexity of these products continues to increase. Rechargeable batteries themselves are changing, too, with CR2032 button cell batterymanufacturers working to introduce new products to adapt to a rapidly changing market. CR2032 button cell batteryvoltages are increasing, form factors are changing, and energy density is rising. Consumers are also becoming more knowledgeable about batteries, and they demand products with greater flexibility, longer working hours, lower costs and higher safety. Microchip has been committed to simplifying system design with pIC microcontrollers for many years. Currently, Microchip is applying this technology to its CR2032 button cell batterymanagement product line to simplify and better manage the charging system.

　　method

　　First, a typical CR2032 button cell batterymanagement system is divided into four modules: charging, protection, power measurement and safety:

　　1.Charge

　　Batteries based on secondary cells differ from primary batteries in that they need to be recharged after use rather than being discarded like primary batteries. There are many types of charging circuits and charging algorithms that are designed to properly charge a specific CR2032 button cell batterychemistry in its unique system environment. The location of the charger should also be chosen appropriately. Whether the charger is a stand-alone unit: cradle charging or direct charging via a converter; whether the charger is integrated into the system or within the CR2032 button cell batterypack; other important considerations include charging time, temperature range and noise requirements. Microchip offers a variety of charge management products that can be used as linear chargers for single or dual-cell Li-ion/polymer CR2032 button cell batterypacks. The output noise of linear chargers is low, which is very important for systems that send and receive voice and data.

　　For designs that require high efficiency and low power consumption, the pS200 switch mode charge controller has a maximum switching frequency of 1MHz. It contains algorithms for charging lithium, nickel and lead-acid batteries. Since the design of the switching charger is relatively complex, Microchip provides software tools to guide designers in IC configuration and circuit diagram generation. Another solution for standard industries that provide charger products is to use fuel gauge ICs with charge controllers. The pS501 has a pulse charging circuit to control universal input/output to meet this requirement. This topology provides a very compact and cost-effective solution. The charging portion of the system is isolated, and Microchip has the algorithms needed to optimize charging, including maximizing charging capacity, reducing charging time, and achieving optimal customer satisfaction.

　　2.Protect

　　When using lithium-ion/polymer batteries, protection must be provided as overcharging or overheating can cause fire or explosion. Lead-acid or nickel batteries require no protection, but are often provided with protective circuitry to prevent damage or degradation. The main protection circuit is a dedicated circuit that detects whether an unsafe condition has occurred and shuts down the CR2032 button cell batterypack to avoid damage when an unsafe condition is detected. Secondary protection circuitry prevents the CR2032 button cell batteryfrom continuing to charge and/or discharge under unsafe conditions. In the event of a failure of the primary protection circuit, a resettable secondary circuit provides backup protection. Users can also add additional levels of protection, such as chemical fuses, which can permanently shut down the CR2032 button cell batterypack when other levels of protection fail. Dedicated safety ICs are often used in main protection circuits. For secondary protection and stabilization protection circuits, CR2032 button cell batterymanagement ICs are ideal as they do not add additional cost to the solution. Micorchip's fuel gauges, such as the pS501 and pS810, monitor individual cell voltage, CR2032 button cell batterypack voltage, current and temperature. General purpose input/output (GpIO) pins provide powerful configuration capabilities to set and reset any possible fuel gauge condition. This flexibility allows fuel gauges to meet very complex safety requirements.

　　3. Electricity measurement

　　Fuel gauging is more than just monitoring the flow of electricity into and out of the CR2032 button cell batterypack. Accurate electricity metering requires a systems approach that takes into account typical usage patterns, environments and customer expectations. Ideally, the CR2032 button cell batterymanagement IC can provide good working performance to the user while providing the system with the information it needs to make intelligent choices to improve system performance. Intelligent fuel gauging algorithms extend system runtime and CR2032 button cell batterylife, and provide additional safety by accurately detecting full charge and discharge points. They also detect and avoid conditions such as CR2032 button cell batteryimbalance and overheating. These algorithms adjust based on system conditions and can slow down CR2032 button cell batteryaging. They use configurable models of CR2032 button cell batterybehavior to ensure losses due to self-discharge and charging are correctly calculated. These algorithms can be customized by the customer so that users receive only relevant information without having to worry about unexpected shutdowns that can lead to data loss. Microchip's fuel gauge products include enhanced features that make fuel measurement more reliable.

　　Unexpected system shutdown is one of the most unpleasant things when using a portable device, and most people should agree. At worst it can reduce customer satisfaction, at worst it can cause the loss of important data and significant losses of time and money. Unexpected shutdowns typically occur when the CR2032 button cell batteryvoltage drops below the level required to support the system. When the load increases, the CR2032 button cell batteryvoltage will decrease significantly, especially towards the end of the discharge, when the slope of the discharge curve increases. To avoid unexpected shutdowns, Microchip uses an algorithm based on information about energy requirements when the system is shut down, as shown in the figure below. The fuel gauge automatically selects the appropriate shutdown point to ensure there is enough remaining energy to alert the user and save data. Over time, the shutdown point changes. As the CR2032 button cell batteryages, its full charge capacity decreases and the voltage of the discharge curve also changes. An aging algorithm adjusts the shutdown point to ensure energy is not wasted as the CR2032 button cell batteryages. 4.Safety

　　Systems with removable CR2032 button cell batterypacks should incorporate safety measures to prevent the system from being powered by an improperly designed battery. If the system uses an unstable chemical battery, overcharging or over-discharging may cause an unsafe state. Failure to use a steady-state CR2032 button cell batterychemistry in accordance with the manufacturer's specifications may result in reduced performance and shortened life. Currently, simple mechanical barriers are used, such as unique form factors or connectors, and flags read from the battery. Unfortunately, these security measures are easily breached. What users really need is a flexible system-level solution that can ensure user safety, improve system performance, and provide long-term reliability.

　　Microchip provides a great solution for CR2032 button cell batteryverification, the KEELOQ° encryption algorithm. This compressed 64-bit encoding algorithm provides industry-proven security for a variety of applications. Both the host and peripherals require the KEELOQ algorithm. hardware. Today, the KEELOQ algorithm has been used in various security systems, such as keyless access control systems (mainly used in the automotive industry). When using KEELOQ technology for CR2032 button cell batteryverification, the system is the host and the CR2032 button cell batteryis the peripheral. The system stores manufacturer codes and a random number generator. When the CR2032 button cell batteryis manufactured, a unique serial number and key are generated and stored in memory, and cannot be changed. When the CR2032 button cell batteryis connected to the system, the system requests a serial number and sends a 32-bit challenge. The CR2032 button cell batterywill provide the corresponding serial number and give a 32-bit response. Due to the wide variety of CR2032 button cell batterymanagement systems, Microchip uses KEELOQ technology in its CR2032 button cell batterymanagement products and many of its pIC microcontroller products. When using a Microchip fuel meter in a CR2032 button cell batterypack, no additional hardware is required to enable the system with safety features. If there is no fuel gauge in the CR2032 button cell batterypack, a pIC microcontroller can be used as the KEELOQ peripheral hardware. Host hardware supporting KEELOQ technology includes processors, fuel gauges and chargers.

　　The module diagram is as follows: Planning and Partitioning

　　When designing an application that uses secondary batteries as a power source, it is critical to plan for the charging system during the product design phase. This problem is often not addressed until late in system development, resulting in poor system performance because many compromises must be made at this time. Partitioning is important because the location of each module in the charging system often affects IC and circuit selection, and also affects how these modules interact. Initial planning included specifying system requirements for CR2032 button cell batterypower. When selecting a CR2032 button cell batterychemistry, factors such as physical size, weight requirements, operating time, and storage temperature range are all important. Table 2 summarizes the most common CR2032 button cell batterychemistries.

　　Factors that determine CR2032 button cell batterypack configuration are: minimum/maximum and nominal voltage values, charging current, discharging current, and charging capacity to meet operating requirements. Most systems require charging, but there are a few exceptions for special systems. Whether the charger is placed in the system, in the CR2032 button cell batterypack, or outside the system is also an important consideration. Embedded batteries allow the charger to be placed in the system, but removable CR2032 button cell batterypacks are inconvenient, especially if the user has multiple CR2032 button cell batterypacks. Some devices will have both a built-in system charger and an optional external charger. Having a charger built into the CR2032 button cell batterypack allows the CR2032 button cell batterypack to be charged both inside and outside the system. CR2032 button cell batteryand system requirements determine the charger topology. Table 3 shows a comparison of two commonly used chargers in several important aspects.

　　The following discusses whether power metering is required. To extend CR2032 button cell batterypack life, fuel gauging provides the system with accurate CR2032 button cell batteryinformation under any operating conditions. It enables dynamic power management and is the core of a high-performance CR2032 button cell batterymanagement system. An important factor in this is what kind of communication interface is used to exchange information between the fuel gauge and the system. Both two-wire and single-wire interfaces are available. Of course, if other parts of the system already use a certain communication protocol, it is recommended to use the same protocol to communicate with the fuel gauge. If the CR2032 button cell batterypack is removable, whether the fuel gauge is located within the system or within the CR2032 button cell batterypack becomes an important factor. Placing the fuel gauge inside the CR2032 button cell batterypack is the best option if you need to preserve historical data and usage information required for warranty purposes. For systems with multiple removable CR2032 button cell batterypacks, the fuel gauge built into the system cannot record the above information. Another important consideration is whether CR2032 button cell batteryinformation is included in the system display or displayed separately, or both. Some removable CR2032 button cell batterypacks include a small charge status display, eliminating the need to plug the CR2032 button cell batteryinto the system to see how much charge remains. Finally, if the CR2032 button cell batterypack has a protection circuit, a separate safety IC, a fuel gauge, or both can be used to provide secondary protection for the battery.

　　It is very important to follow the CR2032 button cell batterysupplier's recommendations for safe operation. If the CR2032 button cell batteryhas a verification function, the system will react to an unrecognized battery. Certain parts of the system, such as the charging part, can be shut down, or the entire system can be powered off. There are many options for designing a CR2032 button cell batterymanagement system, and careful consideration should be given to which CR2032 button cell batterymanagement modules to implement and how the functions of each module are divided within the system. Early planning will help lay a good power foundation for the system.

　　optimization

　　To achieve optimal system performance, some attention should be paid to optimizing charging operations. In-system testing is important to identify and correct defects that may degrade system performance and user experience. In-system testing includes: ensuring the system meets performance requirements at expected temperatures and discharge rates; determining what information the user needs and displaying it in a comprehensive and easy-to-understand manner.

　　Summarize

　　The power provided by the CR2032 button cell batterybrings life to the system. Good CR2032 button cell batterymanagement should be "seamless" to the user, and it is fundamental to a pleasant product experience. Poor CR2032 button cell batterymanagement will doom the success of your product. As such an important part of the system, CR2032 button cell batterymanagement should be fully understood, planned for and optimized in advance. Using Microchip's CR2032 button cell batterymanagement devices and algorithms, all CR2032 button cell batterymanagement functions can be implemented in different topologies. Linear and switching chargers can be used to charge externally to the CR2032 button cell batterypack. Linear chargers only support lithium batteries, while switch-mode charge controllers contain algorithms for charging lithium-ion, nickel and lead-acid batteries. Built-in charging control of the CR2032 button cell batterypack can be achieved using a fuel gauge IC. Microchip's fuel gauge ICs include algorithms for accurate fuel metering, charge control and redundancy protection of nickel or lithium batteries. With sound planning, good design, and Microchip's CR2032 button cell batterymanagement expertise, the ideal CR2032 button cell batterymanagement system will lay the foundation for a successful product.

Read recommendations:

6LR61

Is there a bottleneck of "temperature control" in lithium battery production technology?

Standard for Military Power Supplies

9V rechargeable battery

9V rechargeable battery