Battery charging method for integrated power path management function

　　Author ：Iflowpower – Portable Power Station Supplier

As the design of the battery power supply is becoming more compact, there are more and more power consumption, and the space left to the battery has become more and more limit, and most of the batteries are not detachable. Therefore, the operation of the equipment Some major events. In order to improve the portability of the equipment, everyone often uses a more battery capacity auxiliary charging equipment, such as mobile power of smartphones, charging boxes for earplugs and electronic smoke, etc.

Due to the conflict between the capacity of the portable device and the conflict between the battery size and capacity limit, the mobile power has been widely used as auxiliary charging equipment for many years. However, if you want to move the power supply, it has a more compact design (weight lighter) and higher efficiency (longer operating time), and the equipment of the charging box is also the same. Conventional treatment method is to use a separate charging device-linear charger IC or switch charger IC, and the input and output of the boost converter with blocking FET (see Figure 1).

However, this does not meet the needs of consumers / manufacturers. Figure 1: Traditional IC Charger + Boost Converter New Products MPS Latest Promotion Single Power Management ICMP2696A Configuration Flexible, Enrich. The MP2696A integrates as many analog circuits, with the most economical, simplest microcontroller (MCU), supplies programmable and full-time minimalism processing for mobile power (see Figure 2).

Figure 2: Highly integrated two-way mode compared to traditional processing methods, this method can save customers a switch charger, an inductance and a USB interface IC. The MP2696A is rich in functionality. It can be used in terms of efficiency and performance improvement: two-way working mode, can use a single inductor to charge and discharge integrated JEita battery temperature protection threshold integrated with protection and independent control functions Top-impedance FETs integrated programmable input current limit and input voltage limit function, automatic hibernation mode When you connect to your smartphone, automatic int output integrated USB protocol interface, can supply maximum output power MP2696A can be passed by MCU Interface communication, it works in two-way mode of operation of charging or boost discharge, is the perfect choice for mobile power and charging.

And can be flexibly set by the MCU, and the operating status and fault event can also be indicated by status and fault registers. Charging mode MP2696A is a USB interface design, tolerate up to 16V input voltage. Since the typical input voltage of the USB port is 5V, even if the high pulse voltage inserted in the cable plugging instant, no threat to the mobile power.

It also integrates a programmable input current limit and input voltage limit function. Up to 3A input current limit allows MP2696A compatible with 15WTYPE-C electrical characteristics (see Figure 3). With the MCU program, the MP2696A can set the limit of the input current according to the input power supply to ensure that it meets BC1.

2 and USBTYPE-C specification requirements. In view of the additional input voltage limit function, MP2696A can use the optimized charging current to charge, regardless of the adapter, can shorten the charging time. Figure 3: The power flow discharge mode MP2696A in the charging mode also has a discharge function, which can supply 5V discharge output, the maximum output current can reach 3.

6A (see Figure 4). The MP2696A has an output current loop. When the load current reaches the output current limit, the MP2696A limits the output current through the output current loop.

The MP2696A has an output cable compression compensation function. When the load current increases, the MP2696A will slightly increase the output voltage so that the output voltage after the cable can be constant, and the amplitude of the compensation can also be freely set. The very low-conducting impedance FET makes the MP2696A have very high efficiency, especially suitable for highly integrated small design.

Figure 4: Power flow in the discharge mode 5: Efficiency protection function in discharge mode and unique intelligent test function The MP2696A can supply reliable protection in all modes. In the charging mode, it has input overvoltage protection, battery overvoltage protection, security charging press. In the discharge mode, it has battery undervoltage lock protection and output short circuit protection.

These hardware protection features ensure safe charging when the MCU software is faulty. Battery temperature testing and protection features have become more and more tight to power-on portable equipment. Japan Electronics and Information Technology Industry Association (Jeita) standard - optimizes charging parameters under temperature conditions of different batteries, which has become a mandatory function in battery charging.

MP2696A not only supports Jeita standard, but also has programmable temperature protection threshold adjustment (see Figure 6). Since the thermistor value changes with the temperature change, the MP2696A can monitor the voltage ratio between NTC and VNTC, supply battery temperature information. The MP2696A then compares the measured rated value to the internal rating to determine the temperature range and how to adjust the charging voltage and current.

Therefore, customers can adjust the temperature threshold by changing the parameters in the I2C register, there is no need to change the register voltage divider on the board. This way to configure I2C registers to save software engineers save a lot of MCU encoding work. Figure 6: Temperature protection In the discharge condition, if the load current is less than the set programmable threshold, the MP2696A will notify the MCU: The load has been released.

At this time, after several timing times, the MP2696A can be stopped. Standby mode. In standby mode, MP2696A can test load insertion operation and report to the MCU, determined by the MCU, should be and wake up and wake up.

This does not need to use too much external score to test the load insertion. The MP2696A can also supply information about the battery current, whether it is charging or discharge, the information of the battery current will be proportionally displayed on the IB pin, which can help the system more accurately understand the battery capacity. Conclusion The MP2696A combines simple MCUs, which can use the supply of compact and efficient design processing for mobile power or charging boxes.

The MP2696A integrates low-conducting power FET that supports two-way mode of operation, but also contains load connection test circuits and USB discharge protocol interfaces that achieve more compact design and lower BOM costs. This chip supports programmable Jeita protection to easily meet battery characteristics of different customers, and have outstanding efficiency performance and various hardware protection features. The most important thing is that MP2696A is easy to use, and can save design time using the reference design.