Design a Device to Simplify Your Multi-rail Power Supply

The most basic systems include microcontrollers, sensors and some type of wireless connection, which often have different power supply voltage requirements. If you are designing for a portable device, you may need to make your design powered by batteries or run on energy collection. In this way, your simple monorail system suddenly becomes a more complex multi-rail power supply design, requiring a battery charger. What should you do now?

If complexity, size and integration are not important factors, you can charge the battery with a step-down converter suitable for the main power supply, a low voltage differential regulator (LDO) suitable for other voltage rails and a lithium ion (Li ion) charger. However, three power integrated circuits (ICS) together with all external discrete components will increase the complexity, size and cost of the system.

So why not try the power management multichannel IC solution (PMIC) instead? Small and easy-to-use PMIC solutions range from two simple power rails to 26 rails with load switches, analog-to-digital converters (ADCs), battery chargers, light emitting diode (LED) drivers and other combinations. They are cost-effective and accelerate the time to market because all components are flexible and contained in a single solution. Refer to figure 1 to see how the PMIC solution works.

Figure 1: PMIC can be highly integrated to include more than power supply. The devices that PMIC can integrate are usually external, such as liquid crystal display (LCD) backlight devices, real-time control devices, sequencing devices and battery chargers.

An example of a PMIC designed for wearable and IOT applications is the tps6572x. The small device has a 300mA integrated lithium-ion battery charger, a high-efficiency step-down converter (tps65720 is 200mA, tps65721 is 400mA) and a 200mA LDO. The voltage is easily set by an external resistive voltage divider. In addition, the tps6572x also integrates four-way universal input / output (GPIO), so you can make some space on your own microcontroller to make it easier to route devices such as light emitting diodes (LEDs) and buzzers (usually used in fitness watches and portable industrial applications). The tps6572x is packaged in WCSP (tps65720) or QFN (tps65721). The overall solution (with discrete components) size of tps65720 is 25mm2.

Figure 2 shows a simple block diagram of how the solution can work with an industrial data recording application. Tps6572x can be used for microcontroller and Bluetooth ® Controllers and sensors are powered to create a low-power, compact and efficient design.

Ultra low power msp430f5438a microcontroller (MCU) can support ti's energy trace â„¢ Technology - an advanced energy debugging ecosystem. Energy trace technology enables users to view energy consumption in real time by observing working power consumption, standby power consumption and peripheral power consumption analysis. Using msp430f5438amcu allows the system to continuously detect and record sensor data and make independent decisions. At the same time, it only wakes up wireless appliances such as dual-mode cc2564 Bluetooth controller. In order to consume the least power, cc2564 device can use the communication and power saving mode of MSP430 MCU. The cc2564 Bluetooth device acts as an internet gateway to your smartphone, tablet or personal computer (PC) to collect real-time data from sensors and systems. The tps6572x can supply power to the whole system with only two simple power rails, and can also provide USB battery charging function.

Most devices rely on buttons in sleep or wake-up events. The tps6572x has a button detection function that allows the rest of the system to enter deep sleep mode to save energy or wake-up mode to continue operation. In conclusion, these devices can create small and efficient battery powered applications. These devices can be used together in applications such as fitness belts, heart rate monitors, industrial data recorders and industrial sensors.

Using PMIC to supply power to multi rail system can realize flexible, efficient, simpler and smaller design. Our PMIC can power subsystems, main processors, or both. If you have more than one power rail on your application next time, you might as well consider PMIC.

Figure 2: simple equipment often uses multiple power rails. The multi track output of tps65721 can realize compact and efficient design.