Complete single-inductor mobile power supply design

1206RGB (single)

Single chip microcomputer STM32L151CCU6

inductance

Overview:
Two inductors are often used in mobile power supplies on the market. In the charging circuit, the charging process requires an inductor, and the Boost circuit also needs an inductor during discharge. The working process of the charging circuit is to charge the lithium battery inside the mobile power source through the 5V AC adapter; and the Boost circuit works by boosting the internal lithium battery of the mobile power source to 5V for output, thereby supplying power to the mobile device. However, in the actual operation of the mobile power supply, the two circuits usually do not need to work at the same time, that is, only one inductor of the two inductors is in operation, and only one operation is needed for the two loops.

1. Chip working principle This paper proposes a single-inductor mobile power supply scheme, which not only helps the mobile power source to save the device cost, but also saves the equipment volume and facilitates the miniaturization of the mobile power supply. To make the equipment more stable, the single-inductor mobile power circuit is shown in Figure 1:

(a) Charging chip peripheral circuit

(b) boost chip peripheral circuit

(c) peripheral circuit of single chip microcomputer 1. chip working circuit in circuit
MT2011 is a high efficiency and high current single series lithium battery charge controller designed by Laiyu Technology. It supports 4.5V~6.5V input voltage, the output voltage can follow the lithium battery voltage, the maximum 2A charging current, using a high efficiency synchronous rectification structure, suitable for portable charging equipment and mobile power charging. Integrate current sampling resistors, high-precision current and voltage management circuits, and fully stop charging at full power. MT2011 operating frequency is 1.5MHz, using synchronous rectification structure, the efficiency is up to 93%. With charging current soft start, anti-inverting current diode, charging current sampling and other functions, with complete output short circuit protection and over temperature protection.
The MT5036 is a 95% efficient 800KHz synchronous boost converter designed by Lai Technology, which provides a good power supply solution for parallel connection of single-cell lithium batteries or multi-cell lithium battery packs. The converter obtains a stable output voltage by setting the chip's external FB divider resistor or by using an internal FB divider resistor. The chip conversion efficiency is very high, can provide enough load current, when the supply voltage drops to 3V, it can still output 3A load current when the output voltage is 5V, the peak current in the inductor is limited to 6.6A.MT5036 working frequency Up to 800KHz, which makes the inductor and output capacitors not too large, and with light load PSM function, can ensure the chip to maintain high conversion efficiency in the full load range. With 60uA quiescent current, it can greatly improve the life of lithium battery. With low EMI working mode, it can effectively reduce ringing when working intermittently. The converter can avoid over-discharging of the battery. The load can be completely disconnected from the battery when it is turned off. open.
SN8P2711 is an 8-bit high-performance reduced instruction microcontroller designed and developed in high-speed low-power CMOS process. It has 1K×16-bit one-time programming ROM (OTP-ROM) and 64K×8-bit data register (RAM). Two bidirectional I/O ports, two 8-bit timer/counters, two PWM/Buzzer modules, multiple system clocks, four system operating modes, a five-channel twelve-bit analog-to-digital converter, and five interrupt sources . This MCU can be widely used in measurement, motor control, industrial control, home appliances and toys.
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