I used PMIC in previous projects. Let's talk about PMIC chips and their applications. What is PMIC

PMIC is the abbreviation of power management IC, and Chinese is power management integrated circuit. .
In the CPU system, we often use PMIC. Such as set-top box design, intelligent voice speaker design, large-scale industrial control equipment design, etc.
Analysis of PMIC chip and PMIC in application set-top box
The following introduces the PMIC through the product parameters, documentation and supply information of the chip XP152 " target="_blank">AXP152, which is a highly integrated PMIC from Xinzhihui, mainly used in digital cameras, set-top boxes, network equipment, Monitoring equipment and other products.
Introduction to XP152
AXP152 is a highly integrated power management IC that integrates an adaptive and usb compatible PWM charger, four step-down converters (Buck DC-DC converters), and seven LDOs. It also has protection circuits such as over-voltage/under-voltage protection (OVP/UVP), over-temperature protection, and over-current protection (OCP) to ensure the safety and stability of the power system.
The package of the AXP152 is a 5x5 40-pin QFN package.
Analysis of PMIC chip and application In addition, AXP152 also includes a two-wire serial interface (TWSI), through which the CPU can enable/disable certain power outputs, program voltages to reduce power consumption, and thus provide more complete power management.
Brief Analysis of PMIC Chip and Application
AXP152 internal block diagram

Through the above structural block diagram, we can see that there is a large logic control unit inside the PMIC. All DC-DC and most LDOs are controlled by the logic module. It is only necessary to configure the TWSI interface and change the corresponding configuration register to control the DC. - Output of DC and LDO, we can refer to the datasheet for the configuration manual of the register.
In addition, the SCK/SDA pins of the TWSI interface of AXP152 have been pulled up inside the chip, so the master device (CPU) can flexibly monitor and configure through this interface.
4ch DC-DC and 7ch LDO
The figure below is a comparison chart of 4 channels of DC-DC.

Brief Analysis of PMIC Chip and Application
4-way DC-DC
It can be seen that the output voltage of the 4 channels of DC-DC is adjustable, and the adjustable range is 0.7 to 3.5V, which can meet the power supply requirements of most of the smallest systems. For example, the CPU power supply is 3.3V, and the EMMC is 3.3V or 1.8V. Power, DDR power supply 1.25 to 1.35V. These groups of DC-DC can be satisfied.
The voltage regulation accuracy of DC-DC1 and 3 is 50mV/step, and the voltage regulation accuracy of DC-DC2 and 4 is 25mV/step. If the system needs higher voltage regulation, the DC-DC with an accuracy of 25mV/step can be used. .
The following figure is a comparison chart of 7-channel LDO.

Brief Analysis of PMIC Chip and Application
7 LDOs
These 7 groups of LDOs are generally supplied to the peripherals of the system, such as SRAM or PLL power supply, WiFi Bluetooth module power supply, control circuit power supply, drive circuit power supply, sensor power supply, peripheral interface power supply, etc. The output voltage is between 0.7V-5V. When using, mainly pay attention to the size of the output current. If the peripherals with relatively large power consumption cannot meet the LDO of the PMIC, an external DC-DC or LDO should be provided to provide power.
ALDO1/2 and GPIOLDO in these groups of LDOs are low-noise LDOs, and the analog circuit power supply should be connected to these low-noise LDOs.
Overload and Current Limiting Protection All DC-DCs and LDOs support self-monitoring and current limiting functions. When the load current exceeds the drive capability, all output voltages will be reduced in order to protect the internal circuits. When the DC-DC output voltage is lower than 85% of the set voltage, the PMIC will automatically shut down.
typical application

Analysis of PMIC chip and application block diagram

In the application, we connect the TWSI interface of AXP152 through the I2C interface of the CPU. In addition, we need to give the enable signal and reset signal. It can be seen that for each channel of DC-DC, it only needs to be regarded as a discrete DC-DC to configure. That's it.
The output capacitor is recommended to use a 10uF X7R low ESR ceramic capacitor. When the output voltage is higher than 2.5V, a 3.3uH power inductor is recommended. In addition, the saturation current of the selected inductor should be more than 50% larger than the maximum demand current of the circuit.