Power Management Integrated Circuit（PMIC） is known in Chinese as 电源管理集成电路, and its main feature is high integration, packaging traditional multi-output power supplies into a single chip, making multi-power applications more efficient and compact.
PMIC is an indispensable key component in today’s electronic devices. It provides power for various devices with its excellent performance and multifunctionality, from mobile phones and smartwatches to automotive and industrial equipment.PMIC not only supplies power to electronic devices but also leads new trends in power management to meet the growing demands of the electronics market.
In CPU systems, PMIC is commonly used. Examples include set-top box designs, smart voice speaker designs, and large industrial control equipment designs.
PMIC in Set-Top Boxes
Modern electronic devices often require multiple voltage and current levels to meet the needs of various electronic components. These components may operate at different voltages within the same device, necessitating an effective power management system to coordinate and distribute energy. Additionally, electronic devices often need to dynamically adjust power voltage and current in different operating modes (such as standby, active, sleep, etc.) to improve efficiency and extend battery life.
Some basic functions of PMIC include:
Power Management: PMIC is responsible for distributing power to different parts of the device to meet the power needs of various modules.
Voltage Regulation: PMIC can adjust the output voltage to accommodate different loads and operating modes.
Current Regulation: PMIC can also adjust the output current to meet different load requirements.
Battery Management: For battery-powered devices, PMIC is responsible for battery charging, protection, and state monitoring.
Clock Generator: PMIC can also provide the clock signals required by the device to synchronize the operations of various modules.
2. Examples of PMIC Chips
The main power management chips are the AXP series, including AXP152, AXP155, AXP192, AXP228, AXP288, AXP2402, AXP2585, AXP2601, and AXP15060. The AXP series chips are widely used in tablets, 2-in-1 tablets, TV boxes, dash cameras, sports DV, wireless storage devices, smart hardware, handheld payment terminals, e-books, and micro projectors.
Xinzhi Hui has some multi-power solutions specifically designed for tablets.
AXP15060 supports 23 output power channels, including 6 switching power supplies and numerous LDOs.
A single chip solves multiple problems. Through this product combination, it offers excellent cost-effectiveness and integration:
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High Integration: AXP15060 integrates various functional modules, including battery charging management, power management, battery protection, and system monitoring, achieving a highly integrated design in a compact space, which helps simplify circuit board layout and reduce system size.
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Efficient Battery Charging: Supports multiple battery charging modes, including constant current and constant voltage charging, allowing for the selection of suitable charging modes based on battery type and needs, improving charging efficiency and extending battery life.
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Multiple Power Outputs: AXP15060 provides multiple independent power output channels, including fixed voltage outputs and programmable voltage outputs, meeting the power needs of different devices and offering flexible power supply solutions.
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Battery Protection Features: Integrates various battery protection features, such as overcurrent protection, over-temperature protection, and over-discharge protection, effectively protecting battery safety and extending battery life.
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System Monitoring: Built-in system monitoring functions can monitor battery status, input voltage, output voltage, and other key parameters in real-time, providing real-time feedback and ensuring system stability.
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Low Power Design: AXP15060 adopts advanced low-power design, helping to reduce overall system power consumption and improve battery life, suitable for portable devices with high power consumption requirements.
Overall, AXP15060, as a highly integrated and feature-rich PMIC, provides a reliable power management solution for portable electronic devices, characterized by efficient charging, multiple power outputs, battery protection, and system monitoring, making it suitable for various mobile device designs and applications.
Hard Ten has developed an evaluation board based on AXP15060, and will provide reviews later.
AXP152 is a highly integrated PMIC developed by Xinzhi Hui, mainly used in digital cameras, set-top boxes, network devices, surveillance devices, and other products.AXP152 integrates an adaptive and USB-compatible PWM charger, four buck converters, and seven LDOs.It also features protection circuits, such as over-voltage/under-voltage protection (OVP/UVP), over-temperature protection, and over-current protection (OCP), ensuring the safety and stability of the power system.
AXP152’s package is a 5×5 40-pin QFN package, as shown below.
Additionally, AXP152 includes a two-wire serial interface (TWSI), through which the CPU can enable/disable certain power outputs and program voltages to reduce power loss, thereby providing more comprehensive power management.
Internal Block Diagram of AXP152
From the structural block diagram above, we can see that there is a large logic control unit inside the PMIC, with all DC-DC and most LDOs controlled by the logic module. It is only necessary to configure the TWSI interface and change the corresponding configuration registers to control the outputs of DC-DC and LDOs. We can refer to the datasheet for the configuration manual of the registers.
Furthermore, the SCK/SDA pins of the TWSI interface in AXP152 are already pulled up internally, allowing the master device (CPU) to flexibly monitor and configure via this interface.
The following diagram shows a comparison of four DC-DC outputs.
Four DC-DC Outputs
It can be seen that the output voltages of the four DC-DCs are adjustable, with an adjustable range from 0.7V to 3.5V, which can meet the power supply needs of most minimal systems, such as 3.3V for CPU supply, 3.3V or 1.8V for EMMC, and 1.25V to 1.35V for DDR. All these DC-DCs can meet the requirements.
The voltage adjustment accuracy of DC-DC1 and 3 is 50mV/step, while that of DC-DC2 and 4 is 25mV/step. If the system requires high voltage accuracy adjustment, the DC-DC with 25mV/step accuracy can be used.
The following diagram shows a comparison of seven LDO outputs.
Seven LDO Outputs
These seven LDOs generally supply power to system peripherals, such as powering SRAM or PLL, WiFi and Bluetooth modules, control circuits, drive circuits, sensors, and peripheral interfaces, with output voltages ranging from 0.7V to 5V. When using, it is essential to pay attention to the output current size. If the PMIC’s LDO cannot meet the power requirements of relatively high-power peripherals, an external DC-DC or LDO should be used to provide power.
Among these LDOs, ALDO1/2 and GPIOLDO are low-noise LDOs, and the analog circuit power supply should connect to these low-noise LDOs.
All DC-DCs and LDOs support self-monitoring and current limiting functions. When the load current exceeds the driving capacity, to protect the internal circuits, all output voltages will decrease. When the output voltage of the DC-DC falls below 85% of the set voltage, the PMIC will automatically shut down.
Application Block Diagram
In applications, we connect the TWSI interface of AXP152 through the CPU’s I2C interface, and additional enable and reset signals are required. It can be seen that for each DC-DC, it needs to be configured as a discrete DC-DC.
It is recommended to use a 10uF X7R low ESR ceramic capacitor for the output capacitance. When the output voltage exceeds 2.5V, it is recommended to use a 3.3uH power inductor. Additionally, the saturation current of the inductor should be more than 50% higher than the maximum current demand of the circuit.
3. Future Trends of PMIC
PMIC technology is continuously evolving and innovating to meet the growing demands of the electronics market. Here are some future trends in the PMIC field:
1. Higher Integration
Future PMICs will further enhance integration, incorporating more functions into a single chip to reduce size, improve efficiency, and simplify design.
2. Higher Efficiency
As the importance of energy efficiency increases, PMICs will continue to provide more efficient power management, reducing energy waste.
3. Increased Power Density
PMICs will provide higher power density without increasing size to meet the needs of high-performance devices.
4. Smarter Power Management
Future PMICs will leverage advanced digital signal processing and algorithms to achieve smarter power management.
Source | Hardware Ten Thousand Whys
Editor | Lu Sidi
Proofreader | Wang Gang
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