Digital power management technology and application
This article introduces the basic characteristics of digital power supply, the advantages of digital power supply compared to analog power supply and the main content of digital power management, and also introduces the application of digital power management technology.
The new generation of integrated circuits requires a power supply voltage of 3.3V, 1.8V or even lower. A single device needs multiple voltages to supply power, and the current demand is large, and the voltage must be applied to the device at the correct timing. The voltages that power these devices must be generated on the board (preferably close to the devices) to minimize voltage drop and stabilize the voltage. High-performance DC/DC converters are suitable for wide-range input and can be used as isolated power supplies or non-isolated point-of-load converters. Therefore, most onboard power supply systems have adopted DC/DC conversion modules as the main body of power supply. However, a complete and healthy power system cannot be built without power management circuits. The content of power management includes: power system monitoring, sequencing and tracking, monitoring and fail-safe. Power management devices handle functions such as common-mode rejection, start-up limiting, control of start-up and shutdown, and even power factor correction at the input. The power management device configured on the output side controls the startup sequence and output voltage regulation, and provides corresponding failure protection for over-undervoltage and over-current conditions. Figure 1 Application protection of power management devices in isolated AC/DC power systems. All relevant functional circuits are required to be isolated from the main circuit.
Detailed explanation of digital power management technology and application
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Dedicated digital power management devices have greater advantages in cost, development cycle and reliability than commonly used analog circuits or microcontrollers, programmable logic devices and other methods. A new generation of digital power management devices integrates a fast ADC that can meet real-time monitoring requirements, making it able to reflect failures faster than the off-chip ADC of a general-purpose microcontroller. The monitoring data is transmitted to the main controller of the power supply through the I2C or PMBus bus to achieve precise voltage regulation settings, fault protection and other functions. An internal clock enables fault logging. For the multi-output power system, the digital power main controller reads the monitoring data of each output from the management device of each output terminal in real time through the bus interface, realizing the comprehensive monitoring of the power system. Once the software design is approved, the same source files and configuration files can be used for all products of the design, and the performance is consistent from unit to unit, while analog circuits will have different performance due to differences in the components themselves.
Traditional power system management circuits that rely on analog circuits to implement power management and set various parameters through amplifiers, comparators and RC time delays are no longer as superior as digital power management devices. With the deepening of the design, the components will no longer change with the change of the parameters, and the circuit board will no longer need to be reprocessed repeatedly. Using a special digital power management device, allowing the configuration software to set the operating parameters. Changes during design can be easily implemented in software without hardware changes. The configuration software only requires the designer to adjust a few parameters. After all the parameters are set, they can be downloaded to the digital power management device through the I2C port with the programming download line. Figure 2 is a block diagram of the internal functional units of a typical power management device.
Detailed explanation of digital power management technology and application
In addition to the application of special power management integrated circuits in the monitoring of power systems, the new generation of integrated circuits has also added functions to reduce power consumption and partial power management in its own design, providing digital power and digital power management. device communication interface. This has been reflected in higher-end digital processors. Through the communication between the digital processor, the DC/DC converter and the digital power management unit, the processor can automatically adjust the required power supply voltage according to its current processing speed and task intensity. The digital power supply and power management unit contains several registers. When the voltage required by the processor changes, it receives new data through the bus to configure the relevant registers, or finds the relevant setting values in the lookup table of the internal program of the digital power supply. This kind of scheme is becoming the mainstream application in the fields with strict power consumption requirements. For processors with separate power supplies for internal parts, the functional units in the standby or sleep state can be completely powered off, which will further reduce power consumption, but put forward higher requirements for power supply management. Not only the output ports increase, but also the The setting and monitoring of different ports will significantly increase the complexity of the program in the digital power management unit. The hardware performance monitor inside the processor can provide the lowest supply voltage within a specific time. The information of the monitor comes directly from inside the processor, so the closed loop of the monitoring system is completely inside the processor chip, realizing the SOC design of power management.
