Lingdong Microelectronics has been deeply engaged in MCU products

Recently, the Ministry of Industry and Information Technology of China announced the third batch of "Little Giants" enterprises that are specialized, refined, innovative and new, and Lingdong was honored to be on the list. This is the best of Shanghai's small and medium-sized enterprises that have been selected through layers of selection, and is the backbone of Shanghai's industrial transformation and upgrading and high-quality economic development.

The power supply system of the MCU chip is crucial. It is usually hoped that the power supply system can complete the function with the smallest area to reduce costs. In the power supply of the traditional MCU, BGR1 is an ultra-low power bandgap reference source, LDO1 is a low voltage drop linear regulator, and BGR1+LDO1 provides the first power supply, which has poor accuracy, long startup time, and low power consumption, so it is always turned on. BGR2+LDO2 provides the second power supply, which has high accuracy and fast startup, but high power consumption. The switching between the first power supply and the second power supply is achieved by the HVPMU (power management unit) by controlling the opening and closing of BGR2 and LDO2. However, using high-voltage logic to design HVPMU will bring a larger area and increase system costs.

To this end, Lingdong applied for an invention patent entitled "A power management circuit and method for MCU chip" on September 24, 2019 (application number: 201910905121.3), and the applicant was Shanghai Lingdong Microelectronics Co., Ltd.

Figure 1 Schematic diagram of power management circuit structure

1 is a schematic diagram of the structure of a power management circuit for an MCU chip proposed in the present invention, which includes a first power module 100, which provides a first voltage power supply to power the MCU chip in a dormant state; a second power module 400, which provides a second voltage power supply to power the MCU chip in a non-dormant state; a power management module 200, which is electrically connected to the first power module, adopts a low-voltage logic design, works in a low-voltage domain, and controls the switching of power modes; a level conversion module 300, which is electrically connected to the output end of the power management module, the output end of the first power module, and the input end of the second power module, respectively, and can output a valid high-voltage enable signal when the first voltage power supply is invalid, and the second power module further generates a second voltage power supply at this time; a switch unit 500, which is electrically connected to the output end of the second power module and the output end of the first power module, respectively, and when the second voltage power supply is valid, the switch unit is turned on to short-circuit the second voltage power supply with the first voltage power supply.

When the MCU is in sleep mode, in order to save power consumption, the second power module is turned off, and only the first power module is retained. The first voltage power provided by the first power module is used to power a small part of the logic inside the MCU that still needs to be in working state. This is one power mode. When the MCU is awakened, the second power module is turned on, and the second voltage power provided by the second power module is used to power all modules inside the MCU. This is another power mode. The switching between the two power modes is controlled by the power management module PMU according to the instructions of the MCU. The power management module PMU is powered by the first voltage power supply, and a low voltage device is used to reduce the area of ​​the PMU.

The PMU works in a low voltage domain (i.e., a low voltage power domain) (e.g., 1.5V), and its output is a signal in a low voltage domain, i.e., a low voltage enable signal. The level conversion module is driven by the first voltage power supply and the external high voltage power supply, and converts the low voltage enable signal into a corresponding high voltage enable signal (i.e., a low voltage enable signal of a low level is converted into a high voltage enable signal of a low level, and a high voltage enable signal of a high level is converted into a high voltage enable signal), so that the PMU controls the start and shut down of the second power module through the level conversion module according to the communication with the MCU.

In short, the smart MCU patent reduces the area and cost of the MCU chip power system by using low-voltage devices to design the PMU and determining the initial state of the high-voltage enable signal at power-on, while having the advantage of fast startup at power-on.

Lingdong is a leading domestic supplier of general-purpose 32-bit MCU products and solutions, and is also one of the few general-purpose MCU companies that has established an independent and complete ecosystem. It can provide customers with all-round support from chip hardware to software algorithms, from reference solutions to system design, truly providing underlying technology drive and support for China's electronic information industry.