Isolation type battery power supply scheme

Abstract

The invention provides an isolation type battery power supply scheme. A lithium battery, a resistor R1, a capacitor C1, a flyback isolation power supply chip, a transformer, an enable circuit, a clock power circuit and an alternating current mains supply circuit are adopted in the scheme. The scheme is characterized in that under the alternating current supply condition, the working voltage of the clock power circuit is provided by the alternating current mains supply circuit while the lithium battery only provides quiescent current for the flyback isolation power supply chip; under the alternating current outage condition, the lithium battery is used as a standby power supply by a system and provides the working voltage for the clock power circuit. Meanwhile, the power supply scheme has a lithium battery capacity detection function and sends out a battery replacement notice when the battery capacity is lower. With the adoption of the scheme, a lithium battery power supply system and a circuit of an alternating current mains supply system are isolated, that is, battery replacement electric shock hazards due to the fact that the battery power supply system is common-grounded with the alternating current mains supply system are avoided, and impact damage caused by direct connection of the battery with an MCU (micro controller unit) to MCU pins is also effectively avoided.

Description

technical field [0001] The invention relates to the technical field of electric equipment and the field of integrated circuit design, and specifically refers to an isolated battery power supply scheme applied to smart meters. Background technique [0002] According to the functional specifications of the State Grid smart energy meter, the smart meter uses a lithium battery as a backup power supply for the clock circuit in the absence of AC power, which is used to provide the working voltage of the clock circuit and avoid clock confusion caused by power failure of the clock circuit. As a backup power supply when there is no AC mains, how to design a battery power supply scheme has become an important link in the design process of smart meters. [0003] At present, the battery power supply schemes commonly used in smart meters are: non-isolated lithium battery power supply scheme, that is, the lithium battery power supply circuit and the clock circuit both use AC mains as the ...

AI Technical Summary

Problems solved by technology

The disadvantage of the non-isolated lithium battery power supply scheme is that the operation of replacing the battery is completely exposed to a strong electric environment, which increases the risk of electric shock when replacing the battery. Static Shock Risk to Feet

The isolated lithium battery power supply scheme avoids the risk of electric shock when replacing the battery, but since the lithium battery still directly supplies power to the MCU, there is still the risk of electrostatic shock to the MCU pins caused by operations such as battery replacement

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