Switch power source circuit having standby cell for power supply

Abstract

The invention provides a switch power source circuit having a standby cell for power supply. The switch power source circuit having the standby cell for power supply comprises an input rectification module, a PWM switch control module, a transformer module, an output rectification diode, a negative feedback module, the standby cell, an isolation diode unit and a Zener diode, wherein a positive electrode of the output rectification diode is connected with a positive output end of the transformer module, a negative electrode of the output rectification diode is connected with a negative electrode of the isolation diode unit, a positive electrode of the isolation diode unit is connected with a positive electrode of the standby cell, a negative electrode of the standby cell is connected with anegative output end of the transformer module, a negative electrode of the Zener diode is connected between the negative electrode of the isolation diode unit and the negative electrode of the outputrectification diode, one end of the negative feedback module is connected with a positive electrode of the Zener diode, and the other end is connected with a control port of the PWM switch control module. The switch power source circuit is advantaged in that output loss of a switch power source is reduced, and conversion efficiency of the switch power source is improved.

Description

technical field [0001] The invention relates to the field of electronic technology, in particular to a switching power supply circuit with a backup battery. Background technique [0002] In the prior art, there is a PWM switching power supply with a backup battery, but its structure usually uses a plurality of diode isolation methods to achieve isolation between two power supply units to prevent mutual backflow between the two power supplies, usually in the battery Two diodes are connected in series to the output terminal of the switching power supply to prevent the switching power supply from charging the battery. At the same time, an isolation diode is connected in series to the output terminal of the switching power supply to prevent the battery current from being poured back into the switching power supply, preventing the battery from rapidly depleting and losing the backup function. . [0003] In view of the increasing requirements for power conversion efficiency in va...

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Problems solved by technology

[0002] In the prior art, there is a PWM switching power supply with a backup battery, but its structure usually uses a plurality of diode isolation methods to achieve isolation between two power supply units to prevent mutual backflow between the two power supplies, usually in the battery Two diodes are connected in series to the output terminal of the switching power supply to prevent the switching power supply from charging the battery. At the same time, an isolation diode is connected in series to the output terminal of the switching power supply to prevent the battery current from being poured back into the switching power supply, preventing the battery from rapidly depleting and losing the backup function.

[0003] In view of the increasing requirements for power conversion efficiency in various countries, the existing isolation technology has defects. The isolation diode at the output end of the switching power supply will greatly consume the output power of the switching power supply, greatly reducing the energy conversion efficiency of the switching power supply, and urgently needs to be improved.

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