Circuit with functions of preventing backflow and conducting automatic switching over power supply to achieve voltage-loss-free output

Abstract

The invention discloses a circuit with functions of preventing backflow and automatically switching over a power supply to achieve voltage-loss-free output, and belongs to the technical field of electronics. The circuit comprises a first power supply side, a second power supply side, power supply equipment and a circuit body for automatically switching over the power supply to achieve voltage-loss-free output; the circuit body for automatically switching over the power supply to achieve voltage-loss-free output comprises a voltage reduction device U2, a field effect tube Q1, a field effect tube Q2 and a field effect tube Q3; a positive electrode of the first power supply side is connected with the output end of the U2, the voltage output end of the U2 is connected with the power supply equipment and a drain electrode of the Q1 separately, the grounded end of the U2 is connected with a drain electrode of the Q3, and a source electrode of the Q3 is grounded; a grid electrode of the Q3 isconnected with a grid electrode of the Q1 and a grid electrode of the Q2 separately, a source electrode of the Q1 is connected with a source electrode of the Q2, and a drain electrode of the Q2 is connected with a positive electrode of the second power supply side; negative electrodes of the first power supply side and the second power supply side are both grounded. The circuit makes output voltage continuous when switching over the power supply and guarantees that equipment works stably, loss and damage of devices due to backflow of current can be prevented, so that the output voltage is more stable.

Description

technical field [0001] The invention relates to the field of electronic technology, in particular to an output circuit with automatic switching of anti-backfeed power supply and no pressure loss. Background technique [0002] In the fields of heating, power supply, etc., the equipment is generally powered by batteries. If the battery is damaged or the power is exhausted, the equipment cannot be used. In order to avoid damage to the equipment and ensure the service life of the equipment, higher requirements are put forward for the reliability of the power supply and the quality of the output voltage. For example, when the equipment is powered by mains power, the battery power supply is cut off, and when the mains power is cut off, it is automatically switched to battery power supply through hardware; the voltage output adopts no pressure loss output to improve the quality of power supply, etc. [0003] At present, the power supply switching circuit adopts the principle of di...

AI Technical Summary

Problems solved by technology

Its defect is that the diode has a voltage drop characteristic of 0.3-1V and is greatly affected by temperature, so pressure loss and output voltage instability occur, resulting in delay characteristics in relay switching, resulting in discontinuity of power supply, and no backfill protection

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