Output voltage dual-mode detection circuit of switching power supply

Abstract

The invention discloses an output voltage dual-mode detection circuit of a switching power supply; the output voltage dual-mode detection circuit can be applied when a switching power circuit is located at the same electrical potential or at a different electrical potential; the output voltage dual-mode detection circuit comprises a detection pin introduced from a control chip of a switching power supply and is characterized by comprising a preset resistor and a dual-mode conversion module; one end of the preset resistor is connected with the detection pin and the other end is earthed; the preset resistor is used for generating preset current or preset voltage; a first input end of the dual-mode conversion module is connected with the detection pin and a second input end inputs / receives a reference voltage; the output end of the dual-mode conversion module outputs current transferring signals; the current transferring signals are used for monitoring the output voltage of the switching power supply, so that the control chip closes the output of the switching power supply system when the output voltage is abnormal.

Description

technical field [0001] The invention relates to a dual-mode detection circuit for switching power supply output voltage. Background technique [0002] As we all know, when the switching power supply circuit works in the constant current output mode, the output current is controlled by the switching power supply control chip, and the output voltage changes with the load. When the load variation range is large, such as extreme no-load conditions, the output voltage will exceed the design range. , causing system components to fail, the output voltage detection circuit is required to monitor the output voltage in real time, so that the control chip can turn off the output of the switching power supply system when the output voltage is abnormal. In the switching power supply control chip, the most important thing is the detection circuit of the switching power supply output voltage. [0003] According to the basic theory of switching power supply, when the charging switch is tur...

AI Technical Summary

Problems solved by technology

[0004] For the traditional switching power supply output voltage detection circuit, due to the essential differences in the detection circuit and principle, the control chip can only be used in one of the two conditions of solid ground or floating ground. If the control chip is required to be compatible with both solid ground and floating ground application conditions, two sets of independent detection circuits and two detection pins are required

Therefore, the existing switching power supply line voltage detection circuit has been increasingly unable to meet the needs of users

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