Charging over-current protection circuit and method

Abstract

The invention relates to a charging over-current protection circuit and method. The charging over-current protection circuit comprises a power source interface, an over-current protection module, a power supply closed circuit and a load interface; the power source interface is connected with a power supply device; the load interface is connected with a load device; the power source interface is connected with the load interface through the power supply closed circuit; the power supply closed circuit comprises a current detection module and a load switch which are connected in series; the current detection module is used for detecting the current of the power supply closed circuit; the over-current protection module is used for generating first control signals according to the detection result of the current detection module; the first control signals are transmitted to the control end of the load switch; and if the detection result shows that the magnitude of the current exceeds a first threshold value, the first control signals control the load switch to be switched off. By means of the charging over-current protection circuit, overload protection can be carried out on a chargingcircuit, the influence of a thermistor on load voltage fluctuation is avoided, and normal power supply to a load is guaranteed.

Description

technical field [0001] The invention relates to the field of circuits, in particular to a charging overcurrent protection circuit and method. Background technique [0002] At present, many power supply equipment, such as power cords, do not have the function of abnormal output current detection. When the power supply load is short-circuited due to some abnormality, it is easy to cause damage to the load or the risk of fire. [0003] In the prior art, if it is necessary to protect the charging circuit from overload, it is mainly to connect a thermistor (PTC, Positive Temperature Coefficient, generally referring to a semiconductor material or component with a large positive temperature coefficient) in series in the charging circuit for protection. However, the use of PTC resistors is easily affected by the ambient temperature. When the ambient temperature rises, the resistance response of the PTC resistor increases, and the voltage drop on the resistor increases accordingly, ...

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Problems solved by technology

[0002] At present, many power supply equipment, such as power cords, do not have the function of abnormal output current detection. When the power supply load is short-circuited due to some abnormality, it is easy to cause damage to the load or the risk of fire.

[0003] In the prior art, if it is necessary to protect the charging circuit from overload, it is mainly to connect a thermistor (PTC, Positive Temperature Coefficient, generally referring to a semiconductor material or component with a large positive temperature coefficient) in series in the charging circuit for protection. However, the use of PTC resistors is easily affected by the ambient temperature

When the ambient temperature rises, the resistance response of the PTC resistor increases, and the voltage drop on the resistor increases accordingly, and the temperature of the PTC resistor itself will also increase when it works for a long time, which will lead to large fluctuations in the output load voltage. May cause abnormal power supply to the load

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