High-precision over-current short-circuit protection circuit

Abstract

The invention belongs to the technical field of circuits, and relates to a high-precision overcurrent short-circuit protection circuit. The protection circuit comprises a surge suppression circuit electrically connected between an external input end and an external output end, a bootstrap circuit, a sampling circuit, a comparison circuit, a logic control circuit and a power supply circuit, wherein an output end of the bootstrap circuit is electrically connected with a driver of the surge suppression circuit; an input end of the sampling circuit is electrically connected with an external output end; an input end of the comparison circuit is electrically connected with an output end of the sampling circuit, and an output end of the comparison circuit is electrically connected with an input end of the logic control circuit; an output end of the logic control circuit is electrically connected with a driver of the surge suppression circuit, and the logic control circuit is used for lowering a driving voltage of the surge suppression circuit in an overcurrent working state; and the power supply circuit is electrically connected with the external input end, the bootstrap circuit, the sampling circuit, the comparison circuit and the logic control circuit, and is used for ensuring normal power supply of a post-stage line. According to the power supply circuit, power consumption of the surge suppression circuit during continuous overcurrent and short circuit is effectively reduced, and reliability of the product is improved.

Description

technical field [0001] The invention belongs to the technical field of circuits, and in particular relates to a high-precision overcurrent and short circuit protection circuit. Background technique [0002] The traditional over-voltage linear surge suppression circuit has no over-current and short-circuit protection. When the subsequent module has over-current, the output current exceeds the rated current, resulting in a reduction in the service life of the module; when the over-current is severe or a short-circuit occurs, The current flowing through the power MOSFET is too large, exceeding the junction temperature of the power MOSFET, the MOSFET burns out, and the surge suppression module fails, causing great safety hazards to the downstream equipment. Contents of the invention [0003] In view of this, the present invention provides a high-precision overcurrent short-circuit protection circuit in order to solve the technical problems mentioned above. [0004] Technical ...

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Problems solved by technology

[0002] The traditional over-voltage linear surge suppression circuit has no over-current and short-circuit protection. When the subsequent module has over-current, the output current exceeds the rated current, resulting in a reduction in the service life of the module; when the over-current is severe or a short-circuit occurs, The current flowing through the power MOSFET is too large, exceeding the junction temperature of the power MOSFET, the MOSFET burns out, and the surge suppression module fails, causing great safety hazards to the subsequent equipment

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