High-precision overcurrent protection circuit

Abstract

The invention discloses a high-precision overcurrent protection circuit, which comprises a sampling input module, an amplification comparison module and a clamping current-limiting module, wherein the sampling input module, the amplification comparison module and the clamping current-limiting module are connected in sequence, in the sampling input module, load current IL flowing through a driving tube Q1 forms sampling voltage V + on a sampling resistor Rs, a reference voltage V- is formed on a resistor Rr through reference current output by a constant current source CS, in the amplification and comparison module, the sampling voltage V + and the reference voltage V- are transmitted to the input end of a comparator CMP1 and amplified and compared to obtain a comparison signal Vcmp, the comparison signal Vcmp and a reference signal Vref are input to a comparator CMP2, and when over-current protection is triggered, a gate end control signal N_GATE of the driving tube is pulled down by the CMP2, and is clamped to a rated value by a clamping circuit CLP, so that overcurrent protection of the circuit is realized, and the circuit has the advantages of small temperature excursion, high precision and easiness in debugging.

Description

technical field [0001] The invention relates to the technical field of power supply protection, in particular to a high-precision overcurrent protection circuit. Background technique [0002] With the rise of the power management IC and motor control IC market, the demand for circuit protection is also changing with each passing day. Overcurrent protection is one of the most important parts of circuit protection. The overcurrent protection circuit is to limit the output current of the power supply to a fixed value. Within the range, avoid the damage to the power supply when the output terminal exceeds the rated load or short-circuit, so that the system cannot work normally, so as to realize the protection of the system or load. The common design difficulty of the current over-current protection circuit mainly lies in the over-current protection Excessive point temperature drift, poor precision, and difficulty in debugging the protection point limit the application range of t...

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Problems solved by technology

[0002] With the rise of the power management IC and motor control IC market, the demand for circuit protection is also changing with each passing day. Overcurrent protection is one of the most important parts of circuit protection. The overcurrent protection circuit is to limit the output current of the power supply to a fixed value. Within the range, avoid the damage to the power supply when the output terminal exceeds the rated load or short-circuit, so that the system cannot work normally, so as to realize the protection of the system or load. The common design difficulty of the current over-current protection circuit mainly lies in the over-current protection Excessive point temperature drift, poor accuracy, and difficult debugging of protection points limit the application range of overcurrent protection circuits.

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