DC motor current limiting protection circuit

Abstract

A current-limiting protection circuit of a direct-current motor, comprising a single chip microcomputer unit, a drive unit, an MOS switch transistor (Q5, Q6), a sampling resistor (RD1, RD2) and a fly-wheel diode (D5, D6). An output end of a single chip microcomputer is connected to a gate electrode of the MOS switch transistor through the drive unit, and a drain electrode of the MOS switch transistor is connected to a negative terminal of a direct-current motor (M). A positive terminal of the direct current motor is connected to a positive electrode of a direct-current power source (E). A source electrode of the MOS switch transistor is connected to a negative electrode of the direct-current power source through the sampling resistor. The source electrode of the MOS switch transistor is connected to a sampling current input end of the drive unit, and an overcurrent feedback signal output end of the drive unit is connected to an input end of the single chip microcomputer unit. The fly-wheel diode is reversely connected to the direct-current motor in parallel. By means of the protection circuit, after an electric motor stops operating because of too large a load, the electric motor can operate again so long as the load of the electric motor is reduced without restarting the electric motor, so as to guarantee the consistency of the operation of the electric motor.

Description

technical field [0001] The invention relates to a direct current motor, in particular to a current limiting protection circuit for a direct current motor. Background technique [0002] DC motors are used in many electrical appliances and electric equipment, but when the load increases, the DC motor will stall. For example, a lawn mower cuts smoothly when the grass is sparsely cut. When the grass is densely cut, the load on the motor increases, and the motor will stall. Under the action of an ordinary overload protection circuit, the motor will stop. Another example is a chain saw, which cuts smoothly when cutting thin wood, but when cutting thick wood, the load on the motor increases, causing a stall phenomenon, and the motor will stop under the action of an ordinary overload protection circuit. Therefore, for electric equipment using the above-mentioned common overload protection circuits, the switch needs to be restarted after the rotor is blocked, so that the machine can...

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