Mixing attenuation control circuit in motor drive chip

Abstract

A mixing attenuation control circuit in a motor drive chip comprises an oscillator, a counter, a comparator, a time delay circuit, a first trigger, a second trigger, a logic and preceding-stage drive circuit, a current detection circuit, an H-bridge output stage and an inductive load. The inductive load is connected with the output end of the H-bridge output stage, the H-bridge output stage and the current detection circuit are connected with the input end of the comparator, an output signal of the time delay circuit controls the oscillator, the counter, the first trigger and the second trigger to reset, an output signal of the counter triggers the first trigger and the second trigger so as to control quick attenuation time and slow attenuation time in a mixing attenuation mode of motor coil currents, and an output signal of the logic and preceding-stage drive circuit controls the H-bridge output stage, so that the inductive load is under a charging or attenuation stage. The mixing attenuation control circuit improves control accuracy of currents, improves system stability and reduces design difficulty and design cost of a printed circuit board (PCB).

Description

technical field [0001] The invention relates to a mixed attenuation control circuit, in particular to a mixed attenuation control circuit of a motor coil current in a motor drive chip. Background technique [0002] Current motors, especially stepper motors, need to detect the current in the coil in order to realize chopper constant current drive. When the set current is reached, the drive circuit will control the coil current to enter the decay stage. Currently, there are three modes for controlling current decay: slow decay mode, fast decay mode and mixed decay mode. In the slow decay mode, the voltage difference between the two ends of the coil is basically 0, the current decays very slowly, the cycle is very long, and a large audible noise is introduced; at the same time, when the set current drops, the actual current in the coil is often greater than the set value, causing the motor to The angle subdivision function fails and cannot be accurately positioned. In the fas...

AI Technical Summary

Problems solved by technology

The main disadvantage of the traditional mixed decay mode control circuit is the external resistance, capacitance and voltage source Vd, which increases the difficulty and cost of PCB (Printed Circuit Board) design

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