Driving circuit of voice coil motor

Abstract

The invention provides a driving circuit of a voice coil motor. The driving circuit comprises a driving stage operational amplifier, a switch K1, a switch K2, an imbalance detection and control circuit and an imbalance adjustment control circuit. The first input end of the driving stage operational amplifier is connected with an input voltage through the switch K1, and is grounded through the switch K2. The imbalance detection and control circuit comprises a switch K3, a switch K4, an MOS tube MN1, a resistor Rs, a reference constant-current source, a current comparator and a logic circuit. The MN1 and the resistor Rs are sequentially connected between the first input end and the grounding end of the current comparator. The control end of the MN1 is connected with the output end of the driving stage operational amplifier through the switch K3. The switch K4 is connected between the second input end of the driving stage operational amplifier and the second connecting end of the MN1. Thereference constant-current source is connected between the second input end and the grounding end of the current comparator. The logic circuit outputs a calibration control signal based on a comparison result output by the current comparator. The imbalance adjustment control circuit outputs a current control signal based on the calibration control signal so as to perform the imbalance calibrationon the driving operational amplifier.

Description

【Technical field】 [0001] The invention relates to the technical field of integrated circuit design, in particular to a driving circuit of a voice coil motor. 【Background technique】 [0002] Most of the voice coil motor (VCM) drive circuits used in consumer handheld devices and portable electronic products are DAC (digital-to-analog conversion) products. High-end sensitive VCM requires high resolution of its DAC drive circuit and low output offset current, so the output drive stage of the relevant drive circuit requires very little offset voltage of the op amp. Although the chopping technology can reduce the offset voltage very well, it will introduce additional switching noise when used in this occasion. At present, most designs use fuses or EEROM (Electrically Erasable Read-Only Memory) and other trimming schemes. However, the fuse Adjustment solutions such as wires will increase the cost of development and testing. [0003] Therefore, it is necessary to provide an improv...

AI Technical Summary

Problems solved by technology

Although the chopper technology can reduce the offset voltage very well, it will introduce additional switching noise when used in this occasion. At present, most designs use fuses or EEROM (Electrically Erasable Read-Only Memory) and other trimming schemes. However, the fuse Adjustment schemes such as wires will increase development and testing costs

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