Design And Simulation Optimization And Validation Of The Fan Motor Driver IC

As integrated circuit integration scale is huger and huger, the corresponding power consumption also follow up, causing chip working temperature continues to increase, power supply, chip heat dissipation has become a prominent question, this paper by analyzing and grasping the working principle of the single-phase BLDC fan motor, using UMC 0.6μm Bi CMOS technology, designes a single-phase low noise dc fan motor drive circuit, the IC can be practically use in the server power supply, laptop CPU and the stereo equipment of cooling area.The dirve circuit need an external hall sensors, fan motors use hall sensor to feed back speed and phase information of the rotor, through internal logic operation module identification and processing, hall signal turns into the control signals of the power tube, implement appropriate switching of electromagnetic torque, thus driving the fan correctly according to the original direction continuous rotation. According to the above basis, the design of power operational amplifier in the driving circuit, adopts two stage amplifier structure of first providing high gain and second providing power, using the loop resistance ratio and increased the offset voltage of the amplifier to achieve 360 times linear amplification of the entered hall signal and soft switch function, soft switch function means the adjustment of input hall signal amplitude, can control rise speed of the driver circuit output voltage rising edge, use of the function, fan motor changes with amplitude of the input hall signal, can automatically adjust the commutation rate of output voltage rise, so that the fan is working with low noise characteristics.In addition, the whole circuit contains a bandgap reference, power supply voltage comparator, high temperature protection and deadlock detection and automatic restart function modules, so as to improve the work reliability of chip. Power supply voltage comparator guarantee system can work normally when 2.2 V low voltage power supply; Deadlock detection and automatic restart function means when the fan motor stopped by external obstacles, to prevent motor overheating burned, deadlock detection circuit automatically shut off the drive current 2 seconds, at the same time the automatic restart circuit try to power up motor driver for 0.5 seconds every 2 seconds, until the motor back to work properly.This paper, by using EDA tool CANDENCE for circuit design, at the same time making use of characteristic analysis of circuit simulation software HSPICE to simulation main modules such as power operational amplifier circuit, power supply voltage comparator and deadlock detection and automatic restart and so on, ensure each parameter of the circuit modules meet the design requirements, then simulate the whole circuit and layout design. Finally, to verify whether the main parameters correspond to IC design guideline, the chip samples were tested, the results are very satisfactory. The range working voltage of this chip is 2.2 V to 13.8 V, fan motor speed has a linear relation with the power supply voltage. The chip also has strong load capacity, wide speed adjusting range and low noise characteristics.