The ASIC Design Of Automobile Generator Intelligent Electronic Regulator

AC generator is an essential part of the automobile system, and it is especially important to stabilize the output voltage of generator. As the car is more and more advanced, and more and more electric equipments are used, which requires the performance of the voltage regulator to improve continuously, so it can stabilize the car’s entire power system.I design an intelligent voltage regulator based on analysis of different voltage regulators both home and abroad. A digital intelligent control circuit is designed including the basic function of multifunctional regulator. It also includes the excitation current control of starting state when the engine did not start, load response control and pulse width modulation. Keeping 30% duty cycle can produce current in the field coil, which can increase the rise speed of output voltage. The load response control can make the average excitation current increase at a certain growth rate, which solves the decline of generator’s voltage at the condition of low speed and heavy load. PWM makes the voltage stable at normal speed. PWM mode can make frequency constant and solve voltage swing caused by frequency instability. The design also has the load dump protection, the detection of fault phase, the detection of overvoltage and undervoltage. So I analysis the reference voltage circuit, phase detection and voltage regulate circuit of M3, and also analysis PWM and oscillator circuit of MC33092. I complete the intelligent voltage regulator chip with some of my own circuits. Because of the high power supply voltage and the instability of AC generator output voltage, I use bipolar and I2 L process to design the layout of analog and digital. The I2 L process can be compatible with bipolar, it can also reduce the cost and the area of the chip.The LRC and PWM is the core of the design. The purpose is to stabilize the voltage by pulse width modulation on n-channel MOS power transistor. I also design analog circuit, including the reference voltage, the comparator, the oscillator and the detection of overvoltage and under voltage. A Darlington transistor must be connected outside of the chip to increase the drive current, so that the warning light works. The simulation of the transistor level circuit with Spectre meets the design requirements. Finally, the layout is completed with Virtuoso.