Brushless Dc Motor Driver Chip Central Molecular Circuit Analysis And Design

Brushless DC (BLDC) motor drive chip is more and more attractive in many countries owing to the prevalence of electrical bicycles. Many international companies have made various BLDC motor drive specific integrated circuits, such as MC33035 of MOTOROLA, UC3625 and TMS320 of TI and etc, the advantages of these chips are high-reliability, low cost, small volume and weight. But the BLDC motor drive chips made abroad are based on taking control circuits apart of power stage, which went against to farther compress cost and improve chips performance. In out project, we use the patent of XingBi Chen, not using the method of medium insulation or PN junction insulation (BCD process), but make high voltage power device and low voltage CMOS circuit or BiCMOS circuit on a same silicon wafer through general CMOS or BiCMOS process, which makes the cost of SPIC falling.A BLDC motor drive chip is developed, which has the following features: the breakdown voltage of power MOSFET up to 60V, the switching frequency is 40 KHz, the largest output current is 5A and built-in invariant velocity circuits, current limiter, under-voltage protection circuits. First of all, the thesis briefly introduces the operating principle, servo mode of BLDC motor and plot out the system's framework grounded on F/V (frequency to voltage) servo technology. Secondly, the theory of sub-block circuits which include bias current source, operational amplifier, linear regulator, oscillator and power MOSFET gate drive circuit are analyzed and these sub-block circuits are simulated by Cadence.Finally, the corresponding sub-block circuits'layout design, verification and test have been completed. Besides, the results of test have been shown and analyzed.