The BLDC motor motors for multiple reasons. BLDC motor maximum speed motors (RPM)Mainly restricted by rotor structure, and a brush dc motor speed is mainly restricted by the brush itself. Most of the application with the method of reduce the transmission ratio, the application of motor speed reduced to the required speed. As a result of the brushless dc motor speed many times faster than a brush motor, so by the corresponding adjustment ratio, physical size smaller brushless dc torque motor can produce the same speed and function. Another significant advantage of the brushless dc motor is eliminated the brush wear and serious electromagnetic interference (EMI)。 In terms of lengthen working hours, the obvious advantages of brushless dc motor is high efficiency, generally superior to the similar more than % brush dc motor. Brushless dc motor has its own application problems, mainly drive circuit adds complexity (See figure)。 One-way brush motor drive applications, need only a MOSFET bridge road. Two-way with brush motor driver needs two bridge road. Even a one-way and brushless dc motor applications also need three bridge road. The improvement of this complexity requirements of reducing the volume or high function integrated circuit, to reduce the number of components, bom (BOM)Cost, save a space effectively, especially in the limited space of the application environment, such as a battery-powered electric drill. Three common motor driver application example bridge road battery-powered motor drives should have seven kinds of functions. Since most of the drive motor driver application Bridges need low offset current, controller,General for the digital signal processor (DSP)Or micro controller)Also require low offset current, so the integration of linear regulators (LDO)And with that can control the working voltage of the drive is needed to support bridge, bridge road drive to VDD, for the controller. VCC。 。 Is mechanical switch control 'that can be input to ensure that' no vibration conduction. 。 Ensure low quiescent current, so as to reduce power consumption of the battery. Ideally, the sleep mode can be used, when there is a bridge circuit voltage, and application does not work, ensure that shut down the drive. 。 Under the condition of low battery voltage to V ensure bridge road uninterrupted operation. This can be achieved by ~. V under-voltage lockout. Typical values for conventional bridge circuit drive UVLO. V。 。 Must be able to phase node (HS)High instantaneous negative bias tolerance ability. Bridge road FET switch current increasing has become a trend of motor drive (>A)。 Along with the switch current increase and the constraints of non-ideal PCB layout structure, reduce the PCB parasitic inductance HS pin negative transient high pressure impact is a key problem for PCB design. 。 In a large number of applications must be utmost to decrease the size of packaging, to save cloth plate space. Shrink wrap also facilitate will drive placed near the location of the FET, alleviate poor PCB layout problems. 。 Drive bridge road, rated voltage should reach V battery voltage under the condition of V can reliable operation. Being able to significantly prolong the life time of the lithium battery power supply equipment of power supply and product whole life, drive bridge road is particularly suitable for a new generation of BLDC motor drive motors. Currently on the market, enhance the battery life, equipment service life and high reliability products become the first choice of consumers. New bridge road drive support lithium batteries BLDC motor motors, meet and exceed the market demand.
