ROHM provides more than 220 motor driver ICs, which have extensive track records. The motor types covered by these driver ICs run the gamut, including brushed DC motors, stepping motors, single-phase brushless DC motors, and 3-phase brushless DC motors (including high-voltage models). The ROHM lineups of motor driver ICs feature high efficiency and reliability supporting broad ranges of voltages, currents and packages, and pin-compatible products are also available.
There are 20 models of high-voltage 3-phase brushless DC motor drivers with rated voltages of 250 V and 600 V, and together with versions with voltage ratings for general use, make up a lineup of over 40 models. The diverse lineup of high-voltage versions support motors with Hall sensors, have 120° /150° /180° commutation angles (sine wave), and provide currents from 1.5 A to 2.5 A. They are suitable for use in appliances such as air conditioners and air purifiers, with fan motors in housing, etc.
Features of ROHM High-Voltage 3-Phase Brushless DC Motor Driver ICs
ROHM's high-voltage 3-phase brushless DC motor drivers come in three series, namely controllers, drivers, and controller+driver motor drivers; within each series, pin compatibility is preserved. Each series offers devices with a variety of rated voltages, output currents, and driving methods. There is no need to design a circuit board for each motor specification, and similarly when a change in specifications occurs in the design process, the same board can be used merely by changing the driver IC. Efficiency of development and design is boosted, and the time until market launch of the product can be shortened.
Below is a block diagram illustrating the function categories of controllers, drivers, and motor drivers.
●Abundant protection functions
In order to handle high voltages, numerous protection functions are provided, to enhance safety and reliability. The following is a list of protection functions.
|UVLO (Undervoltage protection function)||Equipped in high-side power supply, Vcc line, internal REG; prevents malfunctions due to power supply voltage drops.|
|TSD (Overtemperature protection function)||Monitors the controller chip temperature, activated when the set temperature is exceeded.|
|CL (Current limiting function)||Monitors the PGND pin voltage, ensures that a certain current is not exceeded.|
|OCP (Overcurrent protection function)||Monitors the PGND pin voltage, and if a certain current is exceeded, turns off all outputs (upper and lower arms).|
|MLP (Motor constraint protection function)||Upon detecting motor locking for a certain duration, sets all outputs (upper and lower arms) to "L".|
|Abnormal Hall input detection function||When all Hall input signals are "L" or "H", sets all outputs (upper and lower arms) to "L".|
|Fault output||Upon detection of either TSD or OCP, sets FOB pin to "L".|
●Advance angle control function (models with 150° commutation angle, sinusoidal commutation control)
In order to maximize motor efficiency, ideally the phase of the magnet (rotor) magnetic field and the phase of the coil (windings) magnetic field should differ by 90° to obtain maximum torque. As indicated in the figure below, the phase torque is the product of the phase induced voltage and the phase current, but the parts of the product that are negative (on the left side in the diagram below, the intervals indicated by the gray bands) results in negative torques. One method of alleviating this problem and improving efficiency is to control the phase of the driver output signal relative to a Hall signal. By advancing the phase of the phase applied voltage and causing the induced voltage phase to coincide with the current phase (right side in the diagram below, green arrow), the negative torque intervals are eliminated.
The optimum value of the advance angle value changes variously depending on the motor characteristics, rotation rate, and load torque (current value), and so an appropriate value must be set according to the conditions of use. ROHM models that support sinusoidal commutation and 150° commutation incorporate a function for setting the advance angle, which can be set using the three methods indicated in the diagram below. Thus, the advance angle can be set so as to obtain maximum efficiency. The advance angle can be set between 0 and +30° in the BM6206FS, BM6207FS, BM6225FS, BM6226FS, BM6224FS, and BM6214FS, and can be set between 0 and +40° in the BM6208FS, BM6209FS, BM6227FS, BM6228FS, BM6215FS, and BM6229FS.
●PrestoMOSTM Adopted as Internal Power MOSFETs (600 V Motor Drivers)
600 V motor drivers with internal power MOSFETs have adopted ROHM's proprietary PrestoMOSs. In a PrestoMOS super-junction MOSFET, the on-resistance and gate capacitance are reduced even while the reverse recovery time (trr) is shortened relative to a conventional superjunction MOSFET, for greatly decreased losses compared with IGBTs. As a result, even more efficient motor driving is possible in high-voltage motor driving applications.
Please refer to this page for more information on PrestoMOS.