Motor driver ICs Fan motor driver IC BA6811F / BA6813F The BA6811F and BA6813F are 2-phase, half-wave motor drivers suited for 12V fan motors. Built-in lock detection and automatic restart mechanisms protect motors. Compact SOP8 (BA6811F / BA6813F) packages reduce the number of external components required. Applications 2-phase fan motors Features 1) Built-in power transistors. 2) Lock detection and automatic restart mechanisms. 3) Built-in thermal shutdown circuit. Absolute maximum ratings (Ta = 25C) Recommended operating conditions (Ta = 25C) 712 4) Alarm output pin. (BA6811F) 5) Hall signal output pin. (BA6813F) 6) Built-in reverse current protection diode. Motor driver ICs BA6811F / BA6813F Block diagram Pin descriptions Hall input / output truth table 713 Motor driver ICs Input / output equivalent circuits Electrical characteristics (unless otherwise noted, Ta = 25C, VCC = 12V) 714 BA6811F / BA6813F Motor driver ICs BA6811F / BA6813F FCircuit operation The BA6811F and BA6813F have motor lock detection and automatic restart circuits. The timing of lock detection and automatic restart is determined by the external capacitor connected to the LD pin. The charge time of the external capacitor is given by : C S (VLDCLVLDCP) TON (Charge time)= ILDC TOFF (Discharge time)= C S (VLDCLVLDCP) ILDD (Typical value) where VLDCL is the LD-pin clamp voltage (1.93V), (0.76V), VLDCP is the LD-pin comparator voltage (2.9µA), ILDC is the LD-pin charge current (0.52µA), ILDD is the LD-pin discharge current C is the capacitance of the LD-pin external capacitor. For C=1µF, for example, the charge (output ON) and discharge (output OFF) times are 0.40s and 2.25s, respectively. The timing chart for an occasion of motor locking is shown in Fig. 1. 715 Motor driver ICs BA6811F / BA6813F Application example Operation notes (1) Thermal shutdown circuit The IC has a built-in thermal shutdown circuit. The is a temperature difference of 25C (typical) between the temperatures at which the circuit is activated and deactivated. The circuit is activated at the temperature of about 175C (typical), so that all outputs are turned OFF. Normal operation resumes when the circuit is deactivated. 716 (2) Power consumption Power consumed in the IC can be calculated from the following equation : PC=PC1)PC2)PC3 PC1 is power consumed by the circuit current. PC1=VCC ICC PC2 is the output current consumption. PC2=VOL IO VOL is the LOW level output voltage of output pins 1 and 2, and IO is the sink current of pins 1 and 2. PC3 is power consumed by the AL and HO pins. PC3=VALL IAL)VHOL IHO / 2 where VALL is the AL-pin LOW level voltage, IAL is the AL-pin sink current, VHOL is the HO-pin LOW level voltage, IHO is the HO-pin sink current. Make sure that your application does not exceed the allowable power dissipation of the IC. Motor driver ICs (3)Hall amplifier input voltage BA6811F / BA6813F Hall current is given by : VCC R1)R2)RH where RH is the Hall device impedance. The R1 and R2 resistances must be set so as to maintain the Hall amplifier input bias voltage within the range of 0V to (VCC*2.8V) including the signal amplitude. The Hall device may be affected by power supply noise due to the PCB conductor pattern. If you have this problem, insert a capacitor C1 as shown in Fig. 5. If the conductor lines from the Hall device output terminals to the Hall inputs of the IC are particularly long, noise can be picked up and fed into the inputs. If you have this problem, insert a capacitor C2 as shown in Fig. 5. Note that the Hall inputs have no hysteresis in this IC. External dimensions (Units: mm) 717