BA6402F

Motor driver ICs 2-phase half-wave motor predriver BA6402F The BA6402F is a 2-phase, half-wave motor predriver suitable for fan motors. FFeatures 1) Lock detection and rotational speed sensing mechanisms are built in. 2) Hall constant current source is built in. FBlock diagram and application example 3) Compact 8-pin SOP package reduces the number of external components required. FAbsolute maximum ratings (Ta = 25_C) FRecommended operating conditions 689 Motor driver ICs FElectrical characteristics (unless otherwise noted, Ta = 25_C and VCC = 12V) BA6402F FRotational speed sensing and lock detection (6 pin) The circuit around pin 6 is described in Fig. 1. Normally, the C6 external capacitor is charging or discharging around the Hall signal when the motor is running. When the motor is locked, discharging does not occur at C6 because the Hall signal stops switching. Charging continues at C6 until the voltage increases to the pin-6 clamp voltage, and then Q1 turns ON to turn OFF the output. With the pin-6 current being constant (I6=6.8µA, typical), the time required after the motor is locked until the output current is turned OFF (duration between B and C in Fig. 2) is determined by the C6 capacitance. Toff=TBXC= (V6CL*VBEQ3) C6 I6 4VBE S C6 6.8µA (Typ.) 4.12 105 C6 (sec) (Typ.) where V6CL is pin-6 clamp voltage (nearly equal to 5VBE) For C6=2.2µF, for example, Toff is about 0.91s (typical). FOperation notes (1) Hall constant current source (3 pin, 6.8mA typically), whi...