FAN8725 Fairchild Semiconductor, FAN8725 Datasheet - Page 13

• Manufacturer Part Number: FAN8725
• Description: Motor / Motion / Ignition Controllers & Drivers BTL Motor Drive IC 3Phase BLDCM+5CH
• Manufacturer: Fairchild Semiconductor
• Type: Spindle Motorr

Specifications of FAN8725

• Operating Temperature Classification: Commercial
• Package Type: QFPH
• Operating Supply Voltage (min): 4.5V
• Operating Supply Voltage (max): 13.2V
• Operating Supply Voltage: 15 V
• Supply Current: 0.6 A
• Mounting Style: SMD/SMT
• Package / Case: QFPH-48
• Operating Temperature: - 35 C to + 85 C
• Lead Free Status / RoHS Status: Compliant

4. TSD (THERMAL SHUTDOWN)
When the chip temperature rises up to about 175C(degree), the Q2 turns on and the output driver shuts down. When the chip
temperature falls off to about 150C(degree), then the Q2 turns off and the driver operates normally. TSD has the temperature
hysteresis of about 25C(degree).
5. ROTATIONAL DIRECTION DETECTION
1) The forward and the reverse rotations of the CD are detected by using the D-F/F and the truth table is shown in the above.
2) The rotational direction of the CD can be explained by the output waveform of the Hall sensors. Let the three outputs of
-- The TSD circuit shuts down all the power drives(spindle and BTL power drives) excluding both CH1 and CH2 power
Hall sensors be H1, H2 and H3 respectively.
When the spindle rotates in reverse direction, the Hall sensor output waveform are shown in Fig.(a). Thus the phases
ordered in H1 H2 H3 with a 120 phase difference.
H2+
H3+
H2-
H3-
drives(actuator part).
BIAS
+
+
-
-
H1
H2
H3
Q2
Controller
D
CK
Gain
D-F/F
Q
Vcc
DIR
8
13
Rotation
Forward
Reverse
(a) Reverse rotation
Low
High
8
DIR
FAN8725 (KA3025)