Diodes AH5798 - Manual (Page 3)

AH5798
SINGLE PHASE HALL EFFECT LATCH SMART
FAN MOTOR CONTROLLER
AH5798
Document number: DS32001 Rev. 2 - 2
3 of 11
www.diodes.com
June 2010
© Diodes Incorporated
Functional Block Diagram
Frequency
Generator
Lock detect,
Shoutdown and
Automatic re-start
Soft Switching
Control
Hall
Sensor
AMP
Vdd FG
O1
O2
Power
Vss
Control
Logic
Full Bridge
Driver
Operating
FG
O1
O2
Ton Toff
“Re-start spinning”
motor locked cleared motor locked detected
Mechanical lock
Magentic
S
N
Normal spinning
Notes: 2. In “Normal spinning”, the FG changes its state at each rising edge of O1.
3. When the motor locks with South pole at the Hall element, O2 is kept on “L” and O1 is a clock with Ton/Toff ratio. When motor
locks with North pole at the Hall element, O1 is kept on “L”, O2 is a clock with Ton/Toff ratio.
4. When “Re-start spinning” occurs, the motor speed ramps up to the “Normal Spinning” speed from zero. Speed ramp-up profile
depends on motor characteristics.