LB11970FV Datasheet, PDF (6/7 Pages) Sanyo Semicon Device – Monolithic Digital IC For Fan Motor Single-phase Full-wave Driver

LB11970FV
*1. Power supply - GND wiring
PGND is connected to the motor power system while SGND is connected to the control circuit power system.
Wiring is made separately for PGND and SGND, and external parts of each control system are connected to SGND.
*2. Power stabilization capacitor for regeneration
CM capacitor is a power stabilizing capacitor for PWM drive and kick-back absorption and has the capacitance of
4.7µF or more. Since this IC performs current regeneration with the lower Tr through switching of the upper Tr,
connect CM with the thick and shortest possible pattern between VM and PGND.
*3. Setting of the temperature detection variable speed
Setting of the triangular wave oscillation voltage
The rotation speed variable range for the temperature is set with the triangular wave oscillation voltage.
There are two setting methods as follows:
3-1 The upper voltage (VCPH) of triangular wave is determined by V[voltage of the R1 connection counterpart]×
(R2/(R1+R2)) and the lower voltage (VCPL) of triangular wave is determined by V× ((R2//R3) / (R1+R2//R3)).
3-2 The upper voltage (VCPH) of triangular wave is determined by V× ((R2+R3) / (R1+R2+R3)) and the lower voltage
(VCPL) of triangular wave is determined by V× (R2/(R1+R2)).
Setting of the thermistor
The resistance (RTU from VCC or 6VREG and the voltage generated through division of thermistor (TH) are input
in the VTH pin. When the voltage at the VTH pin drops below VCPL due to temperature change, the full speed
(thermistor input speed control side only) is obtained.
To set the full speed with the thermistor tripping, connect each pin of 3-3 to VCC and each input voltage is
generated by divided resistance from VCC. When the thermistor trips and the VTH pin is pulled up to VCC, the full
speed (thermistor input speed control side only) is obtained.
*4. Setting the current limiter
The current limiter is activated when the voltage between current detection resistors exceeds 0.48V between VCC and
VM.
The current limiter is activated at IO = 480mA when RL = 1Ω. Setting is made with the Rf resistance.
Short-circuit VCC and VM when the current limiter is not to be used.
When 12V is used, the current limiter must be applied at 1A or less if the coil resistance is 10Ω or less.
*5. Hall input
Wiring must be as short as possible to prevent carrying of noise. The Hall input circuit is a comparator with
hysteresis of 20mV. The Hall input level is recommended to be three times (60mVp-p) or more of this hysteresis.
*6. Capacitor to set the PWM oscillation frequency
Oscillation with f = 25kHz occurs at CP = 100pF and PWM voltage width of 1.6V, and becomes the reference
frequency of PWM.
*7. FG output
This is the open collector output, enabling detection of the rotation speed using the FG output corresponding to the
phase shift. Keep this output OPEN when not used.
*8. HB pin
Hall element bias pin, which is a 1.22V constant-voltage output pin
*9. RMI pin
Minimum speed setting pin for thermistor speed control, which must be pulled up with 6 VREG when not used.
By connecting the capacitor, the time to ignore thermistor input at startup can be set.
*10. PIN pin
Direct PWM speed control pin. Pull down the P-IN input to GND when not using this pin.
The lowest output DUTY setting is made with R4 and R5. Keep R5 open for stop with DUTY at 0%.
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