LB11970FV
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7
*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 4.7F
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 V
CC
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 V
CC
and each input voltage is generated by
divided resistance from V
CC
. 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 V
CC
and VM.
The current limiter is activated at I
O
= 480mA when R
L
= 1. Setting is made with the Rf resistance.
Short-circuit V
CC
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 10 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%.
