njw4303 New Japan Radio Co.,Ltd, njw4303 Datasheet - Page 19

• Manufacturer Part Number: njw4303
• Description: Pwm 3-phase Dc Brushless Motor Controller
• Manufacturer: New Japan Radio Co.,Ltd

Lock Protection can be done by charging/discharging to the capacitor C
time (t
value of the external capacitor C
Detect/Reset Time can be described in equation below: adjustment range for C
When the motor is rotating, electric charge of C
However, when we set the motor to low speed using the speed control application, input time from hall signal is longer,
with this, Ct voltage level will increase and malfunction can be expected. When this occurs, it is recommended to add
Ct discharge circuit by using FG signal output. Please refer to typical application circuit 2.
When using VREF pin, make sure that it is not oscillating.
Use the recommended VCC operational condition.
Input from hall signal requires more than that of the Hall Input Sensitivity
(∆V
Taking measures in keeping noise immunity, when using FG output,
FG jitter can be expected. When this occurs, it is recommended
to add capacitors more than 0.01µF between Hall input pins.
Hall input pins H1-, H2- and H3- are biased to VREF/2.
To keep Hall IC Output voltage within the Hall Input voltage range (V
it needs to add 2 pieces of biased resistor for every H1+, H2+ and H3+ pins.
OSC pin produce Oscillating wave by charging/discharging to the capacitor C
modulated by C
frequency depends on t
can be described in equation below: adjustment range for C
FR Dead band time is divided in two types depending on giving conditions.
The two dead band time are determined by the value of either FRC charged current or FRC discharge current I
and the value of an external capacitor. To adjust the dead band time, change the value of C
be expressed as following: adjustment range for C
Oscillation Frequency
FR Dead Band Time1
FR Dead Band Time2
Figure4: Dead Band Time Calculating Formula
Figure3: Oscillation Frequency Calculating Formula
Lock Protection Block – Detect/Reset Time
Reference Voltage Block – How to use VREF
Hall Amp Block - Capacitor
Hall Amp Block – How to use Hall IC
FUNCTION DESCRIPTION
Oscillation Block - Oscillation Frequency
FR Dead Time Block – Dead Band Time
MIH
Figure1: Lock Protection Detect/ Reset Time Calculating Formula
RCt
=100mV).
Detect Time
) are determined by the value of either Ct charging current (I
Reset Time
OSC
, and determined by charging time (t
CHGOSC
Symbol
Symbol
Symbol
t
t
f
DFRC1
DFRC2
OSC
t
t
in great deal compare to t
DCt
RCt
Ct
. To adjust Detect/Reset Time, change the value of C
t
t
F
t
t
DCt
RCt
DFRC1
DFRC2
OSC
≅ 4.6 10
≅ 0.46 10
≅ 28 10
≅ 140 10
≅ 140 10
Ct
6
capacitor discharging is produced repeatedly by input from hall signal.
-6
6
FRC
C
/ C
3
3
C
Ct
Ct
C
C
OSC
is more than 1pF.
FRC
FRC
DCHGOSC,
OSC
CHGOSC
is 330pF to 2200pF.
Formula
Formula
Formula
so that the calculation formula for oscillation frequency
) and discharging time (t
ICMIH
CHGCt
Ct
),
. Lock Protection Detect time (t
VREF
Hall IC
) or Ct discharging current (I
Ct
is 0.1µF to 10µF.
OSC.
Figure2: Hall IC application
Oscillating frequency (f
10k
20k
Ct
. The calculation formula for
FRC.
DCHGOSC
FR dead band time can
10k
10k
pin connecting
H1+/H2+/H3
NJW4303
H1- to H3-
FR : H → L (open)
FR : L (open) → H
). The oscillation
DCHGCt
DCt
Comments
Comments
Comments
) and Reset
) and the
Hall Amp
DCHGFRC
Block
- 19 -
OSC
) is
,