NJW4302 New Japan Radio Co.,Ltd, NJW4302 Datasheet - Page 4

• Manufacturer Part Number: NJW4302
• Description: Three-phase Dc Brushless Motor Control Ic
• Manufacturer: New Japan Radio Co.,Ltd

NJW4302
2. Output drive circuit
3. Speed lock range
4. PWM frequency
5. Lock detection circuit(CLOCK)
6. Forward / Reverse(F/R)Switching
1. VCO circuit
motor in motion.
- 4 -
(an open collector output)goes “L”. If the motor speed goes out of the lock range, the LD pin goes “H”.
to Pin 15 and Pin 16 and VCO loop filter constants. VCO frequency range must be within 160kH
locked during startup. If the LD output remains “H” (motor lock state) for a certain period (Hold time),all phase of upper
side transistors are to be turned off.
FUNCTIONAL DESCRIPTION
Please be noted that the LD signal may go on during startup.
The speed lock range is ±6.25% of fixed speed. When the motor speed is within the lock range, the LD pin
The hold time can be programmed by capacitor value attached to the CLOCK pin by the following:
With C=0.068µF,the hold time can be programmed for approximately 4.5 sec.
Once Lock detection circuit is activated, the state remains unchanged unless it is turned off, or stopped.
This function can be disabled when the CLOCK pin is connected to the ground.
The direction control can be made with the state of the F/R pin. The direction can be changed even during the
When C=1500pF,R=75KΩ,the PWM frequency goes about 19KHz.
The variable range of PLL circuit is determined by two factors: VCO frequency determined by RC value connected
The typical external value is as follows:
The filter constants are C=0.47µF,R=27kΩ.
The PWM control is made by upper side of external transistor.
The PWM frequency is determined by resistor and capacitor value connected to the CR pin.
The PWM frequency is given by expressed as:
Lock detection circuit protects the driver IC and the motor from fatal over current failure when the motor is
f
R=20kΩ,C=100pF.
Set time(sec) =66×C(µF)
PWM
1/(0.48CR)
Z
to 1.0MH
Z.