NJW4302 データシートの表示（PDF） - Japan Radio Corporation

部品番号

コンポーネント説明

メーカー

NJW4302

THREE-PHASE DC BRUSHLESS MOTOR CONTROL IC

Japan Radio Corporation  

NJW4302

Preliminary

7. Brake Switch

NJW4302 uses a short brake method that turns on all phase of upper side transistors for braking. During the

time, all lower side transistors are turned off.

8. VREG pin/VSH pin

NJW4302 includes a regulator to generate for +5V regulated IC supply when the motor drive circuit

is designed with a single power supply. The VREG pin and V+ pin compose a shunt regulator for 5V±5%

output with a external resistor and a transistor. To use the regulator, the VSH pin must be either “H”, or Open.

Otherwise, the VSH pin must be “L” and the VREG pin is to be opened.

9. Frequency Generator (FG) Amplifier

The internal FG amplifier with few passive components composes a filter amplifier shown in the

application. Circuit for noise rejection. The output voltage of the amplifier must be at least 250mA p-p since it feature

Schmitt comparator.

The capacitor connected between the FGIN+ pin and the ground is necessary for bias voltage

stabilization and initial reset pulse generation for the internal logic. The reset pulse is generated when the

FGIN+ pin goes from 0 to approximately 1.25V.

10. Integration Amplifier

The integration amplifier integrates the D-out and P-out and converts them to speed command voltage. During the

time, it also sets the control loop gain and frequency characteristics using external components.

11. Speed Control Circuit

NJW4302 features two speed control method; speed discriminator circuit with PLL circuit and phase

comparison circuit. The FG pulse frequency is controlled to be the same frequency with a clock frequency input to the CLK

pin. Therefore, the motor speed can be controlled by changing the clock frequency.

The motor speed (N) can be expressed as:

N=CLK (Hz)×(60/FGP)[RPM] ( FGP: Number of FG pulse per one rotation)

Given that the oscillation frequency range is 160kHz~1.0MHZ and the number of counts is 1024,the range of

clock frequency is 156HZ~960HZ , and therefore the motor speed can be changed from 260rpm to 1600rpm.

-5 -

Share Link: