TB6539N/F

2002-06-12

9

Functional Description

1.

Basic operation

The motor is driven by the square-wave turn-on signal based on a positional signal. When the positional

signal reaches number of rotations f = 5 Hz or higher, the rotor position is assumed according to the

positional signal and a modulation wave is generated. The modulation wave and the triangular wave are

compared then the sine-wave PWM signal is generated and the motor is driven.

5 Hz~: When driven by sine-wave PWM (180° turn-on)

2.

Function to stabilize bootstrap voltage

(1)

Turns on the lower transistor at regular (carrier) cycle. (On duty is approx. 8%)

(2)

During sine-wave drive, outputs drive signal as it is.

During square-wave drive, forcibly turns on the lower transistor at regular (carrier) cycle.

(On duty is approx. 8%)

Note: At startup, to charge the upper transistor gate power supply, turn the lower transistor on for a fixed

= 0.2 V.

3.

Dead time function: upper/lower transistor output off-time

When driving the motor by sine-wave PWM, to prevent a short circuit caused by simultaneously turning

on upper and lower external power devices, digitally generates dead time in the IC.

4.

Correcting lead angle

The lead angle can be corrected in the turn-on signal range from 0 to 58° in relation to the induced

voltage.

Analog input from LA pin (0 to 5 V divided by 32)

0 V = 0°

5 V = 58° (when more than 5 V is input, 58°)

5.

Setting carrier frequency

Sets triangular wave cycle (carrier cycle) necessary for generating PWM signal.

(The triangular wave is used for forcibly turning on the lower transistor when driving the motor by

square wave.)

6.

Switching the output of turn-on signal

Switches the output of turn-on signal between high and low.

Pin OS:

High = active high

Low = active low

7.

Outputting reverse rotation detection signal

Detects motor rotation direction every electrical angle of 360°. (The output is high immediately after

reset)

REV terminal increases with a 180° turn-on mode at the time of High-Z.

CW/CCW Pin

Actual Motor Rotating Direction

REV Pin

CW (forward)

High-Z

Low (CW)

CCW (reverse)

Low

CW (forward)

Low

High (CCW)

CCW (reverse)

High-Z