tb6551f TOSHIBA Semiconductor CORPORATION, tb6551f Datasheet - Page 9

• Manufacturer Part Number: tb6551f
• Description: 3-phase Full-wave Sine-wave Pwm Brushless Motor Controller
• Manufacturer: TOSHIBA Semiconductor CORPORATION

Functional Description
1. Basic operation
2. Function to stabilize bootstrap voltage
3. Dead time function: upper/lower transistor output off-time
4. Correcting lead angle
5. Setting carrier frequency
6. Switching the output of turn-on signal
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.
(1)
(2)
When a square wave is generated in full duty cycle mode, the dead time function is turned on to prevent a
voltage.
square wave.)
on upper and lower external power devices, digitally generates dead time in the IC.
short circuit.
The motor is driven by the square-wave turn-on signal based on a positional signal. When the positional
When driving the motor by sine-wave PWM, to prevent a short circuit caused by simultaneously turning
The lead angle can be corrected in the turn-on signal range from 0 to 58° in relation to the induced
Analog input from LA pin (0 V to 5 V divided by 32)
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
Switches the output of turn-on signal between high and low.
Pin OS:
High or Open
From start to 5 Hz: When driven by square wave (120° turn-on) f = f
5 Hz~: When driven by sine-wave PWM (180° turn-on)
T
f
0 V = 0°
5 V = 58° (when more than 5 V is input, 58°)
Carrier cycle = f
High = active high
Low = active low
osc
Turns on the lower transistor at regular (carrier) cycle. (On duty is approx. 8%)
(On duty is approx. 8%)
Note: At startup, to charge the upper transistor gate power supply, turn the lower transistor on for a fixed
When voltage instruction is input at V
When voltage instruction is input at V
OFF
Td Pin
During sine-wave drive, outputs drive signal as it is.
During square-wave drive, forcibly turns on the lower transistor at regular (carrier) cycle.
Low
= reference clock (crystal oscillation)
values above are obtained when fosc = 4.19 MHz.
time with V
osc
e
/252 (Hz)
Internal Counter
< = 0.2 V.
11/f
16/f
osc
osc
e
e
< = 0.2 V:
> 0.2 V:
2.6 ms
3.8 ms
T
9
OFF
f
osc
= Reference clock (crystal oscillation)
When f
osc
/(2
osc
12
= 4 MHz, approx. 5 Hz
´ 32 ´ 6)
2002-12-24
TB6551F