TB6588FG
TOSHIBA BiCD Integrated Circuit
Silicon Monolithic
TB6588FG
3-Phase Full-Wave PWM Driver for Sensorless DC Motors
The TB6588FG is a three-phase full-wave PWM driver for
sensorless brushless DC (BLDC) motors. It controls rotation speed
by changing the PWM duty cycle, based on the voltage of an
analog control input.
Features
•
•
•
•
•
•
•
•
•
•
•
•
•
Sensorless drive in three-phase full-wave mode
PWM chopper control
Controls the PWM duty cycle, based on an analog input
(7-bit ADC)
Output current: I
OUT
= 1.5 A typ. (2.5 A max)
Power supply: VM = 7 to 42 V (50 V max)
Overcurrent protection
Forward and reverse rotation
Lead angle control (0°, 7.5°, 15°, 30°)
Overlapping commutation
Rotation speed detecting signal
DC excitation mode to improve starting characteristics
Adjustable DC excitation time and forced commutation time for a startup operation
Forced commutation frequency control: f
osc
/(6
×
2
16
), f
osc
/(6
×
2
17
), f
osc
/(6
×
2
18
), f
osc
/(6
×
2
19
)
Weight: 0.79 g (typ.)
The following conditions apply to solderability:
About solderability, following conditions were confirmed
(1)Use of Sn-37Pb solder Bath
·solder bath temperature: 230°C
·dipping time: 5 seconds
·the number of times: once
·use of R-type flux
(2)Use of Sn-3.0Ag-0.5Cu solder Bath
·solder bath temperature: 245°C
·dipping time: 5 seconds
·the number of times: once
·use of R-type flux
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2011-02-24
TB6588FG
Pin Assignment
VM1
U
V
CW_CCW
EN
N.C.
FMAX
SEL_LAP
IR1
1
2
3
4
5
6
7
8
9
Fin
36
35
34
33
32
31
30
29
28
Fin
27
26
25
24
23
22
21
20
19
VM3
N.C.
LA1
LA2
FPWM
FST1
FST2
FG_OUT
IR3
IR2
N.C.
W
PGND
OC
WAVEP
WAVEM
VM2
SGND1
10
11
12
13
14
15
16
17
18
OSC_R
OSC_C
IP
START
SC
VSP
VREF
WAVE
SGND2
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TB6588FG
Pin Description
Pin No.
1
2
3
4
Symbol
VM1
U
V
CW_CCW
I/O
―
O
O
I
Description
Motor power supply pin (VM = 7 to 42 V). VM1, VM2 and VM3 are connected together inside the
IC.
U-phase output
V-phase output
Rotation direction select input (This pin has a pull-up resistor.)
H or open: Clockwise (U
→
V
→
W)
L:
Counterclockwise (U
→
W
→
V)
Protection enable input (This pin has a pull-up resistor.)
This input determines whether or not to enable the protection functionality when either of the
following conditions is true:
a) the maximum commutation frequency is exceeded.
b) the rotation speed falls below the forced commutation frequency.
H or open: Protection functionality enabled
L:
Protection functionality disabled
No-connect
Selects the upper limit of the maximum commutation frequency. (This pin has a pull-up resistor.)
Maximum commutation frequency (f
MAX
): cycles per second equivalent to an electrical degree
11
Example: f
MAX
∼
0.8 kHz @ f
osc
= 5 MHz
H or open: f
MAX
∼
f
osc
/3
×
2
−
−
12
Example: f
MAX
∼
0.4 kHz @ f
osc
= 5 MHz
L:
f
MAX
∼
f
osc
/3
×
2
−
−
Overlapping commutation select pin (This pin has a pull-up resistor.)
H or open: 120°commutation
L:
Overlapping commutation
Connection pins for an output shunt resistor
(IR1 and IR2 are connected together inside the IC. However, IR3 is not connected to IR1 or IR2
inside the IC; these three pins must be connected together externally.)
No connect
W-phase output
Power ground pin
Overcurrent detection input (This pin has a pull-down resistor.)
All PWM output signals are stopped when OC
≥
0.5 V (typ).
Positive (+) position signal input
Negative (‒) position signal input
Motor power supply pin (VM = 7 to 42 V). VM1, VM2 and VM3 are connected together inside the
IC.
Signal ground pin (SGND1 and SGND2 are connected together inside the IC.)
Position signal output
Provides a majority of the voltages of the three phase signals.
Reference voltage output; V
REF
= 5 V (typ.)
Duty cycle/motor speed control input (This pin has a pull-down resistor.)
0
≤
V
SP
< V
AD
(L):
Duty = 0%
V
AD
(L)
≤
V
SP
≤
V
AD
(H):
V
AD
(H) < V
SP
≤
V
REF
:
Sets the PWM duty cycle, based on the analog input.
≈100
% duty cycle (127/128)
5
EN
I
6
N.C.
―
7
FMAX
I
8
9
10
11
12
13
14
15
16
17
18
19
20
21
SEL_LAP
IR1
IR2
N.C.
W
PGND
OC
WAVEP
WAVEM
VM2
SGND1
SGND2
WAVE
VREF
I
O
―
O
―
I
I
I
―
―
O
O
22
VSP
I
23
24
25
26
27
28
SC
START
IP
OSC_C
I
O
I
Connection pin for a capacitor to set the startup commutation time and the ramp-up time for the
on state.
DC excitation time setting pins
When V
SP
≥
1 V (typ.), START is driven low, starting DC excitation. When the IP voltage has
reached V
REF
/2, the TB6588FG switches to forced commutation mode.
OSC_C:
OSC_R:
Connection pins for the oscillator capacitor
Connection pins for the oscillator resistor
Example: Internal oscillating frequency (f
osc
)
∼
5.25 MHz (typ.) when OSC_C = 100 pF and
−
OSC_R = 20 kΩ
Connection pin for an output shunt resistor
(IR1 and IR2 are connected together inside the IC. However, IR3 is not connected to IR1 or IR2
inside the IC; these three pins must be connected together externally.)
―
OSC_R
IR3
O
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2011-02-24
TB6588FG
Pin No.
Symbol
I/O
Description
Rotation speed output pin (open-drain)
This output is held low at startup and when an abnormality is detected. In sensorless mode,
pulses are generated at 3 ppr according to the back-EMF.
Note:
3 ppr ;3 pulses per electrical degree (With a four-pole motor, six pulses are generated
per revolution.)
29
FG_OUT
O
30
FST2
I
31
FST1
Forced commutation frequency select inputs (These pins have a pull-down resistor.)
Forced commutation frequency: cycles per second equivalent to an electrical degree
16
FST2: FST1 = H:
H:
f
ST
∼
f
osc
/(6
×
2 )
→
12.7 Hz @ f
osc
= 5 MHz
−
17
FST2: FST1 = H:
L or Open: f
ST
∼
f
osc
/(6
×
2 )
→
6.4 Hz @ f
osc
= 5 MHz
−
18
FST2: FST1 = L or Open: H:
f
ST
∼
f
osc
/(6
×
2 )
→
3.2 Hz @ f
osc
= 5 MHz
−
19
FST2: FST1 = L or Open: L or Open: f
ST
∼
f
osc
/(6
×
2 )
→
1.6 Hz @ f
osc
= 5 MHz
−
PWM frequency (f
PWM
) select input (This pin has a pull-down resistor.)
H:
f
PWM
∼
f
osc
/128)
→
f
PWM
∼
39 kHz @ f
osc
= 5 MHz
−
−
L or Open: f
PWM
∼
f
osc
/256)
→
f
PWM
∼
19.5 kHz @ f
osc
= 5 MHz
−
−
Lead angle select input (These pins have a pull-up resistor.)
LA2: LA1
∼
H or Open : H or Open : 30° lead angleI
−
: 15° lead angle
LA2: LA1
∼
H or Open : L
−
: H or Open : 7.5° lead angle
LA2: LA1
∼
L
−
:L
: 0° lead angle
LA2: LA1
∼
L
−
No connect
Motor power supply pin (VM = 7 to 42 V). VM1, VM2 and VM3 are connected together inside the
IC.
Fin
This pin provides for thermal dissipation. Board traces should be designed, considering thermal
dissipation from the IC. (Since the fin and the package bottom are electrically connected, the Fin
pin should be connected to insulation or ground.)
32
FPWM
I
33
34
35
36
LA2
I
LA1
N.C.
VM3
―
―
Fin
Fin
―
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2011-02-24
TB6588FG
Functional Description
1. Sensorless Drive Mode
Based on the analog voltage input for a startup operation, the rotor is aligned to a known position in DC
excitation mode. Then the forced commutation signal is generated to start the motor rotation. As the motor
rotates, the back-EMF occurs in each phase of the coil.
When a signal indicating the polarity of three phase voltage of the motor, including the back-EMF, is
detected at the position signal inputs (WAVEP, WAVEM), the motor driving signal is automatically switched
from the forced commutation PWM signal to the normal commutation PWM signal that is based on the
position signal input (back-EMF). Then, a BLDC motor starts running in sensorless commutation mode.
2. Startup Operation
At startup, no induced voltage is generated due to the stationary motor, and the rotor position cannot be
detected in sensorless mode. Therefore, the TB6588FG rotor is first aligned to a known position in DC
excitation mode for an appropriate period of time, and then the motor is started in forced commutation mode.
The DC excitation and forced commutation times are determined by external capacitors. These time settings
vary depending on the motor type and load, so that they should be adjusted experimentally.
V
SP
≥
1.0 (V)
VSP
V
SP
SC
START
V
AD (L)
T
UP
V
REF
T
UP
(typ.) = C
1
×
V
SP
/4.5
μA
(s)
IP
V
REF
/2
(a) (b)
T
FIX
(a): DC excitation time: T
FIX
(typ.) = 0.69
×
C
2
×
R
1
(s)
(b): Forced commutation time
GND
V
SP
VSP
TB6588FG
SC
C
1
IP
START
R
1
C
2
The rotor is aligned to a known position specified in DC excitation mode for the period of (a), during which
the IP pin voltage decreases from V
REF
to V
REF
/2. The time constant for the period is determined by C
2
and
R
1
. Then, operation mode is switched to forced commutation mode for the period of (b) as shown above. The
duty cycles for DC excitation and forced commutation modes are determined according to the SC pin voltage.
When the motor rotation frequency exceeds the forced commutation frequency specified by FST1 and FST2,
the operation mode is switched to the sensorless mode. The duty cycle for sensorless mode is determined by
V
SP.
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2011-02-24
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