UL
®
LSI/CSI
LSI Computer Systems, Inc. 1235 Walt Whitman Road, Melville, NY 11747
SEQUENCE SELECT
FAULT INDICATOR
RC
TACHOMETER OUT
ERROR AMP (+)
ERROR AMP (-)
ERROR AMP OUT
OSCILLATOR
LS7560N
LS7561N
(631) 271-0400 FAX (631) 271-0405
March 2006
A3800
BRUSHLESS DC MOTOR CONTROLLER
FEATURES
Open loop motor control
Tachometer output for closed loop motor control
Error Amplifier and PWM Speed Comparator with full accessibility
High noise immunity Schmitt Triggers on Sensor inputs
6V
Reference Supply for external sensors
Cycle-by-cycle current sensing
Static, or current limited dynamic, motor braking
Output enable delay on speed direction reversal
Enable input with fault sensing capability
Fault Indicator output
60°/300° or 120°/240° electrical sensor spacing selection
Selectable PWM of top and bottom drivers or bottom drivers only
CMOS compatible motor outputs with drive capability
Selectable top driver polarity
Low power dissipation
+10V to +18V Power Supply (V
DD
- V
SS
)
•
LS7560N, LS7561N (DIP); LS7560N-SD, LS7561N-SD (Skinny DIP);
LS7560N-S, LS7561N-S (SOIC); LS7560N-TS, LS7561N-TS (TSSOP)
- See Figure 1 -
•
Note:
LS7560N/LS7561N are backward
compatible with LS7560/LS7561
GENERAL DESCRIPTION
The LS7560N/LS7561N are designed to control three or four
phase brushless DC motors in a closed or open loop con-
figuration. The IC consists of a decoder which provides proper
commutation sequencing, a frequency-to-pulse width convert-
er and error amplifier for closed loop motor speed control, a
PWM comparator and sawtooth oscillator for external driver
power control and a 6V reference generator for supplying pow-
er to motor sensors. Also included is Fault detection and in-
dication, overcurrent sensing, dynamic motor braking, forward/
reverse input, sensor spacing selections and an enable input
control. The overcurrent sense condition will disable all output
drivers when using the LS7560N and only the bottom drivers
when using the LS7561N.
The IC operates from 10V to 18V and provides CMOS com-
patible outputs for interfacing with external power devices.
Operating below 10V will activate a Fault Indication Output
and disable all Output Drivers.
INPUT/OUTPUT DESCRIPTION:
(See Figure 2)
SEQUENCE SELECT Input
(Pin 1 )
A High on this input selects 60°/300° and a Low selects 120°/
240° electrical sensor separation. Use of a 300° or 240° motor
will cause opposite direction rotation as compared to a 60° or
120° motor.
F/R Input
(Pin 27)
A High on this input selects Forward direction and a Low se-
lects Reverse direction. The motor drive outputs are disabled
for 2 clock cycles at the onset of a direction change.
7560N-031006-1
FIGURE 1. PIN CONNECTION DIAGRAM
TOP VIEW
LSI
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
1
28
27
26
25
24
23
22
21
20
19
18
17
16
15
V
DD
(+V)
F/R
S3
S2
S1
BRAKE
BRAKE SELECT
PWM CONTROL
TOP DRIVER POLARITY SELECT
V
R
V
SS
(-V)
OUT 1
OUT 2
OUT 3
HALL
SENSORS
ENABLE 2
3
4
5
6
7
8
9
LS7560N
CURRENT SENSE (+) 10
CURRENT SENSE (-) 11
OUT 6 12
OUT 5 13
OUT 4 14
S1, S2, S3 Inputs
(Pins 24, 25, 26)
Hall Sensor inputs which are decoded to determine the Motor
Commutation Sequence. An invalid input code disables all motor
outputs. Inputs have Schmitt Trigger buffers for noise immunity.
BRAKE Input
(Pin 23)
With the Brake Select input Low, a High on the Brake input forces
the Top Drivers to an Off condition and the Bottom Drivers to a
PWM On condition. If the Motor is under Closed Loop control, the
Loop must be opened and the error amplifier output connected to
the Error Amp (-) input. By controlling the voltage at the Error Amp
(+) input, the PWM duty cycle is controlled during braking (see Fig-
ure 8). This manner of braking prevents the Bottom Motor Drivers
from drawing excessive current, a condition which can occur during
normal braking, when the Bottom Drivers are turned ON un-
conditionally. With the Brake Select input High, a High on the
Brake input unconditionally causes the Top Drivers to turn Off and
the Bottom Drivers to turn On. The Brake function has priority over
all other functions.
BRAKE SELECT Input
(Pin 22)
A Low on this input selects PWM control of braking and a High se-
lects unconditional braking.
ENABLE Input
(Pin 2)
When the Enable input is above V
R
/2, all Output Drivers are en-
abled and when it is below V
R
/2.2, all Output Drivers are disabled.
This input has a nominal hysteresis of 0.05V
R
, where V
R
is the in-
ternally generated Reference Voltage available on Pin 19. Because
the Enable input is level sensitive, it can easily be used to control
operation of the IC based on an Analog Fault Condition.
OSCILLATOR
(Pin 9)
An external RC network is connected to this input to set the fre-
quency of the Sawtooth Schmitt Trigger Oscillator. The Sawtooth
is applied to the PWM Comparator along with the output of the Er-
ror Amplifier. The output of the PWM Comparator is a Pulse
Width Modulated Signal which is used to vary the effective drive
to the motor and, hence, the motor speed.
OVERCURRENT SENSE
(Pins 10, 11)
The input to Pin 10 comes from the high side of a fractional ohm
current sensing resistor. The voltage at this input is compared to
an internal 100mV Reference. When the voltage exceeds the
100mV Reference, an Overcurrent Condition exists and the Out-
put Drivers are switched Off until the end of the sawtooth os-
cillator ramp-up. When the sawtooth switches low, the Over-
current Condition is sampled, and if it no longer exists, the Output
Drivers are switched On again. Otherwise, the Output Drivers re-
main Off until the end of the next sawtooth. The input to Pin 11
comes from the low side (Gnd) of the current sensing resistor and
connects to the low side of the internal 100mV Reference.
PWM CONTROL Input
(Pin 21)
A High on this input causes only the Bottom Drivers to be Pulse
Width Modulated. A Low on this input causes both Top and Bot-
tom Drivers to have PWM.
TACHOMETER Output
(Pin 5)
The output of the Frequency To Pulse Width Converter is tied to
this pin. The Converter uses the three Sensor Inputs and external
RC Network to generate a variable frequency output with a fixed
positive pulse width.
RC Input
(Pin 4)
The external RC network connected to this input programs the
positive pulse width of the Frequency to Pulse Width Converter.
V
SS
(Pin 18) Supply Voltage negative terminal.
ERROR AMPLIFIER Inputs
(Pins 6, 7)
Output
(Pin 8)
For closed loop control, the Tachometer Output is applied through
a resistor to the negative input of the Error Amplifier on Pin 7. A
speed control potentiometer is connected to the positive input of
the Error Amplifier on Pin 6. A parallel RC Network is connected
between the Output of the Error Amplifier on Pin 8 and Pin 7. The
Amplifier, configured this way, enables the variable pulse width to
be converted to a DC voltage which is used to control the motor
speed. The potentiometer is used to set the desired motor speed.
For open loop control, configure the Error Amplifier as a voltage
follower by connecting Pin 7 directly to Pin 8 and do not connect
the Tachometer Output signal to the Error Amplifier.
TOP DRIVER POLARITY SELECT Input
(Pin 20)
A High on this input selects a High Polarity to enable the Top Out-
put Motor Drivers and a Low selects a Low Polarity to enable the
Top Output Motor Drivers.
OUTPUT DRIVERS
(Pins 12, 13, 14, 15, 16, 17)
Each Driver Output provides a CMOS compatible signal for driv-
ing Buffers/Power Transistors. The Outputs are capable of sink-
ing/sourcing 25mA with a 1.5V drop across the IC, at V
DD
= 12V.
FAULT INDICATOR Output
(Pin 3)
Open drain output to provide sinking current for driving an ex-
ternal device, such as a LED, through an emitter follower (see
Figure 3) to indicate a malfunction condition. The output occurs
under any of the following conditions:
1) Overcurrent Sense condition
2) Enable Input below V
R
/ 2.2
3) Invalid Sensor code
4) Chip power supply less than 9V
5) V
R
Output less than 4.1V
V
R
Output
(Pin 19)
6V Reference Voltage Output that can supply 20mA of current at
V
DD
= 12V for powering input Sensors.
V
DD
(Pin 28) Supply Voltage positive terminal.
MAXIMUM RATINGS
(Voltages referenced to Vss)
Power Supply Voltage
Voltage at any input
Operating Temperature
Storage Temperature
Output Drive Sink/Source Current
V
R
Output Source Current
SYMBOL
V
DD
V
IN
T
A
T
STG
Io
I
R
VALUE
20
Vs
S
- 0.5 to V
R
-25 to +85
-65 to +150
75
30
UNIT
V
V
°C
°C
mA
mA
ELECTRICAL CHARACTERISTICS
V
DD
= 12V, R
T
= 47kΩ, C
T
= 0.001µF, R
S
= 10kΩ, C
S
= 0.01µF, R
F
= 5.6kΩ (See Figure 3) T
A
= 25°C, unless otherwise specified
PARAMETER
Reference Voltage
Line Regulation
V
DD
= 10V to 18V, I
REF
= 1.0mA
Temperature Stability
T
A =
0°C to 70°C
T
A =
0°C to 85°C
Error Amplifier:
Input Offset Voltage
Input Current
Input Common Mode Voltage Range
Open Loop Voltage Gain (R
L
= 15kΩ)
Common Mode Rejection Ratio
Power Supply Rejection Ratio
7560N-030906-2
SYMBOL
V
R
∆V
R
∆V
R
∆V
R
V
IO
I
IN
V
ICR
A
VOL
C
MRR
P
SRR
MIN
5.7
-
TYP
6.0
100
MAX
6.35
200
UNIT
V
mV
-
-
+/- 1.0
+/- 1.3
-
-
%
%
-
-
(0 to V
R
)
70
60
60
5
0
80
-
-
15
10
-
-
-
mV
nA
V
dB
dB
dB
PARAMETER
Output High State (R
L
= 15kΩ to Ground)
Output Low State (R
L
= 15kΩ to V
R
)
Output Source or Sink Current
Oscillator:
Oscillator Frequency
Percentage Frequency Change per Volt
(V
DD
= 10V to 18V)
Sawtooth High Voltage
Sawtooth Low Voltage
Capacitor Discharge Current
Logic Inputs:
Input Threshold Voltage
(Pins 1, 20, 21, 22, 23, 24, 25, 26, 27)
Brake and Sensor (Pins 23, 24, 25, 26)
High State Input Current (V
IN
= 4V)
Low State Input Current (V
IL
= 0V)
Sequence Select, Top Driver Polarity
Select, PWM Control, Brake Select,
and F/R Select (Pins 1, 20, 21, 22, 27)
High State Input Current (V
IN
= 4V)
Low State Input Current (V
IL
= 0V)
Enable Input Threshold Voltage (Pin 2)
Hysteresis
Enable Input Current
Overcurrent Sense Comparator:
Input Threshold Voltage
Input Current
Outputs:
Closed Loop Control Section:
Tachometer Out
Output High Voltage (I
source
= 1.5mA)
Output Low Voltage (I
sink
= 5mA)
Pulse Width
Capacitor Discharge Current (RC Terminal)
Output Drivers (Pins 12, 13, 14, 15, 16, 17)
Sourcing 25mA
Sourcing 50mA
Sinking 25mA
Sinking 50mA
Switching Times
(C
L
= 250pF)
Switching Times
C
L
= 1000pF)
Fault Output Voltage (I
sink
= 2mA)
Fault Off-State Leakage
Under Voltage Lockout:
For V
DD
Hysteresis
For V
R
Hysteresis
Power Supply Current
V
DD
= 10V
V
DD
= 12V
V
DD
= 18V
7560N-092605-3
SYMBOL
V
OH
V
OL
Io
F
OSC
∆F
OSC
∆V
F
V
OSCP
V
OSCV
I
D
MIN
V
R
-
-
21
-
TYP
-
-
-
24
0.4
MAX
-
1.0
1.0
27
1.0
UNIT
V
V
mA
kHz
%/V
-
0.7
0.6
3.8
1.0
1.0
4.5
-
2.5
V
V
mA
V
IH
V
IL
3.0
-
2.3
1.8
-
1.4
V
V
I
IH
I
IL
-36
-50
-27
-40
-20
-30
µA
µA
I
IH
I
IL
V
IH
V
H
I
IN
-16
-25
2.1
0.2
-
-12
-17
2.8
0.3
-
-8
-10
3.2
0.4
10
µA
µA
V
V
nA
V
IH
I
IN
85
-
100
-
115
10
mV
nA
V
OH
V
OL
T
W
I
D
V
R -
0.8
0.18
95
1.8
V
R -
0.5
0.27
105
3
V
R -
0.3
0.40
115
7.5
V
V
µs
mA
V
OH
V
OH
V
OL
V
OL
T
R
T
F
T
R
T
F
V
FO
I
F
9.5
8
1.0
2.75
30
35
100
130
-
-
10.5
8.8
1.30
3.40
45
50
150
180
-
10
11
9.5
2.0
4.2
60
65
200
230
0.5
-
V
V
V
V
ns
ns
ns
ns
V
nA
V
UV
V
H
V
UVR
V
H
7.0
0.45
3.5
0.16
8.5
0.65
4.1
0.3
10
0.85
4.8
0.4
V
V
V
V
I
DD
I
DD
I
DD
-
-
-
2.0
3.0
7.0
2.5
4.0
11.0
mA
mA
mA
SEQUENCE
SELECT In
V
R
V
R
V
R
1
FAULT INDICATOR Out
3
PWM CONTROL
In
21
V
R
V
R
V
R
TOP DRIVER
POLARITY SELECT In
20
V
DD
26
SENSOR
Inputs
25
DECODER
24
17
O
1
V
R
V
DD
16
O
2
F/R
27
V
DD
ENABLE
In
2
TOP
DRIVER
Outputs
V
R
/2
+
_
15
O
3
FREQUENCY
TO
PULSE WIDTH
CONVERTER
REFERENCE
GENERATOR
V
DD
CONTROL
V
DD
V
DD
14
O
4
V
R
19
RC In
4
LOW V
R
DETECT
TACHOMETER
5
Out
LOW V
DD
DETECT
V
DD
SWITCH
13
O
5
V
DD
12
O
6
BOTTOM
DRIVER
Outputs
V
DD
V
R
EDGE TRIGGERED
DELAY
_
PWM
GEN.
R Q
SWITCH
CONTROL
22
BRAKE SELECT
ERROR AMP (-)
7
ERROR AMP (+)
6
_
ERROR
AMP
+
+
V
R
ERROR AMP Out
8
23
BRAKE In
S
+V
-V
28
18
OSCILLATOR
9
V
DD
V
SS
10
OVERCURRENT
SENSE In
+
- +
100mV
_
S
Q
INTERNAL BOND PAD
11
R
NC FOR LS7560N
V
DD
FOR LS7561N
FIGURE 2. LS7560N / LS7561N MOTOR CONTROLLER BLOCK DIAGRAM
7560N-030906-4
FIGURE 3. THREE PHASE CLOSED LOOP FULL WAVE MOTOR CONTROLLER
V
M
S2
S1
S3
S1
S2
24
25
26
S1
S2
S3
17
OUT1
ROTOR
16
OUT2
S3
27
OUT3
F/R
OUT4
15
14
13
21
20
PWM CNTRL
OUT5
TOP DRV
POL SEL
OUT6
12
22
BRAKE SEL
(+)
OVERCURRENT
SENSE
(-)
10
23
BRAKE
11
1
SEQ SEL
TACH OUT
5
7
*
R2
100k
**
*
R1
1M
2
ENABLE
ERROR
AMP
*
C1
0.1µF
(-)
OUT
(+)
*
TYPICAL
VALUES
8
6
R3
19
V
R
18
V
M
28
V
DD
R
F
*
10k
R
T
C
T
V
R
V
SS
OSC
FIGURE 3.
The closed loop motor control
operation is achieved by ap-
plying the Tachometer Output at
Pin 5 into the negative terminal
of the Error Amplifier (Pin 7)
through an R1-C1-R2 integrating
network. The R1-C1 network is
configured as a feedback circuit
around the amplifier. Since the
Tachometer Output has a fixed
positive pulse width, the average
value of the pulse train is directly
proportional to the motor speed.
The desired speed is selected
by applying a voltage at the pos-
itive input (Pin 6) of the Error
Amplifier. The resultant output
voltage of the Error Amplifier is
applied to an internal Compar-
ator along with a ramp waveform
generated by the RC Network at
Pin 9. The PWM signal at the
Comparator output is used to
drive outputs 1 thru 6 and com-
plete the closed loop. For this
configuration, Pin 20, the Top
Driver Polarity Select must be
tied to Ground.
9
4
RC
C
S
FAULT
R
S
V
R
3
**
Switch used to connect the
error amplifier out and (-) input
together when Brake Select input
is low and Brake is applied. The
speed setting selected by R3 also
sets the PWM rate during braking.
V
R
OUT6
19
V
R
12
V
M
ERROR AMP(-)
7
8
19
OUT5
2
R
C
OUT4
13
V
R
ERROR AMP
OUT
R
T
9
OSC
ERROR AMP(+)
ENABLE
6
C
T
14
10
23
BRAKE
(+)
FIGURE 5. OPEN LOOP CONTROLLER
11
OVERCURRENT
SENSE
(-)
FIGURE 4. THREE-PHASE HALF-WAVE MOTOR CONTROLLER
FIGURE 5.
In this configuration, the PWM output
duty cycle to the motor drivers is directly pro-
portional to the DC voltage applied to Pin 6, since
Pins 7 and 8 are tied together.
FIGURE 4.
This three phase half wave motor controller has no top power tran-
sistor to disconnect the windings from the power supply when the BRAKE is ap-
plied. Instead, a switching transistor is used which will permit braking for a time
determined by the RC time constant. When the capacitor discharges past the
ENABLE input switching point, the outputs will be turned off.
7560N-030906-5
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