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UL
(R)
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 (VDD - VSS) * 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 configuration. The IC consists of a decoder which provides proper commutation sequencing, a frequency-to-pulse width converter 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 power to motor sensors. Also included is Fault detection and indication, 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 compatible 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 selects 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 VR 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 Figure 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 unconditionally. 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 selects unconditional braking. ENABLE Input (Pin 2) When the Enable input is above VR/2, all Output Drivers are enabled and when it is below VR/2.2, all Output Drivers are disabled. This input has a nominal hysteresis of 0.05VR, where VR is the internally 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 frequency of the Sawtooth Schmitt Trigger Oscillator. The Sawtooth is applied to the PWM Comparator along with the output of the Error 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 Output Drivers are switched Off until the end of the sawtooth oscillator ramp-up. When the sawtooth switches low, the Overcurrent Condition is sampled, and if it no longer exists, the Output Drivers are switched On again. Otherwise, the Output Drivers remain 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 Bottom 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. VSS (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 Output 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 driving Buffers/Power Transistors. The Outputs are capable of sinking/sourcing 25mA with a 1.5V drop across the IC, at VDD = 12V. FAULT INDICATOR Output (Pin 3) Open drain output to provide sinking current for driving an external 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 VR / 2.2 3) Invalid Sensor code 4) Chip power supply less than 9V 5) VR Output less than 4.1V VR Output (Pin 19) 6V Reference Voltage Output that can supply 20mA of current at VDD = 12V for powering input Sensors. VDD (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 VR Output Source Current SYMBOL VDD VIN TA TSTG Io IR VALUE 20 VsS - 0.5 to VR -25 to +85 -65 to +150 75 30 UNIT V V C C mA mA
ELECTRICAL CHARACTERISTICS
VDD = 12V, RT = 47k, CT = 0.001F, RS = 10k, CS= 0.01F, RF = 5.6k (See Figure 3) TA = 25C, unless otherwise specified PARAMETER Reference Voltage Line Regulation VDD = 10V to 18V, IREF = 1.0mA Temperature Stability TA = 0C to 70C TA = 0C to 85C Error Amplifier: Input Offset Voltage Input Current Input Common Mode Voltage Range Open Loop Voltage Gain (RL = 15k) Common Mode Rejection Ratio Power Supply Rejection Ratio
7560N-030906-2
SYMBOL VR VR VR VR VIO IIN VICR AVOL CMRR PSRR
MIN 5.7 -
TYP 6.0 100
MAX 6.35 200
UNIT V mV
-
+/- 1.0 +/- 1.3
-
% %
(0 to VR) 70 60 60
5 0 80 -
15 10 -
mV nA V dB dB dB
PARAMETER
Output High State (RL = 15k to Ground) Output Low State (RL = 15k to VR) Output Source or Sink Current Oscillator: Oscillator Frequency Percentage Frequency Change per Volt (VDD = 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 (VIN = 4V) Low State Input Current (VIL = 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 (VIN = 4V) Low State Input Current (VIL = 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 (Isource = 1.5mA) Output Low Voltage (Isink = 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 (CL = 250pF) Switching Times CL = 1000pF) Fault Output Voltage (Isink = 2mA) Fault Off-State Leakage Under Voltage Lockout: For VDD Hysteresis For VR Hysteresis Power Supply Current VDD = 10V VDD = 12V VDD = 18V
7560N-092605-3
SYMBOL
VOH VOL Io FOSC F OSC V F VOSCP VOSCV ID
MIN
VR 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
VIH VIL
3.0 -
2.3 1.8
1.4
V V
IIH IIL
-36 -50
-27 -40
-20 -30
A A
IIH IIL VIH VH IIN
-16 -25 2.1 0.2 -
-12 -17 2.8 0.3 -
-8 -10 3.2 0.4 10
A A V V nA
VIH IIN
85 -
100 -
115 10
mV nA
VOH VOL TW ID
VR - 0.8 0.18 95 1.8
VR - 0.5 0.27 105 3
VR - 0.3 0.40 115 7.5
V V s mA
VOH VOH VOL VOL TR TF TR TF VFO IF
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
VUV VH VUVR VH
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
IDD IDD IDD
-
2.0 3.0 7.0
2.5 4.0 11.0
mA mA mA
SEQUENCE SELECT In VR VR VR
1
FAULT INDICATOR Out
3
PWM CONTROL In
21
VR
VR VR TOP DRIVER POLARITY SELECT In 20 VDD
26
SENSOR Inputs
25
DECODER
24
17 O1
VR
VDD
16 O2
F/R 27 VDD ENABLE In
2
TOP DRIVER Outputs
VR/2
+ _
15 O3
FREQUENCY TO PULSE WIDTH CONVERTER
REFERENCE GENERATOR VDD CONTROL
VDD VDD
14 O4
VR 19 RC In 4 LOW VR DETECT TACHOMETER 5 Out LOW VDD DETECT
VDD SWITCH
13 O5
VDD
12 O6
BOTTOM DRIVER Outputs
VDD VR EDGE TRIGGERED DELAY _ PWM GEN. RQ SWITCH CONTROL
22 BRAKE SELECT
ERROR AMP (-) 7 ERROR AMP (+) 6
_
ERROR AMP
+ +
VR
ERROR AMP Out 8
23
BRAKE In
S +V -V
28 18
OSCILLATOR 9
VDD VSS
10
OVERCURRENT SENSE In
+ -+ 100mV _
S
Q INTERNAL BOND PAD
11
R
NC FOR LS7560N VDD FOR LS7561N
FIGURE 2. LS7560N / LS7561N MOTOR CONTROLLER BLOCK DIAGRAM
7560N-030906-4
FIGURE 3. THREE PHASE CLOSED LOOP FULL WAVE MOTOR CONTROLLER VM
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
0.1F
(-) OUT (+)
* TYPICAL
VALUES
8 6
R3
19 VR 18 VM 28 V DD
RF
*10k
RT CT
VR V SS
OSC
FIGURE 3. The closed loop motor control operation is achieved by applying 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 positive input (Pin 6) of the Error Amplifier. The resultant output voltage of the Error Amplifier is applied to an internal Comparator 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 complete the closed loop. For this configuration, Pin 20, the Top Driver Polarity Select must be tied to Ground.
9
4
RC CS FAULT RS
VR
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.
VR
OUT6 19 VR
12
VM
ERROR AMP(-)
7 8
19
OUT5 2 R C OUT4
13
VR
ERROR AMP OUT
RT 9
OSC ERROR AMP(+)
ENABLE
6
CT
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 proportional 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 transistor to disconnect the windings from the power supply when the BRAKE is applied. 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
VM
VM
S1
S2, S3
S1
17
OUT1
ROTOR
24
S2, S3
S1
1 2
3 VM
25 26
S2
OUT3
15
4
S3
20
TOP OUT4 DRIVER POLARITY SELECT
14
12 23
BRAKE OUT6
(+)
OVERCURRENT SENSE
10
(-)
11
FIGURE 6. FOUR-PHASE FULL-WAVE MOTOR CONTROLLER
FIGURE 6. Four phase motor control requires only two Hall Sensor inputs spaced 90 electrical degrees apart. S1 is connected to one sensor and S2 and S3 are tied together and connected to the other sensor (Refer to Table 1). The Brake input (Pin 23) is used to control the Top Driver Select (Pin 20) and the Top Motor Drivers. When the Brake input is applied, the Top Motor drivers are turned off and the Top Driver Polarity Select is forced low turning on the Outputs 1 and 3. Since Outputs 4 and 6 are also turned on, the motor windings become shorted together.
The information included herein is believed to be accurate and reliable. However, LSI Computer Systems, Inc. assumes no responsibilities for inaccuracies, nor for any infringements of patent rights of others which may result from its use.
7560N-080305-6
19
VR OUT1
17
2
ENABLE OUT3
15
VM 20
TOP DRIVER POLARITY SELECT
OUT4
14 12 10
23
BRAKE OUT6 (+) OVERCURRENT SENSE (-)
11
FIGURE 7. FOUR-PHASE HALF-WAVE MOTOR CONTROLLER
FIGURE 7. This four phase half wave motor controller uses the same Brake circuit as in Figure 4 and switches the Top Driver Select from a high to a low as in Figure 6.
*
VR
TYPICAL VALUES
BRAKE
22
BRAKE
BRAKE SELECT
TACH OUT
5
100k
* R2
7 8 6
BRAKE BRAKE BRAKE
23 BRAKE ERROR AMP
BRAKE
(-) OUT (+)
*R1
1M
*C1
0.1F BRAKE BRAKE
BRAKE
BRAKE
VR
VR
SPEED CONTROL
PWM RATE CONTROL
FIGURE 8. PWM BRAKING
FIGURE 8. Using an analog switch (such as the CD4066) PWM Braking can be employed when the brake is applied. At that time, the error amplifier is configured as a voltage follower and its input is switched from the speed adjustment control to the PWM rate control. By adjusting the PWM rate control, the average motor current during braking can be controlled.
7560N-030906-7
TABLE 1. OUTPUT COMMUTATION SEQUENCE FOR THREE-PHASE OPERATION LS7560N SENSOR ELECTRICAL SEPARATION TOP BOTTOM 60 120 DRIVERS DRIVERS S1, S2, S3 S1, S2, S3 F/R EN BRK OCS O1, O2, O3 O4, O5, O6 FAULT 0 1 1 1 0 0 0 1 0 1 1 1 0 0 0 1 x x x 0 0 1 1 1 0 1 0 0 0 1 1 1 0 1 0 x x x 0 0 0 1 1 1 0 1 0 0 0 1 1 1 0 1 x x x 0 1 1 1 0 0 0 1 0 1 1 1 0 0 0 1 x x x 0 0 0 1 1 1 0 1 0 0 0 1 1 1 0 1 x x x 1 1 0 0 0 1 0 1 1 1 0 0 0 1 0 1 x x x 1 1 1 1 1 1 x x 0 0 0 0 0 0 x x x x x 1 1 1 1 1 1 x x 1 1 1 1 1 1 x x x x 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 x x 0 0 0 0 0 0 x x x 1 x 0 1 1 1 1 0 1 1 1 1 0 0 1 1 1 1 1 1 1 1 1 1 0 0 1 1 1 0 0 1 1 1 1 1 1 1 1 1 1 0 0 1 1 1 1 1 1 1 1 1 0 0 1 1 1 1 1 0 0 1 1 0 0 0 0 1 0 0 0 0 1 0 0 1 0 0 1 1 0 0 0 0 0 0 0 0 0 1 1 0 0 0 1 0 0 0 0 0 0 1 1 0 0 0 1 1 0 0 0 0 0 1 0 0 1 1 1 1 1 1 0 0 1 1 1 1 1 1 0 0 1 0 0
EN = ENABLE BRK = BRAKE OCS = OVER CURRENT SENSE
NOTE 1: This Table assumes the Top Driver Polarity Select (Pin 20) = Logic 0. For Pin 20 = Logic 1, invert the polarity of the top drivers. NOTE 2: For the LS7561N, the Overcurrent Sense = Logic 1 only forces the bottom drivers to a Logic 0. It has no effect on the top driver outputs which are determined by the other inputs as shown in the table.
TABLE 2. OUTPUT COMMUTATION SEQUENCE FOR FOUR-PHASE OPERATION LS7560N SENSOR ELECTRICAL SEPARATION = 90 TOP BOTTOM DRIVERS DRIVERS S1 S2, S3 F/R EN BRK OCS O1, O3 O4, O6 FAULT 0 1 1 0 0 1 1 0 x x x 0 0 1 1 0 0 1 1 x x x 1 1 1 1 0 0 0 0 x x x 1 1 1 1 1 1 1 1 x x 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 x 1 x 1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 1 0 1 0 0 0 1 0 0 0 0 0 1 0 1 0 0 1 0 0 1 1 1 1 1 1 1 1 1 0 0 EN = ENABLE BRK = BRAKE OCS = OVER CURRENT SENSE
NOTE 1: Sequence Input (Pin 1) set at a Logic 1. NOTE 2: This Table assumes the Top Driver Polarity Select (Pin 20) = Logic 1. For Pin 20 = Logic 0, invert the polarity of the top drivers. NOTE 3: For the LS7561N, the Overcurrent Sense = Logic 1 only forces the bottom drivers to a Logic 0. It has no effect on the Top Driver Outputs which are determined by the other inputs as shown on the table.
7560N-030906-8

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