MICRO-LINEAR ML4423CP

July 2000
ML4423*
1, 2, or 3-Phase Variable Speed AC Motor Controller
GENERAL DESCRIPTION
FEATURES
The ML4423 provides the PWM sinewave drive signals
necessary for controlling three phase AC induction motors as
well as single and two phase split capacitor AC induction
motors.
■
Drives single, two, and three phase AC motors
■
Greater than 10:1 variable speed control range
■
Constant V/F ratio with programmable end points
■
Reverse capability for two and three phase motors
■
Low distortion PWM sinewave drive
■
Eliminates run capacitors in PSC motors
■
Coast function for quick power disable
■
Low cost interface for various gate drivers
■
PWM current limit, undervoltage lockout, and
programmable deadtime
■
12V ±20% operation with onboard 8V reference
A constant voltage/frequency ratio can be maintained
over a frequency range of greater than 10:1, providing
15Hz to 150Hz control. The output variable frequency AC
voltages are sensed and fed back to the controller to track the
sinewave frequency and amplitude set at the speed control
input. Direction, on two and three phase motors, is controlled
by changing the relative phase difference between the motor
windings: 90× for two phase motors and 120× and 240× for three
phase motors.
To protect the motor, power devices, high voltage drivers
and control circuitry, the ML4423 includes fixed period,
pulse by pulse variable duty cycle current limit, deadtime
circuitry, and undervoltage lockout. The ML4423 has
selectable output voltage swing of 5V or 12V for
interfacing to different high side drivers and power devices.
(* Indicates Part Is End Of Life As Of July 1, 2000)
BLOCK DIAGRAM
27
SINE A-C
28
13
SINE B-C
FB A
1
15
CT
18
F/R
3PH/2PH
COAST
+
PWM
OSCILLATOR
+
–
RDT
–
FB C
2
5V/12 SELECT
FB B
3
+
+
–
HA
–
CO
SINE A
GENERATOR
12
HB
PWM
SINE
WAVE
CONTROL
GATING
LOGIC
&
OUTPUT
DRIVERS
HC
LA
LB
LC
VSPEED
5
SINE C
GENERATOR
VMIN
4
RSPEED
6
9
25
24
22
23
21
19
20
16
COMP
–
SPEED
CONTROL
SINE B
GENERATOR
ISENSE
+
UVLO
14
0.5V
REFERENCE
26
VDD
GND
17
8
RREF
7
VREF
1
ML4423
PIN CONFIGURATION
ML4423
28-Pin Narrow PDIP (P28N)
28-Pin SOIC (S28)
SENSE A
1
28
CGM2
SENSE C
2
27
CGM1
SENSE B
3
26
VDD
VMIN
4
25
5V/12V SELECT
VSPEED
5
24
HA
RSPEED
6
23
HC
VREF
7
22
HB
RREF
8
21
LA
RDT
9
20
LC
SINE A-C 10
19
LB
SINE B-C 11
18
3PH/2PH
CO 12
17
GND
CT 03
16
ISENSE
COAST 14
15
F/R
TOP VIEW
2
ML4423
PIN DESCRIPTION
PIN
NAME
FUNCTION
PIN
NAME
FUNCTION
1
FB A
Differential input which, in
conjunction with FB C, feeds back the
voltage applied across motor winding
A-C.
13
CT
An external capacitor to ground sets
the PWM triangle frequency in
conjunction with the external resistor
RREF.
2
FB C
Input which feeds back the voltage
applied to motor winding C. Reference
voltage for windings A and B.
14
COAST
A logic low input causes all output
drive transistors to turn OFF. An
internal pull-up drives COAST to VDD
if left unconnected.
3
FB B
Differential input which, in
conjunction with FB C, feeds back the
voltage applied across motor winding
B-C.
15
F/R
A logic high input causes phase A to
lead phase B, while a logic low input
causes phase A to lag phase B. An
internal pull-up drives F/R to VDD if
left unconnected.
16
I SENSE
Motor current sense input.
17
GND
Signal and power ground.
18
3PH/2PH
Leaving this pin unconnected selects
3-phase drive. Connecting this pin to
VDD selects single/2-phase drive.
19
LB
Low side drive output for phase B.
20
LC
Low side drive output for phase C.
21
LA
Low side drive output for phase A.
22
HB
High side drive output for phase B.
23
HC
High side drive output for phase C.
24
HA
High side drive output for phase A.
25
5V/12V
SELECT
Input to select 5V or 12V output drive.
Leaving this pin unconnected selects
5V output drive levels at the driver
outputs. Connecting this pin to VCC
selects 12V output drive levels at the
driver outputs.
26
V DD
12V power supply input.
27
C GM1
An external capacitor to ground sets a
pole in the feedback loop.
28
C GM2
An external capacitor to ground sets a
pole in the feedback loop.
4
5
6
V MIN
V SPEED
R SPEED
The voltage on this pin sets the
minimum sinewave amplitude at low
speeds.
The voltage on this pin sets the
frequency and amplitude of the
sinewaves generated at SINEA and
SINEB.
An external resistor to ground provides
a variable current to the sinewave
generator. The current is proportional
to VSPEED.
7
V REF
8V reference output which can be
used for setting VSPEED and VMIN.
8
R REF
An external resistor to ground provides
a constant current used for setting the
PWM frequency in conjunction with
CT.
9
RDT
An external resistor to ground sets the
deadtime in the output stage to
prevent cross-conduction in the power
devices.
10
SINE A-C
A test output for observing the
internally generated sinewave used for
motor winding A-C.
11
SINE B-C
A test output for observing the
internally generated sinewave used for
motor winding B-C.
12
CO
An external capacitor to ground sets
the sinewave frequency in conjunction
with VSPEED and RSPEED.
3
ML4423
ABSOLUTE MAXIMUM RATINGS
Absolute maximum ratings are those values beyond which
the device could be permanently damaged. Absolute
maximum ratings are stress ratings only and functional
device operation is not implied.
Thermal Resistance (qJA)
Plastic DIP ....................................................... 52ºC/W
Plastic SOIC .................................................... 75ºC/W
V DD .............................................................................................. 15V
Output Drive Current ........................................... ±50mA
Logic Inputs (F/R, COAST) .............................. –0.3 to 7V
Junction Temperature .............................................. 150ºC
Storage Temperature Range ...................... –65ºC to 150ºC
Lead Temperature (Soldering 10 sec) ...................... 260ºC
OPERATING CONDITIONS
Temperature Range
C Suffix ...................................................... 0ºC to 70ºC
I Suffix .................................................... –40ºC to 85ºC
V DD ........................................................... 9.6V to 14.4V
ELECTRICAL CHARACTERISTICS
Unless otherwise specified, VDD = 12V ± 20%, RSPEED = 160kW, RSENSE = 250mW, RREF = 200kW,
C0 = 0.47mF, CPWM = 220pF, RDT = 166kW, TA = Operating Temperature Range (Note 1).
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
7.6
7.8
8.2
V
0.8
V
REFERENCE
VREF
Output Voltage
Line Regulation
Total Variation
Line, Temperature
DIGITAL INPUTS
VIL
Input Low Voltage
VIH
Input High Voltage
2
V
OUTPUT DRIVERS
VOL
VOH
Output Low Voltage
Output High Voltage
IOL = 20mA, 5V/12V SELECT = VDD
1
V
IOL = 2mA, 5V/12V SELECT = open
0.1
V
IOL = –20mA, 5V/12V SELECT = VDD
VDD – 1
V
IOL = –2mA, 5V/12V SELECT = open
5
V
SINE WAVE GENERATOR
V PP
Peak Voltage
VSPEED = 4.4V
3.4
V
Frequency
VSPEED = 4.4V
60
Hz
5
%
25
kHz
Distortion
PWM GENERATOR
Ramp Frequency
CURRENT LIMIT
Threshold Voltage
0.4
0.5
0.6
V
7.8
8.4
9.2
V
UNDERVOLTAGE LOCKOUT
Threshold Voltage
Hysteresis
0.5
V
SUPPLY
I CC
VCC Operating Current
Note 1: Limits are guaranteed by 100% testing, sampling, or correlation with worst-case test conditions.
4
10
14
20
mA
ML4423
FUNCTIONAL DESCRIPTION
The ML4423 generates 2 reference sinewaves separated
by 90º or 60º in a closed loop feedback system. These
sinewaves can be varied in amplitude and frequency by
the speed input. Signals across the motor windings are fed
back and the ML4423 drives the external power output
stage with the PWM sinewave signal necessary to cause
the measured (feedback) output waveform to match the
internal reference sinewaves. The ML4423 provides fixed
period, variable duty cycle current limit protection, and
a programmable dead time circuit to prevent cross
conduction in the power output stage. An undervoltage
lockout circuit turns off the external power transistors if
VDD falls below 9V.
SINEA and SINEB Generators
CIRCUIT BLOCKS AND COMPONENT SELECTION
For RSPEED = 160kW
The capacitor to ground on C0 sets the frequency of the
sinewave according to the following relationship. C0
should be a low temperature coefficient capacitor for
stable output frequency.
fSINE


VSPEED


R SPEED
=

 4C 0 × 0.170V 


R REF
RREF should be set to 200kW. This current along with
CPWM set the PWM frequency.
Speed Control
The voltage on VSPEED (pin 5) controls the sinewave
frequency and amplitude. A 160kW resistor to ground on
RSPEED (pin 6) converts the voltage on VSPEED to a current
which is used to control the frequency of the output PWM
sinewaves. The amplitude of the sinewaves increases
linearly with VSPEED until it reahces 4.4V. Above this
voltage the amplitude remains constant and only the
frequency changes as shown in Figures 1 and 2.
fSINE =
(1)
VSPEED
108, 800 × C 0
(2)
With VSPEED = 3V and C0 = 0.47mF, fSINE = 58.7Hz and
can be observed at test points SINEA (pin 10) and SINEB
(pin 11).
PWM Generator
A triangular PWM frequency will be generated on a
capacitor to ground on CPWM (pin 13). The frequency is
set by the following equation:
fPWM =
1
200, 000 × C PWM
(3)
For CPWM = 220pF, fPWM = 22.7kHz. It is recommended
150
1.25
120
1.00
NORMALIZED OUPTUT (V)
FREQUENCY (Hz)
4.4V
90
60
RSPEED = 160
C0 = 0.47µF
30
0
0.75
0.50
0.25
2
4
VSPEED (V)
6
Figure 1. Frequency vs VSPEED
8
0
2
4
VSPEED (V)
6
8
Figure 2. Normalized Output Voltage vs VSPEED
5
ML4423
Current Limit
OUTPUT DRIVE
Motor current is sensed on ISENSE (pin 16). RLIMIT should
be selected so that
The 6 output drivers of the ML4423 drive the H and L
outputs from 0 to 12 volts (with pin 25 tied to VCC +(12V)).
The outputs will drive about 10mA and are designed to
drive output buffers and high side drivers requiring 12V
swings. The ML4423 provides lower current 0 to 5V drive
for high/low side drivers requiring 5V input signal swings
with pin 25 left unconnected.
RLIMIT = 0.5V
IMAX
(4)
For a 2A current limit, RLIMIT = 0.25W. The 1kW resistor
and 330pF capacitor filter (shown in figure 3) filter the
high frequency flyback pulses (due to the freewheeling
diode recovery currents) occurring at the output. When
IMAX is reached the output power will be turned off for
the remainder of the current PWM cycle, which is
asynchronous with the sinewave frequency. Thus current
limit is fixed-period with variable duty cycle.
PWM SINE Controller
This circuit block compares the sinewaves at SINEA and
SINEB to the sampled inputs SENSEA–SENSEC and
SENSEB–SENSEC, respectively. The PWM loop then
drives the outputs to force these “differential” waveforms
to equal the internal reference waveforms at SINEA and
SINEB. The differential signals SENSEA–SENSEC and
SENSEB–SENSEC will be approximately 1.7 volts zeropeak maximum. The signals at these pins should be
filtered to remove the PWM frequency. The high voltages
at the motor terminals are divided down to 1.7V to
provide voltage feedback to the controller. In figure 3,
the resistors to ground from SENSEA (pin 1) and SENSEB
(pin 3) should be 1kW. SENSEC (pin 2) should have a
500W to ground because it has 1/2 the input impedance
of the other 2 inputs. The 0.15mF capacitors to ground on
SENSEA and SENSEB and the 0.3mF capacitor to ground
on SENSEC will create a 1kHz low pass filter at these
inputs. VPEAK on the motor is set by the divider ratios.
For the values shown in figure 3:


= 1.7V  99k + 1k 
 1k 


= 1.7V  49.5k + 500 


500
= 170V
6
A dead time circuit is provided to prevent shoot through
currents in the power output stage. The dead time is
controlled by a resistor to ground on RDT (pin 9). The dead
time selected should be large enough to prevent cross
conduction between the upper and lower power devices
of each inverter phase leg.
(
tDEAD = 1.2 × 10 −11 RDB
)
(6)
With fPWM = 25kHz, the PWM period is 40ms. With RDB
= 166k, tDEAD = 2ms (~5%).
CGM1 and CGM2
These two external capacitors to ground each set a pole in
the forward path of the feedback loop in conjunction with
a gm of 1/650W. The pole should be placed at a frequency
higher than the PWM frequency.
gm
> fPWM
2πC gm
(7)
APPLICATION
The ML4423 provides all the signals necessary to drive
the output power stage connected to the motor. The
components around the ML4423 for a typical application
are shown in figure 3. The motor DC supply voltage
should be greater than the largest signal waveform
required or output clipping may result. Figure 4 shows an
alternate circuit using the IR2118.
(VSPEED = 4.4V)
VPEAK
PROGRAMMABLE DEADTIME
(5)
12V
A
0.1µF
Figure 3. 3-Phase Motor Controller with INT-100 High Voltage Drivers
C0
26
VREF
0.1µF
RREF
220pF
0.47µF
VCC
CPWM
SINEA
10
12
13
99kΩ
PWM
GENERATOR
7
8V REF
ML4423
200kΩ
2
SINEA
3
VSPEED
5
0.1µF
RSPEED
24
21
160kΩ
VMIN
OUTPUT
DRIVE & SHOOT
THROUGH
PROTECTION
SINEB
4
22
19
23
100kΩ
20
CURRENT
LIMIT
17
GND
27
CGM1
0.001µF
28
CGM2
0.001µF
11
15
SINEB
F/R
14
18
COAST 3PH/2PH
16
25
5V/12V
SELECT
500Ω
1kΩ
0.30µF
+12V
PWM SINE
CONTROLLER
AMPLITUDE
6
1kΩ
0.15µF
SENSEB
UNDER VOLTAGE
LOCKOUT
FREQ.
SPEED
CONTROLLER
99kΩ
SENSEA
SENSEC
49.5kΩ
B
0.15µF
8
1
100kΩ
C
HA
A
DRIVE
LA
+VMOTOR
170–400V
+12V
HB
B
DRIVE
LB
+12V
HC
2
ISENSE
15
1
LC
HIN
10Ω
11
+
1kΩ
PWR
INT100
RLIMIT
330pF
250mΩ
166kΩ
Note: Use Extreme caution with high voltage AC motor control and drive circuitry.
When the motor is spinning at the desired speed, and the speed is rapidly reduced,
the energy stored in the rotation will generate a voltage greater than the +VMOTOR node,
and destruction of the power transistors, high side driver, ML4423
controller and the power supply may occur.
3
8
LIN
4
5
1µF 100Ω
12,13,14
9
RDT
C
7
10Ω
100Ω
HV POWER STAGE
ML4423
7
8
Figure 4. ML4423 Output Stage Using IR2118 High Side Drivers
+12V
25
9
240kΩ
ISENSE 16
L C 20
L B 19
L A 21
H C 23
H B 22
330pF
2N3904
+
1.0µF
1kΩ
2N3906
25V
1.0µF
4
3
N/C 5
N/C
4
IRF740
VS 6
HO 7
VB 8
COM
IN
VCC
3
2
1
N/C 5
VS 6
IR2118
N/C
COM
HO 7
IN
2
MUR150
22Ω
25V
1.0µF
VB 8
VCC
1
IR2118
N/C 5
N/C
4
MUR150
VS 6
HO 7
COM
IN
VB 8
IR2118
VCC
3
2
25V
1.0µF
H A 24
MUR150
1
5V/12V SELECT RDT
ML4423
+12V
170 – 360V
SENSEB 3
SENSEC 2
SENSEA 1
+VMOTOR
22Ω
IRF740
C21
25V
1µF
22Ω
25V
1µF
22Ω
22Ω
25V
1µF
IRF740
250mΩ
22Ω
IRF740
RLIMIT
C
FEEDBACK
NETWORK
B
AC MOTOR
A
+
SENSEC SENSEB SENSEA
IRF740
IRF740
330µF
400V
ML4423
ML4423
PHYSICAL DIMENSIONS
inches (millimeters)
Package: P28N
28-Pin Narrow PDIP
1.355 - 1.365
(34.42 - 34.67)
28
0.280 - 0.296 0.299 - 0.325
(7.11 - 7.52) (7.60 - 8.26)
PIN 1 ID
1
0.045 - 0.055
(1.14 - 1.40)
0.100 BSC
(2.54 BSC)
0.020 MIN
(0.51 MIN)
0.180 MAX
(4.57 MAX)
SEATING PLANE
0.015 - 0.021
(0.38 - 0.53)
0.125 - 0.135
(3.18 - 3.43)
0º - 15º
0.008 - 0.012
(0.20 - 0.31)
Package: S28
28-Pin SOIC
0.699 - 0.713
(17.75 - 18.11)
28
0.291 - 0.301 0.398 - 0.412
(7.39 - 7.65) (10.11 - 10.47)
PIN 1 ID
1
0.024 - 0.034
(0.61 - 0.86)
(4 PLACES)
0.050 BSC
(1.27 BSC)
0.095 - 0.107
(2.41 - 2.72)
0º - 8º
0.090 - 0.094
(2.28 - 2.39)
0.012 - 0.020
(0.30 - 0.51)
SEATING PLANE
0.005 - 0.013
(0.13 - 0.33)
0.022 - 0.042
(0.56 - 1.07)
0.009 - 0.013
(0.22 - 0.33)
9
ML4423
ORDERING INFORMATION
PART NUMBER
TEMPERATURE RANGE
PACKAGE
ML4423CP (End Of Life)
ML4423CS (End Of Life)
0ºC to 70ºC
0ºC to 70ºC
28-Pin Narrow PDIP (P28N)
28-Pin SOIC (S28)
ML4423IP (End Of Life)
ML4423IS (End Of Life)
–40ºC to 85ºC
–40ºC to 85ºC
28-Pin Narrow PDIP (P28N)
28-Pin Narrow PDIP (P28N)
© Micro Linear 2000. is a registered trademark of Micro Linear Corporation. All other trademarks are the property of their
respective owners.
Products described herein may be covered by one or more of the following U.S. patents: 4,897,611; 4,964,026; 5,027,116;
5,281,862; 5,283,483; 5,418,502; 5,508,570; 5,510,727; 5,523,940; 5,546,017; 5,559,470; 5,565,761; 5,592,128; 5,594,376;
5,652,479; 5,661,427; 5,663,874; 5,672,959; 5,689,167; 5,714,897; 5,717,798; 5,742,151; 5,747,977; 5,754,012; 5,757,174;
5,767,653; 5,777,514; 5,793,168; 5,798,635; 5,804,950; 5,808,455; 5,811,999; 5,818,207; 5,818,669; 5,825,165; 5,825,223;
5,838,723; 5.844,378; 5,844,941. Japan: 2,598,946; 2,619,299; 2,704,176; 2,821,714. Other patents are pending.
DS4423-01
10
2092 Concourse Drive
San Jose, CA 95131
Tel: (408) 433-5200
Fax: (408) 432-0295
www.microlinear.com
4/21/98 Printed in U.S.A.