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.