SA12

SA12 SA12 P r o d u SA12 c t IInnnnoovvaa t i o n FFr roomm Pulse Width Modulation Amplifiers FEATURE • • • • • • • HIGH FREQUENCY SWITCHING — 200 kHz WIDE SUPPLY RANGE—16-200V 15A CONTINUOUS TO 65°C case 3 PROTECTION CIRCUITS ANALOG OR DIGITAL INPUTS SYNCHRONIZED OR EXTERNAL OSCILLATOR FLEXIBLE FREQUENCY CONTROL APPLICATIONS • REACTIVE LOADS • LOW FREQUENCY SONAR • LARGE PIEZO ELEMENTS • OFF-LINE DRIVERS • C-D WELD CONTROLLER EXTERNAL CONNECTIONS DESCRIPTION 12-pin Power DIP PACKAGE STYLE CR ISENSE A The SA12 is a pulse width modulation amplifier that can supply 3000W to the load. An internal 400kHz oscillator requires no external components. The clock input stage divides the oscillator frequency by two, which provides the 200 kHz switching frequency. External oscillators may also be used to lower the switching frequency or to synchronize multiple amplifiers. Current sensing is provided for each half of the H-bridge giving amplitude and direction data. A shutdown input turns off all four drivers of the H-bridge output. A high side current limit and the programmable low side current limit protect the amplifier from shorts to supply or ground in addition to load shorts. The H-bridge output MOSFETs are protected from thermal overloads by directly sensing the temperature of the die. The 12-pin hermetic MO-127 power package occupies only 3 square inches of board space. BLOCK DIAGRAM AND TYPICAL APPLICATION TORQUE MOTOR DRIVER Vcc 10 +PWM CLK IN 1 12 CLK OUT +PWM 2 11 -PWM/RAMP 4 3 GND 100pF 5 8 6 7 CLK IN CONTROL SIGNAL GND B OUT I SENSE B Case tied to pin 5. Allow no current in case. Bypassing of supplies is required. Package is Apex MO-127 (STD). See Outline Dimensions/Packages in Apex data book. *See text. As +PWM goes more positive, A OUT duty cycle increases. 9 28K OUTPUT DRIVERS 8 11 2 * +VS 9 +VS PWM –PWM/RAMP 4 CLK OUT * VCC 10 TOP VIEW ILIM/SHDN CURRENT LIMIT 3 A OUT OSC B OUT MOTOR A OUT ÷2 1K 12 SHUTDOWN CONTROL 6 1 5 7 I SENSE A ILIM/SHDN 5K .01μF RSENSE 1K I SENSE B RSENSE 5V 5V SA12U http://www.cirrus.com Copyright © Cirrus Logic, Inc. 2009 (All Rights Reserved) MAY 20091 APEX − SA12UREVH SA12 P r o d u c t I n n o v a t i o nF r o m ABSOLUTE MAXIMUM RATINGS SPECIFICATIONS PARAMETER CLOCK (CLK) CLK OUT, high level4 CLK OUT, low level4 FREQUENCY RAMP, center voltage RAMP, P-P voltage CLK IN, low level4 CLK IN, high level4 OUTPUT TOTAL RON4 EFFICIENCY, 10A output SWITCHING FREQUENCY CURRENT, continuous4 CURRENT, peak4 POWER SUPPLY VOLTAGE, VS VOLTAGE, VCC CURRENT, VCC CURRENT, VCC, shutdown CURRENT, VS SUPPLY VOLTAGE, +VS SUPPLY VOLTAGE, VCC POWER DISSIPATION, internal TEMPERATURE, pin solder - 10s TEMPERATURE, junction3 TEMPERATURE, storage OPERATING TEMPERATURE RANGE, case INPUT VOLTAGE, +PWM INPUT VOLTAGE, –PWM INPUT VOLTAGE, ILIM TEST CONDITIONS2 MIN IOUT ≤ 1mA IOUT ≤ 1mA 4.8 0 392 4. CAUTION 2 MAX UNITS 400 5 4 5.3 .4 408 .9 5.4 V V kHz V V V V VS = 200V OSC in ÷ 2 65°C case .4 204 Ω % kHz A A Full temperature range Full temperature range IOUT = 0 196 15 20 16 14 200 16 125 80 200 V V mA mA mA 110 100 mV nA 1 +85 °C/W °C/W °C 97 200 120 15 No Load 90 THERMAL3 RESISTANCE, junction to case RESISTANCE, junction to air TEMPERATURE RANGE, case TYP 0 3.7 ILIM/SHUTDOWN TRIP POINT INPUT CURRENT NOTES: 1. 2. 3. 200V 16V 250W1 300°C 150°C –65 to +150°C –55 to +125°C 0 to +11V 0 to +11V 0 to +10V Full temperature range, for each die Full temperature range Meets full range specifications 12 –25 Each of the two active output transistors can dissipate 125W. Unless otherwise noted: TC = 25°C, VS, VCC at typical specification. Long term operation at the maximum junction temperature will result in reduced product life. Derate internal power dissipation to achieve high MTTF. For guidance, refer to the heatsink data sheet. Guaranteed but not tested. The SA12 is constructed from MOSFET transistors. ESD handling procedures must be observed. The internal substrate contains beryllia (BeO). Do not break the seal. If accidentally broken, do not crush, machine, or subject to temperatures in excess of 850°C to avoid generating toxic fumes. SA12U SA12 POWER DERATING 0 EACH ACTIVE OUTPUT RESISTOR 0 FLYBACK CURRENT, Isd (A) 96 95 25 50 125 75 100 CASE TEMPERATURE, (°C) REVERSE DIODE 15 12 9 6 3 0 0.6 0.8 1.0 1.2 1.4 SOURCE TO DRAIN DIODE VOLTAGE CONTINUOUS OUTPUT 16 NORMALIZED FREQUENCY, (%) 25 97 F NOMINAL = 400kHz 2 1.5 1 DUTY CYCLE VS ANALOG INPUT 100 60 40 20 110 105 100 50 75 100 125 CASE TEMPERATURE, (°C) Vcc QUIESCENT CURRENT Vcc = 15V F = 22.5 kHz 4 5 6 ANALOG INPUT, (V) 7 Vs QUIESCENT VS VOLTAGE 140 120 NORMAL OPERATION 95 90 85 0 3 NORMALIZED Vs QUIESCENT CURRENT, (%) NORMALIZED Vcc QUIESCENT CURRENT, (%) 115 SHUTDOWN OPERATION 80 –50 –25 0 25 50 75 100 125 CASE TEMPERATURE, (° C) 99.0 98.5 98.0 –50 –25 0 25 50 75 100 125 CASE TEMPERATURE, (°C) 12 100 80 60 40 20 0 25 50 75 100 125 150 175 200 Vs, (V) SA12U TOTAL VOLTAGE DROP 60°C 10 85°C 8 100°C 6 4 125°C 2 0 0 .5 –50 0 50 100 150 JUNCTION TEMPERATURE, TJ (°C) A OUT 8 25 99.5 NORMALIZED ON RESISTANCE DUTY CYCLE, (%) CONTINUOUS AMPS 10 100.0 2.5 B OUT 12 100.5 100K 1M 10K CLOCK LOAD RESISTANCE, (Ω) 80 14 101.0 TOTAL VOLTAGE DROP, (V) 50 98 101.5 NORMALIZED Vcc QUIESCENT CURRENT, (%) 75 99 102.0 NORMALIZED Vs QUIESCENT CURRENT, (%) 100 CLOCK FREQUENCY OVER TEMP CLOCK LOADING 100 NORMALIZED FREQUENCY, (%) 125 NORMALIZED TOTAL RDS ON,(X) INTERNAL POWER DISSIPATION, (W) P r o d u c t I n n o v a t i o nF r o m 100 –55°C 25°C –25°C 3 6 9 12 15 OUTPUT CURRENT, (A) Vcc QUIESCENT CURRENT 90 80 70 60 40 80 120 160 200 SWITCHING FREQUENCY, F (kHz) Vs QUIESCENT VS FREQUENCY 100 80 60 40 20 200 40 160 80 120 SWITCHING FREQUENCY, F (kHz) 3 SA12 P r o d u c t I n n o v a t i o nF r o m GENERAL Please read Application Note 30 on "PWM Basics". Refer to Application Note 1 "General Operating Considerations" for helpful information regarding power supplies, heat sinking and mounting. Visit www.Cirrus.com for design tools that help automate pwm filter design; heat sink selection; Apex Precision Power’s complete Application Notes library; Technical Seminar Workbook; and Evaluation Kits. CLOCK CIRCUIT AND RAMP GENERATOR The clock frequency is internally set to a frequency of approximately 400kHz. The CLK OUT pin will normally be tied to the CLK IN pin. The clock is divided by two and applied to an RC network which produces a ramp signal at the –PWM/ RAMP pin. An external clock signal can be applied to the CLK IN pin for synchronization purposes. If a clock frequency lower than 400kHz is chosen an external capacitor must be tied to the –PWM/RAMP pin.This capacitor, which parallels an internal capacitor, must be selected so that the ramp oscillates 4 volts p-p with the lower peak 3 volts above ground. PWM INPUTS The full bridge driver may be accessed via the pwm input comparator. When +PWM > -PWM then A OUT > B OUT. A motion control processor which generates the pwm signal can drive these pins with signals referenced to GND. PROTECTION CIRCUITS A fixed internal current limit senses the high side current. Should either of the outputs be shorted to ground the high side current limit will latch off the output transistors. The temperature of the output transistors is also monitored. Should a fault condition raise the temperature of the output transistors to 165°C the thermal protection circuit will latch off the output transistors. The latched condition can be cleared by either recycling the Vcc power or by toggling the I LIMIT/SHDN input with a 10V pulse. See Figures A and B. The outputs will remain off as long as the shutdown pulse is high (10V). When supply voltage is over 100V, these circuits may not protect the FET switches in the case of short circuits directly at the pins of the amplifier. However, a small inductance between the amplifier and the short circuit will limit current rise time and the protection circuits will be effective. A pair of 12 inch wires is adequate inductance. CURRENT LIMIT I SENSE A There are two load current R LIMIT sensing pins, I SENSE A and I SENSE B I SENSE B. The two pins can 5K be shorted in the voltage I LIMIT/SHDN R SHUTDOWN FILTER SIGNAL mode connection but both 0/10V must be used in the current IN4148 C FILTER mode connection (see figures A and B). It is recommended FIGURE A. CURRENT LIMIT WITH that RLIMIT resistors be non- SHUTDOWN VOLTAGE MODE. inductive. Load current flows in the I SENSE pins. To avoid errors due to lead lengths connect the I LIMIT/SHDN pin directly to the RLIMIT resistors (through the filter network and shutdown divider resistor) and connect 4 the RLIMIT resistors directly to the GND pin. Switching noise spikes will inR LIMIT variably be found at the I SENSE I SENSE B pins. The noise spikes could trip 5K the current limit threshold which is only 100 mV. RFILTER and CFILTER R LIMIT should be adjusted so as to reduce the switching noise well SHUTDOWN I LIMIT/SHDN R FILTER SIGNAL below 100 mV to prevent 0/10V false current limiting. C FILTER IN4148 The sum of the DC level plus the noise peak will FIGURE B. CURRENT LIMIT WITH determine the current SHUTDOWN CURRENT MODE. limiting value.As in most switching circuits it may be difficult to determine the true noise amplitude without careful attention to grounding of the oscilloscope probe. Use the shortest possible ground lead for the probe and connect exactly at the GND terminal of the amplifier. Suggested starting values are CFILTER = .01uF, RFILTER = 5k . The required value of RLIMIT in voltage mode may be calculated by: RLIMIT = .1 V / ILIMIT where RLIMIT is the required resistor value, and ILIMIT is the maximum desired current. In current mode the required value of each RLIMIT is 2 times this value since the sense voltage is divided down by 2 (see Figure B). If RSHDN is used it will further divide down the sense voltage. The shutdown divider network will also have an effect on the filtering circuit. I SENSE A 5K BYPASSING Adequate bypassing of the power supplies is required for proper operation. Failure to do so can cause erratic and low efficiency operation as well as excessive ringing at the outputs. The Vs supply should be bypassed with at least a 1µF ceramic capacitor in parallel with another low ESR capacitor of at least 10µF per amp of output current. Capacitor types rated for switching applications are the only types that should be considered. The bypass capacitors must be physically connected directly to the power supply pins. Even one inch of lead length will cause excessive ringing at the outputs. This is due to the very fast switching times and the inductance of the lead connection. The bypassing requirements of the Vcc supply are less stringent, but still necessary. A .1µF to .47µF ceramic capacitor connected directly to the Vcc pin will suffice. MODULATION RANGE The high side of the all N channel H-bridge is driven by a bootstrap circuit. For the output circuit to switch high, the low side circuit must have previously been switched on in order to charge the bootstrap capacitor. Therefore, if the input signal to the SA12 demands a 100% duty cycle upon start-up the output will not follow and will be in a tri-state (open) condition. The ramp signal must cross the input signal at some point to correctly determine the output state. After the ramp crosses the input signal one time the output state will be correct thereafter. In addition, if during normal operation the input signal drives the SA12 beyond its linear modulation range (approximately 95%) the output will jump to 100% modulation. SA12U P r o d u c t I n n o v a t i o nF r o m SA12 Contacting Cirrus Logic Support For all Apex Precision Power product questions and inquiries, call toll free 800-546-2739 in North America. For inquiries via email, please contact apex.support@cirrus.com. International customers can also request support by contacting their local Cirrus Logic Sales Representative. To find the one nearest to you, go to www.cirrus.com IMPORTANT NOTICE Cirrus Logic, Inc. and its subsidiaries ("Cirrus") believe that the information contained in this document is accurate and reliable. However, the information is subject to change without notice and is provided "AS IS" without warranty of any kind (express or implied). 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