TL494, NCV494 SWITCHMODETM Pulse Width Modulation Control Circuit The TL494 is a fixed frequency, pulse width modulation control circuit designed primarily for SWITCHMODE power supply control. * * * * * * * * * Complete Pulse Width Modulation Control Circuitry On-Chip Oscillator with Master or Slave Operation On-Chip Error Amplifiers On-Chip 5.0 V Reference Adjustable Deadtime Control Uncommitted Output Transistors Rated to 500 mA Source or Sink Output Control for Push-Pull or Single-Ended Operation Undervoltage Lockout NCV Prefix for Automotive and Other Applications Requiring Site and Control Changes http://onsemi.com MARKING DIAGRAMS 16 16 1 SO-16 D SUFFIX CASE 751B 1 TL494xD AWLYWW MAXIMUM RATINGS (Full operating ambient temperature range applies, unless otherwise noted.) Rating Power Supply Voltage Collector Output Voltage Collector Output Current (Each transistor) (Note 1) Amplifier Input Voltage Range Power Dissipation @ TA 45C Thermal Resistance, Junction-to-Ambient Operating Junction Temperature Storage Temperature Range Operating Ambient Temperature Range TL494B TL494C TL494I NCV494B Derating Ambient Temperature 1. Maximum thermal limits must be observed. Symbol VCC VC1, VC2 IC1, IC2 VIR PD RqJA TJ Tstg TA -40 to +125 0 to +70 -40 to +85 -40 to +125 TA 45 C Value 42 42 500 -0.3 to +42 1000 80 125 -55 to +125 Unit V V 16 mA V mW C/W C C C Device TL494BD TL494BDR2 TL494CD TL494CDR2 TL494CN TL494IN NCV494BDR2* 14 Vref Output 13 Contro l 12 VCC 11 C2 Q2 16 PDIP-16 N SUFFIX CASE 648 1 1 x = B, C or I A = Assembly Location WL, L = Wafer Lot YY, Y = Year WW, W = Work Week *This marking diagram also applies to NCV494. TL494xN AWLYYWW * ORDERING INFORMATION Package SO-16 SO-16 SO-16 SO-16 PDIP-16 PDIP-16 SO-16 Shipping 48 Units/Rail 2500 Tape & Reel 48 Units/Rail 2500 Tape & Reel 25 Units/Rail 25 Units/Rail 2500 Tape & Reel PIN CONNECTIONS Noninv Input 1 Inv Input 2 Compen/PWN Comp Input 3 Deadtime Control 4 CT 5 Oscillator + Error 1 Amp - + 2 Error Amp - VCC 0.1 V 5.0 V REF Noninv 16 Input Inv 15 Input For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specification Brochure, BRD8011/D. *NCV494: Tlow = -40C, Thigh = +125C. Guaranteed by design. NCV prefix is for automotive and other applications requiring site and change control. RT 6 Ground 7 C1 8 Q1 10 E2 9 E1 (Top View) (c) Semiconductor Components Industries, LLC, 2004 1 April, 2004 - Rev. 5 Publication Order Number: TL494/D TL494, NCV494 RECOMMENDED OPERATING CONDITIONS Characteristics Power Supply Voltage Collector Output Voltage Collector Output Current (Each transistor) Amplified Input Voltage Current Into Feedback Terminal Reference Output Current Timing Resistor Timing Capacitor Oscillator Frequency Symbol VCC VC1, VC2 IC1, IC2 Vin lfb lref RT CT fosc Min 7.0 - - -0.3 - - 1.8 0.0047 1.0 Typ 15 30 - - - - 30 0.001 40 Max 40 40 200 VCC - 2.0 0.3 10 500 10 200 Unit V V mA V mA mA kW mF kHz ELECTRICAL CHARACTERISTICS (VCC = 15 V, CT = 0.01 mF, RT = 12 kW, unless otherwise noted.) For typical values TA = 25C, for min/max values TA is the operating ambient temperature range that applies, unless otherwise noted. Characteristics REFERENCE SECTION Reference Voltage (IO = 1.0 mA) Line Regulation (VCC = 7.0 V to 40 V) Load Regulation (IO = 1.0 mA to 10 mA) Short Circuit Output Current (Vref = 0 V) OUTPUT SECTION Collector Off-State Current (VCC = 40 V, VCE = 40 V) Emitter Off-State Current VCC = 40 V, VC = 40 V, VE = 0 V) Collector-Emitter Saturation Voltage (Note 2) Common-Emitter (VE = 0 V, IC = 200 mA) Emitter-Follower (VC = 15 V, IE = -200 mA) Output Control Pin Current Low State (VOC v 0.4 V) High State (VOC = Vref) Output Voltage Rise Time Common-Emitter (See Figure 12) Emitter-Follower (See Figure 13) Output Voltage Fall Time Common-Emitter (See Figure 12) Emitter-Follower (See Figure 13) IC(off) IE(off) - - 2.0 - 100 -100 mA mA V Vsat(C) Vsat(E) IOCL IOCH tr - - tf - - 25 40 100 100 100 100 200 200 ns - - - - 1.1 1.5 10 0.2 1.3 2.5 - 3.5 mA mA ns Vref Regline Regload ISC 4.75 - - 15 5.0 2.0 3.0 35 5.25 25 15 75 V mV mV mA Symbol Min Typ Max Unit 2. Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient temperature as possible. http://onsemi.com 2 TL494, NCV494 ELECTRICAL CHARACTERISTICS (VCC = 15 V, CT = 0.01 mF, RT = 12 kW, unless otherwise noted.) For typical values TA = 25C, for min/max values TA is the operating ambient temperature range that applies, unless otherwise noted. Characteristics ERROR AMPLIFIER SECTION Input Offset Voltage (VO (Pin 3) = 2.5 V) Input Offset Current (VO (Pin 3) = 2.5 V) Input Bias Current (VO (Pin 3) = 2.5 V) Input Common Mode Voltage Range (VCC = 40 V, TA = 25C) Open Loop Voltage Gain (DVO = 3.0 V, VO = 0.5 V to 3.5 V, RL = 2.0 kW) Unity-Gain Crossover Frequency (VO = 0.5 V to 3.5 V, RL = 2.0 kW) Phase Margin at Unity-Gain (VO = 0.5 V to 3.5 V, RL = 2.0 kW) Common Mode Rejection Ratio (VCC = 40 V) Power Supply Rejection Ratio (DVCC = 33 V, VO = 2.5 V, RL = 2.0 kW) Output Sink Current (VO (Pin 3) = 0.7 V) Output Source Current (VO (Pin 3) = 3.5 V) PWM COMPARATOR SECTION (Test Circuit Figure 11) Input Threshold Voltage (Zero Duty Cycle) Input Sink Current (V(Pin 3) = 0.7 V) DEADTIME CONTROL SECTION (Test Circuit Figure 11) Input Bias Current (Pin 4) (VPin 4 = 0 V to 5.25 V) Maximum Duty Cycle, Each Output, Push-Pull Mode (VPin 4 = 0 V, CT = 0.01 mF, RT = 12 kW) (VPin 4 = 0 V, CT = 0.001 mF, RT = 30 kW) Input Threshold Voltage (Pin 4) (Zero Duty Cycle) (Maximum Duty Cycle) OSCILLATOR SECTION Frequency (CT = 0.001 mF, RT = 30 kW) Standard Deviation of Frequency* (CT = 0.001 mF, RT = 30 kW) Frequency Change with Voltage (VCC = 7.0 V to 40 V, TA = 25C) Frequency Change with Temperature (DTA = Tlow to Thigh) (CT = 0.01 mF, RT = 12 kW) UNDERVOLTAGE LOCKOUT SECTION Turn-On Threshold (VCC increasing, Iref = 1.0 mA) TOTAL DEVICE Standby Supply Current (Pin 6 at Vref, All other inputs and outputs open) (VCC = 15 V) (VCC = 40 V) Average Supply Current (CT = 0.01 mF, RT = 12 kW, V(Pin 4) = 2.0 V) (VCC = 15 V) (See Figure 12) ICC - - - 5.5 7.0 7.0 10 15 mA - mA Vth 5.5 6.43 7.0 V fosc sfosc Dfosc (DV) Dfosc (DT) - - - - 40 3.0 0.1 - - - - 12 kHz % % % IIB (DT) DCmax 45 - Vth - 0 2.8 - 3.3 - 48 45 50 50 V - -2.0 -10 mA % VTH II- - 0.3 2.5 0.7 4.5 - V mA VIO IIO IIB VICR AVOL fC- fm CMRR PSRR IO- IO+ 70 - - 65 - 0.3 2.0 - - - 2.0 5.0 -0.1 -0.3 to VCC-2.0 95 350 65 90 100 0.7 -4.0 - - - - - - - 10 250 -1.0 mV nA mA V dB kHz deg. dB dB mA mA Symbol Min Typ Max Unit * Standard deviation is a measure of the statistical distribution about the mean as derived from the formula, s N S (Xn - X)2 n=1 N-1 http://onsemi.com 3 TL494, NCV494 Output Control 13 6 Oscillator RT CT 5 - + 4 Deadtime Control 0.7V - + 0.7mA + 1 - 1 2 3 Feedback PWM Comparator Input 2 PWM Comparator + - 15 16 UV Lockout - + - + 3.5V 14 Ref. Output 7 Gnd 4.9V Reference Regulator 12 VCC Deadtime Comparator Ck D Flip- Flop Q Q2 11 10 Q Q1 8 9 VCC 0.12V Error Amp 1 Error Amp 2 This device contains 46 active transistors. Figure 1. Representative Block Diagram Capacitor CT Feedback/PWM Comp. Deadtime Control Flip-Flop Clock Input Flip-Flop Q Flip-Flop Q Output Q1 Emitter Output Q2 Emitter Output Control Figure 2. Timing Diagram http://onsemi.com 4 TL494, NCV494 APPLICATIONS INFORMATION Description The TL494 is a fixed-frequency pulse width modulation control circuit, incorporating the primary building blocks required for the control of a switching power supply. (See Figure 1.) An internal-linear sawtooth oscillator is frequency- programmable by two external components, RT and CT. The approximate oscillator frequency is determined by: fosc 1.1 RT * CT For more information refer to Figure 3. fosc , OSCILLATOR FREQUENCY (Hz) Output pulse width modulation is accomplished by comparison of the positive sawtooth waveform across capacitor CT to either of two control signals. The NOR gates, which drive output transistors Q1 and Q2, are enabled only when the flip-flop clock-input line is in its low state. This happens only during that portion of time when the sawtooth voltage is greater than the control signals. Therefore, an increase in control-signal amplitude causes a corresponding linear decrease of output pulse width. (Refer to the Timing Diagram shown in Figure 2.) The control signals are external inputs that can be fed into the deadtime control, the error amplifier inputs, or the feedback input. The deadtime control comparator has an effective 120 mV input offset which limits the minimum output deadtime to approximately the first 4% of the sawtooth-cycle time. This would result in a maximum duty cycle on a given output of 96% with the output control grounded, and 48% with it connected to the reference line. Additional deadtime may be imposed on the output by setting the deadtime-control input to a fixed voltage, ranging between 0 V to 3.3 V. Functional Table Input/Output Controls Grounded @ Vref Output Function Single-ended PWM @ Q1 and Q2 Push-pull Operation common mode input range from -0.3 V to (VCC - 2V), and may be used to sense power-supply output voltage and current. The error-amplifier outputs are active high and are ORed together at the noninverting input of the pulse-width modulator comparator. With this configuration, the amplifier that demands minimum output on time, dominates control of the loop. When capacitor CT is discharged, a positive pulse is generated on the output of the deadtime comparator, which clocks the pulse-steering flip-flop and inhibits the output transistors, Q1 and Q2. With the output-control connected to the reference line, the pulse-steering flip-flop directs the modulated pulses to each of the two output transistors alternately for push-pull operation. The output frequency is equal to half that of the oscillator. Output drive can also be taken from Q1 or Q2, when single-ended operation with a maximum on-time of less than 50% is required. This is desirable when the output transformer has a ringback winding with a catch diode used for snubbing. When higher output-drive currents are required for single-ended operation, Q1 and Q2 may be connected in parallel, and the output-mode pin must be tied to ground to disable the flip-flop. The output frequency will now be equal to that of the oscillator. The TL494 has an internal 5.0 V reference capable of sourcing up to 10 mA of load current for external bias circuits. The reference has an internal accuracy of $5.0% with a typical thermal drift of less than 50 mV over an operating temperature range of 0 to 70C. 500 k CT = 0.001 mF VCC = 15 V 100 k fout fosc = 1.0 0.5 10 k 0.01 mF 1.0 k 500 1.0 k 2.0 k 5.0 k 0.1 mF The pulse width modulator comparator provides a means for the error amplifiers to adjust the output pulse width from the maximum percent on-time, established by the deadtime control input, down to zero, as the voltage at the feedback pin varies from 0.5 V to 3.5 V. Both error amplifiers have a 10 k 20 k 50 k 100 k 200 k RT, TIMING RESISTANCE (W) 500 k 1.0 M Figure 3. Oscillator Frequency versus Timing Resistance http://onsemi.com 5 TL494, NCV494 120 110 100 90 80 70 60 50 40 30 20 10 0 1.0 % DT, PERCENT DEADTIME (EACH OUTPUT) A VOL , OPEN LOOP VOLTAGE GAIN (dB) 20 18 16 14 12 10 8.0 6.0 4.0 2.0 0 500 k 1.0 k 10 k 100 k fosc, OSCILLATOR FREQUENCY (Hz) 500 k 0.001 mF CT = 0.001 mF AVOL 10 100 1.0 k 10 k f, FREQUENCY (Hz) 0 20 40 60 80 100 120 140 160 180 100 k 1.0 M Figure 4. Open Loop Voltage Gain and Phase versus Frequency % DC, PERCENT DUTY CYCLE (EACH OUTPUT) , EXCESS PHASE (DEGREES) VCC = 15 V DVO = 3.0 V RL = 2.0 kW Figure 5. Percent Deadtime versus Oscillator Frequency 50 V CE(sat) , SATURATION VOLTAGE (V) 3.5 40 2 30 20 10 0 0 1.0 2.0 3.0 VDT, DEADTIME CONTROL VOLTAGE (IV) 1 VCC = 15 V VOC = Vref 1. CT = 0.01 mF 2. RT = 10 kW 2. CT = 0.001 mF 2. RT = 30 kW 1.9 1.8 1.7 1.6 1.5 1.4 1.3 1.2 1.1 0 100 200 300 IE, EMITTER CURRENT (mA) 400 Figure 6. Percent Duty Cycle versus Deadtime Control Voltage Figure 7. Emitter-Follower Configuration Output Saturation Voltage versus Emitter Current 10 9.0 I CC , SUPPLY CURRENT (mA) 8.0 7.0 6.0 5.0 4.0 3.0 2.0 1.0 0 2.0 VCE(sat), SATURATION VOLTAGE (V) 1.6 1.4 1.2 1.8 1.0 0.8 0.6 0.4 0 100 200 300 IC, COLLECTOR CURRENT (mA) 400 0 5.0 10 15 20 25 30 35 40 VCC, SUPPLY VOLTAGE (V) Figure 8. Common-Emitter Configuration Output Saturation Voltage versus Collector Current Figure 9. Standby Supply Current versus Supply Voltage http://onsemi.com 6 TL494, NCV494 VCC = 15V VCC Deadtime Feedback RT CT (+) (-) Error (+) (-) Output Control Gnd 150 2W C1 E1 C2 E2 150 2W Output 1 Output 2 Error Amplifier Under Test + Vin - Feedback Terminal (Pin 3) + Vref - Other Error Amplifier Test Inputs Ref Out 50k Figure 10. Error-Amplifier Characteristics Figure 11. Deadtime and Feedback Control Circuit 15V RL 68 C Each Output Transistor Q E CL 15pF VC Each Output Transistor Q E RL 68 CL 15pF VEE 15V C 90% VCC 10% tr tf 90% 10% 90% 90% VEE 10% 10% Gnd tr tf Figure 12. Common-Emitter Configuration Test Circuit and Waveform Figure 13. Emitter-Follower Configuration Test Circuit and Waveform http://onsemi.com 7 TL494, NCV494 VO Vref To Output Voltage of System Error Amp + - 2 R2 Positive Output Voltage VO = Vref 1+ R1 R2 Error Amp 3 1 R2 R1 1 + - 2 Negative Output Voltage VO = Vref R1 R2 R1 VO To Output Voltage of System Vref Figure 14. Error-Amplifier Sensing Techniques Output Control Output Q RT 6 5 CT Vref DT R1 4 R2 Output Q Vref DT 4 RS CS 30k 0.001 Max. % on Time, each output 45 - 80 1+ R1 R2 Figure 15. Deadtime Control Circuit Figure 16. Soft-Start Circuit C1 QC Q1 Output Control Single-Ended C2 0 VOC 0.4 V Q2 E2 Q2 QE E1 1.0 mA to 500 mA Output Control Push-Pull 2.4 V VOC Vref Q1 C1 E1 1.0 mA to 250 mA C2 E2 1.0 mA to 250 mA Figure 17. Output Connections for Single-Ended and Push-Pull Configurations http://onsemi.com 8 TL494, NCV494 Vref 6 5 RT CT RT Master CT RS Vin > 40V 1N975A VZ = 39V Vref 270 VCC 12 5.0V Ref Gnd 7 6 RT 5 CT Slave (Additional Circuits) Figure 18. Slaving Two or More Control Circuits Figure 19. Operation with Vin > 40 V Using External Zener +Vin = 8.0V to 20V 12 1 2 1M 33k 0.01 0.01 3 15 16 + - Comp - + OC VREF DT 13 4.7k 4.7k 14 + 10 10k 15k 0.001 4 5 CT 6 RT Gnd 7 9 E1 10 E2 TL494 C2 11 Tip 32 47 VCC C1 8 47 Tip 32 + 50 25V 1N4934 240 T1 1N4934 22 k + 50 35V 4.7k 1.0 +VO = 28 V IO = 0.2 A L1 + 50 35V All capacitors in mF Figure 20. Pulse Width Modulated Push-Pull Converter Test Line Regulation Load Regulation Output Ripple Short Circuit Current Efficiency Conditions Vin = 10 V to 40 V Vin = 28 V, IO = 1.0 mA to 1.0 A Vin = 28 V, IO = 1.0 A Vin = 28 V, RL = 0.1 W Vin = 28 V, IO = 1.0 A Results 14 mV 0.28% 3.0 mV 0.06% 65 mV pp P.A.R.D. 1.6 A 71% L1 - 3.5 mH @ 0.3 A T1 - Primary: 20T C.T. #28 AWG T1 - Secondary: 12OT C.T. #36 AWG T1 - Core: Ferroxcube 1408P-L00-3CB http://onsemi.com 9 TL494, NCV494 1.0mH @ 2A +Vin = 10V to 40V Tip 32A +VO = 5.0 V IO = 1.0 A 47 150 47k 0.1 C2 Comp - 50 50V + + 3 2 1 14 MR850 5.1k 500 10V + 5.1k 5.1k 1.0M 12 VCC 8 C1 11 TL494 Vref CT 5 - 15 16 + RT 6 D.T. O.C. Gnd E1 4 13 7 9 E2 10 + 150 50 10V 0.001 47k 0.1 Figure 21. Pulse Width Modulated Step-Down Converter Test Line Regulation Load Regulation Output Ripple Short Circuit Current Efficiency Conditions Vin = 8.0 V to 40 V Vin = 12.6 V, IO = 0.2 mA to 200 mA Vin = 12.6 V, IO = 200 mA Vin = 12.6 V, RL = 0.1 W Vin = 12.6 V, IO = 200 mA Results 3.0 mV 5.0 mV 40 mV pp 0.01% 0.02% P.A.R.D. 250 mA 72% http://onsemi.com 10 TL494, NCV494 PACKAGE DIMENSIONS PDIP-16 N SUFFIX CASE 648-08 ISSUE R -A- 16 9 NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 2. CONTROLLING DIMENSION: INCH. 3. DIMENSION L TO CENTER OF LEADS WHEN FORMED PARALLEL. 4. DIMENSION B DOES NOT INCLUDE MOLD FLASH. 5. ROUNDED CORNERS OPTIONAL. DIM A B C D F G H J K L M S INCHES MIN MAX 0.740 0.770 0.250 0.270 0.145 0.175 0.015 0.021 0.040 0.70 0.100 BSC 0.050 BSC 0.008 0.015 0.110 0.130 0.295 0.305 0_ 10 _ 0.020 0.040 MILLIMETERS MIN MAX 18.80 19.55 6.35 6.85 3.69 4.44 0.39 0.53 1.02 1.77 2.54 BSC 1.27 BSC 0.21 0.38 2.80 3.30 7.50 7.74 0_ 10 _ 0.51 1.01 B 1 8 F S C L -T- H G D 16 PL SEATING PLANE K J TA M M 0.25 (0.010) M SO-16 D SUFFIX CASE 751B-05 ISSUE J -A- 16 9 NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 2. CONTROLLING DIMENSION: MILLIMETER. 3. DIMENSIONS A AND B DO NOT INCLUDE MOLD PROTRUSION. 4. MAXIMUM MOLD PROTRUSION 0.15 (0.006) PER SIDE. 5. DIMENSION D DOES NOT INCLUDE DAMBAR PROTRUSION. ALLOWABLE DAMBAR PROTRUSION SHALL BE 0.127 (0.005) TOTAL IN EXCESS OF THE D DIMENSION AT MAXIMUM MATERIAL CONDITION. DIM A B C D F G J K M P R MILLIMETERS MIN MAX 9.80 10.00 3.80 4.00 1.35 1.75 0.35 0.49 0.40 1.25 1.27 BSC 0.19 0.25 0.10 0.25 0_ 7_ 5.80 6.20 0.25 0.50 INCHES MIN MAX 0.386 0.393 0.150 0.157 0.054 0.068 0.014 0.019 0.016 0.049 0.050 BSC 0.008 0.009 0.004 0.009 0_ 7_ 0.229 0.244 0.010 0.019 -B- 1 8 P 8 PL 0.25 (0.010) M B S G F K C -T- SEATING PLANE R X 45 _ M D 16 PL M J 0.25 (0.010) TB S A S http://onsemi.com 11 TL494, NCV494 SWITCHMODE is a trademark of Semiconductor Components Industries, LLC. ON Semiconductor and are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. "Typical" parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including "Typicals" must be validated for each customer application by customer's technical experts. SCILLC does not convey any license under its patent rights nor the rights of others. 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