Order this document by TL494/D The TL494 is a fixed frequency, pulse width modulation control circuit designed primarily for SWITCHMODE power supply control. * * * * * * * * SWITCHMODE PULSE WIDTH MODULATION CONTROL CIRCUIT Complete Pulse Width Modulation Control Circuitry SEMICONDUCTOR TECHNICAL DATA On-Chip Oscillator with Master or Slave Operation On-Chip Error Amplifiers On-Chip 5.0 V Reference Adjustable Deadtime Control D SUFFIX PLASTIC PACKAGE CASE 751B (SO-16) Uncommitted Output Transistors Rated to 500 mA Source or Sink Output Control for Push-Pull or Single-Ended Operation Undervoltage Lockout N SUFFIX PLASTIC PACKAGE CASE 648 PIN CONNECTIONS Noninv Input 1 MAXIMUM RATINGS (Full operating ambient temperature range applies, Inv Input 2 unless otherwise noted.) Rating Symbol TL494C TL494I Unit Power Supply Voltage VCC 42 V Collector Output Voltage VC1, VC2 42 V Collector Output Current (Each transistor) (Note 1) IC1, IC2 500 Amplifier Input Voltage Range VIR -0.3 to +42 V Power Dissipation @ TA 45C PD 1000 mW RJA 80 C/W TJ 125 C Tstg -55 to +125 C Compen/PWN Comp Input 3 Deadtime Control 4 + Error 1 Amp - + 2 Error Amp - VCC 5.0 V REF 0.1 V Operating Junction Temperature Storage Temperature Range 14 Vref 12 VCC CT 5 Oscillator mA RT 6 11 C2 Q2 Operating Ambient Temperature Range TL494C TL494I TA Derating Ambient Temperature TA NOTE: Inv 15 Input Output 13 Control Ground 7 Thermal Resistance, Junction-to-Ambient Noninv 16 Input 45 TL494CD TL494CN TL494IN Operating Temperature Range TA = 0 to +70C TA = - 25 to +85C Motorola, Inc. 1996 MOTOROLA ANALOG IC DEVICE DATA 9 E1 ORDERING INFORMATION Device C Q1 (Top View) C 0 to +70 - 25 to +85 1. Maximum thermal limits must be observed. C1 8 10 E2 Package SO-16 Plastic Plastic Rev 1 1 TL494 RECOMMENDED OPERATING CONDITIONS Characteristics Symbol Min Typ Max Unit VCC 7.0 15 40 V VC1, VC2 - 30 40 V IC1, IC2 - - 200 mA Amplified Input Voltage Vin -0.3 - VCC - 2.0 V Current Into Feedback Terminal lfb - - 0.3 mA Reference Output Current lref - - 10 mA Timing Resistor RT 1.8 30 500 k Timing Capacitor CT 0.0047 0.001 10 F Oscillator Frequency fosc 1.0 40 200 kHz Power Supply Voltage Collector Output Voltage Collector Output Current (Each transistor) ELECTRICAL CHARACTERISTICS (VCC = 15 V, CT = 0.01 F, RT = 12 k, 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 Symbol Min Typ Max Unit Vref 4.75 5.0 5.25 V Line Regulation (VCC = 7.0 V to 40 V) Regline - 2.0 25 mV Load Regulation (IO = 1.0 mA to 10 mA) Regload - 3.0 15 mV Short Circuit Output Current (Vref = 0 V) ISC 15 35 75 mA Collector Off-State Current (VCC = 40 V, VCE = 40 V) IC(off) - 2.0 100 A Emitter Off-State Current VCC = 40 V, VC = 40 V, VE = 0 V) IE(off) - - -100 A Vsat(C) Vsat(E) - - 1.1 1.5 1.3 2.5 IOCL IOCH - - 10 0.2 - 3.5 - - 100 100 200 200 - - 25 40 100 100 REFERENCE SECTION Reference Voltage (IO = 1.0 mA) OUTPUT SECTION 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 0.4 V) High State (VOC = Vref) V Output Voltage Rise Time Common-Emitter (See Figure 12) Emitter-Follower (See Figure 13) tr Output Voltage Fall Time Common-Emitter (See Figure 12) Emitter-Follower (See Figure 13) tf A mA ns ns NOTE: 2. Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient temperature as possible. 2 MOTOROLA ANALOG IC DEVICE DATA TL494 ELECTRICAL CHARACTERISTICS (VCC = 15 V, CT = 0.01 F, RT = 12 k, 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 Symbol Min Typ Max Unit Input Offset Voltage (VO (Pin 3) = 2.5 V) VIO - 2.0 10 mV Input Offset Current (VO (Pin 3) = 2.5 V) IIO - 5.0 250 nA Input Bias Current (VO (Pin 3) = 2.5 V) IIB - -0.1 -1.0 A ERROR AMPLIFIER SECTION Input Common Mode Voltage Range (VCC = 40 V, TA = 25C) VICR -0.3 to VCC-2.0 V Open Loop Voltage Gain (VO = 3.0 V, VO = 0.5 V to 3.5 V, RL = 2.0 k) AVOL 70 95 - Unity-Gain Crossover Frequency (VO = 0.5 V to 3.5 V, RL = 2.0 k) fC- - 350 - kHz Phase Margin at Unity-Gain (VO = 0.5 V to 3.5 V, RL = 2.0 k) m - 65 - deg. Common Mode Rejection Ratio (VCC = 40 V) CMRR 65 90 - dB Power Supply Rejection Ratio (VCC = 33 V, VO = 2.5 V, RL = 2.0 k) PSRR - 100 - dB Output Sink Current (VO (Pin 3) = 0.7 V) IO- 0.3 0.7 - mA Output Source Current (VO (Pin 3) = 3.5 V) IO+ 2.0 -4.0 - mA VTH - 2.5 4.5 V II- 0.3 0.7 - mA Input Bias Current (Pin 4) (VPin 4 = 0 V to 5.25 V) IIB (DT) - -2.0 -10 A Maximum Duty Cycle, Each Output, Push-Pull Mode (VPin 4 = 0 V, CT = 0.01 F, RT = 12 k) (VPin 4 = 0 V, CT = 0.001 F, RT = 30 k) DCmax 45 - 48 45 50 50 - 0 2.8 - 3.3 - dB 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 Threshold Voltage (Pin 4) (Zero Duty Cycle) (Maximum Duty Cycle) % Vth V OSCILLATOR SECTION Frequency (CT = 0.001 F, RT = 30 k) fosc - 40 - kHz fosc - 3.0 - % Frequency Change with Voltage (VCC = 7.0 V to 40 V, TA = 25C) fosc (V) - 0.1 - % Frequency Change with Temperature (TA = Tlow to Thigh) (CT = 0.01 F, RT = 12 k) fosc (T) - - 12 % Vth 5.5 6.43 7.0 V - - 5.5 7.0 10 15 - 7.0 - Standard Deviation of Frequency* (CT = 0.001 F, RT = 30 k) 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) ICC Average Supply Current (CT = 0.01 F, RT = 12 k, V(Pin 4) = 2.0 V) (VCC = 15 V) (See Figure 12) * Standard deviation is a measure of the statistical distribution about the mean as derived from the formula, MOTOROLA ANALOG IC DEVICE DATA mA mA N (Xn - X)2 n=1 N-1 3 TL494 Figure 1. Representative Block Diagram VCC Output Control 13 8 6 D Oscillator RT CT 5 - 0.12V Q Q1 Q Q2 11 Deadtime Comparator Ck + 4 Deadtime Control 9 Flip- Flop 10 0.7V - + 1 2 - 1 2 Error Amp 1 + PWM Comparator 0.7mA 12 - + 3 UV Lockout + - 3.5V 15 Feedback PWM Comparator Input Reference Regulator - + VCC 4.9V 16 14 Error Amp 2 Ref. Output 7 Gnd This device contains 46 active transistors. Figure 2. Timing 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 4 MOTOROLA ANALOG IC DEVICE DATA TL494 APPLICATIONS INFORMATION fosc 1.1 RT * CT For more information refer to Figure 3. 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 fout fosc = Input/Output Controls Output Function Grounded Single-ended PWM @ Q1 and Q2 1.0 Push-pull Operation 0.5 @ Vref 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 common mode input range from -0.3 V to (VCC - 2V), and MOTOROLA ANALOG IC DEVICE DATA 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. Figure 3. Oscillator Frequency versus Timing Resistance fosc , OSCILLATOR FREQUENCY (Hz) 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: 500 k 100 k 10 k 1.0 k 500 1.0 k 2.0 k 5.0 k CT = 0.001 F VCC = 15 V 0.01 F 0.1 F 10 k 20 k 50 k 100 k 200 k RT, TIMING RESISTANCE () 500 k 1.0 M 5 TL494 VCC = 15 V VO = 3.0 V RL = 2.0 k 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 % DT, PERCENT DEADTIME (EACH OUTPUT) A VOL , OPEN LOOP VOLTAGE GAIN (dB) 120 110 100 90 80 70 60 50 40 30 20 10 0 1.0 Figure 5. Percent Deadtime versus Oscillator Frequency , EXCESS PHASE (DEGREES) Figure 4. Open Loop Voltage Gain and Phase versus Frequency 20 18 16 CT = 0.001 F 14 12 10 8.0 6.0 0.001 F 4.0 2.0 0 500 k 1.0 k 50 1 40 V CE(sat) , SATURATION VOLTAGE (V) 1.9 VCC = 15 V VOC = Vref 1. CT = 0.01 F 2. RT = 10 k 2. CT = 0.001 F 2. RT = 30 k 2 30 20 10 0 0 1.0 2.0 3.0 1.8 1.7 1.6 1.5 1.4 1.3 1.2 1.1 3.5 VDT, DEADTIME CONTROL VOLTAGE (IV) 0 100 200 300 IE, EMITTER CURRENT (mA) Figure 8. Common-Emitter Configuration Output Saturation Voltage versus Collector Current Figure 9. Standby Supply Current versus Supply Voltage 2.0 10 1.8 9.0 I CC , SUPPLY CURRENT (mA) % DC, PERCENT DUTY CYCLE (EACH OUTPUT) VCE(sat), SATURATION VOLTAGE (V) 500 k Figure 7. Emitter-Follower Configuration Output Saturation Voltage versus Emitter Current Figure 6. Percent Duty Cycle versus Deadtime Control Voltage 1.6 1.4 1.2 1.0 0.8 0.6 400 8.0 7.0 6.0 5.0 4.0 3.0 2.0 1.0 0 0.4 0 6 10 k 100 k fosc, OSCILLATOR FREQUENCY (Hz) 100 200 300 IC, COLLECTOR CURRENT (mA) 400 0 5.0 10 15 20 25 30 35 40 VCC, SUPPLY VOLTAGE (V) MOTOROLA ANALOG IC DEVICE DATA TL494 Figure 10. Error-Amplifier Characteristics Figure 11. Deadtime and Feedback Control Circuit VCC = 15V Error Amplifier Under Test + Vin - Feedback Terminal (Pin 3) VCC Deadtime Test Inputs Feedback RT CT (+) (-) Error (+) (-) Output Control Gnd + - Vref Other Error Amplifier 50k Figure 12. Common-Emitter Configuration Test Circuit and Waveform 150 2W 150 2W C1 E1 Output 1 C2 E2 Output 2 Ref Out Figure 13. Emitter-Follower Configuration Test Circuit and Waveform 15V 15V RL 68 VC C Each Output Transistor C Each Output Transistor CL 15pF Q Q VEE E RL 68 E 90% VEE 90% 90% 90% CL 15pF VCC 10% 10% tr tf MOTOROLA ANALOG IC DEVICE DATA Gnd 10% 10% tr tf 7 TL494 Figure 14. Error-Amplifier Sensing Techniques Vref VO To Output Voltage of System 1 Vref + Error Amp - R2 2 3 VO = Vref Positive Output Voltage VO = Vref 1+ R1 Negative Output Voltage 2 R2 1 + Error Amp - R1 R1 R2 VO To Output Voltage of System R1 R2 Figure 15. Deadtime Control Circuit Figure 16. Soft-Start Circuit Output Control R1 Vref Output Q DT RT 4 Q CT 5 6 CS Vref Output 4 DT R2 RS 0.001 30k Max. % on Time, each output 45 - 80 1 + R1 R2 Figure 17. Output Connections for Single-Ended and Push-Pull Configurations C1 C1 QC Q1 2.4 V VOC Vref Q1 E1 Output Control 1.0 mA to 500 mA Single-Ended 8 Q2 E2 1.0 mA to 250 mA Output Control Push-Pull C2 C2 0 VOC 0.4 V E1 Q2 QE E2 1.0 mA to 250 mA MOTOROLA ANALOG IC DEVICE DATA TL494 Figure 18. Slaving Two or More Control Circuits Figure 19. Operation with Vin > 40 V Using External Zener Vref VCC RS 6 5 RT 12 Vin > 40V RT 1N975A Master VZ = 39V CT CT 5.0V Ref 270 Vref Gnd 7 6 RT 5 Slave (Additional Circuits) CT Figure 20. Pulse Width Modulated Push-Pull Converter +Vin = 8.0V to 20V 12 1 2 1M 33k 3 0.01 0.01 15 16 47 VCC + C1 - - C2 OC VREF DT CT RT Gnd E1 E2 13 14 4 5 6 7 9 10 + 4.7k 4.7k Tip 32 TL494 Comp + 8 T1 10 10k 11 Tip 32 +VO = 28 V IO = 0.2 A 1N4934 22 k L1 + 50 35V 4.7k + 50 25V 47 1.0 1N4934 + 50 35V 240 15k 0.001 All capacitors in F Test Conditions Results Line Regulation Vin = 10 V to 40 V 14 mV 0.28% Load Regulation Vin = 28 V, IO = 1.0 mA to 1.0 A 3.0 mV 0.06% Output Ripple Vin = 28 V, IO = 1.0 A 65 mV pp P.A.R.D. Short Circuit Current Vin = 28 V, RL = 0.1 1.6 A Efficiency Vin = 28 V, IO = 1.0 A 71% MOTOROLA ANALOG IC DEVICE DATA 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 9 TL494 Figure 21. Pulse Width Modulated Step-Down Converter 1.0mH @ 2A +Vin = 10V to 40V +VO = 5.0 V Tip 32A IO = 1.0 A 47 150 12 8 VCC 50 50V 47k 0.1 11 C1 C2 + TL494 CT Comp 3 - 2 + 1 Vref 5 D.T. O.C. Gnd E1 6 4 13 7 9 5.1k 5.1k 14 - 15 16 + RT 1.0M MR850 5.1k 500 10V E2 + + 10 50 10V 150 0.001 47k 0.1 Test 10 Conditions Line Regulation Vin = 8.0 V to 40 V Load Regulation Vin = 12.6 V, IO = 0.2 mA to 200 mA Output Ripple Vin = 12.6 V, IO = 200 mA Short Circuit Current Vin = 12.6 V, RL = 0.1 Efficiency Vin = 12.6 V, IO = 200 mA Results 3.0 mV 0.01% 5.0 mV 0.02% 40 mV pp P.A.R.D. 250 mA 72% MOTOROLA ANALOG IC DEVICE DATA TL494 OUTLINE DIMENSIONS N SUFFIX PLASTIC PACKAGE CASE 648-08 ISSUE R -A- 16 9 1 8 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. B F C DIM A B C D F G H J K L M S L S SEATING PLANE -T- K H G D M J 16 PL 0.25 (0.010) T A M M D SUFFIX PLASTIC PACKAGE CASE 751B-05 (SO-16) ISSUE J -A- 16 1 P 8 PL 0.25 (0.010) 8 M B S G R K F X 45 _ C -T- SEATING PLANE M D 16 PL 0.25 (0.010) M T B S MOTOROLA ANALOG IC DEVICE DATA A S 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 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. 9 -B- 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 J 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 11 TL494 Motorola reserves the right to make changes without further notice to any products herein. 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