TL494, NCV494 SWITCHMODE Pulse Width Modulation Control Circuit

Transcription

1 SWITCHMODE Pulse Width Modulation Control Circuit The TL494 is a fixed frequency, pulse width modulation control circuit designed primarily for SWITCHMODE power supply control. Features Complete Pulse Width Modulation Control Circuitry OnChip Oscillator with Master or Slave Operation OnChip Error Amplifiers OnChip 5.0 V Reference Adjustable Deadtime Control Uncommitted Transistors Rated to 0 ma Source or Sink Control for PushPull or SingleEnded Operation Undervoltage Lockout NCV Prefix for Automotive and Other Applications Requiring Site and Control Changes PbFree Packages are Available* MAXIMUM RATINGS (Full operating ambient temperature range applies, unless otherwise noted.) Rating Symbol Value Unit Power Supply Voltage V CC 4 V Collector Voltage V C, V C 4 V Collector Current (Each transistor) (Note ) I C, I C 0 ma Amplifier Input Voltage Range V IR 0.3 to 4 V Power T A 45 C P D 000 mw Thermal Resistance, JunctiontoAmbient R JA 80 C/W Operating Junction Temperature T J 5 C Storage Temperature Range T stg 55 to 5 C Operating Ambient Temperature Range TL494B TL494C TL494I NCV494B T A 40 to 5 0 to to to 5 C Derating Ambient Temperature T A 45 C Maximum ratings are those values beyond which device damage can occur. Maximum ratings applied to the device are individual stress limit values (not normal operating conditions) and are not valid simultaneously. If these limits are exceeded, device functional operation is not implied, damage may occur and reliability may be affected.. Maximum thermal limits must be observed. x A WL YY, Y WW, W G SOIC6 D SUFFIX CASE 75B PDIP6 N SUFFIX CASE MARKING DIAGRAMS TL494xDG AWLYWW = B, C or I = Assembly Location = Wafer Lot = Year = Work Week = PbFree Package *This marking diagram also applies to NCV494. Noninv Input Inv Input R T Ground C Compen/PWN Comp Input 3 Deadtime Control 4 C T 5 PIN CONNECTIONS Error Amp V CC 5.0 V REF (Top View) 6 Error Amp 6 5 Noninv Input Inv Input 4 0. V 3 Contro l V CC Oscillator 6 C E E * TL494xN AWLYYWWG *For additional information on our PbFree strategy and soldering details, please download the ON Semiconductor Soldering and Mounting Techniques Reference Manual, SOLDERRM/D. ORDERING INFORMATION See detailed ordering and shipping information in the package dimensions section on page 4 of this data sheet. Semiconductor Components Industries, LLC, 005 June, 005 Rev. 6 Publication Order Number: TL494/D

2 RECOMMENDED OPERATING CONDITIONS Characteristics Symbol Min Typ Max Unit Power Supply Voltage V CC V Collector Voltage V C, V C V Collector Current (Each transistor) I C, I C 00 ma Amplified Input Voltage V in 0.3 V CC.0 V Current Into Feedback Terminal l fb 0.3 ma Reference Current l ref 0 ma Timing Resistor R T k Timing Capacitor C T F Oscillator Frequency f osc khz ELECTRICAL CHARACTERISTICS (V CC = 5 V, C T = 0.0 F, R T = k, unless otherwise noted.) For typical values T A = 5 C, for min/max values T A is the operating ambient temperature range that applies, unless otherwise noted. Characteristics Symbol Min Typ Max Unit REFERENCE SECTION Reference Voltage (I O =.0 ma) V Line Regulation (V CC = 7.0 V to 40 V) Reg line.0 5 mv Load Regulation (I O =.0 ma to 0 ma) Reg load mv Short Circuit Current ( = 0 V) I SC ma OUTPUT SECTION Collector OffState Current (V CC = 40 V, V CE = 40 V) Emitter OffState Current V CC = 40 V, V C = 40 V, V E = 0 V) I C(off).0 00 A I E(off) 00 A CollectorEmitter Saturation Voltage (Note ) CommonEmitter (V E = 0 V, I C = 00 ma) EmitterFollower (V C = 5 V, I E = 00 ma) V sat(c) V sat(e) V Control Pin Current Low State (V OC 0.4 V) High State (V OC = ) I OCL I OCH A ma Voltage Rise Time CommonEmitter (See Figure ) EmitterFollower (See Figure 3) t r ns Voltage Fall Time CommonEmitter (See Figure ) EmitterFollower (See Figure 3) t f ns. Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient temperature as possible.

3 ELECTRICAL CHARACTERISTICS (V CC = 5 V, C T = 0.0 F, R T = k, unless otherwise noted.) For typical values T A = 5 C, for min/max values T A is the operating ambient temperature range that applies, unless otherwise noted. Characteristics Symbol Min Typ Max Unit ERROR AMPLIFIER SECTION Input Offset Voltage (V O (Pin 3) =.5 V) V IO.0 0 mv Input Offset Current (V O (Pin 3) =.5 V) I IO 5.0 na Input Bias Current (V O (Pin 3) =.5 V) I IB 0..0 A Input Common Mode Voltage Range (V CC = 40 V, T A = 5 C) V ICR 0.3 to V CC.0 V Open Loop Voltage Gain ( V O = 3.0 V, V O = 0.5 V to 3.5 V, R L =.0 k ) A VOL db UnityGain Crossover Frequency (V O = 0.5 V to 3.5 V, R L =.0 k ) f C 3 khz Phase Margin at UnityGain (V O = 0.5 V to 3.5 V, R L =.0 k ) m 65 deg. Common Mode Rejection Ratio (V CC = 40 V) CMRR db Power Supply Rejection Ratio ( V CC = 33 V, V O =.5 V, R L =.0 k ) PSRR 00 db Sink Current (V O (Pin 3) = 0.7 V) I O ma Source Current (V O (Pin 3) = 3.5 V) I O ma PWM COMPARATOR SECTION (Test Circuit Figure ) Input Threshold Voltage (Zero Duty Cycle) V TH V Input Sink Current (V (Pin 3) = 0.7 V) I I ma DEADTIME CONTROL SECTION (Test Circuit Figure ) Input Bias Current (Pin 4) (V Pin 4 = 0 V to 5.5 V) I IB (DT).0 0 A Maximum Duty Cycle, Each, PushPull Mode (V Pin 4 = 0 V, C T = 0.0 F, R T = k ) (V Pin 4 = 0 V, C T = 0.00 F, R T = 30 k ) Input Threshold Voltage (Pin 4) (Zero Duty Cycle) (Maximum Duty Cycle) DC max 45 OSCILLATOR SECTION Frequency (C T = 0.00 F, R T = 30 k ) f osc 40 khz Standard Deviation of Frequency* (C T = 0.00 F, R T = 30 k ) f osc 3.0 % Frequency Change with Voltage (V CC = 7.0 V to 40 V, T A = 5 C) f osc ( V) 0. % Frequency Change with Temperature ( T A = T low to T high ) (C T = 0.0 F, R T = k ) V th f osc ( T) % UNDERVOLTAGE LOCKOUT SECTION TurnOn Threshold (V CC increasing, I ref =.0 ma) V th V % V TOTAL DEVICE Standby Supply Current (Pin 6 at, All other inputs and outputs open) (V CC = 5 V) (V CC = 40 V) I CC ma Average Supply Current (C T = 0.0 F, R T = k, V (Pin 4) =.0 V) (V CC = 5 V) (See Figure ) 7.0 ma * Standard deviation is a measure of the statistical distribution about the mean as derived from the formula, N (X n X) n = N 3

4 ORDERING INFORMATION Device Package Shipping TL494BD SOIC6 48 Units / Rail TL494BDG SOIC6 (PbFree) 48 Units / Rail TL494BDR SOIC6 0 Tape & Reel TL494BDRG SOIC6 (PbFree) 0 Tape & Reel TL494CD SOIC6 48 Units / Rail TL494CDG SOIC6 (PbFree) 48 Units / Rail TL494CDR SOIC6 0 Tape & Reel TL494CDRG SOIC6 (PbFree) 0 Tape & Reel TL494CN PDIP6 5 Units / Rail TL494CNG PDIP6 (PbFree) 5 Units / Rail TL494IN PDIP6 5 Units / Rail TL494ING PDIP6 (PbFree) 5 Units / Rail NCV494BDR* SOIC6 0 Tape & Reel NCV494BDRG* SOIC6 (PbFree) 0 Tape & Reel For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specifications Brochure, BRD80/D. *NCV494: T low = 40 C, T high = 5 C. Guaranteed by design. NCV prefix is for automotive and other applications requiring site and change control. 4

5 Control 3 V CC 6 R T C T 5 4 Deadtime Control Oscillator 0.V 0.7V 0.7mA Deadtime Comparator PWM Comparator D Ck UV Lockout Flip Flop 3.5V 4.9V Reference Regulator V CC Gnd Error Amp Feedback PWM Comparator Input Error Amp Ref. This device contains 46 active transistors. Figure. Representative Block Diagram Capacitor C T Feedback/PWM Comp. Deadtime Control FlipFlop Clock Input FlipFlop FlipFlop Emitter Emitter Control Figure. Timing Diagram 5

6 APPLICATIONS INFORMATION Description The TL494 is a fixedfrequency pulse width modulation control circuit, incorporating the primary building blocks required for the control of a switching power supply. (See Figure.) An internallinear sawtooth oscillator is frequency programmable by two external components, R T and C T. The approximate oscillator frequency is determined by: f osc. R T C T For more information refer to Figure 3. pulse width modulation is accomplished by comparison of the positive sawtooth waveform across capacitor C T to either of two control signals. The NOR gates, which drive output transistors and, are enabled only when the flipflop clockinput 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 controlsignal amplitude causes a corresponding linear decrease of output pulse width. (Refer to the Timing Diagram shown in Figure.) 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 0 mv input offset which limits the minimum output deadtime to approximately the first 4% of the sawtoothcycle 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 deadtimecontrol input to a fixed voltage, ranging between 0 V to 3.3 V. Input/ Controls Functional Table Function f out f osc = Grounded Singleended Pushpull Operation 0.5 The pulse width modulator comparator provides a means for the error amplifiers to adjust the output pulse width from the maximum percent ontime, 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 (V CC V), and may be used to sense powersupply output voltage and current. The erroramplifier outputs are active high and are ORed together at the noninverting input of the pulsewidth modulator comparator. With this configuration, the amplifier that demands minimum output on time, dominates control of the loop. When capacitor C T is discharged, a positive pulse is generated on the output of the deadtime comparator, which clocks the pulsesteering flipflop and inhibits the output transistors, and. With the outputcontrol connected to the reference line, the pulsesteering flipflop directs the modulated pulses to each of the two output transistors alternately for pushpull operation. The output frequency is equal to half that of the oscillator. drive can also be taken from or, when singleended operation with a maximum ontime of less than % is required. This is desirable when the output transformer has a ringback winding with a catch diode used for snubbing. When higher outputdrive currents are required for singleended operation, and may be connected in parallel, and the outputmode pin must be tied to ground to disable the flipflop. The output frequency will now be equal to that of the oscillator. The TL494 has an internal 5.0 erence capable of sourcing up to 0 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 mv over an operating temperature range of 0 to 70 C. f osc, OSCILLATOR FREUENCY (Hz) 0 k 00 k 0 k C T = 0.00 F 0.0 F V CC = 5 V 0. F.0 k 0.0 k.0 k 5.0 k 0 k 0 k k 00 k 00 k 0 k.0 M R T, TIMING RESISTANCE ( ) Figure 3. Oscillator Frequency versus Timing Resistance 6

7 I TL494, NCV494 VOL, OPEN LOOP VOLTAGE GAIN (db) A A VOL V CC = 5 V V O = 3.0 V R L =.0 k k 0 k 00 k 80.0 M f, FREUENCY (Hz) 0 0 Figure 4. Open Loop Voltage Gain and Phase versus Frequency φ , EXCESS PHASE (DEGREES) φ % DT, PERCENT DEADTIME (EACH OUTPUT) C T = 0.00 F F k.0 k 0 k 00 k 0 k f osc, OSCILLATOR FREUENCY (Hz) Figure 5. Percent Deadtime versus Oscillator Frequency % DC, PERCENT DUTY CYCLE (EACH OUTPUT) V CC = 5 V V OC = М. C T = 0.0 F М. R T = 0 k М. C T = 0.00 F М. R T = 30 k V DT, DEADTIME CONTROL VOLTAGE (IV) Figure 6. Percent Duty Cycle versus Deadtime Control Voltage V CE(sat), SATURATION VOLTAGE (V) I E, EMITTER CURRENT (ma) Figure 7. EmitterFollower Configuration Saturation Voltage versus Emitter Current.0 0 VCE(sat), SATURATION VOLTAGE (V) CC, SUPPLY CURRENT (ma) I C, COLLECTOR CURRENT (ma) V CC, SUPPLY VOLTAGE (V) Figure 8. CommonEmitter Configuration Saturation Voltage versus Collector Current Figure 9. Standby Supply Current versus Supply Voltage 7

8 V in Error Amplifier Under Test Other Error Amplifier Feedback Terminal (Pin 3) Test Inputs k V CC = 5V V CC Deadtime Feedback R T C T () () Error () () Control Gnd C E C E Ref Out W W Figure 0. ErrorAmplifier Characteristics Figure. Deadtime and Feedback Control Circuit 5V Each Transistor C E R L 68 C L 5pF V C Each Transistor C E R L 68 5V C L 5pF V EE 90% V CC 0% 90% 0% Gnd 0% 90% 90% V EE 0% t r t f t r t f Figure. CommonEmitter Configuration Test Circuit and Waveform Figure 3. EmitterFollower Configuration Test Circuit and Waveform 8

9 R R V O To Voltage of System Error Amp Positive Voltage V O = М 3 R R Error Amp Negative Voltage R V O = R R R V O To Voltage of System Figure 4. ErrorAmplifier Sensing Techniques Control 4 D T R 30k 6 R T 5 C T 0.00 R 4 D T C S R S Max. % on Time, each output R R Figure 5. Deadtime Control Circuit Figure 6. SoftStart Circuit Control SingleEnded C E C C.0 ma to 0 ma.4 V V OC Control PushPull C E C.0 ma to ma 0 V OC 0.4 V E E E.0 ma to ma Figure 7. Connections for SingleEnded and PushPull Configurations 9

10 R T C T 6 5 R T C T Master R S V in > 40V V Z = 39V N975A V CC 5.0V Ref 6 5 R T C T Slave (Additional Circuits) 70 Gnd 7 Figure 8. Slaving Two or More Control Circuits Figure 9. Operation with V in > 40 V Using External Zener V in = 8.0V to 0V V CC 47 T N4934 V O = 8 V I O = 0. A M 33k Comp TL494 6 OC V REF DT C T R T Gnd E E k 0 4.7k 0k k C C 8 47 Tip 3 Tip 3 5V L N V 4.7k.0 k 35V All capacitors in F Figure 0. Pulse Width Modulated PushPull Converter Test Conditions Results Line Regulation V in = 0 V to 40 V 4 mv 0.8% Load Regulation V in = 8 V, I O =.0 ma to.0 A 3.0 mv 0.06% Ripple V in = 8 V, I O =.0 A 65 mv pp P.A.R.D. Short Circuit Current V in = 8 V, R L = 0..6 A Efficiency V in = 8 V, I O =.0 A 7% L A T Primary: 0T C.T. #8 AWG T Secondary: OT C.T. #36 AWG T Core: Ferroxcube 408PL003CB 0

11 V in = 0V to 40V Tip A V O = 5.0 V I O =.0 A 47 47k V 8 V CC C C TL494 C T R T D.T. O.C. Gnd E E k Comp M 5.k 5.k 5.k MR8 0 0V 0V 0. Figure. Pulse Width Modulated StepDown Converter Test Conditions Results Line Regulation V in = 8.0 V to 40 V 3.0 mv 0.0% Load Regulation V in =.6 V, I O = 0. ma to 00 ma 5.0 mv 0.0% Ripple V in =.6 V, I O = 00 ma 40 mv pp P.A.R.D. Short Circuit Current V in =.6 V, R L = 0. ma Efficiency V in =.6 V, I O = 00 ma 7%

12 PACKAGE DIMENSIONS SOIC6 D SUFFIX CASE 75B05 ISSUE J A B P 8 PL 0.5 (0.00) M B S NOTES:. DIMENSIONING AND TOLERANCING PER ANSI Y4.5M, 98.. CONTROLLING DIMENSION: MILLIMETER. 3. DIMENSIONS A AND B DO NOT INCLUDE MOLD PROTRUSION. 4. MAXIMUM MOLD PROTRUSION 0.5 (0.006) PER SIDE. 5. DIMENSION D DOES NOT INCLUDE DAMBAR PROTRUSION. ALLOWABLE DAMBAR PROTRUSION SHALL BE 0.7 (0.005) TOTAL IN EXCESS OF THE D DIMENSION AT MAXIMUM MATERIAL CONDITION. T SEATING PLANE G K C D 6 PL 0.5 (0.00) M T B S A S M R X 45 J F MILLIMETERS INCHES DIM MIN MAX MIN MAX A B C D F G.7 BSC 0.0 BSC J K M P R

13 PACKAGE DIMENSIONS PDIP6 N SUFFIX CASE ISSUE T 6 A 8 9 B NOTES:. DIMENSIONING AND TOLERANCING PER ANSI Y4.5M, 98.. 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. H G F D 6 PL S C K 0.5 (0.00) M T SEATING T PLANE A M J L M INCHES MILLIMETERS DIM MIN MAX MIN MAX A B C D F G 0.00 BSC.54 BSC H 0.0 BSC.7 BSC J K L M S

14 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. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner. PUBLICATION ORDERING INFORMATION LITERATURE FULFILLMENT: Literature Distribution Center for ON Semiconductor P.O. Box 63, Phoenix, Arizona 883 USA Phone: or Toll Free USA/Canada Fax: or Toll Free USA/Canada orderlit@onsemi.com N. American Technical Support: Toll Free USA/Canada Japan: ON Semiconductor, Japan Customer Focus Center 9 Kamimeguro, Meguroku, Tokyo, Japan Phone: ON Semiconductor Website: Order Literature: For additional information, please contact your local Sales Representative. TL494/D