FEATURES
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
1IN+
1IN−
FEEDBACK
DTC
CT
RT
GND
C1
2IN+
2IN−
REF
OUTPUT CTRL
V CC
C2
E2
E1
D, DB, N, NS, OR PW PACKAGE
(TOP VIEW)
DESCRIPTION
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
SLVS074E–JANUARY1983–REVISED FEBRUARY2005
•Complete PWM Power-Control Circuitry
•Uncommitted Outputs for200-mA Sink or
Source Current
•Output Control Selects Single-Ended or
Push-Pull Operation
•Internal Circuitry Prohibits Double Pul at
Either Output
•Variable Dead Time Provides Control Over
Total Range
•Internal Regulator Provides a Stable5-V
Reference Supply With5%Tolerance
•Circuit Architecture Allows Easy
Synchronization
The TL494incorporates all the functions required in the construction of a pul-width-modulation(PWM)control circuit on a single chip.Designed primarily for power-supply control,this device offers the flexibility to tailor the power-supply control circuitry to a specific application.
外墙施工合同
The TL494contains two error amplifiers,an on-chip adjustable oscillator,a dead-time control(DTC)comparator, a pul-steering control flip-flop,a5-V,5%-precision regulator,and output-control circuits.
The error amplifiers exhibit a common-mode voltage range from–0.3V to V CC–2V.The dead-time control comparator has a fixed offt that provides approximately5%dead time.The on-chip oscillator can be bypasd by terminating RT to the reference output and providing a sawtooth input to CT,or it can drive the common circuits in synchronous multiple-rail power supplies.
The uncommitted output transistors provide either common-emitter or emitter-follower output capability.The TL494provides for push-pull or single-ended output operation,which can be lected through the output-control function.The architecture of this device prohibits the possibility of either output being puld twice during push-pull operation.
The TL494C is characterized for operation from0°C to70°C.The TL494I is characterized for operation from –40°C to85°C.
AVAILABLE OPTIONS
PACKAGED DEVICES(1)
SHRINK SMALL THIN SHRINK T A SMALL OUTLINE PLASTIC DIP SMALL OUTLINE
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OUTLINE SMALL OUTLINE
(D)(N)(NS)
(DB)(PW) 0°C to70°C TL494CD TL494CN TL494CNS TL494CDB TL494CPW –40°C to85°C TL494ID TL494IN———
(1)The D,DB,NS,and PW packages are available taped and reeled.Add the suffix R to device ,TL494CDR).
Plea be aware that an important notice concerning availability,standard warranty,and u in critical applications of Texas
Instruments miconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.Copyright©1983–2005,Texas Instruments Incorporated Products conform to specifications per the terms of the Texas
Instruments standard warranty.Production processing does not
necessarily include testing of all parameters.
GND
V CC
C1E1
C2E2
FEEDBACK
REF
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
SLVS074E–JANUARY 1983–REVISED FEBRUARY 2005
FUNCTION TABLE
INPUT TO OUTPUT FUNCTION OUTPUT CTRL V I =GND Single-ended or parallel output V I =V ref
Normal push-pull operation
FUNCTIONAL BLOCK DIAGRAM
2
Absolute Maximum Ratings(1) Recommended Operating Conditions PULSE-WIDTH-MODULATION CONTROL CIRCUITS
SLVS074E–JANUARY1983–REVISED FEBRUARY2005
冰柜什么牌子好over operating free-air temperature range(unless otherwi noted)
MIN MAX UNIT
V CC Supply voltage(2)41V
V I Amplifier input voltage V CC+0.3V
V O Collector output voltage41V
I O Collector output current250mA
D package73
DB package82
θJA Package thermal impedance(3)(4)N package67°C/W
NS package64
PW package108 Lead temperature1,6mm(1/16inch)from ca for10conds260°C
T stg Storage temperature range–65150°C (1)Stress beyond tho listed under"absolute maximum ratings"may cau permanent damage to the device.The are stress ratings
only,and functional operation of the device at the or any other conditions beyond tho indicated under"recommended operating conditions"is not implied.Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
(2)All voltages are with respect to the network ground terminal.
(3)Maximum power disipation is a function of T J(max),θJA,and T A.The maximum allowable power dissipation at any allowable ambient
temperatire is P D=(T J(max)–T A)/θJA.Operating at the absolute maximum T J of150°C can affect reliability.
(4)The package thermal impedance is calculated in accordance with JESD51-7.
MIN MAX UNIT
V CC Supply voltage740V
V I Amplifier input voltage–0.3V CC–2V
V O Collector output voltage40V Collector output current(each transistor)200mA
Current into feedback terminal0.3mA
f OSC Oscillator frequency1300kHz
C T Timing capacitor0.4710000nF
R T Timing resistor 1.8500kΩ
TL494C070
T A Operating free-air temperature°C
TL494I–4085
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Electrical Characteristics
Reference Section
Oscillator Section
Error-Amplifier Section
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
SLVS074E–JANUARY 1983–REVISED FEBRUARY 2005
over recommended operating free-air temperature range,V CC =15V,f =10kHz (unless otherwi noted)
今天我TL494C,TL494I PARAMETER
TEST CONDITIONS (1)UNIT MIN TYP (2)MAX Output voltage (REF)I O =1mA 4.75
莫愁路5 5.25V Input regulation V CC =7V to 40V 225mV Output regulation
I O =1mA to 10mA 115mV Output voltage change with temperature ∆T A =MIN to MAX 210
mV/V Short-circuit output current (3)REF =0V
25
mA
(1)For conditions shown as MIN or MAX,u the appropriate value specified under recommended operating conditions.(2)All typical values,except for parameter changes with temperature,are at T A =25°C.(3)
Duration of short circuit should not exceed one cond.
C T =0.01µF,R T =12k Ω(e Figure 1)
TL494C,TL494I PARAMETER
TEST CONDITIONS (1)
UNIT MIN TYP (2)
MAX
Frequency
10kHz Standard deviation of frequency (3)All values of V CC ,C T ,R T ,and T A constant 100Hz/kHz
Frequency change with voltage V CC =7V to 40V,T A =25°C 1
Hz/kHz Frequency change with temperature (4)∆T A =MIN to MAX
10Hz/kHz
(1)For conditions shown as MIN or MAX,u the appropriate value specified under recommended operating conditions.(2)All typical values,except for parameter changes with temperature,are at T A =25°C.
(3)
Standard deviation is a measure of the statistical distribution about the mean as derived from the formula:
(4)
Temperature coefficient of timing capacitor and timing resistor are not taken into account.
See Figure 2
TL494C,TL494I PARAMETER
TEST CONDITIONS
UNIT MIN TYP (1)
MAX Input offt voltage V O (FEEDBACK)=2.5V 210mV Input offt current V O (FEEDBACK)=2.5V 25250nA Input bias current
V O (FEEDBACK)=2.5V 0.2
1
µA –0.3to Common-mode input voltage range V CC =7V to 40V
V V CC –2
Open-loop voltage amplification ∆V O =3V,V O =0.5V to 3.5V,R L =2k Ω70
95dB Unity-gain bandwidth V O =0.5V to 3.5V,R L =2k Ω800kHz Common-mode rejection ratio ∆V O =40V,T A =25°C
6580dB Output sink current (FEEDBACK)V ID =–15mV to –5V,V (FEEDBACK)=0.7V 0.30.7
mA Output source current (FEEDBACK)V ID =15mV to 5V,V (FEEDBACK)=3.5V
–2mA
(1)
All typical values,except for parameter changes with temperature,are at T A =25°C.
4
Electrical Characteristics Output Section
Dead-Time Control Section PWM Comparator Section Total Device
Switching Characteristics PULSE-WIDTH-MODULATION CONTROL CIRCUITS
SLVS074E–JANUARY1983–REVISED FEBRUARY2005
over recommended operating free-air temperature range,V CC=15V,f=10kHz(unless otherwi noted)
PARAMETER TEST CONDITIONS MIN TYP(1)MAX UNIT Collector off-state current V CE=40V,V CC=40V2100µA Emitter off-state current V CC=V C=40V,V E=0–100µA
Common emitter V E=0,I C=200mA 1.1 1.3
Collector-emitter saturation voltage V
Emitter follower V O(C1or C2)=15V,I E=–200mA 1.5 2.5什么是油性皮肤
Output control input current V I=V ref 3.5mA (1)All typical values,except for temperature coefficient,are at T A=25°C.
See Figure1
PARAMETER TEST CONDITIONS MIN TYP(1)MAX UNIT Input bias current(DEAD-TIME CTRL)V I=0to5.25V–2–10µA
V I(DEAD-TIME CTRL)=0,C T=0.01µF,
Maximum duty cycle,each output45%
R T=12kΩ
Zero duty cycle3 3.3
Input threshold voltage(DEAD-TIME CTRL)V
清朝的建立Maximum duty cycle0
(1)All typical values,except for temperature coefficient,are at T A=25°C.
See Figure1
PARAMETER TEST CONDITIONS MIN TYP(1)MAX UNIT Input threshold voltage(FEEDBACK)Zero duty cyle4 4.5V Input sink current(FEEDBACK)V(FEEDBACK)=0.7V0.30.7mA (1)All typical values,except for temperature coefficient,are at T A=25°C.
PARAMETER TEST CONDITIONS MIN TYP(1)MAX UNIT
V CC=15V610
R T=V ref,
Standby supply current mA
All other inputs and outputs open V
CC
=40V915
Average supply current V I(DEAD-TIME CTRL)=2V,See Figure17.5mA (1)All typical values,except for temperature coefficient,are at T A=25°C.
T
A
=25°C
PARAMETER TEST CONDITIONS MIN TYP(1)MAX UNIT Ri time100200ns
Common-emitter configuration,See Figure3
Fall time25100ns
Ri time100200ns
Emitter-follower configuration,See Figure4
Fall time40100ns
(1)All typical values,except for temperature coefficient,are at T A=25°C.
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