Texas Instruments TL494 Datasheet
TL494
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
SLVS074D – JANUARY 1983 – REVISED MAY 2002
D
Complete PWM Power-Control Circuitry
D
Uncommitted Outputs for 200-mA Sink or
Source Current
D
Output Control Selects Single-Ended or
Push-Pull Operation
D
Internal Circuitry Prohibits Double Pulse at
Either Output
D
Variable Dead Time Provides Control Over
Total Range
D
Internal Regulator Provides a Stable 5-V
D, DB, N, NS, OR PW PACKAGE
FEEDBACK
1IN+
1IN–
DTC
CT
RT
GND
C1
(TOP VIEW)
16
1
15
2
14
3
13
4
12
5
11
6
10
7
8
9
2IN+
2IN–
REF
OUTPUT CTRL
V
CC
C2
E2
E1
Reference Supply With 5% Tolerance
D
Circuit Architecture Allows Easy
Synchronization
description
The TL494 incorporates all the functions required in the construction of a pulse-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.
The TL494 contains two error amplifiers, an on-chip adjustable oscillator, a dead-time control (DTC)
comparator, a pulse-steering control flip-flop, a 5-V, 5%-precision regulator, and output-control circuits.
The error amplifiers exhibit a common-mode voltage range from –0.3 V to V
comparator has a fixed offset that provides approximately 5% dead time. The on-chip oscillator can be bypassed
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.
– 2 V. The dead-time control
CC
The uncommitted output transistors provide either common-emitter or emitter-follower output capability. The
TL494 provides for push-pull or single-ended output operation, which can be selected through the
output-control function. The architecture of this device prohibits the possibility of either output being pulsed twice
during push-pull operation.
The TL494C is characterized for operation from 0°C to 70°C. The TL494I is characterized for operation from
–40°C to 85°C.
AVAILABLE OPTIONS
PACKAGED DEVICES
T
A
0°C to 70°C TL494CD TL494CN TL494CNS TL494CDB TL494CPW
–40°C to 85°C TL494ID TL494IN — — —
The D, DB, NS, and PW packages are available taped and reeled. Add the suffix R to device type (e.g.,
TL494CDR).
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
SMALL
OUTLINE
(D)
PLASTIC
DIP
(N)
SMALL
OUTLINE
(NS)
SHRINK
SMALL
OUTLINE
(DB)
THIN SHRINK
SMALL
OUTLINE
(PW)
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
Copyright 2002, Texas Instruments Incorporated
1
TL494
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
SLVS074D – JANUARY 1983 – REVISED MAY 2002
FUNCTION TABLE
functional block diagram
6
RT
5
CT
≈ 0.1 V
4
DTC
Error Amplifier 1
+
–
1IN+
1IN–
1
2
INPUT TO
OUTPUT CTRL
VI = GND Single-ended or parallel output
VI = V
ref
Oscillator
Dead-Time Control
Comparator
PWM
Comparator
OUTPUT FUNCTION
Normal push-pull operation
(see Function Table)
1D
C1
Pulse-Steering
Flip-Flop
OUTPUT CTRL
13
Q1
Q2
11
10
8
C1
9
E1
C2
E2
2IN+
2IN–
FEEDBACK
16
15
3
Error Amplifier 2
+
–
0.7 mA
Reference
Regulator
12
14
V
CC
REF
7
GND
2
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
TAO erating free-air tem erature
°C
TL494
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
SLVS074D – JANUARY 1983 – REVISED MAY 2002
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
Supply voltage, V
Amplifier input voltage, V
Collector output voltage, V
Collector output current, I
Package thermal impedance, θ
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds 260°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storage temperature range, T
†
Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and
functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
NOTES: 1. All voltage values are with respect to the network ground terminal.
2. Maximum power dissipation is a function of TJ(max),
ambient temperature is PD = (TJ(max) – TA)/
3. The package thermal impedance is calculated in accordance with JESD 51-7.
(see Note 1) 41 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CC
V
I
41 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
O
250 mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
O
(see Note 2 and 3): D package 73°C/W. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
JA
DB package 82°C/W. . . . . . . . . . . . . . . . . . . . . . . . . . . .
N package 67°C/W. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
NS package 64°C/W. . . . . . . . . . . . . . . . . . . . . . . . . . . .
PW package 108°C/W. . . . . . . . . . . . . . . . . . . . . . . . . .
–65°C to 150°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
stg
θ
, and TA. The maximum allowable power dissipation at any allowable
θ
JA
JA
. Operating at the absolute maximum TJ of 150°C can affect reliability.
CC
+ 0.3 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
recommended operating conditions
MIN MAX UNIT
V
V
V
f
C
R
CC
I
O
osc
T
T
Supply voltage 7 40 V
Amplifier input voltage –0.3 VCC–2 V
Collector output voltage 40 V
Collector output current (each transistor) 200 mA
Current into feedback terminal 0.3 mA
Oscillator frequency 1 300 kHz
Timing capacitor 0.47 10000 nF
Timing resistor 1.8 500 kΩ
p
p
TL494C 0 70
TL494I –40 85
°
†
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
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