Datasheet TL494 Datasheet (Texas Instruments)

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.

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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

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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

°

†

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3

TL494

PARAMETER

TEST CONDITIONS

†

UNIT

PARAMETER

TEST CONDITIONS

†

UNIT

PARAMETER

TEST CONDITIONS

UNIT

PULSE-WIDTH-MODULATION CONTROL CIRCUITS

SLVS074D – JANUARY 1983 – REVISED MAY 2002

electrical characteristics over recommended operating free-air temperature range, VCC = 15 V,
f = 10 kHz (unless otherwise noted)

reference section

TL494C, TL494I

TYP

TYP

‡

MAX

‡

MAX

MIN

Output voltage (REF) IO = 1 mA 4.75 5 5.25 V
Input regulation VCC = 7 V to 40 V 2 25 mV
Output regulation IO = 1 mA to 10 mA 1 15 mV
Output voltage change with temperature ∆TA = MIN to MAX 2 10 mV/V
Short-circuit output current

†

For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.

‡

All typical values, except for parameter changes with temperature, are at TA = 25°C.

§

Duration of the short circuit should not exceed one second.

§

REF = 0 V 25 mA

oscillator section, CT = 0.01 µF, RT = 12 kΩ (see Figure 1)

TL494, TL494I

MIN

Frequency 10 kHz
Standard deviation of frequency
Frequency change with voltage VCC = 7 V to 40 V, TA = 25°C 1 Hz/kHz
Frequency change with temperature

†

For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.

‡

All typical values, except for parameter changes with temperature, are at TA = 25°C.

¶

Standard deviation is a measure of the statistical distribution about the mean as derived from the formula:

N

ȍ

Ǹ

s

+

(xn*

n+1

N*1

¶

#

2

X)

All values of VCC, CT, RT, and TA constant 100 Hz/kHz

∆TA = MIN to MAX 10 Hz/kHz

#

Temperature coefficient of timing capacitor and timing resistor are not taken into account.

error-amplifier section (see Figure 2)

TL494, TL494I

TYP

‡

MAX

MIN

Input offset voltage VO (FEEDBACK) = 2.5 V 2 10 mV
Input offset current VO (FEEDBACK) = 2.5 V 25 250 nA
Input bias current VO (FEEDBACK) = 2.5 V 0.2 1 µA

Common-mode input voltage range VCC = 7 V to 40 V
Open-loop voltage amplification ∆VO = 3 V, RL = 2 kΩ, VO = 0.5 V to 3.5 V 70 95 dB

Unity-gain bandwidth VO = 0.5 V to 3.5 V, RL = 2 kΩ 800 kHz
Common-mode rejection ratio ∆VO = 40 V, TA = 25°C 65 80 dB
Output sink current (FEEDBACK) VID = –15 mV to –5 V, V (FEEDBACK) = 0.7 V 0.3 0.7 mA
Output source current (FEEDBACK) VID = 15 mV to 5 V, V (FEEDBACK) = 3.5 V –2 mA

‡

All typical values, except for parameter changes with temperature, are at TA = 25°C.

–0.3 to

VCC–2

V

4

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Collector-emitter saturation voltage

V

Input threshold voltage (DEAD-TIME CTRL)

V

Standby supply current

RT

V

All other inputs and outputs open

mA

Common-emitter configuration

See Figure 3

Emitter-follower configuration

See Figure 4

TL494

PULSE-WIDTH-MODULATION CONTROL CIRCUITS

SLVS074D – JANUARY 1983 – REVISED MAY 2002

electrical characteristics over recommended operating free-air temperature range, VCC = 15 V,
f = 10 kHz (unless otherwise noted)

output section

PARAMETER TEST CONDITIONS MIN

Collector off-state current VCE = 40 V, VCC = 40 V 2 100 µA
Emitter off-state current VCC = VC = 40 V, VE = 0 –100 µA

Common emitter VE = 0, IC = 200 mA 1.1 1.3
Emitter follower V

Output control input current VI = V

†

All typical values except for temperature coefficient are at TA = 25°C.

O(C1 or C2)

= 15 V, IE = –200 mA 1.5 2.5

ref

dead-time control section (see Figure 1)

PARAMETER TEST CONDITIONS MIN

Input bias current (DEAD-TIME CTRL) VI = 0 to 5.25 V –2 –10 µA
Maximum duty cycle, each output VI (DEAD-TIME CTRL) = 0, CT = 0.01 µF, RT = 12 kΩ 45%

p

†

All typical values except for temperature coefficient are at TA = 25°C.

Zero duty cycle 3 3.3
Maximum duty cycle 0

TYP

TYP

†

MAX UNIT

3.5 mA

†

MAX UNIT

PWM comparator section (see Figure 1)

PARAMETER TEST CONDITIONS MIN

Input threshold voltage (FEEDBACK) Zero duty cycle 4 4.5 V
Input sink current (FEEDBACK) V (FEEDBACK) = 0.7 V 0.3 0.7 mA

†

All typical values except for temperature coefficient are at TA = 25°C.

TYP

†

MAX UNIT

total device

PARAMETER TEST CONDITIONS MIN

pp

Average supply current VI (DEAD-TIME CTRL) = 2 V, See Figure 1 7.5 mA

†

All typical values except for temperature coefficient are at TA = 25°C.

=

ref

,

p

p

VCC = 15 V 6 10

p

VCC = 40 V 9 15

TYP

†

MAX UNIT

switching characteristics, TA = 25°C

PARAMETER TEST CONDITIONS MIN

Rise time
Fall time
Rise time
Fall time

†

All typical values except for temperature coefficient are at TA = 25°C.

,

,

†

TYP

MAX UNIT

100 200 ns

25 100 ns

100 200 ns

40 100 ns

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5

TL494
PULSE-WIDTH-MODULATION CONTROL CIRCUITS

SLVS074D – JANUARY 1983 – REVISED MAY 2002

PARAMETER MEASUREMENT INFORMATION

VCC = 15 V

Voltage

at C1

Voltage

at C2

Test

Inputs

50 kΩ

12 kΩ

0.01 µF

4

DTC

3

FEEDBACK

6

RT

5

CT

1

1IN+

2

1IN–

16

2IN+

15

2IN–

13

OUTPUT
CTRL

12

V

CC

Error
Amplifiers

GND

7

TEST CIRCUIT

C1

C2

REF

E1

E2

8
9

11

10

14

150 Ω
2 W

150 Ω
2 W

Output 1

Output 2

V

0 V
V

0 V

CC

CC

Voltage

at CT

Threshold Voltage

DTC

0 V

Threshold Voltage

FEEDBACK

0.7 V

Duty Cycle

0%

VOLTAGE WAVEFORMS

MAX

0%

Figure 1. Operational Test Circuit and Waveforms

6

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TL494

PULSE-WIDTH-MODULATION CONTROL CIRCUITS

SLVS074D – JANUARY 1983 – REVISED MAY 2002

PARAMETER MEASUREMENT INFORMATION

Amplifier Under Test

+

V

I

–

+

FEEDBACK

15 V

Each Output
Circuit

TEST CIRCUIT OUTPUT VOLT AGE WA VEFORM

NOTE A: CL includes probe and jig capacitance.

Figure 3. Common-Emitter Configuration

15 V

Each Output
Circuit

V

ref

–

Other Amplifier

Figure 2. Amplifier Characteristics

68 Ω
2 W

Output

CL = 15 pF
(See Note A)

90%

10%

t

f

10%

90%

t

r

CL = 15 pF

(See Note A)

TEST CIRCUIT OUTPUT VOLTAGE W AVEFORM

NOTE A: CL includes probe and jig capacitance.

Figure 4. Emitter-Follower Configuration

Output

68 Ω
2 W

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90%

10%

90%

10%

t

r

t

f

7

TL494
PULSE-WIDTH-MODULATION CONTROL CIRCUITS

SLVS074D – JANUARY 1983 – REVISED MAY 2002

TYPICAL CHARACTERISTICS

OSCILLATOR FREQUENCY AND

FREQUENCY VARIATION

†

vs

TIMING RESISTANCE

100 k

40 k

–2%

10 k

4 k

1 k

400

100

40

10

f – Oscillator Frequency and Frequency Variation – Hz

1 k 4 k 10 k 40 k 100 k 400 k 1 M

†

Frequency variation (∆f) is the change in oscillator frequency that occurs over the full temperature range.

–1%

0%

0.1 µF

CT = 1 µF

RT – Timing Resistance – Ω

0.01 µF

Df = 1%

VCC = 15 V
TA = 25°C

0.001 µF

†

Figure 5

AMPLIFIER VOLTAGE AMPLIFICATION

vs

FREQUENCY

100

90

80

70
60

50

40

30

20

A – Amplifier Voltage Amplification – dB

10

0

1 10 100 1 M

1 k

f – Frequency – Hz

VCC = 15 V
∆VO = 3 V
TA = 25°C

10 k

Figure 6

100 k

8

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