Pulse-Width-Modulation Control Circuits
FEATURES
●
Complete PWM Power Control Circuitry
●
Uncommitted Outputs for 200 mA Sink or Source Current
●
Output Control Selects Single-Ended or Push-Pull Operation
●
Internal Circuitry Prohibits Double Pulse at Either Output
●
Variable Dead-Time Provides Control over Total Range
●
Internal Regulator Provides a Stable 5-V Reference Supply,5%
●
Circuit Architecture Allows Easy Synchronization
Error
AMP 1
NONINV
INPUT
INV INPUT
FEEDBAC
K
DEAD-TIME
CONTROL
CT
RT
GND
C1
1
2
3
4
5
6
7
8
TL494
SOP16/DIP16
(TOP VIEW)
16
15
14
13
12
11
10
9
NONINV
INPUT
INV INPUT
REF OUT
OUTPUT
CONTROL
Vcc
C2
E2
E1
Error
AMP 2
●
Moisture Sensitivity Level 3
DESCRIPTION
The TL494 incorporate on a single monolithic chip all the functions
required in the construction of a pulse-width-modulation control,
these devices offer the systems engineer the flexibility to tailor
the power supply control circuitry to his application.
The TL494 contains an error amplifier, an on-chip adjustable
oscillator, a dead-time control comparator, pulse-steering control
flip-flop, a 5-volt, 5% precision regulator, and output-control circuit.
The error amplifier exhibits a common-mode voltage range from -0.3 volts to Vcc -2 volts. The dead-time control
comparator has a fixed offset that provides approximately 5% dead time when externally altered. The on-chip
oscillator may be bypassed by terminating R
T
(pin 6) to the reference output and providing a sawtooth in put to
CT (pin 5), or it may be used to drive the common circuits in synchronous multiple-rail power supplies. The
uncommited output transistors provide either common-emitter or emitter-follower output capability. Each Device
provides for push-pull or single-ended output operation, which may be selected through the output-control funct
-ion. The architecture of these devices prohibits the possibility of either output being pulsed twice during push
-pull operation.
ORDERING INFORMATION
Device
TL494D
TL494N
Package
16 SOP
16 DIP
Functional Block Diagram
R
T
C
T
OUTPUT CONTROL
OSCILLATOR
Q1
C1
E1
DEAD
TIME
CONTROL
0.1V
DEAD-TIME CONTROL COMPARATOR
C1
Q2
C2
E2
PWM COMPARATOR
ERROR AMPLIFIER
PULSE-STEERING FLIP-FLOP
NONINVERTING INPUT
INVERTING INPUT
+
1
-
Vcc
ERROR AMPLIFIER
NONINVERTING INPUT
+
2
INVERTING INPUT
-
FEEDBACK
REFERENCE
Vref
GND
2008 - Ver. 1.2
HTC
1/6
HTC [ HTC KOREA TAEJIN TECHNOLOGY CO. ]
