GL494 Datasheet, PDF (1/7 Pages) Hynix Semiconductor – PWM CONTROL CIRCUIT

GL494
GL494
PWM CONTROL CIRCUIT
Description
The GL494 incorporates on a single monolithic chip all the
functions required in the construction of a pulse-width-
modulation control circuit. Designed primarily for power
supply control, the GL494 contains an on-chip 5-volt
regulator, two error amplifiers, adjustable oscillator, dead-
time control comparator, pulse-steering flip-flop, and
output-control circuitry. The uncommitted output
transistors pro-vide either common-emitter or emitter-
follower output capability. Push-pull or single-ended
output operation may be selected through the output-
control function. The ar-chitecture of the GL494 prohibits
the possibility of either output being pulsed twice during
push-pull operation.
Features
— Complete PWM Power Control Circuitry
— Uncommitted Outputs for 200mA Sink or Source
— Output Control Selects Single-Ended or Push-Pull
Operation
— Internal Circuitry Prohibits Double Pulse at Either
Output
— Internal Regulator Provides a Stable 5V Reference
Supply
— Variable Dead-Time Provides Control Over Total
Range
Pin Configuration
NONINV INPUT 1
INV. INPUT 2
FEEDBACK 3
DEAD TIME CONTROL 4
Cr 5
Rr 6
GND 7
C1 ₈
16 NON INV INPUT
15 INV. INPUT
14 REF. OUT
13 OUTPUT CONTROL
12 Vcc
11 C2
10 E2
9
E1
Function Table
Output Control
Grounded
At V_ref
Output Function
Single-ended or Parallel Output
Normal Push-Pull Operation
Block Diagram
RT
CT _OSCILLATOR
DEAD ^0.1V
TIME
CONTROL ⁽⁴⁾
ERROR AMPLIFIERS
NONINVERTING(1)
INPUT
+
INVERTING (2)
−
INPUT
ERROR AMP1
NONINVERTING(16)
INPUT
INVERTING (15)
INPUT
(3)
FEEDBACK
+
−
ERROR AMP2
OUTPUT
CONTROL
(See Function Table)
PULSE STEERING
(13)
FLIP FLOP
Q
T
Q
PWM
COMPARATOR
REFERENCE
REGULATOR
VCC
(12)
REF OUT
(14)
GND
(7)
E1(9) C1(8)
E1(10) C2(11)
1