GL494
1
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
Function Table
Output Control
Output Function
Grounded
Single-ended or Parallel Output
At
ref
V
Normal Push-Pull Operation
Block Diagram
OSCILLATOR
REFERENCE
REGULATOR
NONINV INPUT
INV. INPUT
FEEDBACK
DEAD TIME CONTROL
Cr
Rr
GND
C1
NON INV INPUT
INV. INPUT
REF. OUT
OUTPUT CONTROL
Vcc
C2
E2
E1
R
T
C
T
DEAD
TIME
CONTROL
NONINVERTING(1)
INPUT
INVERTING (2)
INPUT
NONINVERTING(16)
INPUT
INVERTING (15)
INPUT
FEEDBACK
ERROR AMPLIFIERS
PWM
COMPARATOR
OUTPUT
CONTROL
(See Function Table)
PULSE STEERING
FLIP FLOP
V
CC
REF OUT
GND
E1(9) C1(8)
E1(10) C2(11)
(4)
(3)
(7)
(12)
(14)
(13)
T
Q
Q
0.1V
+
+
-
-
ERROR AMP1
ERROR AMP2
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
GL494
2
Absolute Maximum Ratings
Supply Voltage,
CC
V
.................................................................................
.. 41 V
Amplifier Input Voltage
........................................................................
..
CC
V
+0.3 V
Collector Output Voltage
.................................................................................
41 V
Continuous Total dissipation at (or below) 25
C
.............................................
. 1000 mW
Operating Free-Air Temperature Range
......................................................
-20 to 85
C
Storage Temperature Range
...............................................................
.
...
.. -65 to 150
C
Collector Output Current
...........................................................................
.. 250 mA
Recommended Operation Conditions
PARAMETER
MIN
MAX
UNIT
Supply Voltage,
CC
V
7
40
V
Amplifier Input Voltage,
1
V
-0.3
CC
V
-2
V
Collector Output Voltage, Vo
40
V
Collector Output Current
(Each Transistor)
200
mA
Current Into Feed back Terminal
0.3
mA
Timing Capacitor,
T
C
0.47
10,000
nF
Timing Resistor,
T
R
1.8
500
K
Oscillator Frequency
1
300
KHz
Operating Free-Air Temperature
-20
85
C
Electrical Characteristics (Temperature
C
85
~
20
-
,
CC
V
=15V, f=10KHz)
Reference Section
PARAMETER
TEST CONDITIONS
MIN TYP(1) MAX UNIT
Output voltage (
ref
V
)
mA
1
I
O
=
4.75
5
5.25
V
Input regulation
V
7
V
CC
=
to 40V,
C
25
T
A
=
2
25
mV
Output regulation
1
I
O
=
to 10mA,
C
25
T
A
=
1
15
mV
Output Voltage change
with temperature
C
20
T
A
-
=
to
C
85
0.2
1
%
Short-circuit
Output current(2)
0
V
ref
=
35
mA
Oscillator Section
PARAMETER
TEST CONDITIONS
MIN TYP(1) MAX UNIT
Frequency
F
01
.
0
C
T
=
,
=
k
12
R
T
10
KHz
Standard deviation
of frequency (3)
All values of
CC
V
,
A
T
T
T
,
R
,
C
Constant
10
%
Frequency change with
Voltage
V
7
V
CC
=
to 40V,
C
25
T
A
=
0.1
%
Frequency change with
temperature
F
01
.
0
C
T
=
,
=
k
12
R
T
C
20
T
A
-
=
to
C
85
2
%
GL494
3
Dead Time Control Section
PARAMETER
TEST CONDITIONS
MIN TYP(1) MAX UNIT
Input bias current (pin 4) V
I
=0 to 5.25V
-2
-10
A
Maximum duty cycle,
Each output
)
4
pin
(
I
V
=0V
45
%
Zero duty cycle
3
3.3
V
Input threshold voltage
(pin 4)
Maximum duty cycle
0
V
Error Amp Sections
PARAMETER
TEST CONDITIONS
MIN TYP(1) MAX UNIT
Input offset voltage
V
5
.
2
V
)
3
PIN
(
O
=
2
10
mV
Input offset current
V
5
.
2
V
)
3
PIN
(
O
=
25
250
nA
Input bias current
V
5
.
2
V
)
3
PIN
(
O
=
0.2
1
A
LOW
-0.3
Common-mode input
voltage range
V
7
V
CC
=
to 40V
HIGH
2
V
CC
-
V
Open-loop voltage
Amplification
5
.
0
V
,
V
3
V
O
O
=
=
to3.
5V
70
95
dB
Unity-gain bandwidth
800
KHz
Common-mode rejection ratio
V
40
V
CC
=
,
C
25
T
A
=
65
80
dB
Output sink current (pin 3)
mV
15
V
ID
-
=
to 5V,
V
7
.
0
V
)
3
pin
(
O
=
0.3
0.7
mA
Output source current (pin 3)
mV
15
V
ID
=
to 5V,
V
5
.
3
V
)
3
pin
(
O
=
-2
mA
PWM Comparaor Section
PARAMETER
TEST CONDITIONS
MIN TYP(1) MAX UNIT
Input threshold voltage (pin 3) Zero duty cycle
4
4.5
V
Input sink current (pin 3)
V
7
.
0
V
)
3
pin
(
O
=
0.3
0.7
mA
Switching Characteristics
PARAMETER
TEST CONDITIONS
MIN TYP(1) MAX UNIT
Output Voltage rise time
100
200
ns
Output Voltage fall time
Common-emitter configuration,
See Test Circuit 3
25
100
ns
Output Voltage rise time
100
200
ns
Output Voltage fall time
Emitter-follower configuration,
See Test Circuit 4
40
100
ns
GL494
4
Output Section
PARAMETER
TEST CONDITIONS
MIN TYP(1) MAX UNIT
Collector off-state current
V
40
V
,
V
40
V
CC
CE
=
=
2
100
mA
Emitter off-state current
0
V
,
V
40
V
V
E
C
CC
=
=
=
-100 mA
Common-emitter
mA
200
I
,
0
V
C
E
=
=
1.1
1.3
Collector-emitter
Saturation voltage Emitter-follower
mA
200
I
,
V
15
V
E
C
-
=
=
1.5
2.5
V
Output control input current
ref
I
V
V
=
3.5
mA
Total Device
PARAMETER
TEST CONDITIONS
MIN TYP(1) MAX UNIT
V
15
V
CC
=
6
10
mA
Standby supply current
All other inputs &
Outputs open
V
40
V
CC
=
9
15
mA
Average supply current
V
2
V
)
4
pin
(
=
See Test circuit 1
7.5
mA
Notes:
(1) All typical values except for temperature coefficients are at
C
25
T
A
=
(2) Duration of the short circuit should not exceed one second.
(3) Standard deviation is a measure of the statistical distribution about the mean as derived from the formula
1
N
)
X
X
(
N
1
n
2
n
-
-
=
=
GL494
5
Parameter Measurement Information
1.Dead time and Feedback Control
2. Error Amplifier Characteristics
3. Common-Emitter Configuration
TEST CIRCUIT OUTPUT VOLTAGE WAVEFORM
DEAD TIME (4) (8) C1
FEEDBACK (3) (9) E1
Re (6)
Cr (5) (11) C2
(+) (16) ERROR (12) E2
(-) (15) AMP
(+) (1) ERROR
(-) (2) AMP
OUTPUT
CONTROL
Vcc=15V
TEST
INPUTS
OUTPUT 1
OUTPUT 2
(14) REF
OUT
GND (7)
(13)
50k
150
2W
150
2W
12k
0.01
F
VOLTAGE
AT C1
VOLTAGE
AT C2
VOLTAGE
AT C
T
DEAD-TIME
CONTROL
INTPUT
FEEDBACK
MAX
DUTY
CYCLE
MAX
THRESHOLD VOLTAGE
THRESHOLD VOLTAGE
Vcc
Vcc
0
0
0%
0%
0V
0.7V
V1
ERROR AMPLIFIER
UNDER TEST
FEEDBACK
TERMINAL
OTHER
ERROR
AMPLIFIER
V
REF
+
+
(EACH OUTPUT
CIRCUIT)
OUTPUT
15V
68
2W
C
L
=15pF
(INCLUDES PROBE AND
JIG CAPACITANCE)
90%
90%
10%
10%
t
f
t
r
TEST CIRCUIT
VOLTAGE WAVEFORMS
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