układ pc494, ELEKTRONIKA, naprawa zasilaczy komputerowych, elementy i opisy

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DATA SHEET
BIPOLAR ANALOG INTEGRATED CIRCUIT
m
PC494
SWITCHING REGULATOR CONTROL CIRCUIT
PC494 is an inverter control unit which provides all the control circuitry for PWM type switching regulators.
Included in this device is the voltage reference, dual error amplifiers, oscillator, pulse width modulator, pulse
steering flip flop, dual alternating output switches and dead-time control.
m
FEATURES
·
Complete PWM power control circuit.
·
Adjustable dead-time (0 to 100%).
·
No double pulsing of same output during load transient condition.
·
Dual error amplifiers have wide common mode input voltage capability (
-
0.3 V to V
CC
-
2 V).
·
Circuit architecture provides easy synchronization.
·
Uncommitted outputs for 250-mA sink or source.
·
With miss-operation prevention circuit for low level supply voltage.
·
Full pin-compatible TL494C.
H
ORDERING INFORMATION
H
PIN CONFIGURATION (Top View)
Part Number
Package
Non-Inv. Input
1
16
Non-Inv. Input
m
PC494C
16-pin plastic DIP (7.62 mm (300))
Inv. Input
2
15
Inv. Input
m
PC494G
16-pin plastic SOP (9.53 mm (375))
Feed-Back
3
14
Ref Out
Dead-Time
Control
m
PC494GS
16-pin plastic SOP (7.62 mm (300))
4
13
Output Control
C
T
5
12
V
CC
R
T
6
11
C
2
GND
7
10
E
2
C
1
8
9
E
1
The information in this document is subject to change without notice. Before using this document, please
confirm that this is the latest version.
Not all devices/types available in every country. Please check with local NEC representative for
availability and additional information.
Document No. G12649EJ4V0DS00 (4th edition)
(Previous No. IC-1299)
Date Published November 2000 NS CP(K)
Printed in Japan
The mark
H
shows major revised points.
©
1988,2000
DESCRIPTION
The
m
PC494
BLOCK DIAGRAM
V
CC
12
13
Output Control
Ref Out
14
Reference
Regulator
Low Voltage
Stop
GND
7
F
/
F
8C
1
9E
1
11 C
2
10 E
2
T
R
T
6
Oscillator
Dead-Time
Comparator
C
T
5
Dead-Time
Control
+
4
–
+
Non-Inv. Input
1
+
EA I
–
PWM
Comparator
Inv. Input
2
–
EA II
Non-Inv. Input
16
+
Inv. Input
15
–
Feed-Back
3
2
Data Sheet G12649EJ4V0DS00
m
PC494
H
ABSOLUTE MAXIMUM RA
TINGS (T
A
= 25
°
C, unless otherwise noted)
Characteristics
Symbol
m
PC494C
m
PC494G
m
PC494GS
Unit
Supply Voltage
V
CC
-
0.3 to +41
-
0.3 to +41
-
0.3 to +41
V
Error Amplifier Input Voltage
V
ICM
-
0.3 to V
CC
+ 0.3
-
0.3 to V
CC
+ 0.3
-
0.3 to V
CC
+ 0.3
V
Output Voltage
V
CER
-
0.3 to +41
-
0.3 to +41
-
0.3 to +41
V
Output Current
I
C
250
250
250
mA
Total Power Dissipation
P
T
1000
780
Note
650
Note
mW
Operating Ambient Temperature
T
A
-
20 to +85
-
20 to +85
-
20 to +85
°
C
Storage Temperature
T
stg
-
65 to +150
-
65 to +150
-
65 to +150
°
C
Note
With 25 cm
2
x 1.6 mm glass-epoxy substrate.
H
Caution Product quality may suffer if the absolute maximum rating is exceeded even momentarily for any
parameter. That is, the absolute maximum ratings are rated values at which the product is on the
verge of suffering physical damage, and therefore the product must be used under conditions that
ensure that the absolute maximum ratings are not exceeded.
RECOMMENDED OPERATING CONDITIONS
Characteristics
Symbol
MIN.
TYP.
MAX.
Unit
Supply Voltage
V
CC
7
40
V
Output Voltage
V
CER
-
0.3
40
V
Output Current
I
C
200
mA
Error Amplifier Sink Current
I
OAMP
-
0.3
mA
Timing Capacitor
C
T
0.47
10000
nF
Timing Resistance
R
T
1.8
500
k
W
Oscillation Frequency
f
OSC
1
300
kHz
Operating Temperature
T
opt
-
20
+70
°
C
H
Caution The recommended operating range may be exceeded without causing any problems provided that
the absolute maximum ratings are not exceeded. However, if the device is operated in a way that
exceeds the recommended operating conditions, the margin between the actual conditions of use
and the absolute maximum ratings is small, and therefore thorough evaluation is necessary. The
recommended operating conditions do not imply that the device can be used with all values at
their maximum values.
Data Sheet G12649EJ4V0DS00
3
 m
PC494
H
ELECTRICAL SPECIFICATIONS (V
CC
= 15 V, f = 10 kHz,
-
20
±
T
A
± +70
°
C, unless otherwise noted)
(1/2)
Block
Characteristics
Symbol
Conditions
MIN.
TYP.
MAX.
Unit
Reference
Section
Output Voltage
V
REF
I
REF
= 1 mA, T
A
= 25
°
C
4.75
5
5.25
V
Line Regulation
REG
IN
40 V,
I
REF
= 1 mA, T
A
= 25
±
V
CC
±
8
25
mV
°
C
Load Regulation
REG
L
1 mA ± I
REF
± 10 mA,
T
A
= 25
°
C
1
15
mV
Temperature Coefficient
D
V
REF
/
D
T
-
20
°
C
±
T
A
±
+85
°
C,
0.01
0.03
%/
°
C
I
REF
= 1 mA
Short Circuit Output Current
Note1
I
SHORT
V
REF
= 0 V
50
mA
Oscillator
Section
Frequency
f
OSC
C
T
= 0.01
m
F,
10
kHz
R
T
= 12 k
W
, T
A
= 25
°
C
Standard Deviation of Frequency
Note2
7 V ± V
CC
± 40 V,
T
A
= 25
°
C, C
T
, R
T
,
const.
10
%
Frequency Change with
Temperature
0
°
C
±
T
A
±
70
°
C,
1
2
%
C
T
= 0.01
m
F,
R
T
= 12 k
W
Frequency Change with Voltage
7 V
±
V
CC
±
40 V,
1
%
C,
C
T
= 0.01
°
m
F, R
T
= 12 k
W
Dead-
Time
Control
Section
Input Bias Current
0 V ± V
I
± 5.25 V
-
2
-
10
m
A
Maximum Duty Cycle (Each Output)
V
I
= 0 V
45
49
%
Input Threshold Voltage 1
V
TH1
Output pulse 0% duty
cycle
3
3.3
V
Input Threshold Voltage 2
V
TH2
Output pulse maximum
duty cycle
0
V
Error
Amplifier
Section
Input Offset Voltage
V
IO
V
OAMP
= 2.5 V
2
10
mV
Input Offset Current
I
IO
V
OAMP
= 2.5 V
25
250
nA
Input Bias Current
V
OAMP
= 2.5 V
0.2
1
m
A
Common Mode
Input Voltage
Low
V
ICM
7 V
±
V
CC
±
40 V
-
0.3
V
High
V
CC
-
2
Open Loop Voltage Amplification
A
V
V
OAMP
= 0.5 to 3.5 V,
T
A
= 25
60
80
dB
°
C
Unity Gain Bandwidth
T
A
= 25
°
C
500
830
kHz
Common Mode Rejection Radio
CMR
V
CC
=
40 V, T
A
= 25
°
C
65
80
dB
Output Sink Current
V
OAMP
= 0.7 V
0.3
0.7
mA
Output Source Current
V
OAMP
= 3.5 V
-
2
-
10
mA
PWM
Section
Input Threshold Voltage (3-pin)
Output pulse 0% duty
cycle, see
Figure 1
.
4
4.5
V
Input Sink Current
V
(pin 3)
=
0.7 V
0.3
0.7
mA
Remark
The TYP. values are values at T
A
= 25
°
C, except for the characteristics of temperature.
4
Data Sheet G12649EJ4V0DS00
7 V
T
A
= 25
 m
PC494
(2/2)
Block
Characteristics
Symbol
Conditions
MIN.
TYP.
MAX.
Unit
Output
Section
Collector Cut-off Current
I
CER
V
CE
=
40 V, V
CC
=
40 V,
100
m
A
Common Emitter
Emitter Cut-off Current
V
CC
=
V
C
=
40 V,
V
E
= 0 V,
-
100
m
A
Emitter Follower
Collector Saturation
Voltage
Common
Emitter
V
CE(sat)
I
C
= 200 mA, V
E
= 0 V
0.95
1.3
V
Emitter
Follower
V
CE(ON)
I
E
=
-
200 mA, V
C
= 15 V
1.6
2.5
V
Output Voltage Rise
Time
Common
Emitter
t
r1
V
CC
=
15 V, R
L
= 150
W
,
100
200
ns
I
C
@
100 mA, T
A
= 25
°
C,
Output Voltage Fall
Time
t
f1
see
Figure 1
.
70
200
ns
Output Voltage Rise
Time
Emitter
Follower
t
r2
V
C
=
15 V, R
L
= 150
W
,
100
200
ns
I
E
@
100 mA, T
A
= 25
°
C,
Output Voltage Fall
Time
t
f2
see
Figure 1
.
70
200
ns
Total
Device
Standby Current
I
CC(S.B)
V
CC
= 15 V,
all other pins open.
8
12.5
mA
Bias Current
I
CC(BI)
2 V,
see
Figure 1
.
10
mA
Remark
The TYP. values are values at T
A
= 25
°
C, except for the characteristics of temperature.
Notes 1.
The short circuit output current flows for no more than 1 second. Repeat operation is possible if the internal
heat accumulation is not within a harmful range.
2.
Standard deviation is a measure of the statistical distribution about the mean as derived from the formula ;
s
=
N
å
(X
n
-
X)
2
n=1
N
-
1
Calculation expression of frequency f
OSC
is as follows ;
f
OSC
@
0.817 R
T
·
C
T
+ 1.42
·
10
-
6
1
(Hz)
[R
T
]
=
W
,
[C
T
]
=
F
Data Sheet G12649EJ4V0DS00
5
V
(pin 4)
=
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