T
PJ3842B / PJ3843B
High Performance Current Mode Controller
he PJ3842B and PJ3843B series are high performance
fixed frequency current mode controllers. This is
cycle-by-cycle
current
limiting,
programmable
output
deadtime, and a latch for single pulse metering.
This device is available in 8-pin dual-in-line plastic
packages as well as the 8-pin plastic surface mount (SOP-8).
The SOP-8 package has separate power and ground pins for
the totem pole output stage.
The PJ3842B has UVLO thresholds of 16V (on) and 10V
(off), ideally suited for off-line converters. The PJ3843B is
tailored
for
lowervoltage
applications
having
UVLO
thresholds of 8.5V (on) and 7.6V (off).
specifically designed for Off-Line and DC-to-DC converter
applications offering the designer a cost effective solution
with minimal external components.This integrated circuits
feature a trimmed oscillator for precise duty cycle control, a
temperature compensated reference, high gain error amplifier,
current sensing comparator,and a high current totem pole
output ideally suited for driving a power MOSFET.
Also included are protective features consisting of input
and reference undervoltage lockouts each with hysteresis,
FEATURES
DIP-8
SOP-8
•
•
•
•
•
•
•
•
Trimmed Oscillator Discharge Current for Precise Duty
Cycle Control
Current Mode Operation to 500KHz
Automatic Feed Forward Compensation
Latching PWM for Cycle-By-Cycle Current Limiting
Internally
Lockout
High Current Totem Pole Output
Undervoltage Lockout with Hystersis
Low Start-Up and Operating Current
Trimmed
Reference
with
Undervoltage
Pin：1. Compensation
Pin：2.
Voltage Feedback
Pin：3.
Current Sense
Pin：4.
R
T
/C
T
5
. Gnd
6. Output
7. Vcc
8. Vref
ORDERING INFORMATION
Device
PJ3842/3843BCD
PJ3842/3843BCS
SIMPLIFIED BLOCK DIAGRAM
Operating Temperature
(Ambient)
-20℃ TO +85℃
Package
DIP-8
SOP-8
The document contains information on a new product.Specifications and information herein are subject to change without notice.
1-14
2004/11.Rev B
PJ3842B / PJ3843B
High Performance Current Mode Controller
MAXIMUM RATING
Parameter
Supply Voltage (low impedance source)
Supply Voltage (Ii<30mA)
Output Current
Output Energy (capacitive load )
Analog Inputs (pins 2,3 )
Error Amplifier Output Sink Current
Storage Temperature Range
Symbol
Vi
Vi
IO
EO
Value
30
Self Limiting
±1
5
-0.3 to 6.3
10
-65 to +150
Unit
V
A
V
mJ
mA
℃
Tstg
*
All voltages are with respect to pin 5,all currents are positive into the specified terminal.
ELECTRICAL CHARACTERISTICS
(
U
nless
otherwise stated , these specifications apply for 0<Tamb<70℃；
V
i
= 15V (Note 5), R
T
=10K, C
T
=3.3nF
)
Parameter
Symbol
Test Conditions
PJ3842B / PJ3843B
Min
Typ
Max
4.90
-
-
-
Line,Load, Temperature(2)
10Hz<f<10kHz
T
J
=25℃ (2)
Tamb=125℃, 1000Hrs(2)
Isc
fs
T
J
=25℃
12<Vi<25V
T
MIN
<Tamb<T
MAX
(2)
V
4
V
2
I
B
A
VOL
2<Vo<4V
B
SVR
I
sink
I
Source
V
OH
V
OL
V
PIN2
=2.7V, V
PIN1
=1.1V
V
PIN2
=2.3V, V
PIN1
=5V
V
PIN2
=2.3V,
R
L
=15KΩ to Ground
V
PIN2
=2.7V,
R
L
=15KΩ to Pin8
VPIN1=2.5V
4.82
-
-
-30
47
-
-
-
2.42
-
65
0.7
60
2.0
-0.5
4.55
-
5.00
6
6
0.2
-
50
5
-100
52
0.5
5
1.7
2.50
-0.3
90
1.0
70
6
-0.8
4.85
0.7
5.10
20
25
0.4
5.18
-
25
-180
57
3
-
-
2.58
-2.0
-
-
-
-
-
-
1.1
V
V
Unit
REFERENCE SECTION
Output Voltage
Line Regulation
Load Regulation
Temperature Stability (Note2)
Total Output Variantion
Output Noise Voltage
Long Term Stability
Output Short Circuit
OSCILLATOR SECTION
Initial Accuracy
Voltage Stability
Temperature Stability
Amplitude VPIN4 Peak to Peak
ERROR AMPLIFIER SECTION
Input Voltage (Vo=2.5V)
Input Bias Current
Unity Gain Bandwidth (2)
Supply Voltage Rejection
Output Current
Sink
Source
Output Voltage Swing
High State
Output Voltage Swing
Low State
V
Vn
V
REF
△V
REF
△V
REF
△V
REF
/△T
Io=1mA,T
J
= 25℃
12V<Vi<25V
1<Io<20mA
V
mV
mV
mV/℃
V
mV
mV
mA
KHz
%
%
V
V
mΑ
dB
MHz
dB
2-14
2004/11.Rev B
PJ3842B / PJ3843B
High Performance Current Mode Controller
Parameter
CURRENT SENSE SECTION
Current Sense Input Voltage
Gain (Note 3 &4 )
Maximum Input Signal
Supply VoltageRejection
Input Bias Current
Delay to Output
OUTPUT SECTION
Output Voltage
Low State
High State
Output Voltage Rise Time
Output Voltage Fall Time
Start-Up Threshold
PJ3842B
PJ3843B
Minimum Operating Voltage
After Turn-On
PJ3842B
PJ3843B
PWM SECTION
Max. Duty Cycle
TOTAL STANDBY CURRENT
Start-Up Current
Operating Supply Current
Zener Voltage
Note:
1. Toggle flip flop used only in PJ3844 and PJ3845.
2. These parameters, although guaranteed, are not 100% tested in production.
3. Parameter measured at trip point of latch with VPIN2=0
4. Gain defined as : A =
I
st
Ii
Viz
V
PIN2
=V
PIN3
=0V
Ii=25mA
-
-
30
0.1
11
34
0.5
20
-
mA
mA
V
DCmax
93
97
100
%
Vth
14.5
7.8
16
8.4
17.5
9.0
V
V
OL
V
OH
tr
tf
Isink=20mA
Isink=200mA
Isource=20mA
Isource=200mA
T
J
=25℃, C
L
=1.0nF (Note2 )
T
J
=25℃, C
L
=1.0nF (Note2 )
-
-
13
12
-
-
0.1
1.5
13.5
13.5
50
50
0.4
2.2
-
-
150
150
ns
ns
V
Symbol
Test Conditions
PJ3842B / PJ3843B
Min
Typ
Max
Unit
Gv
V
3
SVR
I
B
T
d
V
PIN1
=5V(Note 3 )
12<Vi<25V(Note 3 )
2.8
0.9
-
-
-
3.0
1.0
70
-2.0
150
3.2
1.1
-
-10
300
V/V
V
dB
mΑ
ns
UNDER-VOLTAGE LOCKOUT SECTION
V
CC(min)
8.5
7.0
10
7.6
11.5
8.2
V
∆V
PIN1
；0≦V
PIN3
≦0.8V.
∆V
PIN3
5. Adjust Vi above the start threshold before setting at 15V.
3-14
2004/11.Rev B
PJ3842B / PJ3843B
High Performance Current Mode Controller
FIGURE 1- OUTPUT DEAD TIME versus
OSCILLATOR FREQUENCY
FIGURE 2- TIMING RESISTOR versus OSCILLATOR
FREQUENCY
FIGURE 3-OSCILLATOR DISCHARGE CURRENT
versus TEMPERATURE
FIGURE 4-MAXIMUM OUTPUT DUTY CYCLE versus
TIMING RESISTOR
FIGURE 5-ERROR AMP SMALL SIGNAL TRANSIENT
RESPONSE
FIGURE 6-ERROR AMP LARGE SIGNAL TRANSIENT
RESPONSE
4-14
2004/11.Rev B
PJ3842B / PJ3843B
High Performance Current Mode Controller
FIGURE 7-ERROR AMP OPEN-LOOP GAIN AND
PHASE versus FREQUENCY
FIGURE 8-CURRENT SENSE INPUT THRESHOLD
versus ERROR AMP OUTPUT VOLTAGE
FIGURE 9-REFERENCE VOLTAGE CHANGE versus
SOURCE CURRENT
FIGURE 10-REFERENCE SHORT CIRCUIT CURRENT
versus TEMPERATURE
FIGURE 11- REFERENCE LOAD REGULATION
FIGURE 12-REFERENCE LINE REGULATION
5-14
2004/11.Rev B
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