YOUDA INTEGRATED CIRCUIT
YD3843
CURRENT MODE PWM CONTROL CIRCUITS--YD3843
DESCRIPTION
The YD3843 provides the necessary features to implement off-line or DC to DC fixed frequency current mode
control schemes with a minimal external parts count.
FEATURES
*Optimized for off-line and DC to DC converts
*Low start up current(<1mA)
*Automatic feed forward compensation
*Pulse-by-Pulse current limiting
*Enhanced load response characteristic
*Under-voltage lookout with hysteresis.
*Double pulse Suppression
*High current totem pole output
*Internally trimmed band-gap reference
*500kHz operation
*Low Ro error amp
BLOCK DIAGRAM
8
7
6
1/2
1/3
VCC
5V
REF
S/R
UVL
5
1
2
3
4
R S
OSC
+
-
EA
1V
WuXi YouDa Electronics Co., Ltd
Add: No.5 Xijin Road, National Hi-Tech Industrial Development Zone, Wuxi Jiangsu China
Tel: 86-510-85205117 86-510-85205106 Fax: 86-510-85205110 Website: www.e-youda.com
SHENZHEN OFFICE Tel 86-755-83740369 Fax 86-755-83741418
Ver 5.0 1 of 4 2006-7-10
YOUDA INTEGRATED CIRCUIT
YD3843
ABSOLUTE MAXIMUM RATINGS
(Tamb=25)
PARAMETER SYMBOL
VALUE
UNIT
Supply Voltage(Low impedance Source)
Vcc
30
V
Supply Voltage(Icc30mA) Vcc
Self
Limiting
V
Output Current
Io
1 A
Output Energy(Capacitive Load)
5
J
Analog Inputs(pin 2, 3)
V
I(ANA)
-0.3 to +6.3
V
Error Amplifier Output Sink Current
l
SINK(EA)
10 mA
Power Dissipation
P
D
At
Tamb25 1.0
W
Lead Temperature
Tlead
300
Storage Temperature
Tstg
-65--+150
Note 1:Ta25, P
D
derated with 8mW/.
ELECTRICAL CHARACTERISTICS
(Vcc=15V, R
T
=10k, C
T
=3.3nF, Tamb=070, unless otherwise specified)
PARAMETER SYMBOL
TEST
CONDITIONS
MIN
TYP
MAX
UNIT
Reference Section
Output Voltage
V
REF
Tj=25, Io=1mA
4.90
5.00
5.10
V
Line Regulation
V
REF
12
V
IN
25
V
6 20
mV
Load Regulation
V
REF
1lo=20mA
6
25
MV
Output Noise Voltage
Vose
10Hzf10kHz,
Tj=25(note 2)
50 6 mV
Long Term Stability
Ta=25, 1000Hrs(note
2)
5 25
mV
Output Short Circuit
lsc
-30
-100
-180
mA
Oscillator Section
Initial Accuracy
f
Tj=25 47
52
57
kHz
Voltage Stability
f/
Vcc 12Vcc25V
0.2
1
%
Temp Stability
TminT
A
Tmax(note
2)
5 %
Amplitude
Vosc
Vpin 4 peak to peak
1.7
V
Error Amplifier Section
Input Voltage
V
I(EA)
Vpin
1=2.5V
2.42
2.50
2.58
V
Input Bias Current
l
BIAS
-0.3
-2
A
A
VOL
2Vo4V 60
90
dB
Unity Gain
Bandwidth
Tj=25(note 2)
0.7
1
6.0
mHz
PSRR
12Vcc25V 60
70
dB
Output Sink Current
lsink
Vpin2=2.7V,
Vpin 1=1.1V
2 6 mA
WuXi YouDa Electronics Co., Ltd 2 of 4 Website: www.e-youda.com
YOUDA INTEGRATED CIRCUIT
YD3843
Output Source
Current
lsource
Vpin 2=2.3V, Vpin
1=5V
-0.5 -0.8 mA
Vout High
V
OH
Vpin 2=2.3V, R
L
=15k
to GND
5 6 V
Vout Low
V
OL
Vpin 2=2.7V, Vpin
1=1.1V
0.7
1.1 V
Current Sense Section
Gain
Gv
(note 3, 4)
2.85
3
3.15
V/V
Maximum Input
Signal
V
I(MAX)
Vpin 1=5V(note 3)
0.9
1
1.1
V
PSRR
12Vcc25V
70
dB
Input Bias Current
l
BIAS
-2
-10
A
Delay to Output
Vpin 3=0 to 2V
150
300
ns
Output Section
lsink=20mA
0.1
0.4
V
Output Low Level
V
OL
lsink=200mA
1.5
2.2
V
lsource=20mA 13
13.5
V
Output High Level
V
OH
lsource=200mA 12
13.5
V
Rise Time
t
R
Tj=25, C
L
=1nF
(note 2)
50
150
ns
Fall Time
t
F
Tj=25, C
L
=1nF(note 2)
50
150
ns
UVLO Saturation
Vcc=5V, lsink=10mA
0.7
1.2
V
Under-Voltage Lockout Output Section
Start Threshold
V
TH(ST)
7.8
8.4
9.0
V
Min. Operating
Voltage
After Turn On
V
OPR
(min
)
7.6
8.0
8.4
V
PWM Section
Maximum Duty
Cycle
D
(MAX)
95
07
100
%
Minimum Duty
Cycle
D
(MIN)
0
%
Total Standby Current
Start-up Current
l
ST
0.5
1
mA
Operating Supply
Current
Icc
(OPR)
Vpin 2=Vpin 3=0V
11
17
mA
Vcc Zener Voltage
Vz
Icc=25mA
34
V
WuXi YouDa Electronics Co., Ltd 3 of 4 Website: www.e-youda.com
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