LD7552D
12/19/2007
Green-Mode PWM Controller with Integrated Protections and
Adjustable OLP Delay Time
REV: 00
General Description
The LD7552D are specifically designed for the low total
system cost by integrating many functions, protections, and
the EMI-improved solution in a SOP-8 package which
usually need a lot of extra components or circuits on the
general designs.
The implemented functions include low startup current,
green-mode power-saving operation, leading-edge blanking
of the current sensing and internal slope compensation.
And the LD7552D features more protections like OLP (Over
Load Protection) and OVP (Over Voltage Protection) to
prevent the circuit damage from the abnormal conditions.
Features
High-Voltage CMOS Process with Excellent ESD
protection
Very Low Startup Current (<20μA)
Current Mode Control
Non-audible-noise Green Mode Control
UVLO (Under Voltage Lockout)
LEB (Leading-Edge Blanking) on CS Pin
Adjustable OLP Delay Time.
Internal Slope Compensation
OVP (Over Voltage Protection) on Vcc Pin
OLP (Over Load Protection)
500mA Driving Capability
Applications
Switching AC/DC Adaptor and Battery Charger
Open Frame Switching Power Supply
Typical Application
1
Leadtrend Technology Corporation
LD7552D-DS-00 December 2007
www.leadtrend.com.tw
LD7552D
Pin Configuration
SOP-8 / DIP-8 (TOP VIEW)
VCC
OUT
8
7
6
NC
5
CS
TOP MARK
YYWW##
1
2
3
4
YY : Year code (D: 2004, E: 2005…..)
WW : Week code
##
: Production code
GND
COMP
VCC
Ordering Information
Part number
LD7552D PS
LD7552D GS
LD7552D PN
SOP-8
SOP-8
DIP-8
Package
PB Free
Green Package
DIP-8
TOP MARK
LD7552DPS
LD7552DGS
LD7552DPN
Shipping
2500 /tape & reel
2500 /tape & reel
3600/tube /carton
The LD7552D is ROHS Complaint/ Green Package.
Pin Descriptions
PIN
1
2
3
4
5
6
7
8
NAME
GND
COMP
VCC
CT
NC
CS
VCC
OUT
Ground
Voltage feedback pin (same as the COMP pin in UC384X), By connecting
a photo-coupler to close the control loop and achieve the regulation.
Supply voltage pin
This pin is to program the frequency of the low frequency timer.
connecting a capacitor to ground to set the OLP delay time.
Unconnected pin
Current sense pin, connect to sense the MOSFET current
Supply voltage pin
Gate drive output to drive the external MOSFET
By
FUNCTION
CT
2
Leadtrend Technology Corporation
LD7552D-DS-00 December 2007
www.leadtrend.com.tw
LD7552D
Block Diagram
VCC
32V
16.0V/
10.0V
UVLO
Comparator
internal bias
& Vref
VCC OK
PG
All
Blocks
OVP
Comparator
OVP
CT
Internal
Oscillator
Vref OK
28.0V
OLP
Delay
Protection
Driver
Stage
OUT
Green-Mode
Control
S
Q
COMP
PWM
Comparator
2R
R
R
∑
+
Slope
Compensation
CS
Leading
Edge
Blanking
0.85V
+
OCP
Comparator
Protection
5.0V
OLP
Comparator
OLP Delay
Counter
OVP
OLP
PG
S
Q
R
OLP Delay
GND
3
Leadtrend Technology Corporation
LD7552D-DS-00 December 2007
www.leadtrend.com.tw
LD7552D
Absolute Maximum Ratings
Supply Voltage VCC
COMP, CT, CS
OUT
Junction Temperature
Operating Ambient Temperature
Storage Temperature Range
Package Thermal Resistance (SOP-8)
Package Thermal Resistance (DIP-8)
Power Dissipation (SOP-8, at Ambient Temperature = 85°C)
Power Dissipation (DIP-8, at Ambient Temperature = 85°C)
Lead temperature (Soldering, 10sec)
ESD Voltage Protection, Human Body Model
ESD Voltage Protection, Machine Model
Gate Output Current
30V
-0.3 ~7V
Vcc+0.3V
150°C
-40°C to 85°C
-65°C to 150°C
160°C/W
100°C/W
400mW
650mW
260°C
3.0 KV
300 V
500mA
Caution:
Stresses beyond the ratings specified in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only
rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not
implied.
Recommended Operating Conditions
Item
Supply Voltage Vcc
CT Value
Start-up resistor
Min.
11
0.047
1.2
Max.
25
0.1
1.4
Unit
V
μF
MΩ
4
Leadtrend Technology Corporation
LD7552D-DS-00 December 2007
www.leadtrend.com.tw
LD7552D
Electrical Characteristics
(T
A
= +25 C unless otherwise stated, V
CC
=15.0V)
PARAMETER
Supply Voltage (Vcc Pin)
Startup Current
Operating Current
(with 1nF load on OUT pin)
UVLO (off)
UVLO (on)
OVP Level
Voltage Feedback (COMP Pin)
Short Circuit Current
Open Loop Voltage
Green Mode Threshold V
COMP
Current Sensing (CS Pin)
Maximum Input Voltage, Vcs(off)
Leading Edge Blanking Time
Input impedance
Delay to Output
Oscillator for Switching Frequency
Frequency
Green Mode Frequency
Trembling Frequency
Temp. Stability
Voltage Stability
Low Frequency Timer (CT pin)
Low Frequency Period
Gate Drive Output (OUT Pin)
Output Low Level
Output High Level
Rising Time
Falling Time
OLP (Over Load Protection)
OLP Trip Level
CT value is in proportion to OLP delay time.
o
CONDITIONS
MIN
TYP
12
MAX
20
UNITS
μA
mA
mA
mA
V
COMP
=0V
V
COMP
=3V
Protection tripped (OVP)
9.0
15.0
26.8
V
COMP
=0V
COMP pin open
2.5
3.0
0.5
10.0
16.0
28.0
1.5
6.0
2.35
0.80
1
60
0.85
240
0.90
11.0
17.0
29.2
V
V
V
mA
V
V
V
nS
MΩ
nS
Internal Fixed
60
65
20
±4
70
KHz
KHz
KHz
(-40°C ~105°C)
(VCC=11V-25V)
CT=0.047μF
VCC=15V, Io=20mA
VCC=15V, Io=20mA
Load Capacitance=1000pF
Load Capacitance=1000pF
V
COMP
(OLP)
CT=0.047μF
8
50
30
5.0
40
4.7
5
1
%
%
mS
1
160
60
V
V
nS
nS
V
mS
5
Leadtrend Technology Corporation
LD7552D-DS-00 December 2007
www.leadtrend.com.tw
PCB设计
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