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DI-78 参数 Datasheet PDF下载

DI-78图片预览
型号: DI-78
PDF下载: 下载PDF文件 查看货源
内容描述: 低成本为1.6W CV / CC充电器/适配器 [Low Cost 1.6 W CV/CC Charger/Adapter]
分类和应用:
文件页数/大小: 2 页 / 458 K
品牌: POWERINT [ POWER INTEGRATIONS, INC. ]
 浏览型号DI-78的Datasheet PDF文件第2页  
Design Idea DI-78
®
LinkSwitch-HF
Low Cost 1.6 W
CV/CC Charger/Adapter
Application
Charger/Adapter
Device
LNK353
Power Output
1.6 W
Input Voltage
85-265 VAC
Output Voltage
5.2 V
Topology
Flyback
Design Highlights
Low cost, low component count solution
No-load power consumption <300 mW – meets worldwide
energy efficiency requirements
Low leakage current design, <10
µA
Universal AC input range – single design worldwide
Secondary-side feedback gives accurate voltage and
constant current output
Small size and weight
Meets EN55022 B EMI limits
through the use of transformer shield windings, a snubber (R4
and C9) across the output diode, and by the internal switching
frequency jitter of
LinkSwitch-HF.
LinkSwitch-HF
uses ON/OFF control to regulate the output.
Current >49
µA
fed from the BYPASS pin capacitor C5 into
the FEEDBACK pin disables the MOSFET for that switching
cycle.
To maximize efficiency, a Schottky diode (D7) is used to rectify
the secondary. Filtering is provided by a low ESR capacitor
C6 and for most battery chargers, no additional filtering is
required.
During CV operation the output voltage is determined by the
sum of the Q1 V
BE
voltage and VR1. As the voltage increases
above this level, Q1 is biased on and current is fed through the
optocoupler LED, thus inhibiting switching cycles to maintain
regulation. The transition to CC operation occurs when the
voltage developed across R9 and R8 exceeds the LED forward
voltage of U2 (~1 V). Resistors R7 and R8 limit the optocoupler
current during transients. Resistor R5 limits the base current of
Q1 and R6 provides a bias current through VR1 (~0.5 mA).
C10
100 pF
Y1
C9
R4 680 pF
62
100 V
L2
Bead
R5
5.1
R6
1.2 kΩ
5.2 V,
320 mA
J3
C7
100
µF
10 V
Q1
2N3906
VR1
BZX79-
B5V1
5.1 V, 2%
Operation
The AC input is rectified and filtered and applied to one
side of the primary winding. The other end of the primary is
connected to the DRAIN pin of U1. During the on-time of
U1, energy is stored in the transformer and delivered to the
load when U1 switches off. A simple RCD clamp (D5, R2,
C3 and R3) limits the peak drain voltage.
A simple pi (π) filter formed by C1, L1 and C2 together with
RF1 are sufficient to attenuate differential conducted EMI.
Common mode and radiated EMI generation is minimized
C3
R3
2.2 nF
200 kΩ 400 V
BR1
MD5S
0.5 A,
600 V
1
C1
2.2
µF
400 V
R1
200 kΩ
7
D7
10BQ060
RF1
J1
8.2
85-265
VAC
J2
R2
200
4
C2
2.2
µF
400 V
D5
1N4007G
D
6
NC NC
T1
EP10
Lp = 900
µH
C6
470
µF
10 V
R7
390
R8
100
1%
FB
BP
L1
Bead
LinkSwitch-HF
U1
LNK353
S
U2B
PC817D
C5
0.1
µF
50 V
U2A
PC817D
R9
3
1/2 W
J4
RTN
PI-3899-072204
Figure 1. Schematic of a 1.6 W, 5.2 V Constant Voltage, 320 mA Constant Current Charger Using LNK353P.
DI-78
www.powerint.com
November 2004