5秒后页面跳转
DI-70 PDF预览

DI-70

更新时间: 2022-04-23 23:00:11
品牌 Logo 应用领域
帕沃英蒂格盛 - POWERINT /
页数 文件大小 规格书
2页 348K
描述
PoE Detection and Classification (Class 0) Interface Circuit

DI-70 数据手册

 浏览型号DI-70的Datasheet PDF文件第2页 
Design Idea DI-70  
DPA-Switch® PoE Detection and  
Classification (Class 0) Interface Circuit  
Topology  
Device  
Power Output  
Input Voltage  
Output Voltage  
Application  
Forward  
PoE/VoIP  
12.94 W  
34-57 VDC  
DPA424P  
5 V / 7.5 V / 20 V  
to identify the device class (Class 0 specifies 0 mA to  
4 mA). This is again accomplished by resistor R51.  
Design Highlights  
• Simple, low-cost, discrete PoE interface circuit  
• Low cost bipolar pass-switch: 87% efficient (Figure 5)  
• MOSFET pass-switch: 97% efficient (Figures 2 and 5)  
• Fully compliant with IEEE 802.3af  
Bipolar Transistor Pass-Switch  
In the third phase, the bipolar pass-switch (Q51 in Figure 1)  
connects the input voltage to the power supply at voltages  
above approximately 30 VDC (28 V + VR52). Zener diode  
VR51 conducts, driving current through resistor R52 to  
the base of Q51. Resistor R53 prevents turn-on under other  
conditions. Once the power supply has started, components  
D51, D52, C51 and R54 enhance the base-current drive by  
coupling power from the power supply bias winding.  
Operation  
Power over Ethernet (PoE) is becoming widely adopted for  
networking and (VoIP) telecom applications. A typical PD  
solution is shown in Figure 1, having a PoE interface circuit  
and a DPA-Switch DC-DC converter block (see DI-69 for full  
details of operation of the DC-DC converter).  
MOSFET Pass-Switch  
ThePoEspecificationrequiresthePDtoprovidethreefunctions:  
detection, classification, pass-switch connection.  
An alternative MOSFET-based third phase solution  
(Figure 2) connects the input to the power supply at input  
voltages above approximately 30 VDC (28 V + VG(Q51)).  
Resistor R53 prevents turn-on under other conditions and  
ZenerdiodeVR52limitstheQ51gate-sourcevoltagewhenthe  
input voltage is high (>42 VDC). In the last phase of start up,  
When an input voltage is first applied to the PD, it must present  
the correct detection impedance in the voltage range of 2.5VDC  
to 10 VDC. This impedance is provided by R51.  
The second (classification) phase occurs at input voltages  
14.5 VDC to 20.5 VDC. The PD must draw a specified current  
D41  
BAV19WS  
20 V, 10 mA  
J2-4  
C41  
4.7 µF, 35 V  
VR41  
D42  
Ethernet  
4
3
6
6.8 V IN4148  
(RJ-45)  
D101  
D31  
L1  
Connector  
DL4002  
PoE Interface  
20CJQ060  
1 µH 2.5 A  
7.5 V, 0.4 A  
J2-3  
1
3
8
(1,2)  
7
C31  
100 µF  
10 V  
Q22  
Si4804  
7
6
C25  
VR51  
28 V  
L2  
16 µH 4 A  
DL4002  
D102  
C22-C24  
100 µF 5 V  
R4 1 µF  
C21  
2.2 nF  
5 V, 2.4 A  
J2-2  
160 Ω  
10 V  
R1  
649 kΩ  
1%  
5
2
8
R21  
10 Ω  
R22  
10 Ω  
7
4
R52  
20 k  
D6  
BAV  
D103  
DL4002  
RTN  
J2-1  
5
19WS  
Q21  
Si4804  
VR21  
D21  
SL13  
15 V  
T1  
(4,5)  
C1  
1 µF  
100 V  
C2  
1 µF  
100 V  
R23  
174 k  
1%  
C6  
4.7 µF  
20 V  
R23  
10 kΩ  
R51  
24.9 kΩ  
1% 1/4 W  
U2  
R16  
10.0 kΩ  
DL4002  
D104  
1%  
R21  
10 k  
Q20  
MMBTS3906  
R22  
10 kΩ  
D105  
DL4002  
U2  
PC357  
N1T  
(3,6)  
R11  
10 k  
DPA-Switch  
C51  
C12  
100 nF  
R12  
150 Ω  
U1  
1 nF  
D51  
BAV19  
DPA424P  
D
L
50 V  
DL4002  
D106  
R13  
CONTROL  
11 Ω  
C
D11  
BAV19WS  
D52  
BAV19  
R3  
S
X
F
R14  
C11  
2.2 µF  
10 V  
C13  
68 nF  
VR1  
SMAJ  
150  
1.0 Ω  
1 kΩ  
D107  
DL4002  
C4  
220 nF  
R2  
R53  
R54  
20 Ω  
C5  
47 µF  
10 V  
20 k  
U3  
R15  
10.0 kΩ  
1%  
(7,8)  
LM431AIM3  
13.3 kΩ  
1%  
Q51  
PI-3824-111005  
TIP29C (100 V/1 A)  
or MMBTA06  
DL4002  
D108  
Figure 1. PoE Interface Circuit–Using a Bipolar Transistor Pass-Switch and DPA424P.  
November 2005  
DI-70  
www.powerint.com  

与DI-70相关器件

型号 品牌 描述 获取价格 数据表
DI-74 POWERINT 1.25 W Non-Isolated Constant Current LED Driver

获取价格

DI740 ETC Interface IC

获取价格

DI-75 POWERINT Low Cost 2.5 W Regulated Charger/Adapter

获取价格

DI-76 POWERINT 3.1 W Low Parts Count Power Supply

获取价格

DI-77 POWERINT 3 W Adapter: <200 mW No-Load Consumption

获取价格

DI-78 POWERINT Low Cost 1.6 W CV/CC Charger/Adapter

获取价格