DPA424PN Power Integrations, DPA424PN Datasheet - Page 17

• Manufacturer Part Number: DPA424PN
• Description: IC CONV DC-DC DPA SWITCH 8DIP
• Manufacturer: Power Integrations
• Series: DPA-Switch®r

Specifications of DPA424PN

• Applications: Converter, Power Over Ethernet and Telecom Applications
• Voltage - Input: 16 ~ 75 V
• Number Of Outputs: 1
• Voltage - Output: 220V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Through Hole
• Package / Case: 8-DIP (0.300", 7.62mm)
• Output Voltage: 9 V
• Output Current: 3.5 A
• Input Voltage: - 0.3 V to + 220 V
• Switching Frequency: 282 KHz to 425 KHz
• Operating Temperature Range: - 40 C to + 150 C
• Mounting Style: Through Hole
• Duty Cycle (max): 79 %
• For Use With: 596-1009 - KIT DESIGN ACCELERATOR DC-DC596-1007 - KIT DESIGN ACCELERATOR POE CONV
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 596-1014-5

Figure 27. PoE Interface Circuit Using a Bipolar Transistor Pass-Switch and DPA424P.
and C11 together with C4 and R4. Capacitor C10 provides a
soft-finish characteristic, preventing output overshoot during
start-up.
Low Cost PoE VoIP Phone Converter
The basic circuitry to support IEEE standard 802.3af Power
over Ethernet (PoE) is straightforward. Class 0 signature and
classification circuits can be implemented with a single resistor
and the required under-voltage lockout function is a voltage
controlled pass-switch. By adding this circuitry to the front
end of a DPA converter, a low cost and low component count
PoE powered device (PD) power supply can be implemented.
Figure 27 shows a typical PD solution.
The PoE specification requires the PD to provide three
fundamental functions: discovery, classification, and pass-
switch connection.
When input voltage is applied to the PD, it must present the
correct discovery signature impedance in the voltage range of
Voltage
Input
DC
J1-1
RTN
J1-2
+
1% 1/4 W
24.9 kΩ
500 mW
R51
TIP29C (100 V/1 A)
BAV19
VR51
PoE Interface
28 V
D51
20 kΩ
R52
20 kΩ
R53
Q51
BAV19
D52
20 Ω
1 nF
50 V
R54
C51
1 µH 2.5 A
100 V
1 µF
C1
L1
619 kΩ
SMBJ
VR1
100 V
150
1 µF
1%
R1
C2
1
3
4
D
S
T1
CONTROL
X
5
8
7
6
L
DPA-Switch
13.3 kΩ
F
DPA424P
10 Ω
2.2 nF
R21
1%
R2
C21
220 nF
C
10 Ω
R22
U1
C4
Si4804
Si4804
Q21
Q22
10 kΩ
R23
2.5 VDC to 10 VDC. This impedance is provided by R51 in
Figure 27.
The second “classification” phase occurs at input voltages
15 VDC to 20 VDC. The PD must draw a specified current to
identify the device class (Class 0 specifies 0.5 mA to 4 mA).
This is again accomplished by resistor R51.
In the third phase, the bipolar pass-switch (Q51 in Figure 27)
connects the input voltage to the power supply at voltages
above approximately 30 VDC (28 V+VR52). Zener diode VR51
conducts, driving the 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.
Once the three start up phases have been successfully completed,
the DPA-Switch is allowed to function as a forward converter
(described in Figure 25 and accompanying text).
20CJQ060
VR21
D31
PC357N1T
SL13
15 V
U2
D21
1.0 Ω
47 µF
R3
10 V
C5
4
7
8
7
BAV19WS
16 µH 4 A
19WS
4.7 µF
BAV
D41
20 V
D6
L2
C6
3
6
5
2
10 kΩ
R11
BAV19WS
LM431AIM3
2.2 µF
10 V
C11
VR41
6.8 V
4.7 µF, 35 V
D11
U3
100 µF 5 V
150 Ω
C22-C24
R12
U2
C41
IN4148
100 µF
10 V
D42
C31
68 nF
C13
100 nF
11 Ω
R13
C12
DPA423-426
160 Ω
R4
PI-3824-081905
10.0 kΩ
10.0 kΩ
1 kΩ
R14
R16
R15
1%
1%
10 V
1 µF
C25
20 V, 10 mA
7.5 V, 0.4 A
7/05
5 V, 2.4 A
P
J2-3
J2-4
J2-2
RTN
J2-1
17