TOP258PN Power Integrations, TOP258PN Datasheet - Page 22

IC OFFLINE SWIT PROG OVP 8DIP

TOP258PN

Manufacturer Part Number
TOP258PN
Description
IC OFFLINE SWIT PROG OVP 8DIP
Manufacturer
Power Integrations
Series
TOPSwitch®-HXr
Type
Off Line Switcherr
Datasheet

Specifications of TOP258PN

Output Isolation
Isolated
Frequency Range
119 ~ 145kHz
Voltage - Output
700V
Power (watts)
77W
Operating Temperature
-40°C ~ 150°C
Package / Case
8-DIP (0.300", 7.62mm), 7 Leads
Output Voltage
700 V
Input / Supply Voltage (max)
9 V
Input / Supply Voltage (min)
- 0.3 V
Duty Cycle (max)
78 %
Switching Frequency
132 KHz
Operating Temperature Range
- 40 C to + 150 C
Mounting Style
SMD/SMT
Maximum Operating Temperature
+ 150 C
Minimum Operating Temperature
- 40 C
Output Current
6.88 A
Output Power
48 W
For Use With
596-1193 - KIT REF DESIGN TOP HX FOR TOP258
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Other names
596-1189-5
A High Effi ciency, 150 W, 250 – 380 VDC Input
Power Supply
The circuit shown in Figure 42 delivers 150 W (19 V @ 7.7 A) at
84% effi ciency using a TOP258Y from a 250 VDC to 380 VDC
input. A DC input is shown, as typically at this power level a
power factor correction stage would precede this supply,
providing the DC input. Capacitor C1 provides local decoupling,
necessary when the supply is remote from the main PFC output
capacitor.
The fl yback topology is still usable at this power level due to the
high output voltage, keeping the secondary peak currents low
enough so that the output diode and capacitors are reasonably
sized. In this example, the TOP258YN is at the upper limit of its
power capability.
Resistors R3, R6 and R7 provide output power limiting,
maintaining relatively constant overload power with input voltage.
Line sensing is implemented by connecting a 4 MΩ resistor from
the V pin to the DC rail. Resistors R4 and R5 together form the
4 MΩ line sense resistor. If the DC input rail rises above
450 VDC, then TOPSwitch-HX will stop switching until the
voltage returns to normal, preventing device damage.
Due to the high primary current, a low leakage inductance
transformer is essential. Therefore, a sandwich winding with a
copper foil secondary was used. Even with this technique, the
leakage inductance energy is beyond the power capability of a
simple Zener clamp. Therefore, R1, R2 and C3 are added in
parallel to VR1 and VR3, two series TVS diodes being used to
reduce dissipation. During normal operation, very little power is
Rev. F 01/09
Figure 42. 150 W, 19 V Power Supply using TOP258YN.
250 - 380
22
VDC
4 A
F1
8.06 k
22 F
400 V
5
RT1
C1
1%
R3
TOP252-262
t
O
1.5 k
1.5 k
1.5 k
4.7 M
4.7 M
2 W
R20
R21
2 W
R22
2 W
R7
R6
120 pF
1N4937
1 kV
C18
D5
2.0
2.0 M
D
S
R5
R4
CONTROL
X
V
VR1, VR3
F
TOPSwitch-HX
C
TOP258YN
100 nF
68 k
50 V
C11
2 W
R1
4.7
R19
U1
68 k
2 W
R2
47 F
4.7 nF
6.8
10 V
R10
C10
1 kV
C3
D1
1
4
dissipated by VR1 and VR3, the leakage energy instead being
dissipated by R1 and R2. However, VR1 and VR3 are essential
to limit the peak drain voltage during start-up and/or overload
conditions to below the 700 V rating of the TOPSwitch-HX
MOSFET. The schematic shows an additional turn-off snubber
circuit consisting of R20, R21, R22, D5 and C18. This reduces
turn-off losses in the TOPSwitch-HX.
250 VAC
The secondary is rectifi ed and smoothed by D2, D3 and C5,
C6, C7 and C8. Two windings are used and rectifi ed with
separate diodes D2 and D3 to limit diode dissipation. Four
capacitors are used to ensure their maximum ripple current
specifi cation is not exceeded. Inductor L1 and capacitors C15
and C16 provide switching noise fi ltering.
Output voltage is controlled using a TL431 reference IC and
R15, R16 and R17 to form a potential divider to sense the
output voltage. Resistor R12 and R24 together limit the
optocoupler LED current and set overall control loop DC gain.
Control loop compensation is achieved using components C12,
C13, C20 and R13. Diode D6, resistor R23 and capacitor C19
form a soft fi nish network. This feeds current into the control
pin prior to output regulation, preventing output voltage
overshoot and ensuring startup under low line, full load
conditions.
Suffi cient heat sinking is required to keep the TOPSwitch-HX
device below 110
and maximum ambient temperature. Airfl ow may also be
required if a large heat sink area is not acceptable.
EI35
2.2 nF
T1
C4
1N4148
13,14
12
11
10 F
9,10
7
5
D4
50 V
C9
PC817B
4.7
R8
U2
0.5 W
0.5 W
R14
22
22
0.125 W
15 k
10 F
50 V
R23
MBR20100CT
MBR20100CT
D3
D2
47 pF
1 kV
°
C when operating under full load, low line
47 pF
0.125 W
PC817A
1N4148
C14
1 kV
240
R12
U2
D6
0.125 W
TL431
30
R24
U3
2%
0.125 W
1.0 F
50 V
1 k
C20
R11
C5-C8
820 F
25 V
0.125 W
4.7 nF
56 k
R13
C12
50 V
3.3 H
L1
100 nF
www.powerint.com
C13
50 V
C15-C16
820 F
25 V
4.75 k
PI-4795-092007
562
R17
R16
1%
R15
1%
1%
+19 V,
7.7 A
RTN

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