TOP242YN Power Integrations, TOP242YN Datasheet - Page 29

IC OFFLINE SWIT UVLO HV TO220

TOP242YN

Manufacturer Part Number
TOP242YN
Description
IC OFFLINE SWIT UVLO HV TO220
Manufacturer
Power Integrations
Series
TOPSwitch®-GXr
Type
Off Line Switcherr
Datasheet

Specifications of TOP242YN

Output Isolation
Isolated
Frequency Range
66 ~ 132kHz
Voltage - Output
700V
Power (watts)
22W
Operating Temperature
-40°C ~ 150°C
Package / Case
TO-220-7 (Formed Leads), 5 Leads
Output Voltage
12 V
Input / Supply Voltage (max)
265 VAC
Input / Supply Voltage (min)
85 VAC
Duty Cycle (max)
83 %
Switching Frequency
132 KHz
Supply Current
1.6 mA
Operating Temperature Range
- 40 C to + 150 C
Mounting Style
Through Hole
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Other names
596-1067-5
Input Capacitor
The input capacitor must be chosen to provide the minimum DC
voltage required for the TOPSwitch-GX converter to maintain
regulation at the lowest specified input voltage and maximum
output power. Since TOPSwitch-GX has a higher DC
TOPSwitch-II, it is possible to use a smaller input capacitor.
For TOPSwitch-GX, a capacitance of 2 µF per watt is possible for
universal input with an appropriately designed transformer.
Primary Clamp and Output Reflected Voltage V
A primary clamp is necessary to limit the peak TOPSwitch-GX
drain to source voltage. A Zener clamp requires few parts and
takes up little board space. For good efficiency, the clamp
Zener should be selected to be at least 1.5 times the output
reflected voltage V
time short. When using a Zener clamp in a universal input
application, a V
for the absolute tolerances and temperature variations of the
Zener. This will ensure efficient operation of the clamp circuit
and will also keep the maximum drain voltage below the rated
breakdown voltage of the TOPSwitch-GX MOSFET.
A high V
of TOPSwitch-GX. An RCD clamp provides tighter clamp
voltage tolerance than a Zener clamp and allows a V
as 150 V. RCD clamp dissipation can be minimized by reducing
the external current limit as a function of input line voltage (see
Figures 21 and 35). The RCD clamp is more cost effective than
the Zener clamp but requires more careful design (see Quick
Design Checklist).
Output Diode
The output diode is selected for peak inverse voltage, output
current, and thermal conditions in the application (including
heatsinking, air circulation, etc.). The higher DC
TOPSwitch-GX, along with an appropriate transformer turns
ratio, can allow the use of a 60 V Schottky diode for higher
efficiency on output voltages as high as 15 V (see Figure 41: A
12 V, 30 W design using a 60 V Schottky for the output diode).
Bias Winding Capacitor
Due to the low frequency operation at no-load a 1 µF bias
winding capacitor is recommended.
Soft-Start
Generally, a power supply experiences maximum stress at
start-up before the feedback loop achieves regulation. For a
period of 10 ms, the on-chip soft-start linearly increases the duty
cycle from zero to the default DC
the primary current limit increases from 85% to 100% over the
same period. This causes the output voltage to rise in an orderly
manner, allowing time for the feedback loop to take control of
the duty cycle. This reduces the stress on the TOPSwitch-GX
MOSFET, clamp circuit and output diode(s), and helps prevent
OR
is required to take full advantage of the wider DC
OR
of less than 135 V is recommended to allow
OR
, as this keeps the leakage spike conduction
MAX
at turn on. In addition,
OR
OR
MAX
as high
MAX
than
MAX
of
Figure 46a. TOPSwitch-II Full Range EMI Scan (100 kHz, No Jitter).
Figure 46b. TOPSwitch-GX Full Range EMI Scan (132 kHz, With
transformer saturation during start-up. Also, soft-start limits the
amount of output voltage overshoot and, in many applications,
eliminates the need for a soft-finish capacitor.
EMI
The frequency jitter feature modulates the switching frequency
over a narrow band as a means to reduce conducted EMI peaks
associated with the harmonics of the fundamental switching
frequency. This is particularly beneficial for average detection
mode. As can be seen in Figure 46, the benefits of jitter increase
with the order of the switching harmonic due to an increase in
frequency deviation.
The FREQUENCY pin of TOPSwitch-GX offers a switching
frequency option of 132 kHz or 66 kHz. In applications that
require heavy snubbers on the drain node for reducing high
-10
-10
-20
-10
-10
-20
80
70
60
50
40
30
20
80
70
60
50
40
30
20
0
0
0.15
0.15
Jitter) with Identical Circuitry and Conditions.
TOPSwitch-GX (with jitter)
TOPSwitch-II (no jitter)
Frequency (MHz)
Frequency (MHz)
1
1
TOP242-250
EN55022B (QP)
EN55022B (AV)
EN55022B (QP)
EN55022B (AV)
10
10
11/05
O
29
30
30

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