TNY376 View Datasheet(PDF) - Power Integrations, Inc
Part Name
Description
MFG CO.
TNY376
Power Integrations, Inc
'TNY376' PDF : 20 Pages View PDF
TNY375-380
Copper area for
heat sinking
+
HV
-
TOP VIEW
Return bias winding
directly to input capacitor
Safety Spacing
Y1-
Capacitor
Input Filter Capacitor
D
S
S
EN/UV
S
PRI
T
BIAS
r
a
n
PRI
s
f
o
r
m
BIAS
e
r
SEC
Maximize hatched copper
areas (
) for optimum
heatsinking
Output
Rectifier
S
BP
CBP
RUV
Bypass capacitor connection
to device should be short
Figure 16. Layout Considerations for TinySwitch-PK Using P Package.
Opto-
coupler
Route connections to EN/UV pin
(including undervoltage resistor)
away from drain connected traces
- DC +
OUT
PI-4675-051507
Y-Capacitor
The placement of the Y-capacitor should be directly from the
primary input filter capacitor positive terminal to the common/
return terminal of the transformer secondary. Such a placement
will route high magnitude common mode surge currents away
from the TinySwitch-PK device. Note – if an input π (C, L, C)
EMI filter is used, then the inductor in the filter should be placed
between the negative terminals on the input filter capacitors.
Optocoupler
Place the optocoupler physically close to the TinySwitch-PK
device to minimize the primary side trace lengths. Keep the
high current, high voltage drain and clamp traces away from the
optocoupler to prevent noise pick up.
Output Diode
For best performance, the area of the loop connecting the
secondary winding, the Output Diode, and the Output Filter
Capacitor should be minimized. In addition, for axial diodes,
sufficient copper area should be provided at the anode and
cathode terminal of diode for heatsinking. A larger area is
preferred at the quiet cathode terminal. A large anode area can
increase high frequency radiated EMI.
Quick Design Checklist
As with any power supply design, all TinySwitch-PK designs
should be verified on the bench to make sure that component
specifications are not exceeded under worst case conditions.
The following minimum set of tests is strongly recommended:
1. Maximum drain voltage – Verify the VDS does not exceed
650 V at highest input voltage and peak (overload) output
power. The 50 V margin to the 700 V BVDSS specification
gives margin for design variation.
2. Maximum drain current – At maximum ambient temperature,
maximum input voltage, and peak output (overload) power,
verify drain current waveforms for any signs of transformer
saturation and excessive leading edge current spikes at
startup. Repeat under steady state conditions and verify that
the leading edge current spike event is below IINIT at the end
of the t . LEB(Min) Under all conditions the maximum drain
current should be below the specified absolute maximum
ratings.
3. Thermal Check – At specified maximum output power,
minimum input voltage, and maximum ambient temperature,
verify that the temperature specifications are not exceeded
for TinySwitch-PK device, transformer, output diode, and
output capacitors. Enough thermal margin should be
allowed for part-to-part variation of the RDS(ON) of
TinySwitch-PK device as specified in the data sheet. Under
low-line maximum power, a maximum TinySwitch-PK device
SOURCE pin temperature of 110 °C is recommended to
allow for these variations.
Design Tools
Up-to-date information on design tools can be found at the
Power Integrations web site: www.powerint.com.
www.powerint.com
11
Rev. A 05/07
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