tny274 Power Integrations, Inc., tny274 Datasheet - Page 2

• Manufacturer Part Number: tny274
• Description: Energy Ef?cient, Of?ine Switcher With Enhanced Flexibility And Extended Power Range
• Manufacturer: Power Integrations, Inc.

Pin Functional Description
DRAIN (D) Pin:
This pin is the power MOSFET drain connection. It provides
internal operating current for both startup and steady-state
operation.
BYPASS/MULTI-FUNCTION (BP/M) Pin:
This pin has multiple functions:
1. It is the connection point for an external bypass capacitor
2. It is a mode selector for the current limit value, depending
3. It provides a shutdown function. When the current into
Figure 2. Functional Block Diagram.
MULTI-FUNCTION
2
for the internally generated 5.85 V supply.
on the value of the capacitance added. Use of a 0.1 µF
capacitor results in the standard current limit value. Use of
a 1 µF capacitor results in the current limit being reduced to
that of the next smaller device size. Use of a 10 µF capacitor
results in the current limit being increased to that of the next
larger device size for TNY275-280.
the bypass pin exceeds I
BP/M voltage drops below 4.9 V, during a power down.
This can be used to provide an output overvoltage function
TNY274-280
VOLTAGE
ENABLE/
115 µA
UNDER-
BYPASS/
(EN/UV)
(BP/M)
G
6/06
ENABLE
1.0 V + V
1.0 V
25 µA
T
SD
, the device latches off until the
6.4 V
LINE UNDER-VOLTAGE
OSCILLATOR
LATCH
JITTER
COUNTER
RESTART
DC MAX
OVP
CLOCK
AUTO-
RESET
PRESENT
FAULT
Figure 3. Pin Configuration.
ENABLE/UNDERVOLTAGE (EN/UV) Pin:
This pin has dual functions: enable input and line undervoltage
sense. During normal operation, switching of the power
SELECT AND
LIMIT STATE
CAPACITOR
CURRENT
MACHINE
BYPASS
with a Zener connected from the BP/M pin to a bias winding
supply.
SHUTDOWN
THERMAL
S
R
5.85 V
EN/UV
4.9 V
BP/M
Q
Q
G Package (SMD-8C)
D
P Package (DIP-8C)
+
-
1
2
4
BYPASS PIN
UNDER-VOLTAGE
REGULATOR
5.85 V
CURRENT LIMIT
COMPARATOR
BLANKING
LEADING
EDGE
8
7
6
5
V
S
S
S
S
I LIMIT
+
-
PI-4077-062306
PI-4078-080905
SOURCE
DRAIN
(D)
(S)