TNY274-280
BYPASS/
MULTI-FUNCTION
(BP/M)
REGULATOR
5.85 V
LINE UNDER-VOLTAGE
DRAIN
(D)
115
µA
25
µA
AUTO-
RESTART
COUNTER
6.4 V
FAULT
PRESENT
+
-
BYPASS PIN
UNDER-VOLTAGE
RESET
CURRENT
LIMIT STATE
MACHINE
5.85 V
4.9 V
V
I
LIMIT
CURRENT LIMIT
COMPARATOR
ENABLE
-
+
JITTER
CLOCK
1.0 V + V
T
DCMAX
THERMAL
SHUTDOWN
OSCILLATOR
ENABLE/
UNDER-
VOLTAGE
(EN/UV)
1.0 V
S
Q
R
Q
LEADING
EDGE
BLANKING
SOURCE
(S)
PI-4077-013106
Figure 2. Functional Block Diagram.
Pin Functional Description
DRAIN (D) Pin:
This pin is the power MOSFET drain connection. It provides
internal operating current for both start-up 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
for the internally generated 5.85 V supply.
2. It is a mode selector for the current limit value, depending
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.
3. It provides a shutdown function. When the current into the
bypass pin exceeds 5.5 mA, the device latches off until the
BP/M voltage drops below 4.9 V, during a power down.
This can be used to provide an output overvoltage function
P Package (DIP-8C)
G Package (SMD-8C)
EN/UV
BP/M
1
2
8
7
S
S
6
D
S
S
4
5
PI-4078-080905
Figure 3. Pin Configuration.
with a Zener connected from the BP/M pin to a bias winding
supply.
ENABLE/UNDER-VOLTAGE (EN/UV) Pin:
This pin has dual functions: enable input and line under-voltage
sense. During normal operation, switching of the power
2
E
2/06
POWERINT [ POWER INTEGRATIONS, INC. ]
