TNY263-268
BYPASS
(BP)
REGULATOR
5.8 V
LINE UNDER-VOLTAGE
240
µA
50
µA
FAULT
PRESENT
DRAIN
(D)
+
-
CURRENT
LIMIT STATE
MACHINE
5.8 V
4.8 V
BYPASS PIN
UNDER-VOLTAGE
AUTO-
RESTART
COUNTER
6.3 V
RESET
VI
LIMIT
CURRENT LIMIT
COMPARATOR
ENABLE
-
+
JITTER
CLOCK
1.0 V + VT
DCMAX
THERMAL
SHUTDOWN
OSCILLATOR
ENABLE/
UNDER-
VOLTAGE
(EN/UV)
1.0 V
S
Q
R
Q
LEADING
EDGE
BLANKING
SOURCE
(S)
PI-2643-030701
Figure 2. Functional Block Diagram.
Pin Functional Description
DRAIN (D) Pin:
Power MOSFET drain connection. Provides internal operating
current for both start-up and steady-state operation.
BYPASS (BP) Pin:
Connection point for a 0.1
µF
external bypass capacitor for the
internally generated 5.8 V 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
MOSFET is controlled by this pin. MOSFET switching is
terminated when a current greater than 240
µA
is drawn from
this pin. This pin also senses line under-voltage conditions
through an external resistor connected to the DC line voltage.
If there is no external resistor connected to this pin,
TinySwitch-II
detects its absence and disables the line under-
voltage function.
P Package (DIP-8B)
G Package (SMD-8B)
BP
S
S
EN/UV
1
2
3
4
8
7
S (HV RTN)
S (HV RTN)
5
D
PI-2685-101600
Figure 3. Pin Configuration.
SOURCE (S) Pin:
Control circuit common, internally connected to output
MOSFET source.
SOURCE (HV RTN) Pin:
Output MOSFET source connection for high voltage return.
2
E
4/04
POWERINT [ POWER INTEGRATIONS, INC. ]
