TNY263-268
PI-2381-1030801
200
V
EN
CLOCK
D
100
0
10
V
DC-INPUT
MAX
5
0
V
BYPASS
I DRAIN
400
200
0
0
1
2
V
DRAIN
Time (ms)
V DRAIN
Figure 11. TinySwitch-II Power-up without Optional External UV
Resistor Connected to EN/UV Pin.
PI-2348-030801
PI-2661-072400
Figure 9.
TinySwitch-II Operation at Very Light Load.
200
100
V
DC-INPUT
two main benefits. First, for a nominal application, this
eliminates the cost of a bias winding and associated
components. Secondly, for battery charger applications, the
current-voltage characteristic often allows the output voltage
to fall close to zero volts while still delivering power. This type
of application normally requires a forward-bias winding which
has many more associated components. With TinySwitch-II,
neither are necessary. For applications that require a very low
no-load power consumption (50 mW), a resistor from a bias
winding to the BYPASS pin can provide the power to the chip.
The minimum recommended current supplied is 750
μA.
The
BYPASS pin in this case will be clamped at 6.3 V. This method
will eliminate the power draw from the DRAIN pin, thereby
200
100
0
10
5
0
400
200
0
0
1
2
V
V
BYPASS
V
DC-INPUT
0
400
300
200
100
0
0
.5
1
V
DRAIN
Time (s)
Figure 12. Normal Power-down Timing (without UV).
PI-2383-030801
200
100
0
400
300
200
100
V
DRAIN
V
DC-INPUT
DRAIN
0
0
2.5
5
Time (ms)
Figure 10. TinySwitch-II Power-up with Optional External UV
Resistor (2 MΩ) Connected to EN/UV Pin.
Time (s)
Figure 13. Slow Power-down Timing with Optional External
(2 MΩ) UV Resistor Connected to EN/UV Pin.
6
Rev. H 02/09
www.powerint.com
PI-2395-030801
POWERINT [ POWER INTEGRATIONS, INC. ]
