®
TNY256
TinySwitch Plus
Energy Efficient, Low Power Off-line Switcher
Product Highlights
TinySwitch Plus
Features
• Extended power range
• Fully integrated auto-restart reduces short circuit current
• Line under-voltage sense eliminates turn-off glitches
• Frequency jittering dramatically reduces EMI (5 to 10 dB)
• TO-220 package option
Lowest Cost, Low Power Switcher Solution
• Lower cost than RCC, discrete PWM and other
integrated/hybrid solutions
• Cost effective replacement for bulky linear adapters
• Lowest component count
• Simple ON/OFF control – no loop compensation components
• No bias winding – simpler, lower cost transformer
• Designed to work with low cost external components
+
Optional
UV Resistor
®
+
DC Output
–
Wide-Range
HV DC Input
D
EN/UV
BP
TinySwitch Plus
S
–
PI-2363-022699
Figure 1. Typical Standby Application.
OUTPUT POWER CAPABILITY*
ORDER
PART
NUMBER
TNY256P
TNY256G
TNY256Y
PACKAGE
DIP-8
SMD-8
TO-220-7B
8-19 W
5-11 W
230 VAC or
115 VAC
w/Doubler
85-265
VAC
Extremely Energy Efficient
• Consumes only 30/60 mW at 115/230 VAC with no load
• Meets Blue Angel, Energy Star, Energy 2000 and
200mW European cell phone requirements for standby
• Saves $1 to $4 per year in energy costs (at $0.12/kWHr)
compared to bulky linear adapters
• Ideal for cellular phone chargers and adapters
High Performance at Low Cost
• High voltage powered – ideal for charger applications
• High bandwidth provides fast turn on with no overshoot
• Current limit operation rejects line frequency ripple
• Built-in current limit and thermal protection
8-15 W
5-10 W
Table 1. * The low end of the power ranges shown represent enclosed
adapters with minimal heat sinking whereas, the high end of the power
ranges represent open frame power supplies with adequate heat
sinking, both measured at an ambient of 50
o
C. Please refer to the Key
Application Considerations section for more details.
Description
The TNY256 extends the power range of the
TinySwitch
family
of energy efficient, low power off-line switchers.
TinySwitch
devices use a breakthrough design to provide the lowest cost,
high efficiency, off-line switching solution for low power
applications. They integrate a 700 V power MOSFET, oscillator,
high voltage switched current source, current limit and thermal
shutdown circuitry into a single, monolithic device. The
devices start-up and operate on power derived from the DRAIN
voltage, eliminating the need for a transformer bias winding and
associated circuitry.
TinySwitch's
low operating current allows
power supply no-load consumption to be kept under 100 mW,
even at 265 VAC input.
The
TinySwitch Plus
incorporates auto-restart, line under-voltage
sense, and frequency jittering features. The auto-restart circuit
safely limits output power during fault conditions such as output
short or open loop. The auto-restart circuit is fully integrated and
does not require external timing components. The line under-
voltage sense threshold can be externally programmed using a line
sense resistor. During start-up, this feature keeps the TNY256 off
until the input line voltage reaches the under-voltage threshold.
When the input line voltage is removed, the line under-voltage
circuit prevents auto-restart attempts after the output goes out of
regulation. This eliminates power down glitches caused by the
slow discharge of input storage capacitors present in applications
such as standby supplies. A single resistor is used to implement
this feature, eliminating what normally takes five to six components.
The line sense resistor is optional. The TNY256 operating frequency
of 130 kHz is jittered (frequency modulated) to reduce both quasi-
peak and average EMI, minimizing filtering costs.
July 2001
POWERINT [ POWER INTEGRATIONS, INC. ]
