Energy-Efficient, Off-Line Switcher With Line-Compensated Overload Power
Typical Standby Application


With line-compensated overload power protection, TinySwitch-4 devices dramatically reduce the maximum overload variation over the universal input voltage range. It is particularly helpful in applications such as PC standby and CV adapters to limit the maximum output power during the overload fault condition. TinySwitch-4 also incorporates a 725 V MOSFET that easily allows 80% de-rating for high reflected voltage and high bus voltage designs. The BP/M pin permits the MOSFET current limit to be adjusted up or down, allowing designers to optimize power delivery and efficiency in a variety of physical implementations. An on-time extension function extends the low-line regulation range, enabling hold-up time to be met with lower values of input capacitance.

Product Highlights

Lowest System Cost with Enhanced Flexibility

  • 725 V rated MOSFET
    • Increases BV de-rating margin
  • Line compensated overload power – no additional components
    • Dramatically reduces max overload variation over universal input voltage range
  • ±5% turn on UV threshold: line voltage sense with single external resistor
  • Simple ON/OFF control, no loop compensation needed
  • Selectable current limit through BP/M capacitor value
    • Allows optimum TinySwitch-4 choice by swapping devices with no other circuit redesign
  • Tight I2f parameter tolerance reduces system cost
    • Maximizes MOSFET and magnetics utilization
  • ON-time extension – extends low-line regulation range/hold-up time to reduce input bulk capacitance
  • Self-biased: no bias winding or bias components
  • Frequency jittering reduces EMI filter costs

Enhanced Safety and Reliability Features

  • Accurate hysteretic thermal shutdown protection with auto¬matic recovery eliminates need for manual reset
  • Auto-restart delivers <3% of maximum power in short-circuit and open loop fault conditions
  • Output overvoltage shutdown with optional Zener
    • Fast AC reset with optional UV external resistor
  • Very low component count enhances reliability and enables single-sided printed circuit board layout
  • High bandwidth provides fast turn-on with no overshoot and excellent transient load response

EcoSmart™ – Energy Efficient

  • Easily meets all global energy efficiency regulations
  • No-load <30 mW with bias winding, <150 mW at 265 VAC without bias winding
  • ON/OFF control provides constant efficiency down to very light loads – ideal for mandatory CEC regulations and EuP standby requirements


  • PC Standby and other auxiliary supplies
  • DVD/PVR and other low power set top decoders
  • Supplies for appliances, industrial systems, metering, etc
  • Chargers/adapters for cell/cordless phones, PDAs, digital cameras, MP3/portable audio, shavers, etc.

Building Your Own Power Supply With PI

Available in These Packages

Output Power (Watts)
PRODUCT3 230 VAC ±15% 85-265 VAC
Adapter2 Open Frame2
(or Peak)
Adapter1 Open Frame2
(or Peak)
TNY284P/D/K 6 11 5 8.5
TNY285P/D 8.5 15 6 11.5
TNY285K 11 15 7.5 11.5
TNY286P/D 10 19 7 15
TNY286K 13.5 19 9.5 15
TNY287D 11.5 23.5 7 18
TNY287P 13 23.5 8 18
TNY287K 18 23.5 11 18
TNY288P 16 28 10 21.5
TNY288D 14.5 26 9 19.5
TNY288K 23 28 14.5 21.5
TNY289P 18 32 12 25
TNY289K 25 32 17 25
TNY290P 20 36.5 14 28.5
TNY290K 28 36.5 20 28.5


  1. Minimum continuous power in a typical non-ventilated enclosed adapter measured at +50 °C ambient. Use of an external heat sink will increase power capability.
  2. Minimum peak power capability in any design or minimum continuous power in an open frame design (see Key Applications Considerations).
  3. Packages: D: SO-8C, P: DIP-8C, K: eSOP-12B. See Part Ordering Information.

Product Documents
Package Informationpackageinfo.pdf
Data Sheettinyswitch-4_family_datasheet.pdf

Reference Designs*
RDK-399 <30 mW No Load, 12 W Power Supply
RDK-295 20 W Standby Power Supply

*DAKs/RDKs include a working power supply, sample devices, unpopulated pcb, data sheet, comprehensive engineering report, PI Expert design software and other related documentation.

Visit the Design Examples page for additional circuits using this product family.