TNY278 Off-Line Switcher IC: Pinout, Product Highlights and Datasheet

The following figure is the diagram of TNY278 pinout.

Pinout

The followings are TNY278 Symbol, Footprint, and 3D Model.

PCB Symbol

PCB Footprint

3D Model

TinySwitch-III TNY278 combines a high voltage power MOSFET switch with a power supply controller in one device. Unlike conventional PWM (pulse width modulator) controllers, it uses a simple ON/OFF control to regulate the output voltage. The controller consists of an oscillator, enable circuit (sense and logic), current limit state machine, 5.85 V regulator, Undervoltage, overvoltage circuit, and current limit selection circuitry, over-temperature protection, current limit circuit, leading-edge blanking, and a 700 V power MOSFET. This makes it suitable for many applications.

This article will introduce TNY278 systematically from its product highlights, pinout to its specifications, applications, also including TNY278 datasheet and so much more.

Lowest System Cost with Enhanced Flexibility

● Simple ON/OFF control, no loop compensation needed

● Selectable current limit through BP/M capacitor value

   ◆ Higher current limit extends peak power or, in open frame applications, maximum continuous power

   ◆ Lower current limit improves efficiency in enclosed adapters/chargers

   ◆ Allows optimum TinySwitch-III choice by swapping devices with no other circuit redesign

● Tight I²f parameter tolerance reduces system cost

   ◆ Maximizes MOSFET and magnetics power delivery

   ◆ Minimizes max overload power, reducing cost of transformer, primary clamp & secondary components

● 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

● Pin-out simplifies heatsinking to the PCB

● SOURCE pins are electrically quiet for low EMI

Enhanced Safety and Reliability Features

● Accurate hysteretic thermal shutdown protection with automatic recovery eliminates need for manual reset

● Improved auto-restart delivers <3% of maximum power in short circuit and open loop fault conditions

● Output overvoltage shutdown with optional Zener

● Line undervoltage detect threshold set using a single optional 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

● Extended creepage between DRAIN and all other pins improves field reliability

EcoSmart^® – Extremely Energy Efficient

● Easily meets all global energy efficiency regulations

● No-load <150 mW at 265 VAC without bias winding, <50 mW with bias winding

● ON/OFF control provides constant efficiency down to very light loads – ideal for mandatory CEC regulations and 1 W PC standby requirements

The following is the Block Diagram of TNY278.

Functional Block Diagram

TNY278PG, TNY274P, TNY275P, TNY276P, TNY277P, TNY279

The reason behind Power Integration and their ICs popularity is that they are easy-to-use, have enormous availability of support documents, low external parts count, and reduced cost.

The example circuit above shows you how a low cost, high efficiency, flyback power supply designed for 12 V, 1 A output from universal input using the TNY278. The supply features Undervoltage lockout, primary sensed output overvoltage latching shutdown protection, high efficiency (>80%), and very low no-load consumption (<50 mW at 265 VAC). Output regulation is accomplished using a simple Zener reference and optocoupler feedback. As the TinySwitch-III devices are completely self-powered, there is no requirement for an auxiliary or bias winding on the transformer. However, by adding a bias winding, the output overvoltage protection feature can be configured, protecting the load against open feedback loop faults.

● Chargers/adapters for cell/cordless phones, PDAs, digital cameras, MP3/portable audio, shavers, etc.

● PC Standby and other auxiliary supplies

● DVD/PVR and other low power set top decoders

● Supplies for appliances, industrial systems, metering, etc. 

The following diagrams show the TNY278 package.

View A

View B

View C

Power Integrations is a leading supplier of high-performance electronic components used in high-voltage power-conversion systems. Our integrated circuits and diodes enable compact, energy-efficient AC-DC power supplies for a vast range of electronic products including mobile devices, TVs, PCs, power tools, smart appliances (IoT), smart utility meters and LED lights.