TOP256EN

TOP256EN DESCRIPTION

The TOP256EN is an enhanced Eco Smart, Integrated Off-line Switcher with 30W peak, advanced feature set and extended power range. TOP Switch-HX cost-effectively incorporates with  a 700V power MOSFET which is highly reliable and used in  high voltage switched current source and also PWM control, oscillator, thermal shutdown circuit and the fault protection and other control over the circuitry onto a monolithic device is also provided by this device.

TOP256EN pin configuration

Table: Pin function description       

  TOP256EN Features

● Multi-mode operation maximizes efficiency at all loads and gives it wider range of operation

●  This device shows Low thermal impedance junction-to-case (2°C per watt)

●  This device shows  Low height is ideal for adapters where space is limited

●  This device can be used as Simple mounting using a clip to aid low cost manufacturing

●  This device provides Line under-voltage (UV) detection prevents turn-off glitches

●  Line over voltage (OV) shutdown extends line surge limit so it gives better circuit protection

●  This device shows Accurate programmable current limit

●  This device is Optimized line feed-forward for line ripple rejection

●  Half frequency option for video applications is used in many applications

●  The Frequency jittering reduces EMI filter cost so it gives a wider operational area

●  Heat sink is connected to SOURCE for low EMI and better circuit protection

●  The Fully integrated soft-start for minimum start-up stress is shown by this device

●  The Energy efficient over entire load range is shown by this device

●  Less than 200mW at 230VAC and the no load consumption is another specification

●  Standby power for 1W input is shown by this device

TOP256EN Specifications

●  Input Voltage AC Min: 85V  

●  Input Voltage AC Max: 265V  

●  No. of Pins: 7Pins  

●  Power Rating: 86W  

●  Topology: Flyback  

●  Operating Temperature Min: -40℃  

●  Operating Temperature Max: 150℃

Figure: Functional Block Diagram

Working Principal of TOP256EN

TOP256EN is an integrated switched mode power supply chip that converts a current at the control input to a duty cycle at the open drain output of a high voltage power MOSFET.  During normal operation,of the device the duty cycle of the power MOSFET decreases linearly with increasing CONTROL pin current.

 Applications of TOP256EN

● A High Efficiency, 20 W continuous 80 W Peak voltage is supplied, Universal Input Power Supply: The circuit shown in Figure below takes advantage of several of TOP Switch-HX features to reduce system cost and power supply size and the other features and to improve power supply efficiency while delivering significant peak power for a short duration. This design delivers continuous 20 W and the peak voltage of 80 W at 32 V from an 90 VAC to 264 VAC input. A nominal efficiency of 82% at full load is achieved using TOP256EN. The M-package part has an optimized current limit for this device to enable design of power supplies capable of delivering high power for a short duration.

● A High Efficiency, 150 W, 250 – 380 VDC Input Power Supply :The circuit shown in below Figure delivers 150 W (19 V @ 7.7 A) at 84% efficiency using a TOP258Y from a 250 VDC to 380 VDC input is supplied. A DC input is shown for this , as typically at this power level a power factor correction stage would precede this supply, providing the DC input. Capacitor C1 which provides local decoupling, necessary when the supply is remote from the main PFC output capacitor.

● A High Efficiency, 65 W, Universal Input Power Supply: The circuit of this IC delivers 65 W at 88% efficiency using a TOP256EN operating over an input voltage range of 90 VAC to 265 VAC.