The TNY277GN is an energy-efficient offline Switcher incorporates a 700V power MOSFET, oscillator, high voltage switched current source, current limit and thermal shutdown circuitry. It uses an ON/OFF control scheme and offers a design flexible solution with a low system cost and extended power capability. TinySwitch-III combines a high voltage power MOSFET switch with a power supply controller in one device. Unlike conventional PWM controllers, it uses a simple ON/OFF control to regulate the output voltage. The controller consists of an oscillator and enables circuit, current limit state machine, 5.85V regulator, BYPASS/MULTI-FUNCTION pin undervoltage, overvoltage circuit and current limit selection circuitry, over-temperature protection, current limit circuit, leading edge blanking. TinySwitch-III incorporates additional circuitry for line undervoltage sense, auto-restart, adaptive switching cycle on-time extension and frequency jitter.
Feature
- Simple ON/OFF control, no loop compensation needed
- Selectable current limit through BP/M capacitor value
- Higher current limit extends peak power/in open frame, continuous power
- Lower current limit improves efficiency in enclosed adapters/chargers
- Allows optimum TinySwitch-III choice by swapping devices with no other circuit redesign
- Maximizes MOSFET and magnetic power delivery
- 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
- Pin-out simplifies heat sinking to the PCB
- SOURCE pins are electrically quiet for low EMI
- Accurate hysteretic thermal shutdown protection with automatic recovery eliminates need for reset
- 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
- Easily meets all global energy efficiency regulations
- No-load <150mW at 265VAC without bias winding, <50mW with bias winding
