ONSEMI SG6858 Green Mode PWM Controller for Flyback Converters

This highly integrated PWM controller provides several special enhancements designed to meet the low standby power needs of low-power SMPS. The proprietary green-mode function provides off-time modulation to linearly decrease the switching frequency under light-load conditions to minimise standby power consumption. This green-mode function enables the power supply to meet even the strictest power conservation requirements.

The BiCMOS fabrication process reduces the start-up current to 10uA and the operating current to 2.5mA. To further improve power conservation, a large start-up resistance can be used. Built-in synchronised slope compensation ensures the stability of peak current mode control. Proprietary internal compensation provides a constant output power limit over a universal AC input range (90Vac to 264Vac). Pulse-by-pulse current limiting ensures safe operation even during short circuits.

To protect the external power MOSFET from being damaged by supply over-voltage events, the SG6858’s output driver is clamped at 17V. sG6858 controllers can be used to improve the performance and reduce the production cost of power supplies and can replace linear and RCC-mode power adapters. It is available in 8-pin DIP and 6-pin SOT-26 packages.

Features

• Green-mode PWM
• Supports the “Blue Angel” standard
• Low start-up current (10uA)
• Low operating current (2.5mA)
• Leading-edge blanking
• Constant output power limit
• Universal input
• Built-in synchronised slope compensation
• Current-mode operation
• Cycle-by-cycle current limiting
• Under-voltage lockout (UVLO)
• Programmable PWM frequency
• VoD over-voltage protection (auto-restart)
• Gate output voltage-clamped at 17V
• Low cost
• Few external components required
• Small SOT-26 and DIP-S packages

Applications

• Battery chargers for cellular phones, cordless phones,
• PDAs, digital cameras, and power tools
• Power adapters for inkjet printers, video game
• consoles, and portable audio players
• Open-frame SMPS for TV/DVD standby and
• auxiliary supplies, home appliances, and consumer
• electronics
• Replacements for linear transformers and RCC SMPs
• PC 5V standby power

Datasheet

Specifications