ST 3845B High Performance Current Mode PWM Controller

STMicroelectronics 3845B is a high Performance current mode PWM controller. The 3845B control IC family provides the features required to implement off-line or DC to DC fixed frequency current mode control schemes with a low external part count. Internally implemented circuits include a trimmed oscillator with start-up current less than 0.5mA for precise DUTY CYCLE CONTROL under voltage lock-out, a precision reference trimmed for accuracy at the error amp input, logic to ensure latched operation, a PWM comparator with current limit control, and a totem pole output stage designed to source or sink high peak current. In the off-state, the output stage is low, making it suitable for driving N-Channel MOSFETs.

Features

• Trimmed oscillator for precise frequency control
• Oscillator frequency guaranteed at 250KHz
• Automatic feed forward compensation
• Latching PWD for cycle-by-cycle current limiting
• High current totem pole output
• Low start-up and operating current

Datasheet

Specifications