FEATURES

• 10 to 200 V Input Range

• Current-Mode Control

• Internal Start-Up Circuit

• Buffer Slope Compensation Voltage

• Soft-Start

• 2.7 MHz Error Amp

• 500 mA Output Drive Current

• Light Load Frequency Fold-Back

• Low Quiescent Current

• Programmable Maximum Duty Cycle, with 80 as

Default

DESCRIPTION

The Si9118/Si9119 are a BiC/DMOS current-mode pulse

width modulation (PWM) controller ICs for high-frequency

dc/dc converters. Single-ended topologies (forward and

flyback) can be implemented at frequencies up to 1 MHz.

The controller operates in constant frequency mode during

the full load and automatically switches to pulse skipping

mode under light load to maintain high efficiency throughout

the full load range. The maximum duty cycle is easily

programmed with a resistor divider for optimum control.

The push-pull output driver provides high-speed switching to

external MOSPOWER devices large enough to supply 50 W

of output power. Shoot-through current for internal push-pull

stage is almost eliminated to minimize quiescent supply

current.

The push-pull output driver provides high-speed switching to

external MOSPOWER devices large enough to supply 50 W

of output power. Shoot-through current for internal push-pull

stage is almost eliminated to minimize quiescent supply

current.

The high-voltage DMOS transistor permits direct operation

from bus voltages of up to 200 V. Other features include a

1.5 accurate voltage reference, 2.7 MHz bandwidth error

amplifier, standby mode, soft-start and undervoltage lockout

circuits.

The Si9118/Si9119 are available in both standard and lead

(Pb)-free packages.