UC3844BN is a fixed-frequency, current-mode pulse-width modulator integrated circuit (PWM IC) from STMicroelectronics. It is a monolithic integrated type circuit intended primarily for use as a single-order, fixed-frequency current-mode PWM controller. The UC3844 provides an improved valley-fill switch mode power supply (PFC) control, as well as normal PWM power supply control. It is suitable for a wide range of low-power switch mode applications, such as lighting and power supplies up to 650V. It contains a adjustable undervoltage lockout circuit, a temperature compensation circuit, an adjustable current limit circuit, an adjustable oscillator, and an output stage. The device also has built in latch protection and crowbar shutdown circuit.