The LYT2004E from Power Integrations is a 5V, 1A, secondary-side synchronous stepdown converter. It works by taking a higher input voltage, such as from a USB power supply, and then creating a lower output voltage. This device is used mainly for USB battery charging applications, as it provides a stable, regulated output voltage for maximum battery charging performance. The LYT2004 also integrates a power switch, low on-resistance synchronous rectifier, and PWM control circuitry, making it an efficient and reliable power supply solution.