US211/A/B/C

Preliminary

CMOS IC

UNISONICTECHNOLOGIESCO.,LTD

5 of 8

www.unisonic.com.tw

QW-R502-A67.a



APPLICATION INFORMATION(Cont.)

Current Limiting and Short-Circuit Protection

The current limit circuit protects the MOSFET switch and the hub downstream port from damage. This circuit can

deliver load current up to the current limit threshold of typically 0.8A through the switch of US211, 1.5A for US211A,

1.7A for US211B and 2.0A for US211C. When an enabled switch applies a heavy load or short circuit, a

large-desired transient current occurs which can cause the current limit circuit response. If this current becomes

higher than the current limit threshold, the devices enter constant current mode until thermal shutdown occurs or the

fault is removed.

Thermal Shutdown

The thermal shutdown circuit is used to prevent damage occurs when the die temperature becomes higher than

approximately 130°C. After 20°C of hysteresis, the switch will automatically restart if it enabled. When these devices

are disabled or the fault is removed, the output and FLG signal will continue to cycle on and off.