TPS65282

The TPS65282 incorporates dual N-channel MOSFET power switches for USB power distribution systems that require dual power switches in a single package. It also integrates a buck monolithic converter. The device is intended to provide a total USB power distribution solution for digital TV, set-top boxes, tablet PC and VOIP phones etc applications, where precision current limiting is required or heavy capacitive loads or short circuits are encountered.

Dual 100-mΩ independent power distribution switch limits the output current to a programmable current limit threshold between typical 75 mA and 2.7 A by using an external resistor. The current limit accuracy can be achieved as tight as ±6% at higher current limit setting. TPS65282 device limits output current to a safe level by using a constant current mode when output load exceeds the current limit threshold. After deglitching time, TPS65282 provides circuit breaker functionality by latching off the power switch during over-current or reverse-voltage situations. Two back-to-back power MOSFETs prevents the current injects from output to input in shutdown. An internal reverse-voltage comparator disables the power switch when the output voltage is driven higher than the input to protect the circuits on the input side of the switch in normal operation. The nFAULT1/2 output asserts low during over-current and reverse-voltage conditions.

The buck DC/DC converter integrates power MOSFETs for optimized power efficiency and reduced external component. A wide 4.5-V to 18-V input supply range to buck encompasses most intermediate bus voltages operating off 5-V, 9-V, 12-V or 15-V power bus. Peak current mode control simplifies the compensation and fast transient response. Equipped with enable and soft-start pin, the DC/DC can be precisely sequenced and ramp up in order to align with other rails in the system. Cycle-by-cycle over-current protection and operating in hiccup mode limit MOSFET power dissipation during buck output short circuit or over loading fault conditions. The switching frequency of the converter can be programmed from 300 kHz to 1.4 MHz with an external resistor at ROSC pin. With ROSC pin connecting to V7V pin, floating, or grounding, a default fixed switching frequency can be selected. The buck also features a pulse skipping mode (PSM), which allows a power loss reduction on the input power supplied to the system to achieve high efficiency at light loading.

The device implements an internal thermal shutdown to protect itself if the junction temperature exceeds 160°C. The thermal shutdown forces the device to stop operating when the junction temperature exceeds thermal trip threshold. Once the die temperature decreases below 140°C, the device reinitiates the power up sequence. The thermal shutdown hysteresis is 20°C.

The TPS65282 is available in a 24-lead thermally enhanced QFN (RGE) 4-mm × 4-mm thin package.