TPS65231A2

The TPS652x provides one PWM buck controller, two adjustable, synchronous buck regulators, two independent USB power switches and a supply voltage supervisor (SVS) to provide main power functions for satellite set top boxes, xDSL and cable modem applications operating off a single 12- to 22-V supply.

The SMPS have integrated switching FETs for optimized power efficiency and reduced external component count. Each USB switch provides up to 0.5-A (TPS65230) or 1-A (TPS65231) of current as required by downstream USB devices. All power blocks have thermal and over current/short circuit protection.

The SVS provides two inputs for monitoring positive supply rails. The active-low open-drain output remains low for at least 180 ms after all supply rails rise above their rising edge threshold. Threshold value for VMON1 input is set for monitoring a 3.3-V rail without the need for additional external components. Threshold for VMON2 input is set to 0.8 V and requires resistor dividers on the input to monitor any positive voltage in the system. The nBOR/nHOT open-drain output is pulled low if the input supply drops below 9.3 V or the chip temperature approaches the thermal shutdown limit. This allows the system processor to save critical data and shut down gracefully before the supply fails.

The TPS65230 and TPS65231 can be controlled either through parallel I/Os or through I²C interface. When the pull-up resistor on the USBFLAG2/nINT pin is connected to a 3.3-V or lower supply the I²C interface is disabled and the device is controlled through parallel I/O pins only. With the pull-up resistor connected to 6 V the I²C interface is enabled and the device is controlled by writing to the control registers. Any fault or abnormal operating condition is flagged by the interrupt pin. The interrupt is cleared by reading the status register via the I²C interface.