ADI now offers Power by Linear LTC7862, an efficient switching surge suppressor with overvoltage and overcurrent protection for high availability systems. The device drives an N-channel power MOSFET stage. During normal operation, the device passes the input voltage to the output with minimal conduction loss. When input overvoltage conditions occur, the device begins to switch as a high-efficiency DC-DC regulator, protecting critical downstream components by limiting output voltage and current.
The device builds universal linear surge suppressors, such as the LTC4363, by providing efficient switching protection to increase output current capability and reduce power loss during transients and faults. When the load current in a long-inductance power bus changes suddenly, the supply voltage surges. In automotive applications, this can be exacerbated by the energy saved in the alternator inductance, resulting in a voltage surge and expansion caused by load dumps. The power handling capability of a surge suppressor is limited by the power loss in the protection circuit. In a linear surge suppressor, the power capability is defined by the size of the transmitting MOSFET, while in a switching surge suppressor, the power capability is defined by the conversion efficiency. Due to its lower power loss,
The device operates from an input voltage of 4V to 140V with a maximum of 150V abs. When the power loss reaches the highest level, the external fault timer capacitor can be configured with a limited time in overvoltage mode and keeps the switching surge suppressor below the safe peak operating temperature. The fault timer saves system cost and size by enabling component selection to be optimized for normal mode, rather than overvoltage transients and fault conditions.
