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Circuit protection controller

A circuit protection controller from Linear Technology has been developed to ensure safe voltage and current levels for 2.5V to 60V electronics in battery-powered automotive, industrial and portable systems.
According to the company, the LTC4368 replaces fuses, transient voltage suppressors and discrete circuitry, shielding electronics from overcurrent and over, under and reverse voltages.

It controls back to back N-channel MOSFETs to provide a low loss current path during normal operation, turning them off for overcurrent faults in the forward or reverse direction. Two variants are available: the LTC4368-1 provides symmetric forward and reverse current thresholds to protect batteries from excessive charge and discharge currents; while the LTC4368-2 circuit breaker trips off when reverse current is detected to prevent backfeeding and hold up the output.

Both parts disconnect the load from input voltages exceeding an adjustable and precise overvoltage threshold. Adjustable undervoltage lockout disables operation for low input voltages, avoiding deeply discharged batteries. Reverse supply protection isolates the load from batteries inserted with incorrect polarity, eliminating a diode in the power path.

The LTC4368-1 provides a 50mV reverse circuit breaker sense threshold, whereas the LTC4368-2 has a 3mV reverse threshold. After an overcurrent fault, a pin configuration determines if the MOSFETs are latched off or turned on after a delay.

Specified for use in the 0 to 70°C commercial, -40 to 85°C industrial and -40 to 125°C automotive temperature ranges, the LTC4368 is available in a 10pin MSOP or a 3 x 3mm DFN.

Device current consumption is said to be 80µA in normal operation and 5µA in shutdown mode.

Author
Graham Pitcher

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