Electronic breaker needs no sense resistor

A novel electronic circuit breaker senses load currents using the on-resistance of an external MOSFET, eliminating the need for a sense resistor.

Linear Technology has introduced the LTC4213, an electronic circuit breaker that senses load currents using the on-resistance of an external MOSFET, eliminating the need for a sense resistor.

This new method not only reduces voltage and power loss in the switch path, but also lowers the cost and simplifies design.

This is especially beneficial to low voltage systems since the sense resistor voltage drop constitutes a significant portion of the supply voltage.

For ultra-low-voltage applications, the LTC4213 operates over a bias supply range of 2.3 to 6V and monitors voltages from ground up to 6V.

The electronic circuit breaker offers three pin-selectable VDS thresholds of 25, 50 and 100mV.

The select pin can be stepped dynamically, allowing a higher circuit breaker threshold at startup and a lower threshold after the supply current has settled.

The circuit breaker also provides dual level and dual response time functions for overcurrent protection by integrating a slow and a fast comparator.

This further enhances the circuit breaker performance by differentiating between slight overcurrent faults or catastrophic short circuit conditions.

The precise performance of the LTC4213 makes it ideal for systems requiring continual protection of low voltage supplies.

Offered in 12-lead DFN package and specified over the commercial and industrial temperature ranges, pricing for the LTC4213 starts at $1.50 each in 1000-piece quantities.

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