1- The original standard circuit breaker (with its deceptively simple schematic symbol) is actuated by thermal or electromagnetic energy and has only one function: to provide overcurrent protection, which it performs consistently and reliably. (Photo courtesy of Wikipedia)While having a singular concentration is admirable, it can be constraining in terms of system design flexibility and variety. An electronic circuit breaker (ECB), such as Analog Devices’ LTC4249, comes in handy in this situation (Fig. 2). This dual ECB has capabilities, functionalities, and flexibility that a traditional circuit breaker does not have.
2- The LTC4249 dual electronic circuit breaker (ECB) is rated at 65 V/1.2 A and has capabilities and functions that a normal breaker does not have. It’s used to provide bias for the 1-A servo function of a sequenced GaN power amplifier with 1.2-A protection.
Due to its relatively high voltage rating along with a 1.2-A current rating, it’s able to deliver current oversight and protection across a wide range of applications, including protection for power-amplifier arrays, industrial safety, equipment-condition monitoring, relay replacement, and load switching.
It’s worth noting that the relationship between a traditional circuit breaker and an electronic circuit breaker is similar in some respects to the relationship between a traditional fusible-link device (fuse) and an electronic fuse (eFuse). The former has a single-minded functionality but lacks flexibility—which may be good or bad, depending on your point of view—while the latter is more sophisticated but adds more features, functions, and alternatives to the designer and circuit approach. The open-drain RDY status output pulls low after any circuit-breaker “event,” and the ECB latches into the off state. After a one-second cool-off time, the user can switch the ECB back on by toggling the enable input. The circuit breakers’ cool-off timer, overtemperature sensor, short-circuit detector, and inrush controller all prohibit operation outside the circuit breakers’ safe working region.
Voltage sequencing and closed-loop-bias current-control applications are made easier by the LTC4249’s precision enable inputs, ready outputs, and analog current-monitor outputs. 5 percent accurate analog current-monitor outputs, filtered (50 s) main overcurrent threshold, quick (2 s) secondary overcurrent threshold, and integrated 75-m switches are among the other significant requirements. The LTC4249, with a temperature range of 40 to +125°C, costs $2.39. (1,000 pieces). The chip is packaged in a 16-lead, 3-mm LQFN package. A 12-lead “skipped leading” 3- 4″ mm LQFN package is also available for applications that must fulfill creepage and clearance specifications up to 65 V.
