Do away with diodes

Linear Technology Corporation

recently introduced the LTC4414, an “ideal diode” PowerPath controller for driving large PFETs with substantial gate capacitance.

The LTC4414 permits low-loss OR-ing of multiple input DC power sources. Its 20mV forward voltage is said to be at least 10 times lower than that of a Schottky diode. As a result, the device increases efficiency by an order of magnitude, due to much lower power loss and less self-heating, in systems requiring automatic switching or load sharing between power sources.

Linear says the LTC4414 is guaranteed to meet performance specifications over a wide range of user conditions including an ambient temperature range of –40 degrees C to 125 degrees C and operating voltage range of 3V to 36V. The LTC4414 also provides reverse battery, overcurrent and MOSFET protection circuitry in a small MSOP package.

In addition, the device offers a digital control input and an open-drain status output pin to simplify interfacing to a microcontroller. Applications include systems that typically take power from multiple input sources, including high current power path switches, uninterruptible power supplies, backup battery systems, logic-controlled power switches and automotive and industrial systems.

Multiple LTC4414 devices can be used to enable switchover between multiple batteries or charging of multiple batteries from a single charger. The LTC4414 status pin (STAT) can be used to control a second P-channel MOSFET power switch so that both Schottky diodes are eliminated from the diode-OR circuit.

The IC’s 30uA quiescent current is independent of the load current. In addition, the LTC4414 utilises a strong gate drive for gate turn-on and turn-off times of 600us and 20us, respectively.

The LTC4414 is offered in an eight-lead MSOP package. The 1,000-piece price starts at $1.85 each.