The high heat dissipated by the Schottky blocking diodes, traditionally utilized to protect a load from the faulty power supplies, relates directly to hefty 0.5V forward voltage drop. Replacing the diodes with low on-resistance MOSFETs, which have typical forward voltages of under 100mV, means that power dissipation is significantly reduced. The new ZXGD3102 is particularly designed to control the MOSFETs in high-reliability N+1 redundant power systems.
Sinking a peak turn-off current of 5A, the controller’s gate drive is able to attain a typical MOSFET turn-off time of 160ns, ensuring rapid load protection that is required to avoid any variation in the bus voltage in the event of a power supply failure and hot-swapping. To meet fault handling needs, turn-on time can be adjusted to allow a smooth handover between supplies. The new chip’s input voltage blocking capability is 180V.
The new chip is housed in a compact SM8 package and needs a minimal external component count. The new ZXGD3102 utilizes a 5 to 15V low-current bias rail, which is easily derived using a miniature zener diode.
