초록 ▼

An active protection circuit for a MOSFET isolated switched power supply system operates to control the switching of the MOSFET isolation switches. A monitoring circuit operates to sense and turn off the isolation switch of the currently active power supply if it senses reverse current flowing throu

An active protection circuit for a MOSFET isolated switched power supply system operates to control the switching of the MOSFET isolation switches. A monitoring circuit operates to sense and turn off the isolation switch of the currently active power supply if it senses reverse current flowing through the switch. Simultaneously, a controller receives indication that the active power supply is out of specification, and actively switches the system voltage source to the other power supply. The controller actively ensures that the isolation switch of the out-of-specification power supply remains off until it determines otherwise.

대표청구항 ▼

1. An active protection circuit for a MOSFET isolated switched power supply system, said system comprising a first power supply operatively connected to a node via a first isolation switch and a second power supply operatively connected to said node via a second isolation switch, said active protect

1. An active protection circuit for a MOSFET isolated switched power supply system, said system comprising a first power supply operatively connected to a node via a first isolation switch and a second power supply operatively connected to said node via a second isolation switch, said active protection circuit comprising: a first power supply monitoring circuit which monitors a first power supply output voltage of said first power supply and generates a first output indicating whether said first power supply output voltage deviates from a first pre-selected voltage level by a first pre-selected amount; and a controller connected to control said first isolation switch and said second isolation switch, said controller connected to receive said first output from said first power supply monitoring circuit and, if said first power supply output voltage deviates from said first pre-selected voltage level by said first pre-selected amount, turn said first isolation switch to an OFF mode to prevent current from flowing therethrough and turn said second isolation switch to an ON mode to allow current to flow therethrough from said second power supply; a first reverse current monitoring circuit which detects reverse current flowing through said first isolation switch and generates a reverse current indicator if reverse current is detected; wherein if said reverse current is detected flowing through said first isolation switch, said first reverse current monitoring circuit turns said first isolation switch to said OFF mode and turns said second isolation switch to an ON mode; and wherein said first reverse current monitoring circuit comprises: a first differential amplifier operatively connected between a first input and a first output of said first isolation switch to generate a first differential amplifier output representative of a voltage drop between said first input and said first output; and a first voltage comparator operatively connected to receive said first differential amplifier output and a pre-selected voltage reference to generate a first voltage comparator output indicative of whether reverse current is flowing through said first isolation switch. 2. An active protection circuit in accordance with claim 1, comprising: a second reverse current monitoring circuit which detects reverse current flowing through said second isolation switch and generates said reverse current indicator if reverse current is detached; wherein if said reverse current is detected flowing through said second isolation switch, said second reverse current monitoring circuit turns said second isolation switch to said off mode and turns said first isolation switch to an ON mode; and wherein said second reverse current monitoring circuit comprises: a second differential amplifier operatively connected between a second input and a second output of said second isolation switch to generate a second differential amplifier output representative of a voltage drop between said second input and said second output; and a second voltage comparator operatively connected to receive said second differential amplifier output and a pre-selected voltage reference to generate a second voltage comparator output indicative of whether reverse current is flowing through said second isolation switch.