HI,
If I am designing a piece of medical equipment which uses an automatic voltage doubler for use on US supplies, there is a risk of this circuit failing.
If failure occurs when operating on 240V mains the bus voltage will rise to approx 680V and cause extensive damage to inboard circuitry. One solution to this is to put gas discharge tubes (or other breakover protection device) across the series bulk capacitors - these will fire on this failure and blow an internal fuse. However it seems from 60601-1-1 8.11 this is not allowed, as its possible to trip other supplies in an operating theatre.
I was just wondering if anyone had come across this issue and found a solution? If the protection is just omitted something will probably blow and cause a fuse blow anyway and the ecaps will vent with a lot of damage to the equipment.
Thanks
Nick
If I am designing a piece of medical equipment which uses an automatic voltage doubler for use on US supplies, there is a risk of this circuit failing.
If failure occurs when operating on 240V mains the bus voltage will rise to approx 680V and cause extensive damage to inboard circuitry. One solution to this is to put gas discharge tubes (or other breakover protection device) across the series bulk capacitors - these will fire on this failure and blow an internal fuse. However it seems from 60601-1-1 8.11 this is not allowed, as its possible to trip other supplies in an operating theatre.
I was just wondering if anyone had come across this issue and found a solution? If the protection is just omitted something will probably blow and cause a fuse blow anyway and the ecaps will vent with a lot of damage to the equipment.
Thanks
Nick
