Peak current on Zener diodes

[cts_casemod]

Hi,

I need to charge a capacitor using a zenner diode. The device uses 100mA @ 320VDC and a series 100Ohm resistor results in an instantaneous maximum current of 3.5Amps. Zener is rated at 110mA max continuous current.

I know normal diodes, as used in rectifier circuits can handle this overload very well for short periods of time, but there is nothing referring that in the zener datasheet.

Any inputs here? Regards

 

[chuckey]

If you connect a zener between the base and collector of a power transistor, you end up with a power zener between the collector and the emitter terminal. Can be good for 10A!!
Frank

 

[cts_casemod]

I thought about that, bit I am looking to reduce the supply voltage by a about 80V. So Vout = Vin - 80V. The transistor approach will keep a fixed output voltage same as the reference zener.

Amy workaround for this?

 

[chuckey]

If you use a series of zeners to get a 80V zener , connect it to the power transistor then connect them to the Vin, it will reduce the Vo to Vin - 80 V. Depending on the time the 100mA flows, you may need a heat sink (80 X .1 A = 8W ).
Frank