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High Voltage Switch (Read 5824 times)
bki
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High Voltage Switch
Oct 20th, 2014, 9:56am
 
Hi,

i need a switch that connects 150V to the load. That means, if the switch is closed i have 150V on the drain side and 150V on the source side.

Any idea, how can i realize this switch? Maybe is there a solution available on the market?

As far as i know, the most Power MOSFETs only accept such high voltages only on the drain sides but not on the source sides.

Please help!
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loose-electron
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Re: High Voltage Switch
Reply #1 - Oct 20th, 2014, 4:34pm
 
discrete transistors here right?

what is important is the

max Vds
max Vgs

and depending on the architecture of the transistors (a lot of discrete MOSFET's are not symmetric in their doping profiles)

sometimes max Vdg

give us a simple drawing of what you are trying to do and perhaps we can help.


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bki
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Re: High Voltage Switch
Reply #2 - Oct 21st, 2014, 12:39am
 
Attached is the picture.

The problem is, i have a gate voltage of 5V. So, if Vgs is maximum 20V for example, it means that on the source side can be maximum 25V. correct?
So i would need a transistor that has Vgs=155V, if the source should withstand 150V. correct?
Does anyone know a suitable solution?
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Re: High Voltage Switch
Reply #3 - Oct 21st, 2014, 8:54am
 
bki,
assuming Vcap < Vboost, the standard solution is a "floating voltage source", that drives the gate 5V above the source.
- B O E
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loose-electron
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Re: High Voltage Switch
Reply #4 - Oct 21st, 2014, 11:35pm
 
look at the architecture associated with "high side driver circuits" commonly used in half bridge drivers and similar power transistor control circuits.
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bki
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Re: High Voltage Switch
Reply #5 - Oct 22nd, 2014, 2:11am
 
Vcap is -40V and should become 150V when the switch is closed.
Isnīt there a simple solution to connect the 150V with the output?
The High Side MOSFET concept seems not to be a solution.
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loose-electron
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Re: High Voltage Switch
Reply #6 - Oct 28th, 2014, 10:19am
 
loose-electron wrote on Oct 21st, 2014, 11:35pm:
look at the architecture associated with "high side driver circuits" commonly used in half bridge drivers and similar power transistor control circuits.


Start by putting the above into search.
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