[IC] Electrostatic charge in switched-capacitor circuit

[Boki]

Dear good guys,

We have a question in switched-capacitor circuit that is

when we design switched-capacitor circuits, do we have to consider the
problem of "electrostatic charge" ?

does it is possible the capacitor was "full of electrostatic charge" before
circuit connected to power supply?

does it is possible the full of electrostatic charge capacitor causes IC
borken?


Thank you very much!

Best regards,

Boki.

 

[Sir Charles W. Shults III]

"Boki" <bokiteam@ms21.hinet.net> wrote in message
news:c7o3k7$l56@netnews.hinet.net...

Dear good guys,

We have a question in switched-capacitor circuit that is

when we design switched-capacitor circuits, do we have to consider the
problem of "electrostatic charge" ?

does it is possible the capacitor was "full of electrostatic charge"
before
circuit connected to power supply?

does it is possible the full of electrostatic charge capacitor causes IC
borken?

I think I understand you - and yes, capacitors can hold a charge that is
present when you turn a circuit on. You must add a "bleed down" resistor to
each capacitor that is high enough in value to not interfere with normal
operation, but when power is removed this will allow the charge to
dissipate.
If you connected these capacitors to a circuit without discharging them,
then yes- it is entirely possible (without seeing the circuit, a guess) that
this could damage the circuitry.

Cheers!

Chip Shults

 

[Fred Bartoli]

"Sir Charles W. Shults III" <NOaichipSPAM@cfl.rr.com> a écrit dans le
message news: gHPnc.16080$2f6.610935@twister.tampabay.rr.com...

"Boki" <bokiteam@ms21.hinet.net> wrote in message
news:c7o3k7$l56@netnews.hinet.net...
Dear good guys,

We have a question in switched-capacitor circuit that is

when we design switched-capacitor circuits, do we have to consider the
problem of "electrostatic charge" ?

does it is possible the capacitor was "full of electrostatic charge"
before
circuit connected to power supply?

does it is possible the full of electrostatic charge capacitor causes IC
borken?


I think I understand you - and yes, capacitors can hold a charge that
is
present when you turn a circuit on. You must add a "bleed down" resistor
to
each capacitor that is high enough in value to not interfere with normal
operation, but when power is removed this will allow the charge to
dissipate.
If you connected these capacitors to a circuit without discharging
them,
then yes- it is entirely possible (without seeing the circuit, a guess)
that
this could damage the circuitry.

Cheers!

Chip Shults

Don't confuse him, Chip.
Boki is in the IC design trip, and I guess he's working on a switched cap
filter, or something like this.
The question is : are the caps you're worried about on chip or on board.

In the first case, there're no concern (well I can't imagine anything that
could go wrong), unless you've done stupid things, like having 1 cap driving
on a mosfet across the supply rails.

In the second case, yes it may happen, but it's more a matter of board
design.

Thanks,
Fred.

 

[boki]

Thank you very mcuh.

Regards,

Boki.

"Fred Bartoli" <fred._canxxxel_this_bartoli@RemoveThatAlso_free.fr_AndThisToo> wrote in message news:<409fd83f$0$12736$636a15ce@news.free.fr>...

"Sir Charles W. Shults III" <NOaichipSPAM@cfl.rr.com> a écrit dans le
message news: gHPnc.16080$2f6.610935@twister.tampabay.rr.com...
"Boki" <bokiteam@ms21.hinet.net> wrote in message
news:c7o3k7$l56@netnews.hinet.net...
Dear good guys,

We have a question in switched-capacitor circuit that is

when we design switched-capacitor circuits, do we have to consider the
problem of "electrostatic charge" ?

does it is possible the capacitor was "full of electrostatic charge"
before
circuit connected to power supply?

does it is possible the full of electrostatic charge capacitor causes IC
borken?


I think I understand you - and yes, capacitors can hold a charge that
is
present when you turn a circuit on. You must add a "bleed down" resistor
to
each capacitor that is high enough in value to not interfere with normal
operation, but when power is removed this will allow the charge to
dissipate.
If you connected these capacitors to a circuit without discharging
them,
then yes- it is entirely possible (without seeing the circuit, a guess)
that
this could damage the circuitry.

Cheers!

Chip Shults



Don't confuse him, Chip.
Boki is in the IC design trip, and I guess he's working on a switched cap
filter, or something like this.
The question is : are the caps you're worried about on chip or on board.

In the first case, there're no concern (well I can't imagine anything that
could go wrong), unless you've done stupid things, like having 1 cap driving
on a mosfet across the supply rails.

In the second case, yes it may happen, but it's more a matter of board
design.

Thanks,
Fred.

 

[boki]

Is this right? : )
C
vin -------/ ----||---- \------->OP input
| | |
| | |
/ | \
| | |
| | |
GND | GND
|
R
|
\ Switch_R
|
GND


Regards,
Boki

"Sir Charles W. Shults III" <NOaichipSPAM@cfl.rr.com> wrote in message news:<gHPnc.16080$2f6.610935@twister.tampabay.rr.com>...

"Boki" <bokiteam@ms21.hinet.net> wrote in message
news:c7o3k7$l56@netnews.hinet.net...
Dear good guys,

We have a question in switched-capacitor circuit that is

when we design switched-capacitor circuits, do we have to consider the
problem of "electrostatic charge" ?

does it is possible the capacitor was "full of electrostatic charge"
before
circuit connected to power supply?

does it is possible the full of electrostatic charge capacitor causes IC
borken?


I think I understand you - and yes, capacitors can hold a charge that is
present when you turn a circuit on. You must add a "bleed down" resistor to
each capacitor that is high enough in value to not interfere with normal
operation, but when power is removed this will allow the charge to
dissipate.
If you connected these capacitors to a circuit without discharging them,
then yes- it is entirely possible (without seeing the circuit, a guess) that
this could damage the circuitry.

Cheers!

Chip Shults