This is merely a historical archive of years 2008-2021, before the migration to mailman3.
A maintained and still updated list archive can be found at https://lists.osmocom.org/hyperkitty/list/simtrace@lists.osmocom.org/.
Harald Welte laforge at gnumonks.orgHi Kevin,
On Mon, May 09, 2011 at 07:26:58PM +0200, Kevin Redon wrote:
> here v0.8 : https://gsm.tsaitgaist.info/SIMtrace/v0.8/
> Compared to v0.7+, I added 2 1n4148 after the parallel voltage regulator
> outputs.
> I wanted to avoid the regulators to fuzz each other, but I don't know if
> it's right. Maybe an additional zener diode is also required.
I understand the intention, but I doubt it's a good idea. First, the
1N4148 is quite low-power/low-current, i.e. it will be the weakest
element in the chain. Second, it's a silicium diode and thus causes a
voltage drop of 0.7V, i.e. we will have 3.3-0.7= 2.6V only, which is
really bad.
I think you should just leave them out. You could simplify the design
by removing the DC/DC converter (SC120) and simply attach the battery
connector to the +5V input. The TPS73633 is a ultra-low-drop regulator,
i.e. from voltages >= 3.375V on it will provide a stable 3.3V output.
This means a battery pack with 3 or 4 1.2V cells should do just fine.
What do you think? We can save the step-up regulator and loose the
design risk of leaking power from the USB into the step-up regulator at
the same time...
Regards,
Harald
--
- Harald Welte <laforge at gnumonks.org> http://laforge.gnumonks.org/
============================================================================
"Privacy in residential applications is a desirable marketing option."
(ETSI EN 300 175-7 Ch. A6)