Power Consumption
OBiSupport:
Quote from: idahowayne on October 08, 2014, 06:11:06 pm
Thank you support. How about the 202, does it draw any more current than the 200?
When it comes to power consumption, the OBi202 is almost identical to the OBi200. OBi200 needs 110-120 milliamps while idle and 160 milliamps while talking. If there is a second simultaneous call on the other phone port of the OBi202, then the consumption will increase by a proportionate amount.
Shale:
Quote from: Jackson on October 10, 2014, 09:25:26 am
Would this simple approach work? 12V zeners are quite inexpensive.
http://www.learningaboutelectronics.com/Articles/Overvoltage-protection-circuit.php
No. That circuit presumes a power supply whose voltage is less than the zener point, and the zener is only absorbing short overvoltage spikes.
When a zener diode used as a regulator, there needs to be a resistor in series with the power source. That type of regulator is very inefficient. Instead you would want to use a low-dropout regulator.
sailing:
Jackson, in addition to what Shale said, the circuit you linked to is for overvoltage protection. That circuit is for if the voltage goes over the zener voltage, the fuse will open. A zener requires a properly chosen resistor in front of it so the zener will regulate the voltage by shunting the current through the resistor.
Since idahowayne is so concerned about energy consumption, a linear regulator is still the wrong approach. There are dc/dc converters with efficiencies of 98% no matter what the input voltage is. You can find them at Digikey, Mouser or Newark Electronics.
A linear regulator regulating an input voltage of say 15V must drop 3V at 110ma to dissipate 0.33 watts. It isn't much but when running off grid, every watt reduces the run time of the battery.
dircom:
I assume, over/under dc/dc voltage regulators use more energy, the farther the presented voltage is from the target voltage?
ie, 9vdc -> 12 volts uses less power than say 18vdc -> 12 vdc?
or 14vdc -> 12vdc uses less power than 18vdc -> 12vdc?
sailing:
dircom, The efficiency ratings will not change for the voltage ranges you gave. In fact, there are dc/dc converters that will maintain 98% efficiency stepping 56V to 12V. The losses aren't in dropping the voltage. These converters chop the voltage at high frequency then pass them through a transformer to step down the voltage. The losses are in the chopping process which doesn't change much over the voltages we are talking about.
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