Ok so I am looking to regulate a 6v power supply down to 3v
Constraints are:
Extremely limited board space (no room for any IC)
Must be power efficient as the module is powered by 2x button cell batteries. (IE as close to 0 drain when off as possible)
my first thought was to use 2x resistors of equal value in series and pull the power from between them to regulate to 3v, but my only concern here is that in this scenario there is a constant connection between Vcc and Vdd (through 2 resistors) which would cause a constant drain on the battery.
If using a high resistor value it will limit the constant draining but will also limit current to the only IC used. Low value and the opposite is true.
So i'm just wondering my options here, would a schottky diode be appropriate?
Oh yeah this is supplying power to a simple 3v PIC microprocessor, which is driving a 3v SMD RGB LED so it must have enough current to drive both.
Thanks in advance for the help
Best regards,
-J
Best Answer
There is the NCP4680x regulator. It comes in a tiny 0.8mm x 0.8mm footprint: -
Downside with any regulator is that it needs input and output capacitors but you might be able to mount them on top or have something closeby that will do the job. This version has an absolute max input voltage of 6V but it was just about the first hit when I googled "smallest voltage regulator".
Output voltages available in 0.1V steps from 0.8 volts to 3.6 volts and it can supply 150mA but watch the thermal situation because it has a thermal resistance of 350degC/watt. I'd recommend a dropper resistor with this device to both reduce power heating of the chip AND drop voltage to maybe 5V under minimum load conditions.