How to make 3 different voltages in a circuit?

[q1212]

I have 1 circuit composed from 3 little very simple circuits I want to power them all from a 5V@1A power source.
All of these 3 circuits must be powered at different voltages.
Their current draw I measured for each of them.
A=4V @10mA, B=3.4V @1.6mA, C= 5V @24mA
What can you suggest?
Thank you.

 

[KlausST]

Hi,

5V: you have already
3.4V: a 3V3 zener in shunt configuratiin with high bias current
4V: 4V shunt regulator, small voltage regulator, Opamp

Klaus

 

[BradtheRad]

Your power consumption is small. It's feasible to install a diode to drop a fraction of a volt.

A diode in series drops 0.6 V.
Two diodes, 1.2V.
A red led, 1.8v.
Etc.

By adding a resistor in series you can make further adjustments. Example, suppose you drop 5v to 4.4v by means of one diode. You want 4V 10mA. Then install a resistor 40 ohms to drop 0.4v.
Regulation isn't as good, although it should turn out okay if the load is unchanging.

 

[d123]

Hi,

5V in would mean the 5V output is taken care of by the supply itself, only the 4V and 3.4V would need to be generated.

PMICs are worth looking at and other ICs dealing with power management. A dual adjustable output LDO is another option. You could just use e.g. two TL431s (or TLV431s or TLVH431s) as shunt regulators as that can easily cope with 10mA, PCB space permitting.