common ground to different dc out put voltages

Hi all.

My circuit board needs two supply voltages (5v and 15v ) from
external power supply .I used two switching regulators ,one of which
gives 5v o/p with 4amps and other one 15v o/p with 3amps.i have taken
these voltages as input to the different ic's.i want to know that
shall i connect the two grounds of the different supply voltages as
common to the ground in my circuit board.please clear me ,because i am
not getting the required output voltage.
Thanks in advance.

With Regards,
bhanuprakash.

 

There should be no reason that two independent power supplies can't
coexist with the same ground - unless power is being sourced from one
and sicked by the other. Powering IC's on a board with the ground
reference to the digital and/or analog circuits should present no
problem.

Connecting both PS to the same ground on the circuit board is the way
it is done . . .

You can't take two power supplies with 5 and 15 and expect them to
power an audio amplifier that wants to see Plus and Minus 10 volt
supply rails to ground - that would smoke your speakers (at least).

What are you really trying to do?

 

Dear Sir,

Let me explain you the problem i am facing ,this may
take a few minutes to read out ,but please give me a solution to
this.my application board is in the devicenet network,Actually my
circuit board requires 3.3v ,for that i have taken 24v dc from the
devicenet(source of ps) and i used a regulator(which gives o/p
[email protected] with wide input range 4.7v-25vdc) that converts 24v dc to
3.3v and gives an output current of 300ma.In my circuit board i have
differntiated the ground from the devinet(source of ps) to analog and
digital.when i am measuring the output voltage using an DMM(digital
multimeter),with DMM +ve terminal placing at output of ic and -ve
terminal at the ic ground(which is digital ground).i am getting
1.2v.When placing the DMM -ve terminal at the devinet(source of ps)
-ve,i am getting a 2v ,what could be the problem.Why i am getting
differenet voltages by movingthe DMM -ve terminal to two
locations.Please give me your possible solution to fix the error.

 

Dear Sir,

Let me explain you the problem i am facing ,this may
take a few minutes to read out ,but please give me a solution to
this.my application board is in the devicenet network,Actually my
circuit board requires 3.3v ,for that i have taken 24v dc from the
devicenet(source of ps) and i used a regulator(which gives o/p
[email protected] with wide input range 4.7v-25vdc) that converts 24v dc to
3.3v and gives an output current of 300ma.In my circuit board i have
differntiated the ground from the devinet(source of ps) to analog and
digital.when i am measuring the output voltage using an DMM(digital
multimeter),with DMM +ve terminal placing at output of ic and -ve
terminal at the ic ground(which is digital ground).i am getting
1.2v.When placing the DMM -ve terminal at the devinet(source of ps)
-ve,i am getting a 2v ,what could be the problem.Why i am getting
differenet voltages by movingthe DMM -ve terminal to two
locations.Please give me your possible solution to fix the error.

Regards,
banuprakash