Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

simulation of bandgap circuit

Status
Not open for further replies.
S

sys_eng

Full Member level 4
Joined
Aug 3, 2016
Messages
193
Helped
0
Reputation
2
Reaction score
1
Trophy points
18
Activity points
1,489
I got a bandgap circuit for constant output of vref=550mV .

but i simulated , I don't get that, too much difference, I got 4.362 V output for vref and its not independent of supply voltage
what's wrong. It's nowhere near the ball park.

bandgap2.png

my actual circuit.

circuit.png

the current should be around 1.2uA
but my actual circuit is 100uA+, or near 200uA.

current.png

should I scale the transistor much smaller? I didnt' scale my transistor size in circuit so probably default to 100u.
 
Last edited:

First thing I modified is the sizing of transistors to reduce the current, I have changed W=100u to 10u, on M21 but the current still remains strong at 192.9uA. I want to bring it down to 1.2uA. How do I do that?

reduction.png
 

Match M21 and M22. Mismatch M29 and M30 rather
than making them both 1 square but different W=L.
The 10K load on VB is a bad idea, jacks the diff amp
badly. There is not enough available drive or gain
for that loading.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top