The Designer's Guide Community Forum

The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl
Design >> Analog Design >> Bandgap Transient Analysis
https://designers-guide.org/forum/YaBB.pl?num=1258963823

Message started by Leila on Nov 23^rd, 2009, 12:10am

Title: Bandgap Transient Analysis
Post by Leila on Nov 23^rd, 2009, 12:10am

Hi,

During the transient analysis, whether it is vdd=1.2 V or step from 0 to 1.2, I will get a weird answer and a jump in bandgap reference voltage, the simulation results are including the voltage from the ideal current source branch Vrefid and the mirror current branch Vref.

The circuit doesn't have the startup. could you advice me what makes the change in voltage especially vbias?!

Regards,leyla

Title: Re: Bandgap Transient Analysis
Post by raja.cedt on Nov 23^rd, 2009, 1:15am

hi,
where is op amp in your schematic

Thanks,
Rajasekhar.

Title: Re: Bandgap Transient Analysis
Post by Leila on Nov 23^rd, 2009, 1:20am

Hi, I have used the ideal opamp!

Thanks,leyla

Title: Re: Bandgap Transient Analysis
Post by Mayank on Nov 26^th, 2009, 6:44am

Hello Leila,
I dont exactly understand which anomaly are you referring to ??

BUT Here's a point :--- Why dont you try using a Non-ideal Amplifier ??
Ideal Voltage Source has infinite bandwidth, So the gain never falls down to ZERO before phase crosses 180 degrees, Hence your feedback loop will never be stable with an ideal amplifier with Infinite Bandwidth....

thanx,
mayank.