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bias current generator (low voltage, low tempco) - question

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cmos_ajay

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Hello,
I need a bias current generator whose ouput current (ZTAT) is typically 200nA.
The desired temperature co-efficient is 250 ppm/degree Celcius
Supply voltage VDD = 1.3 volt
Temperature: -40 to +125 degree celcius
Any ideas or schematic for this bias current generator ??
Regards.
 

Well I would recommend google - there is tons of stuff about this, Like the one attached. What I did not like is Idd. So I made my own @ 3uA which works @1.2V but can not share. Sorry.
 

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  • 1_volt_high_psrr_cmos_bandgap_voltage_reference.pdf
    260.3 KB · Views: 130

42_1305963326.gif

A simple way:
a deplete NMOS + a enhanced NMOS.
 

Hello, I will also recommend reading 'A CMOS subbandgap reference circuit with 1-v power supply voltage' by J. Doyle .....
I used the bandgap voltage and gave it to a V-to-I converter to obtain a i(ztat)
I tried the recommended circuit , but the i(ztat) was 900 ppm/degreeC and I needed only 250 ppm/degreeC
 

If necessary, some curvature compensation can be introduced for you BG circuit.
 

Many Japanese IC companies use this structure to design voltage reference and achieve +/-100ppm TC for LDO products.
42_1305963326.gif

A simple way:
a deplete NMOS + a enhanced NMOS.
 

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