• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 63 subscribers
  • Views 232 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS65251

AGXIN
Intellectual 510 points
Other Parts Discussed in Thread: TPS65251

Hi

I have done the calculation for the TPS65251 With three different O/P voltages as 3.7,3.3,1.8 

I need to check this values we are having few doubts in the calculation of compensation circuit ?

Are the compensation values proper what are the parameters get affected due to improper compensation circuit selection?

can we simulate this effects due to wrong compensation values in TINA how to do that?

Please provide an exel based calculator tool which will be even reliable for designs with TPS65251 ?

Input Specifications Input Specifications Input Specifications
Buck Converter 1 Buck Converter 2 Buck Converter 3
Parameter Value  Unit Parameter Value  Unit Parameter Value  Unit
Vin 9 V Vin 9 V Vin 9 V
Vout 3.7 V Vout 3.3 V Vout 1.8 V
Io 1.5 A Io 1.5 A Io 1.5 A
Fsw 800 kHz Fsw 800 kHz Fsw 800 kHz
K_ind 0.3 K_ind 0.3 K_ind 0.3
Itrans 1.5 A Itrans 1 A Itrans 1 A
Vrip 37 mV Vrip 33 mV Vrip 18 mV
Tss 3.76 ms Tss 3.76 ms Tss 3.76 ms
Rref1 47  K ohm Rref1 40.2  K ohm Rref1 41.2  K ohm
I_thresh 3 A Over current threshold I_thresh 2 A I_thresh 2 A
T_en 0 ms Enable delay T_en 5 ms T_en 10 ms
V_dip 100 mV During Transient V_dip 100 mV V_dip 100 mV
Resr 0.1 ohm Resr 0.1 ohm Resr 0.1 ohm
Selection values Selection values Selection values
Parameter Value Unit Parameter Value Unit Parameter Value Unit
Lo 6.052469136 uH eq 16 page 19 Lo 5.805555556 uH Lo 4 uH
Irip 0.45 A Ripple current eq 17 pg 19 Irip 0.45 A Irip 0.45 A
Ipeak 1.725 A Peak current in inductor Ipeak 1.725 A Ipeak 1.725 A
Css 23.5 nF Soft start capacitor eq 24 pg 20 Css 23.5 nF Css 23.5 nF
Cbst 0.047 uF Boost strap capacitor Cbst 0.047 uF Cbst 0.047 uF
Rref2 12.96551724 K ohm eq 3 pg 13 Rref2 12.864 K ohm Rref2 32.96 K ohm
Co(min) 36.80555556 uF eq 20 Co(min) 17.59259259 uF Co(min) 22.22222222 uF
Co(min) 1.900337838 uF eq 21 Co(min) 2.130681818 uF Co(min) 3.90625 uF
Co 36.80555556 uF Final Value Co 17.59259259 uF Co 22.22222222 uF
Rcomp 14.22393162 K ohm eq 26 pg 21 Rcomp 6.798860399 K ohm Rcomp 8.588034188 K ohm
Rosc 223.5024473 K ohm eq 1 pg 12 Rosc 223.5024473 K ohm Rosc 223.5024473 K ohm
Rlim 105 K ohm fig 17 pg 14 Rlim 140 K ohm Rlim 165 K ohm
C_en 0 nF Enable capacitor C_en 1.838235294 nF C_en 3.676470588 nF
C_c 12.1616242 nF eq 11 pg 18 C_c 12.1616242 nF C_c 12.1616242 nF
C_roll 258.7579618 pF eq 14 pg19 C_roll 258.7579618 pF C_roll 258.7579618 pF