TPS54260: Inverting Power Supply

Hi Hirokazu

LMR16020 is better choice for this conversion.

Please try PSPICE if TINA doesn't work.

B R
Andy

Hello Andy-san

Thanks for your reply and suggestion.
But please answer for below my question in previous post.
Can TPS54260 support the inverting power supply?
Is it possible to simulate such an inverting power circuit with Tina TI?

Regarding your LMR16020 suggestion,
Why do you recommend LMR16020?
Does the simulation model of LMR16020 support the inverting output circuit?

Best Regards,
Hirokazu Takahashi

Hi Hirokazu

TPS54260 can support the inverting power supply. you can try to simulate the circuit with TINA as TPS54260 has TINA model.

LMR16020 is new generation converter with better features over TPS54260, but it only has PSPICE model, 

B R

Andy

Hello Andy-san

I used TINA TI to simulate the circuit as TPS54260 .

But I couldn't simulate well .

Can you show me how to simulate the inverting power supply with TINA as TPS54260 ?

Thank you .

Niu

Hi Niu,

What's input range, Vout, load current and Fsw? can you upload your TINA file?

B R
Andy

Hi Andy-san

Input = 24V  Output = -6V Load = 0.03A  Fsw=1000kH

Thank you for you help.

Niu

Hi Andy-san

Input = 24V  Output = -6V Load = 0.03A  Fsw=1000kH

Thank you for you help.

Niu

Hi Niu,

The RT resistor R6 should be 115K for Fsw=1MHz, 1.15K is too small here.

L1 is also too big, 47uH is good start point, C4 can be 47uF as start point, also add 1K dummy load on output.

B R

Andy

Hi Andy-san

Thanks  for you reply .

I used this formula  to calculation the Inductor value.

ILavg = Iout/(1-D)   ,   L=Vin×D/(fsw×ILavg×0.25)

When the output current is small, the inductance is large .

Is it okay to use a small inductor?

Thank you for you help.

Niu

Hi Andy-san

Thanks  for you reply .

I used this formula  to calculation the Inductor value.

ILavg = Iout/(1-D)   ,   L=Vin×D/(fsw×ILavg×0.25)

When the output current is small, the inductance is large .

Is it okay to use a small inductor?

Thank you for you help.

Niu

Hi Niu,

The formula is for CCM operation, the inductor is quite big if calculated with small load current, the inductor size is also very big if considering output short condition, so for 60mA load current, it's better to design circuit with DCM operation. 

On other hand, big inductor and small output cap make it difficult to design the loop compensation in BUCK/Boost conversion, you can compare it in TINA simulation.

B R

Andy

Hello Andy-san

I'll send  Tina-TI file to you by e-mail instead of Niu-san.

Could you please review it?

Hirokazu Takahashi