TPS65288: Reference design

Nanjun Xu1

Part Number: TPS65288

Dear TI Team,

I am designing the circuit for TPS65288RHAR for three output channels 3.3V/3A, 3.3V/2A and 3.3V/2A. Since the referenc design is not supported by WEBENCH, may I ask for further help?

I am not clear about the calculation of the "Loop Compensation". After the calculation the Cout is 47 uF (part number 6SVP47M) and the Fsw is 400kHz. The deduced Resr = 70 mOhm. However, how can I estimate the RL to calculate the Cc? Moreover, could you help me to review my schematic?

Thank you in advance.

/cfs-file/__key/communityserver-discussions-components-files/196/7674.Circuit.pdf

Kind regards,

Nanjun Xu

over 2 years ago

0 Lucia Gao over 2 years ago

TI__Mastermind 19610 points

Hi Nanjun,

Thanks for coming to us with your queries.

1. Since three output channels is 3.3V/3A, 3.3V/2A and 3.3V/2A which means RL for three bucks are 1.1Ω, 1.65Ω, 1.65Ω, you can use these three values to calculate compensation parameters.

2. Sure, I will help review the schematic and give you feed once finished. BTW, what is the value of input voltage, do you need USB power switches?

Thanks!

BRs

Lucia

0 Lucia Gao over 2 years ago

TI__Mastermind 19610 points

Hi Nanjun,

Please kindly find comments of the schematic shown below:

1. If USB power switches are not used, it is recommended to connect USB1_EN and USB2_EN to GND.

2. If the output current for three Bucks are 3A, 2A, 2A, typically we can set current limit to 3.5A, 2.5A, 2.5A.

Let us know if there is any more concern. Thanks!

BRs

Lucia

0 Nanjun Xu1 over 2 years ago in reply to Lucia Gao

Intellectual 350 points

Hello Lucia

Thanks for your reply. The USB power switch is not required.

Could you please give me an email address, by which I can send you the modified circuit design?

Kind regards,
Nanjun

0 Lucia Gao over 2 years ago in reply to Nanjun Xu1

TI__Mastermind 19610 points

Hi Nanjun,

Sure. Please send to my email lucia-gao@ti.com. Thanks!

BRs

Lucia

0 Lucia Gao over 2 years ago in reply to Lucia Gao

TI__Mastermind 19610 points

Hi Nanjun,
I will close this threat first. Please re-open it if there is any future question. Thanks!
BRs,
Lucia

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TPS65288: Reference design