Original question:

LM5170-Q1: How to get higher voltages without changing the topology of 2 switch solution

LM5170-Q1: How to get higher voltages without changing the topology of 2 switch solution

Prodigy 60 points
atish tailor

Part Number: LM5170-Q1

Unfortunately, the other thread got locked however just to continue where we last left it,

First of all thank you Youhao and Garrett.

For the first stage, Is there any reason why I cannot use a clamp to drop 46V and run at cira 126V? That way, the ramp measurement and controller believes its actually at 80V?

Alternatively, the Ramp R and C can also be adjusted to ensure it remains within the recommended 5V (although the datasheet implies up to 14V is ok)

For the second stage current sense, I can use a differential amplifier with unity gain?

I accept its a convoluted solution but principally, can you think of any more issues?

Best regards

Atish

Prodigy 60 points
atish tailor

1 Reply

  • Mastermind 19740 points
    Youhao Xi
    Hi Atish,

    Thank you for your interests in the Lm5170. Regarding the RAMP, we really require the RAMP peak voltage to be 5V when the input line is 48V. We want the RAMP and the HV voltage to stay in that ratio for proper operation.

    RAMP 14V is just the absolute max rating. For normal operation, RAMP voltage should be stay at about 10V max, or it will be tip clipping by VCC voltage.

    Regarding the current sense, can you show your idea in a schematic?

    Thanks,
    Youhao

All content and materials on this site are provided "as is". TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with regard to these materials, including but not limited to all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement of any third party intellectual property right. TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with respect to these materials. No license, either express or implied, by estoppel or otherwise, is granted by TI. Use of the information on this site may require a license from a third party, or a license from TI.

Content on this site may contain or be subject to specific guidelines or limitations on use. All postings and use of the content on this site are subject to the Terms of Use of the site; third parties using this content agree to abide by any limitations or guidelines and to comply with the Terms of Use of this site. TI, its suppliers and providers of content reserve the right to make corrections, deletions, modifications, enhancements, improvements and other changes to the content and materials, its products, programs and services at any time or to move or discontinue any content, products, programs, or services without notice.

TI Worldwide | Contact Us | my.TI Login | Site Map | Corporate Citizenship | mobile m.ti.com (Mobile Version)

TI is a global semiconductor design and manufacturing company. Innovate with 100,000+ analog ICs and
embedded processors, along with software, tools and the industry’s largest sales/support staff.

© Copyright 1995-2018 Texas Instruments Incorporated. All rights reserved.
Trademarks | Privacy Policy | Terms of Use