TPS61046: TPS61046, PWM PFM Mode boundary

Genius 17165 points

Part Number: TPS61046

Hi all

My customer is using the TPS61046 in a design with these specs:

5V => 8.5V / 20mA

And they find the part to operate in PFM-Mode with a high ripple.

They like to increase the load current to a value to ensure PWM operation.

Please comment as to how to calculate / determine the PWM - PFM-Mode boundary.

Best regards

over 8 years ago

0 Jasper Li over 8 years ago

TI__Mastermind 46905 points

hello Ue
please modify the inductance to 4.7uH or 6.8uH, the device should in PWM mode at 20mA. the device operates at PWM if the inductor peak current is higher than 140mA
what is ripple value currently? why customer concern about the ripple?

0 Ue over 8 years ago in reply to Jasper Li

TI__Genius 17165 points

Hello Jasper

Thank you for the quick reply and understood.

As the peak inductor current needs to be above 140mA for PWM mode a smaller value inductor should be used to ensure PWM operation.

A good tool to visualize DC-DC voltages and currents is

http://www.ti.com/tool/powerstage-designer

Best regards

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0 Ue over 8 years ago in reply to Ue

TI__Genius 17165 points

TPS61046_PWM.pdf

.... Power Stage Designer Screen Shots inserted ....

Power management

Power management forum

TPS61046: TPS61046, PWM PFM Mode boundary