TPS62442-Q1: 180 Degree Phase Shifted Operation

Tom Lynskey

Part Number: TPS62442-Q1

Hi,

My customer is looking at using the TPS62442-Q1 for a dual output application but they are concerned about EMC. Can you provide more details about the phase shifted operation and how SS works with the phase shifting feature?

over 1 year ago

0 Excel Regidor over 1 year ago

TI__Mastermind 34181 points

Hi Tom,

Thanks for reaching out to us.

The dual internal buck converters in TPS6244x-Q1operate in the same switching frequency. However, the internal clock signal of converter 2 is phase shifted by 180 deg. C with converter 1. It means the converter 2 will only start switching at the midpoint of the switching cycle of converter 1. For example, the IC is set to operate at 2.2MHz. The converter 2 high-side FET will only turn-on after ~220ns delay with respect to converter 1. I hope the diagram below helps in showing the switching behavior of the two converters .

The spread spectrum clocking (SS) features also helps in reducing the converter's EMI emission by varying the switching frequency up to 20% above the nominal set by RCF. This helps in lowering input peak currents seen across the converter.

Please refer to the app note link below to have a better overview on the effects of operating two converters 180 deg. out of phase (page 8) and SSC function (page 14).

https://www.ti.com/lit/an/slvaeg8/slvaeg8.pdf?ts=1701863983487&ref_url=https%253A%252F%252Fwww.google.com%252F

Best regards,

Excel