Data Sheet Rev. B, September 2020 | Subject to change without notice

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ACT4529M

40 V/3.0 A CV/CC Buck Converter Featuring QC2.0, USB Auto-Detect and USB-PD

APPLICATIONS INFORMATION

Current Sense Resistor

The traces leading to and from the sense resistor can

be significant error sources. With small value sense

resistors, trace resistance shared with the load can

cause significant errors. It is recommended to connect

the sense resistor pads directly to the CSP and CSN

pins using “Kelvin” or “4-wire” connection techniques as

shown below.

Current Limit Setting

When the output current reaches current limit, the IC

limits the peak switch current on a cycle-by-cycle basis.

This reduces the output voltage to keep the output

current at a constant value.

The following equation calculates the peak current limit.

*+*, - =

66 +

/0 +1

(6)

Where Rcs is current sense resistor.

The maximum, output current is defined by

=

*+*, −

1

2

(7)

PCB Load

Trace

Kevin Sense

Traces

Sense

Resistor