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Output Current Measurement
The output current of the module can be measured using the I
signal. If this pin is not loaded its output voltage will follow the typical
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equation,
V
= 4*I
/I
, where I
is the maximum rated current for the module.
I_OUT
OUT
RATED
RATED
Note that the I
output voltage is representative of the internal inductor current not the actual load current. However, this will only have an
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influence during dynamic events. It is recommended to add an external buffer amplifier (as shown below) when using the I
signal to
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measure the output current as loading the I
signal, even with microamps can cause the current limit to be reduced. If it is required to
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measure the output current and adjust the output current limit simultaneously, this can be achieved by using a clamp circuit instead of a voltage
source to adjust the current limit, while continuing to use an amplifier to measure the output current. An example circuit is shown below. In this
case V
will control the current limit while the buffered I
signal will provide a measurement of the output current.
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CONTROL
Measuring output current
Measuring & controlling output current
CM4 App Note 260424 issue 2.1.docx
Document No. 260424
Page 18 of 29
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