ZXCT1011 View Datasheet(PDF) - Diodes Incorporated.

Part Name

Description

Manufacturer

ZXCT1011

High-side low drift current monitor

Diodes Incorporated. 

ZXCT1011

Pin description

Pin no.

1

2

Pin name

N/C

Iout

3

Rshunt

4

Vsense-

5

Vsense+

Pin function

No connection

Output current - follows transconductance of sense voltage gm = 10mA/V

for Rshunt=120⍀

Trimming resistor Input. - used to trim gain value 60⍀ Յ Rshunt Յ 240⍀

Low side current sense input. – connect to load/battery etc. Must be

lower than Vsense+ for correct operation. Cannot be grounded

without additional series resistor.

High side current sense input. – Connect to supply rail. Must be

higher than Vsense+ for correct operation.

Application information

Design example

The following lines describe how to scale a load current to an output voltage.

Defining then

since

Vsense = (Vsense+) - (Vsense-) = Iload x Rsense

Iout = Iq + Vsense x gm

gm= 1.2 / Rshunt

Iout = Iq + [ (Vsense x 1.2) / Rshunt ]

= Iq + [ (1.2 x Iload x Rsense / Rshunt) ]

Note: Iq is embedded into the specification of the ZXCT1011 and therefore appears an offset error.

∴Vout = (Rout x Ioffset) + [(1.2 x Rout x Iload x Rsense) / Rshunt]

The output current of the ZXCT1011 is directly related to the size of the trimming resistor used. It

is important to ensure the tolerance of Rshunt is considered. A 1% change in Rshunt will cause a

1% change in output.

Consider the following: -

Issue 1- July 2005

5

© Zetex Semiconductors plc 2005

www.zetex.com

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