OPA186DBVT datasheet(25/48 Pages) TI1

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8.2 Typical Applications

8.2.1 High-Side Current Sensing

–

+ 24 V –

24 V

–

OPA2186

Load Current

R1 = R3, R2 = R4

Figure 8-2. High-Side Current Monitor

8.2.1.1 Design Requirements

A common systems requirement is to monitor the current being delivered to a load. Monitoring makes sure that

normal current levels are being maintained, and also provides an alert if an overcurrent condition occurs.

Fortunately, a relatively simple current monitor design can be achieved using a precision rail-to-rail input/output

op amp such as the OPAx186. This device has an input common-mode voltage (VCM) range that extends

200 mV beyond each power supply rail allowing for operation at the supply rail.

The OPAx186 is configured as a difference amplifier with a predetermined gain. The difference amplifier

inputs are connected across a sense resistor through which the load current flows. The sense resistor can be

connected to the high side or low side of the circuit through which the load current flows. Commonly, high-side

current sensing is applied. Figure 8-2 shows an applicable OPAx186 configuration. Low-side current sensing can

be applied as well if the sense resistor can be placed between the load and ground.

Use the following parameters for this design example:

• Single supply: 24 V

• Linear output voltage range: 0.3 V to 3.3 V

• Load current, IL: 1 A to 11 A

The following design details and equations can be used to reconfigure this design for different output voltage

ranges and current loads.

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OPA186, OPA2186, OPA4186

SBOS968C – JUNE 2022 – REVISED JULY 2023

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OPA186DBVT 데이터시트(PDF) 25 Page - Texas Instruments