2

1

F

OUT

G

R

V

V

V

R

§

·

¨

¸

©

¹

+

±

OPA2834-1

3.6 k

Ÿ

0.45V

720

Ÿ

720

Ÿ

10 m

Ÿ

LOA D

3.6 k

Ÿ

5 V

ADS704 6

+

±

Sho rt-

Circuit Fault

Detection

+

±

OPA2834-2

5 V

2.7 k

Ÿ

900

Ÿ

3.6 V

TL V3201

-

F

G

R

G =

R

13

OPA2834

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SBOS973 – JUNE 2019

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Copyright © 2019, Texas Instruments Incorporated

Application Information (continued)

The signal gain of the circuit is given by

and output signals swing. Output signals are 180

must be 3.6 kΩ for inverting gains.

9.2 Typical Applications

9.2.1 Low-Side Current Sensing

Power stages use current feedback for phase current control and regulation. One of the commonly used methods

for this current measurement is low-side current shunt monitoring. Figure 12 shows a representative schematic of

such a system. The use of the OPA2834 is described in this section for a low-side current-shunt monitoring

application.

Figure 12. Low-Side Current Sensing

9.2.1.1 Design Requirements

The OPA2834 is used in a gain of 20 V/V while also driving the input of the ADS7046 when sampling at 1 MSPS.

A comparator is connected to the ADC input for short-circuit fault detection. This design example is illustrated for

the following specifications:

•

Switching frequency: 50 kHz

•

Shunt resistance: 10 mΩ

•

•

•

Amplifier supply voltage: 5 V

9.2.1.2 Detailed Design Procedure

One of the channels of the OPA2834 is connected to the shunt resistor in Figure 12 in a 5-V/V difference

amplifier configuration. Equation 3 gives the gain of this circuit.

where

•

(3)