Op-amp amplifies current sense voltage in demo boards

Article By : STMicroelectronics

Current sense voltage can be amplified by a low-voltage operational amplifier, which is useful for protecting your applications.

The STEVAL-ISQ013V1 is a demonstration board specifically designed for low-side current sensing with the TS507 operational amplifier.

Power management mechanisms are found in most electronic systems. So, current sensing is useful for protecting your applications. The low-side current sensing method consists in placing a sense resistor between the load and the circuit’s ground. The common-mode voltage is close to ground, despite the voltage of the power source. Therefore, the current sense voltage can be amplified by a low-voltage operational amplifier.

The TS507 amplifier operates from 2.7 to 5.5V, and has a rail-to-rail configuration on both its input and output. Depending on the type of application, various component values can be selected, such as Rshunt or resistors for the amplifier gain.

You can accurately measure current with a limited number of components even if the sense current is noisy. With the theoretical equations, you can easily predict the maximum error on the output voltage. To minimise errors, you must select the components correctly according to the parameters described.

Learn more: Download the full application note

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