CL

LIM

(15000)(4.75)

R

13750

I

=

-

W

Differential

Amplifier

Voltage

Amplifier

High Current

Output Stage

Biasing

Current Limiting

Enable/Disable

Alarms

E/S

V-

V+

OPA548

SBOS070C – OCTOBER 1997 – REVISED JUNE 2015

www.ti.com

8 Detailed Description

8.1 Overview

The OPA548 device uses a PNP input stage (resulting in negative bias currents at each input) without input bias

current compensation so matched resistances on the inputs will reduce errors. After the main voltage gain stage

is the high current output stage with temperature compensated class A/B biasing to reduce crossover distortion.

Local feedback in the output stage may require additional compensation for highly reactive loads (see Output

Stage Compensation).

8.2 Functional Block Diagram

8.3 Feature Description

8.3.1 Adjustable Current Limit

The OPA548 features an accurate, user-selected current limit. The current limit is set from 0 A to 5 A by

current path, the OPA548 senses the load indirectly. This allows the current limit to be set with a 0-

μA to 330-μA

control signal. In contrast, other designs require a limiting resistor to handle the full output current (5 A in this

case).

With the OPA548, the simplest method for adjusting the current limit uses a resistor or potentiometer connected

(1)

The low-level control signal (0

μA to 330 μA) also allows the current limit to be digitally controlled.

current limit, typically 5 A.

12

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