10µF

OPA541

0.1µF

0.1µF

10µF

–V

S

D

2

D

1

L

Inductive or

EMF-Generating

Load

+V

S

D – D : IN4003

1

2

OPA541

1

2

8

R

CL

Not Required

OPA501

1

2

8

R

CL

R

CL

+

–

Pin 2 is open on OPA541.

OPA541

www.ti.com

SBOS153B – SEPTEMBER 2000 – REVISED JANUARY 2016

Application Information (continued)

Figure 12. Isolating Capacitive Loads

Because one resistor carries the current previously carried by two, the resistor may require a high power rating.

Minor adjustments may be required in the resistor value to achieve the same current limit value. Often, however,

the change in current limit value when changing models is small compared to its variation over temperature.

Many applications can use the same current limit resistor.

8.2 Typical Applications

8.2.1 Clamping Output for EMF-Generating Loads

Figure 13. Clamping Output for EMF-Generating Loads

8.2.1.1 Design Requirements

•

Motor drive with reversal requiring output clamping

•

20-V motor

•

1-

Ω DC resistance

•

10-µH inductance

•

40°C maximum ambient temperature

8.2.1.2 Detailed Design Procedure

8.2.1.2.1

Power Supply Requirements

Select the power supply based on the requirement to achieve a ±20-V output with up to a 5-A load. The

maximum value for output voltage swing at 5-A is approximately within 4 V of either rail and ±25. These supplies

provide sufficient output swing.

8.2.1.2.2

Current Limit and SOA (Safe Operating Area)

Set the current limit to the highest possible value for the application which generally corresponds to a short circuit

on the output. In this application this corresponds to 25-V stress on the output device and examination of the

SOA (Safe Operating Area) graph in Figure 11 indicates that a 5-A current limit is within the 25°C SOA.

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