TL499A

L = 50 µH

SERIES IN1

SW REG IN2

RCL = 500 Ω

OUTPUT

CF = 470 µF

RE1

RE2 = 4.7 kΩ

CP = 0.01 µF

SERIES IN1

SW REG IN2

REF

SW CURRENT

CTRL

OUTPUT

SW IN

GND (PWR)

GND

+

1

3

8

7

6

5

8

1

2

3

4

TL499A

www.ti.com

SLVS029H – JANUARY 1984 – REVISED NOVEMBER 2015

8 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component

specification, and TI does not warrant its accuracy or completeness. TI’s customers are

responsible for determining suitability of components for their purposes. Customers should

validate and test their design implementation to confirm system functionality.

8.1 Application Information

One or two power sources will be regulated to an output voltage set by two feedback resistors.

8.2 Typical Application

Figure 3 shows the basic configuration of the two power source voltage regulator

Figure 3. TL499A Basic Configuration

8.2.1 Design Requirements

Provide one or more of the following power sources:

•

SERIES IN1 voltage greater than OUTPUT voltage by more than dropout voltage

•

SW REG IN2 voltage less than OUTPUT voltage

Select RCL value based on Table 1 through Table 5.

Table 1. Maximum Output Current vs Input and Output Voltages for Step-Up Switching Regulator With

RCL = 150 Ω

SWITCHING REGULATOR INPUT VOLTAGE (SW REG IN2) (V)

OUTPUT

1.1

1.2

1.3

1.5

1.7

2

2.5

3

5

6

9

VOLTAGE (V)

OUTPUT CURRENT (mA)

30

65

90

25

50

80

100

20

20

25

30

85

100

100

15

15

20

30

45

55

100

100

100

12

10

15

20

25

30

40

55

70

100

100

100

10

15

20

25

30

35

45

65

80

100

100

9

20

25

25

35

40

50

70

90

100

100

6

30

35

40

45

55

75

95

100

Copyright © 1984–2015, Texas Instruments Incorporated

Submit Documentation Feedback

7

Product Folder Links: TL499A