L6910 - L6910A

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11 APPLICATION IDEA 3: BUCK-BOOST REGULATOR 3V TO 5.5V INPUT/-5V

3A OUTPUT

In applications where a negative output voltage is required, a standard Buck-Boost topology can be implement-

ed. The considerations related to the maximum output current are the same of the "Positive Buck-Boost" (Ap-

plication Idea 2).

verting 5V to -5V, the device undergoes 10V voltage. It must be checked that the sum of the input and output

voltage is lower than the maximum operating input voltage of the device.

Figure 32. buck-boost regulator 3V to 5.5V input / -5V 3A Output Circuit

Table 14. Part List

Reference

Description

Manufacturer

R1

910 Ohm 5% 125mW

NEOHM

SMD 0805

R2

10K 5% 125mW

NEOHM

SMD 0805

R3

4.7K 5% 125mW

NEOHM

SMD 0805

R4

1K Ohm 5% 125mW

NEOHM

SMD 0805

R5

2.7K 5% 125mW

NEOHM

SMD 0805

R6

1K 5% 125mW

NEOHM

SMD 0805

R7

10 Ohm 5% 125mW

NEOHM

SMD 0805

C1,C2

100

µF - 20V

OSCON 20SA100M

RADIAL 10X10.5

C13,C14

330

µF - 6.3V

POSCAP 6TPB330M

SMD7343

C12,C4,C5,C8

100nF

KEMET

SMD0805

C3

1nF

KEMET

SMD0805

C6

4.7

µF - 16V

AUX

SMA6032

C7

100nF

KEMET

L1

R1

C1- C2

C3

C13

-

14

Q2

Q1

D2

C6

13

14

10

11

3

1

U1

L6910/A

VIN (3V to 5.5V )

VOUT (-5V 3A)

6

12

5

4

2

15

7

9

VCC

GND

VREF

SS

OSC

OCSET

UGATE

PHASE

LGATE

PGND

PGOOD

C9

C8

C4

D1

GNDOUT

C7

C5

R7

C10

C12

8

R5

R3

R4

C11

R6

EAREF

BOOT

G1

VCC (5V)

GNDCC

L1

R1

C1- C2

C3

C13

-

14

Q2

Q1

D2

C6

13

14

10

11

3

1

U1

L6910/A

VIN (3V to 5.5V )

VOUT (-5V 3A)

6

12

5

4

2

15

7

9

VCC

GND

VREF

SS

OSC

OCSET

UGATE

PHASE

LGATE

PGND

PGOOD

C9

C8

C4

D1

GNDOUT

C7

C5

R7

C10

C12

8

R5

R3

R4

C11

R6

EAREF

BOOT

G1

VCC (5V)

GNDCC

L1

R1

C1- C2

C1- C2

C3

C13

-

14

Q2

Q1

D2

C6

13

14

10

11

3

1

U1

L6910/A

VIN (3V to 5.5V )

VOUT (-5V 3A)

6

12

5

4

2

15

7

9

VCC

GND

VREF

SS

OSC

OCSET

UGATE

PHASE

LGATE

PGND

PGOOD

C9

C8

C8

C4

D1

GNDOUT

GNDOUT

C7

C7

C5

R7

C10

C12

C12

8

R5

R3

R4

C11

R6

EAREF

BOOT

G1

VCC (5V)

GNDCC