Step-Up(Boost)Mode

(A)

(B)

OFF

ON

ON

OFF

C

PUMP

Q

2

Q

4

C

OUT

V

OUT

C

PUMP

Q

2

Q

4

C

OUT

V

OUT

OFF

ON

Q

1

Q

3

ON

OFF

Q

1

Q

3

C

IN

V

IN

C

IN

V

IN

OFF

SWITCHED

Step-Down(Buck)Mode

OFF

ON

C

PUMP

Q

1

Q

3

Q

2

Q

4

C

IN

C

OUT

V

OUT

V

IN

REG71050, REG71055, REG710

www.ti.com

SBAS221H – DECEMBER 2001 – REVISED OCTOBER 2015

8 Detailed Description

8.1 Overview

The REG710 regulated charge pump provides a regulated output voltage for input voltages which are not

regulated with a value that can be lower or higher than the regulated output voltage. This is accomplished by

automatic mode switching within the device. When the input voltage is greater than the required output, the

device operates as a variable frequency switched-mode regulator. This operation is shown in Figure 5.

voltage.

When the input voltage is less than the required output voltage, the device switches to a step-up or boost mode

of operation, as shown in Figure 6.

A conversion clock of 50% duty cycle is generated. During the first half cycle the FET switches are configured as

During the second half cycle the FET switches are configured as shown in Figure 6 (B), and the voltage on

Figure 5. Simplified Schematic of the REG710 Operating in the Step-Down Mode

Figure 6. Simplified Schematic of the REG710 Operating in the Step-Up or Boost Mode

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