Data Sheet

ADPL76030

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Rev.0

19 of 40

THEORY OF OPERATION

The ADPL76030 is a current-mode DC/DC controller that can regulate output voltage, and input or output current

from input voltage above, below, or equal to the output voltage. The ADI proprietary peak-buck, peak-boost current-

mode control scheme uses a single inductor current-sense resistor and provides smooth transition between buck

region, buck-boost region, and boost region. Its operation is best understood by seeing the BLOCK DIAGRAM.

Power Switch Control

Figure 35 shows a simplified diagram of how the four power switches A, B, C, and D are connected to the inductor L,

the current-sense resistor RSENSE, power input VIN, power output VOUT, and ground. The current-sense resistor RSENSE,

connected to the LSP and LSN pins, provides inductor current information for both peak current-mode control and

reverse current detection in buck region, buck-boost region, and boost region. Figure 36 shows the current-mode

control as a function of VIN/VOUT ratio, and Figure 37 shows the operation region as a function of VIN/ VOUT ratio. The

power switches are properly controlled to smoothly transition between modes and regions. Hysteresis is added to

prevent chattering between modes and regions.

There are four states:

(1) Peak-buck current-mode control in buck region.

(2) Peak-buck current-mode control in buck-boost region.

(3) Peak-boost current-mode control in buck-boost region.

(4) Peak-boost current-mode control in boost region.

The following sections give detailed description for each state with waveforms, in which the shoot-through

protection dead time between switches A and B, and between switches C and D are ignored for simplification.

Figure 35. Simplified Diagram of the Power Switches

Figure 36. Current Mode vs. VIN/VOUT Ratio

VOUT

D

A

SW1

SW2

TG2

BG2

TG1

BG1

B

C

L

VIN

RSENSE

PEAK-BUCK

PEAK-BOOST

VIN/VOUT