Datasheet

RESET

MPPT PM

SOFT-START

ƒIout < Iout_th ƒIout >= Iout_th

ƒEvery 60 seconds after going into Panel Mode,

MPPT mode will be entered for a maximum of 4

seconds time to check whether or not the converter

is operating at maximum power point

ƒThere is an x% change in power from the power

when panel mode was engaged. This percentage

can be set on ADC Ch 2

ƒ PM pin is pulled low

ƒIn Buck-Boost mode for x seconds where x can be set on

ADC Ch 2

ƒRST pin is pulled lowƒRST pin is pulled low

PM_STARTUP

ƒIout > Iout_th

AND

Starting time

elapsed

ƒIout < Iout_th

SM72442

www.ti.com

SNVS689H –OCTOBER 2010–REVISED APRIL 2013

Operation Description

OVERVIEW

The SM72442 is a programmable MPPT controller capable of outputting four PWM gate drive signals for a 4-

switch buck-boost converter with an independent Panel Mode. The typical application circuit is shown in Figure 2.

The SM72442 uses an advanced digital controller to generate its PWM signals. A maximum power point tracking

(MPPT) algorithm monitors the input current and voltage and controls the PWM duty cycle to maximize energy

harvested from the photovoltaic module. MPPT performance is very fast. Convergence to the maximum power

point of the module typically occurs within 0.01s. This enables the controller to maintain optimum performance

under fast-changing irradiance conditions.

Transitions between buck, boost, and Panel Mode are smoothed and advanced digital PWM dithering techniques

are employed to increase effective PWM resolution. Output voltage and current limiting functionality are

integrated into the digital control logic. The controller is capable of handling both shorted and no-load conditions

and will recover smoothly from both conditions.

Figure 4. High Level State Diagram for Startup

Product Folder Links: SM72442