Data brief

For further information contact your local STMicroelectronics sales office.

November 2011

Doc ID 022232 Rev 1

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STEVAL-ISV005V1

250 W solar battery charger based on PV voltage-boost controller

SPV1020, bypass diode SPV1001N and CC-CV controller SEA05

Features

with 0.2% accuracy

protections

improved efficiency at low solar radiation

Description

The STEVAL-ISV005V1 demonstration board is

mainly based on the SPV1020 device, a

monolithic DC-DC boost converter designed to

maximize the power generated by photovoltaic

panels independently of temperature and amount

of solar radiation.

The optimization of the power conversion is

obtained with an embedded logic which performs

the MPPT (max power point tracking) algorithm

on the PV cells connected to the converter.

One or more converters can be housed in the

connection box of the PV panels, replacing the

bypass diodes. Since the maximum power point is

locally computed, the efficiency at system level

will be higher than that of conventional topologies,

where the MPP is computed in the main

centralized inverter.

For a cost-effective application solution and

miniaturization requirements, the SPV1020

embeds the power MOSFETs for active switches

and synchronous rectification, minimizing the

number of external devices. Furthermore, the 4-

phase interleaved topology of the DC-DC

converter renders unnecessary the use of

electrolytic capacitors, which would severely limit

the lifetime.

The SPV1020 works at fixed frequency in PWM

mode, where the duty cycle is controlled by the

embedded logic running a “Perturb & Observe”

MPPT algorithm. The switching frequency,

internally generated and set by default at 100

kHz, can be tuned externally, while the duty cycle

ranges from 5% to 90% with a step of 0.2%.

Safety of the application is guaranteed by

stopping the drivers in case of output overvoltage

or overtemperature.

The bypass diodes SPV1001N guarantee very

high application efficiency even when the PV

panel voltage is lower than the UVLO threshold of

the SPV1020 (6.5 V) and the connection is in

series consisting of two or more PV panels.

The SEA05 is connected to the output stage of

the application and is used to implement the

output current limitation (not available with the

SPV1020 alone) through the current sensing

resistors R9 and R10.

STEVAL-ISV005V1

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