October 2015

DocID028457 Rev 1

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STEVAL-ISA176V1

ALTAIR05T-800 5 W wide range CV-CC optoless adapter

evaluation board

Data brief

Features



Universal input mains range: 90 - 264 V AC,

frequency 45-65 Hz



Output voltage: 5 V @ 1 A continuous

operation



Optoless constant voltage - constant current

output regulation



Standby mains consumption: < 100 mW @

230 V AC



Average efficiency: >70%



EMI: in accordance with EN55022-Class-B



RoHS compliant

Description

The STEVAL-ISA176V1 evaluation board

implements a 5 W (5 V / 1 A) wide-range mains

battery charger with constant voltage/constant

current, tailored for AC-DC chargers for mobile

phones and adapters or other hand-held

equipment.

The core of the application is the ALTAIR05T-

800, the first “all-primary sensing switching

regulator” of the ALTAIR family.

The IC combines a high-performance, low-

voltage PWM controller chip and an 800 V,

avalanche-rugged power MOSFET in the same

package.

The PWM chip is a quasi-resonant (QR) current

mode controller IC specifically designed for QR

ZVS (zero voltage switching at switch turn-on)

flyback converters.

The device is capable of providing constant

output voltage (CV) and constant output current

(CC) regulation using primary-sensing feedback.

This eliminates the need for the optocoupler, the

secondary voltage reference and the current

sensor, while still maintaining quite accurate

regulation.

In addition, it is possible to compensate the

voltage drop on the output cable to improve CV

regulation on the externally accessible terminals.

Extremely low consumption under no load

conditions is ensured thanks to controlled burst

mode operation that, along with the built-in high

voltage startup circuit and the low operating

current of the device, helps minimize the residual

input consumption. Although an auxiliary winding

is required in the transformer to correctly perform

CV/CC regulation, the chip can be powered

directly from the rectified mains. This is useful

particularly during CC regulation, where the

flyback voltage is generated by the winding

drops.