Miniature step-up converter boosts efficiency for handheld display-driving duties

The AS1340 is a boost converter for driving portable displays. Capable of generating up to 50V from a 2.7V-5.5V supply, it can produce 50mA at 24V or 30mA at 36V from a single Li-ion cell.

An integrated 1.4A MOSFET saves external components, while the fixed 1MHz switching frequency allows use of small external passives. Constant-frequency switching also results in low, predictable output noise that can be easily filtered.

Low power consumption and high efficiency are particular strengths of the AS1340, which can achieve 90% efficiency in normal operation and achieves high efficiency even at the highest output voltages. At light loads the device automatically enters powersave mode to optimise efficiency. Together with 30µA operating current and a 1µA shutdown mode, the AS1340 enables increased battery life in a wide variety of mobile and portable instruments. In shutdown mode, an output-disconnect switch separates the input from the output.

The output voltage is accurate to within 2%, and the converter features status-monitoring circuitry to indicate when the output voltage is within 10% of regulation.

 

FEATURES 3mm x 3mm TDFN-8 package High output currents: 100mA @ 12V from 3.3V input 50mA @ 24V from 3.3V input 30mA @ 36V from 3.3V input

APPLICATIONS Handheld computers Data loggers Test and measurement equipment Point-of-Sale (POS) terminals Consumer electronic products

 

 

 

• Freescale’s MCF5227x, page 080603
• Zetex Semiconductors’ ZXMN series MOSFETs, page 080620

 

 

austriamicrosystems / AS1340