Product category:
Power Supply ICs and Controllers
News Release from: Torex Semiconductor | Subject: XC9223/24 series
Edited by the Electronicstalk Editorial
Team on 02 December 2004
Synchronous step-down convertors save
space
The XC9223/24 series are synchronous step-down DC/DC convertors that can provide output currents of up to 1.2A with output voltages down to 0.8V.
The XC9223/24 series are synchronous step-down DC/DC convertors that can provide output currents of up to 1.2A with output voltages down to 0.8V With switching frequencies of 1 or 2MHz, small inductors can be used, making the series ideally suited to applications where height and PCB area is limited
This article was originally published on Electronicstalk on 28 Aug 2008 at 8.00am (UK)
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Depending on application conditions, efficiencies up to 94% can be achieved.
For applications influenced by switching noise, the XC9223/24 series can be synchronised with an external clock signal within the range of +/-25% toward an internal clock signal via the mode/sync pin.
The series automatically operates in PWM mode when synchronised in this way.
The mode/sync pin also allows the user to select fixed PWM mode or PFM/PWM auto-switching control.
With PFM/PWM control, the XC9223/24 series selects the best switching mode depending on output load thus ensuring the highest efficiencies from light to heavy loads.
The series also has a built-in current limiter circuit which enables the user to fix either a 0.5 or 1.5A threshold thereby allowing a smaller inductor to be used in the knowledge that it will be protected from overcurrent.
For example, a 2.2mH inductor can be used in place of a typical 10mH inductor.
A built-in voltage comparator is also available for low battery protection or monitoring the startup sequence.
To prevent an overcurrent state, the IC detects overshoot current by analysing the voltage difference between the VDD and Lx pin.
After an overcurrent state continues for a few milliseconds, the IC's operation goes into suspension mode and the driver transistor is turned off.
The series also incorporates a thermal shutdown circuit which operates if the IC's junction temperature reaches 150C.
When the temperature drops to 130C or less, the IC performs the soft start function and full operation is resumed.
In addition the short-circuit protection will shut down the IC when the FB voltage decreases to less than half the setting voltage.
The series is available in either MSOP10 or USP10 packages.
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