AT1454/AT1454A/AT1454B
Preliminary Product Information
Photoflash Capacitor Charger for DSC
Auto-Refresh
AT1454 supports auto-refresh function required in some DCS application. When the
output capacitor is charged complete, the READY pin will goes high and Vout will
decrease slightly due to leakage current. The refresh block trip point is VFBx90%.
While the Vout is decreased to the refresh trip point, it enables the charge block,
disable the refresh block and pull low the READY pin. This cycle of recharge
operation will repeat again until charge pin is pulled low.
Thermal-Overload Protection
Thermal-overload protection limits total power dissipation in the AT1454 series.
When the junction temperature exceeds Tj=140 ℃, a thermal sensor activates the
thermal protection, which shuts down the IC, allowing the IC to cool. Once the device
cools down by 15 ℃, IC will automatically recover normal operation. For continuous
operation , do not exceed the absolute maximum junction-temperature rating of
Tj=130 ℃.
Prevent the Leakage of READY pin
CHARGE
READY
VCC
READY
If pull-high resistor of READY signal connect to Charge pin, then it can reduce power
consumption on pull-high resistor of READY during charge pin goes low.
Board Layout
The high voltage operation of the AT1454/AT1454A/AT1454B demands careful
attention to board layout. You will not get advertised performance with careless layout.
Keep the area for the high voltage end of the secondary as small as possible. Also note
the larger than minimum spacing for all high voltage nodes in order to meet
breakdown voltage requirements for the circuit board. Remember that lethal voltages
are present in this circuit. Use caution when working with the circuit.
7F, No.9,PARK AVENUE. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878
3/24/2006 REV:1.2
Fax: 886-3-563-0879
WWW: http://www.aimtron.com.tw
Email: service@aimtron.com.tw
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AIMTRON [ AIMTRON TECHNOLOGY ]
