AP2007 Ver la hoja de datos (PDF) - Anachip Corporation
Número de pieza
componentes Descripción
Fabricante
AP2007 Datasheet PDF : 7 Pages
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Synchronous PWM with VFC Controller
AP2007
(Preliminary)
Function Description (Continued)
Hiccup Mode
During power up, the SS/ SHDN pin is internally
pulled low until VCC reaches the under-voltage
lockout level of 4V. Once VCC has reached 4V, the
SS/ SHDN pin is released and begins to source
10uA of current to the external soft-start capacitor.
As the soft-start voltage rises, the inverting input of
the error comparator is clamped to this voltage.
When the error signal reaches the level of the
internal 0.8V reference, the output voltage is to have
reached its programmed voltage. If an over-current
condition has not occurred the soft-start voltage will
continue to rise and level off at about 2.5V.
An over-current condition occurs when the high-side
drive is turned on, but the PHASE node does not
reach the voltage level set at the OCSET pin. Once
an over-current occurs, the high-side drive is turned
off and the low-side drive turns on and the
SS/ SHDN pin begins to sink 2uA. The soft-start
voltage will begin to decrease as the 2uA of current
discharge the external capacitor. When the soft-start
voltage reaches 0.2V, the SS/ SHDN pin will begin to
source 10uA and begin to charge the external
capacitor causing the soft-start voltage to rise again.
If the over-current condition is no longer present,
normal operation will continue. If the over-current
condition is still present, the SS/ SHDN pin will again
begin to sink 2uA. This cycle will continue indefinitely
until the over-current condition is removed.
In order to prevent substrate glitching, a small-signal
diode should be placed in close proximity to the chip
with cathode connected to PHASE and anode
connected to GND.
Marking Information
(Top View)
AP2007
YY WW X
SOP-8L
Logo
Part No.
ID code: internal
Xth week: 01~52
Year: "01" =2001
"02" =2002
Anachip Corp
www.anachip.com.tw
Rev. 1.0 Apr 1, 2005
6/7
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