參數(shù)資料
型號: AP2002SLA
英文描述: Synchronous PWM Controller
中文描述: 同步PWM控制器
文件頁數(shù): 6/7頁
文件大?。?/td> 180K
代理商: AP2002SLA
AP2002
Synchronous PWM Controller
Function Description
(Continued)
Hiccup Mode
Anachip Corp.
www.anachip.com.tw Rev. 0.2 Apr 14, 2004
6/7
During power up, the SS/
SHDN
pin is internally
pulled low until V
CC
reaches the under-voltage
lockout level of 4.2V. Once V
CC
has reached 4.2V,
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 output of the
internal error amplifier is clamped to this voltage.
When the error signal reaches the level of the
internal triangular oscillator, which swings from 1V
to 2V at a fixed frequency of 200KHz, switching
occurs. As the error signal crosses over the
oscillator signal, the duty cycle of the PWM signal
continues to increase until the output comes into
regulation. If an over-current condition has not
occurred the soft-start voltage will continue to rise
and level off at about 2.2V.
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. The PHASE node is sampled only once per
cycle during the vally of the triangular oscillator.
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 0.8V, the SS/
SHDN
pin
will begin to source 10uA and begin to charge the
external capacitor causing the soft-start voltage to
rise again. Again, when the soft-start voltage
reaches the level of the internal oscillator, switching
will occur.
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 conclusion, above is shown a typical “12V
Application Circuit” which has a BSTH voltage
derived by bootstrapping input voltage to the
PHASE node through diode D1. This circuit is very
useful in cases where only input power of 5V(or
12V) is available.
In
order
to
prevent
small-signal diode should be placed in close
proximity to the chip with cathode connected to
PHASE and anode connected to PGND.
substrate
glitching,
a
Marking Information
( Top View )
SOP-14L
1
8
7
AC
AP2002
YY WW
X X
Logo
ID code: internal
Blank: normal
L: Lead Free Package
Year: "01" = 2001
"02" = 2002
Xth week: 01~52
~
14
Part No.
相關PDF資料
PDF描述
AP2003 Synchronous PWM Controller
AP2003S Synchronous PWM Controller
AP2003SA Synchronous PWM Controller
AP2003SL Synchronous PWM Controller
AP2003SLA Synchronous PWM Controller
相關代理商/技術參數(shù)
參數(shù)描述
AP2003 制造商:ANACHIP 制造商全稱:Anachip Corp 功能描述:Synchronous PWM Controller
AP2003S 制造商:ANACHIP 制造商全稱:Anachip Corp 功能描述:Synchronous PWM Controller
AP2003SA 制造商:ANACHIP 制造商全稱:Anachip Corp 功能描述:Synchronous PWM Controller
AP2003SL 制造商:ANACHIP 制造商全稱:Anachip Corp 功能描述:Synchronous PWM Controller
AP2003SLA 制造商:ANACHIP 制造商全稱:Anachip Corp 功能描述:Synchronous PWM Controller