FAN8038 (KA3038)
• Short Circuit Protection function when GND and is short, ERRI become LOW and ERRO HIGH and it makes capacitor
charging. fanally AMP3 is OFF.(figure 5)
Figure 3. DC/DC Converter Control Circuit
Switching off time depen on a capacitor of the SCP . and the equation is as follow.
t
=
CSCP
×
-V----T----H--
ISCP
(VTH = 1.25V, ISPRT = 10µA)
• Max Duty can be controlled resistor. the equation is as follow.
t = CDEDSET × R
(R = 65KΩ)
• Capacitor of the SCP terminal can control disable switiching time and it can be calculated by as follow equation.
t
=
CSCP
×
---V----T---H-----
ISTOP
(VTH = 1.25V, IOFF = 20µA)
• Over Voltage Protection BATT Voltage is over 9.7V charging SCP terminal Capacitor, it reach to VTH SW terminal signal
is OFF the equation is as follow
t
=
CSCP
×
V-----T---H--
IHV
(VTH = 1.25V, IHV = 20µA)
• If Output Voltage of RSTOUT Circuit DC/DC Conver is over than 90%, RSTOUT terminal turn to HIGH and Hysteresis is
50mV. and RSTOUT stste is ON.
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