AA18375AP Agamem Microelectronic, AA18375AP Datasheet - Page 11

• Manufacturer Part Number: AA18375AP
• Description: Switching Regulator Controller
• Manufacturer: Agamem Microelectronic

PRELIMINARY
■ HOW TO SET OUTPUT VOLTAGE
■
©Copyright Agamem Microelectronics Inc.
The output voltage is set using the connection shown below. The error amplifiers are supplied to the
internal reference voltage circuit as are the other internal circuits. The common-mode input voltage range
is from − 0.2 V to +1.45 V. When the amplifiers are operated non-inverting, tie the inverting terminal to
V
If the load condition drastically changes due to a load short-circuit and if low-level signals (1.1 V or lower)
are input to the non-inverting inputs of the short-circuit protection comparator from the error amplifiers, the
short circuit protection comparator outputs a “Low” level. The protection enable terminal voltage is
discharged, and then the short-circuit protection comparator charges the externally connected protection
enable capacitor C
When the power supply is turned on, the output is considered to be short-circuited state so that the S.C.P.
terminal voltage starts charging. It is necessary to set the external capacitor so as to start up the DC-DC
converter output voltage before setting the latch circuit in the later stage. Especially, pay attention to the
delay of the start-up time when applying the soft-start function.
HOW TO SET TIME CONSTANT FOR TIMER LATCH SHORT PROTECTION CIRCUIT
REF
≒1.28 V). When the amplifiers are operated inverting, tie the non-inverting terminal to ground.
V
0.65 = 50 mV + t
C
PE
PE
= 50 mV + t
= t
PE
/0.6 (µ F)
PE
R1
R1
Agamem Microelectronics Inc.
according to the following formula:
Vref
PE
PE
Vref
x 10
x 10
R2
R2
-6
-6
/C
/C
+
-
PE
+
-
PE
Vo+ [=Vref X (1+R2/R1)]
PIN5 or PIN12
Vo
PIN5 or PIN12
11
-
[= -Vref X (R2/R1)]
AA18375AP
Switching Regulator Controller
www.agamem.com.tw
2006/6/27