7585AILZ データシートの表示（PDF） - Renesas Electronics
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7585AILZ Datasheet PDF : 19 Pages
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EL7585A
For the EL7585A, the minimum drive current is:
I_DRVL_min = 8mA
The minimum base-emitter resistor, RBL, can now be
calculated as:
RBL_min = VBE_max/(I_DRVL_min - Ic/Hfe_min) =
1.25V/(8mA - 500mA/100) = 417
This is the minimum value that can be used - so, we now
choose a convenient value greater than this minimum value;
say 500. Larger values may be used to reduce quiescent
current, however, regulation may be adversely affected, by
supply noise if RBL is made too high in value.
VBOOST
LX
0.9V
PG_LDOP +
-
+
-
GMP
LDO_ON
0.1µF
36V
ESD
CLAMP
CP (TO 36V)
RBP
7k
DRVP
FBP
0.1µF
Q3
VON (TO 35V)
RP1
RP2
20k
CON
1: Np
FIGURE 21. VON FUNCTIONAL BLOCK DIAGRAM
LX
0.1µF
PG_LDON -
+
0.4V
LDO_OFF
VREF
FBN
RN2
20k
1: Nn
-
+
GMN
36V
ESD
CLAMP
RN1
DRVN
RBN
Q2
3k
CP (TO -26V)
0.1µF
VOFF (TO -20V)
COFF
FIGURE 22. VOFF FUNCTIONAL BLOCK DIAGRAM
FN7523 Rev 3.00
March 9, 2006
0.9V
PG_LDOL +
-
LDO_LOG
VIN OR VPROT
(3V TO 6V)
RBL
500
DRVL
FBL
Q5 VLOGIC
(1.3V TO 3.6V)
CLOG
RL1
10µF
-
+
GML
1: N1
RL2
20k
FIGURE 23. VLOGIC FUNCTIONAL BLOCK DIAGRAM
The VON power supply is used to power the positive supply
of the row driver in the LCD panel. The DC-DC consists of an
external diode-capacitor charge pump powered from the
inductor (LX) of the boost converter, followed by a low
dropout linear regulator (LDO_ON). The LDO_ON regulator
uses an external PNP transistor as the pass element. The
onboard LDO controller is a wide band (>10MHz)
transconductance amplifier capable of 4mA drive current,
which is sufficient for up to 40mA or more output current
under the low dropout condition (forced beta of 10). Typical
VON voltage supported by EL7585A ranges from +15V to
+36V. A fault comparator is also included for monitoring the
output voltage. The under-voltage threshold is set at 25%
below the 1.2V reference.
The VOFF power supply is used to power the negative
supply of the row driver in the LCD panel. The DC-DC
consists of an external diode-capacitor charge pump
powered from the inductor (LX) of the boost converter,
followed by a low dropout linear regulator (LDO_OFF). The
LDO_OFF regulator uses an external NPN transistor as the
pass element. The onboard LDO controller is a wide band
(>10MHz) transconductance amplifier capable of 4mA drive
current, which is sufficient for up to 40mA or more output
current under the low dropout condition (forced beta of 10).
Typical VOFF voltage supported by EL7585A ranges from
-5V to -20V. A fault comparator is also included for
monitoring the output voltage. The undervoltage threshold is
set at 200mV above the 0.2V reference level.
The VLOGIC power supply is used to power the logic circuitry
within the LCD panel. The DC-DC may be powered directly
from the low voltage input, 3.3V or 5.0V, or it may be
powered through the fault protection switch. The
LDO_LOGIC regulator uses an external PNP transistor as
the pass element. The onboard LDO controller is a wide
band (>10MHz) transconductance amplifier capable of
16mA drive current, which is sufficient for up to 160mA or
Page 12 of 19
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