s-8333aaca-t8t1g Seiko Instruments Inc., s-8333aaca-t8t1g Datasheet - Page 13

• Manufacturer Part Number: s-8333aaca-t8t1g
• Description: Step-up, For Lcd Bias Supply, 1-channel, Pwm Control Switching Regulator Controller
• Manufacturer: Seiko Instruments Inc.

Rev.2.3
STEP-UP, FOR LCD BIAS SUPPLY, 1-CHANNEL, PWM CONTROL SWITCHING REGULATOR CONTROLLER
Change in current (I
Integration of the above equation is as follows:
During t
the energy of the capacitor (C
after M1 is turned ON (t
the pin voltage of C
voltage: V
Next, this ripple voltage is determined as follows.
I
When t
Based on equation (7),
When substituting equation (10) for equation (9):
Electrical charge ∆Q
When substituting equation (12) for equation (9):
A rise voltage (V
When taking into consideration I
When substituting equation (11) for equation (15):
Therefore to reduce the ripple voltage, it is important that the capacitor connected to the output pin has a large
capacity and a small ESR.
OUT
_00
vs t
*1.
∴
I
I




∆
t
∆
V
V
V
dI
L
OUT
dt
1
OFF
V
Q
Q
P
P
P
t
L
=
ON
1
1
=
−
−
−
OUT
1
1
P
P
P
(time) from after t
=
I
=
p-p
PK
, energy is stored in L and is not transmitted to V
, I
=
t
Equivalent Series Resistance
=
=
(
OFF
=
=
=
I
V
I
L
) when the current flowing through the diode into V
PK
L
PK
∫
I
−
L
= 0 (when the energy of the inductor is completely transmitted):
+
0
PK
∆
(I
1 t
∆
C
C

 

−
=
I
Q
PK
−
L
−
Q
V
L
V
p-p
L
L
I
−
OUT

 

dt
1
D
1
V




OUT
2
) due to ∆Q
L
V
−
OUT
L
1
2
) flowing through the diode into V
=
I
=
−
I
OUT
1
=
OUT
I
)
rises drastically. Because V
I
PK
PK
(
OUT




which is charged in C
I
+
C
V
C
I
PK
ON
PK
1
V
1
+
L
IN
V
L
L
+
OUT
L
). When M1 is turned OFF, the energy stored in L is transmitted via the diode to C




V
D

 

)
−

 

L
t
V




∫
D
ON
2
OFF
0
−
1 t
D
I
I
I
=
+
OUT
PK
−
PK
, when V
t
L
dt
V
C
) is used. As a result, the pin voltage of C
OFF
−
L
1
V
V
IN
:
t
I
L
D
V
.................................................................................................................... (11)
IN
OUT
+
OFF
−
+
PK
2
)
2

 

IN
−
I
I
t
V
OUT
t
OUT
+
1
................................................................................................................. (6)
V

 

consumed during t
OUT
............................................................................................................... (7)
IN

 

............................................................................................................ (10)
=
t
OUT
1
Seiko Instruments Inc.




I
I

 


 

PK
.......................................................................................................... (8)
PK
......................................................................................................... (9)
t
t
+
1
1
reaches the maximum level:
L
................................................................................................... (14)
+
V
+
L
+
2
2
D
during t
I

 

I
OUT
OUT
−
I
PK
V
OUT

 

IN
t
+
R
1
2
1
OUT
is a time function indicating the maximum value (ripple
I
:
................................................................................... (13)
ESR
∫
OUT
0
1
1 t
and ESR
tdt
during t

 

........................................................................... (16)
OUT
R
=
ESR
. When receiving output current (I
I
OUT
PK
OFF
*1
−
t
and the load current I
:
(R
1
I
−
OUT
ESR
C
L
V
is reduced, and goes to the lowest level
L
) of C
OUT
t
1
.............................................. (15)
+
L
:
L
V
D
−
V
IN
OUT
2
1
S-8333 Series
match.
t
1
2
................. (12)
OUT
) from V
L
, and
OUT
13
,