s-8337aaca-t8t1g Seiko Instruments Inc., s-8337aaca-t8t1g Datasheet - Page 14

• Manufacturer Part Number: s-8337aaca-t8t1g
• Description: Step-up, 1.2 Mhz High-frequency, Pwm Control Switching Regulator Controller
• Manufacturer: Seiko Instruments Inc.

14
STEP-UP, 1.2 MHz HIGH-FREQUENCY, PWM CONTROL SWITCHING REGULATOR CONTROLLER
S-8337/8338 Series
Change in current (I
Integration of the above equation is as follows:
During t
from V
goes to the lowest level after M1 is turned ON (t
transmitted via the diode to C
function indicating the maximum value (ripple voltage: V
diode into V
Next, this ripple voltage is determined as follows.
I
When M1 is turned ON (after t
Based on equation (7),
When substituting equation (10) for equation (9):
Electrical charge ΔQ
When substituting equation (12) for equation (9):
A rise voltage (V
When taking into consideration I
V
OUT
p
−
vs t
*1.
∴
p
I
I
⎛
⎜
⎝
t
Δ
Δ
V
dl
OUT
dt
L
1
=
V
Q
Q
p
OUT
L
t
=
=
1
OUT
1
1
−
ON
1
Δ
=
I
t
=
C
p
PK
OFF
=
=
=
(time) from when M1 is turned OFF (after t
Q
Equivalent Series Resistance
, the energy of the capacitor (C
, energy is stored in L and is not transmitted to V
L
(
=
V
I
I
I
∫
1
L
+
PK
PK
PK
−
1 t
0
OUT
L
=
Δ
L
−
V
C
I
⎛
⎜
⎝
=
L
−
Q
−
−
⎛
⎜
⎝
C
D
V
dt
L
1
I
I
1
and the load current I
⎛
⎜
⎝
2
V
1
OUT
I
L
OUT
OUT
−
p-p
PK
V
=
=
OUT
(
•
V
I
OUT
PK
) due to ΔQ
I
⎛
⎜
⎝
L
C
IN
PK
)
) flowing through the diode into V
⎞
• ⎟
⎠
1
+
I
•
1
PK
L
+
⎞
⎟
⎠
−
L
V
⎛
⎜
⎝
which is charged in C
∫ •
•
+
t
L
=
I
V
OFF
D
V
+
OUT
⎛
⎜
⎝
L
2
V
0
D
1 t
−
OUT
t
I
I
I
OFF
OUT
PK
D
PK
dt
−
V
…………………………………………………………………………………(11)
)
−
V
•
IN
+
−
+
2
V
IN
…………………………………………………………………..………….(10)
t
⎞
• ⎟
⎠
L
I
1
⎞
• ⎟
⎠
L
OFF
, and the pin voltage of C
V
V
1
OUT
IN
=
:
…………………………………………………………..…………………(6)
Seiko Instruments Inc.
D
OUT
t
⎞
• ⎟
⎠
OUT
t
1
I
), I
−
PK
…………………………………………………………..……………(14)
⎞
• ⎟
⎠
…………………………………………………………………………(7)
t
V
1
+
L
consumed during t
+
………………………………………………….………………...…(8)
IN
t
2
L
OUT
= 0 (when the energy of the inductor is completely transmitted):
V
1
I
OUT
+
⎞
⎟
⎠
D
……………………………………………………………...…...(9)
⎛
⎜
⎝
−
L
match.
I
) is used. As a result, the pin voltage of C
PK
V
•
L
IN
t
1
+
during t
2
…………………………………………………….…….(13)
∫ •
I
OUT
ON
1 t
0
). When M1 is turned OFF, the energy stored in L is
tdt
⎞
• ⎟
⎠
ON
1
=
R
OUT
:
) to when V
I
ESR
1
PK
L
p-p
and ESR
during t
rises drastically. Because V
•
) when the current flowing through the
−
OUT
t
1
I
OUT
−
. When receiving output current (I
C
V
L
OUT
•
OFF
*1
OUT
t
1
(R
:
…………….………………….(15)
+
reaches the maximum level:
L
ESR
V
D
) of C
−
V
IN
•
L
:
2
1
t
1
2
L
……….…...(12)
is reduced, and
OUT
Rev.3.1
is a time
OUT
_00
)