s-8337aaca-t8t1g Seiko Instruments Inc., s-8337aaca-t8t1g Datasheet - Page 13

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

Rev.3.1
6. Error amplifier
7. Operation
Peak current (I
The error amplifier outputs the PWM control signal so that the voltage of the FB pin is held at a specific
value (1 V). By connecting a resistor (RZ) and capacitor (CZ) to the output pin (CC pin) of the error
amplifier in series, an optional loop gain can be set, enabling stabilized phase compensation.
Voltage at the CONT pin at the moment M1 is turned ON (current I
Change in I
Integration of the above equation:
When M1 is turned OFF (t
voltage (V
V
The voltage on the CONT pin rises only by V
_00
L
STEP-UP, 1.2 MHz HIGH-FREQUENCY, PWM CONTROL SWITCHING REGULATOR CONTROLLER
:
The following are basic equations [(1) through (7)] of the step-up switching regulator (refer to
Figure 10).
V
*1.
The energy stored in L is represented by
*2.
I
I
I
V
dl
L
L
PK
dt
A
L
flows while M1 is ON (t
L
=
= V
=
=
=
⎛
⎜
⎝
V
V
(
⎛
⎜
⎝
V
L
V
V
S
S
).
D
L
V
L
IN
OUT
*1
: Non-saturated voltage of M1
L
: Diode forward voltage
IN
over time:
L
……………………………………………………………………………………………….…(1)
−
=
PK
Figure 10 Step-up Switching Regulator Circuit for Basic Equations
L
−
V
+
) after t
V
V
S
V
IN
S
⎞
• ⎟
⎠
D
L
⎞
• ⎟
⎠
V
−
*2
IN
t
V
)
…………………………………………………………………….…………….……(3)
t
S
ON
−
ON
…………………………………………………………………………………..…(2)
V
:
……………………………………………………………………………………(4)
IN
OFF
……….………………………………………………………..………………(5)
), the energy stored in L is released via a diode, generating a reverse
on
L
). This time is determined by the oscillation frequency of OSC.
Seiko Instruments Inc.
M1
CONT
OUT
1
2
+ V
EXT
• L(I
D
D
.
PK
)
VSS
2
.
FB
L
V
flowing through L is zero), V
OUT
S-8337/8338 Series
C
L
A
13
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