KIT33701DWBEVB Freescale Semiconductor, KIT33701DWBEVB Datasheet - Page 30

• Manufacturer Part Number: KIT33701DWBEVB
• Description: KIT FOR 33701 POWER SUPPLY
• Manufacturer: Freescale Semiconductor
• Type: LDO Controllers & Regulatorsr

Specifications of KIT33701DWBEVB

• Main Purpose: DC/DC, Step Down with LDO
• Outputs And Type: 2, Non-Isolated
• Voltage - Input: 2.8 ~ 6V
• Regulator Topology: Buck
• Frequency - Switching: 300kHz
• Board Type: Fully Populated
• Utilized Ic / Part: MC34701
• Product: Power Management Modules
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output: -
• Voltage - Output: -
• Power - Output: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• For Use With/related Products: 34701

BUCK REGULATOR CONTROL CIRCUIT
topology with feed-forward to achieve an excellent line and
external resistor R4 provides the feed-forward ramp
waveform, the amplitude of which is proportional to the input
voltage, thus providing the feed-forward function.
control loop gain and phase versus frequency.
buck regulator output L-C filter, and its frequency can be
calculated as:
is the inductance value of the output filter inductor L.
as follows.
30
34701
TYPICAL APPLICATIONS
The 34701 buck regulator utilizes a PWM Voltage Mode
The integrated 40pF capacitor C
Figure 30
The first double pole on the Bode plot is created by the
Where C
The frequency of the compensating zero can be calculated
O
shows the Bode plot of the 34701 buck regulator
is the value of the buck output capacitor and L
f
LC
=
----------------------
2π C
1
O
F
L
charged through the
Figure 29. Buck Regulator Control Circuit
TYPICAL APPLICATIONS
load regulation. The control circuit block diagram is shown in
Figure
integrated capacitor C
transfer function, the frequency of which can be calculated
from the following formula.
The Feed-Forward implemented by resistor R4 and
Where V
29.
f
p FF
(V
V
V
generator (V
(
IN
m1
Ref
Ref
)
is the buck regulator input voltage,
is the ramp generated by the internal ramp
=
L
= 0.8V typ.) at the INV pin,
is the buck regulator reference voltage
--------------------------------------------------------------- -
-------
f
sw
1
f
z c ( )
×
m1
F
(
------------------------------- -
Analog Integrated Circuit Device Data
V
=
creates a pole in the overall loop
IN
= 0.5V typ.).
R4C
--------------------------------------- -
2πC2 R1
V
–
IN
V
F
Ref
(
1
)
Freescale Semiconductor
+
+
V
R3
m1
)
×
-------------------- -
2πR4C
1
F