MP2307 MPS, MP2307 Datasheet - Page 6

• Manufacturer Part Number: MP2307
• Description: 340KHz Synchronous Rectified Step-Down Converter
• Manufacturer: MPS

OPERATION
FUNCTIONAL DESCRIPTION
The MP2307 regulates input voltages from
4.75V to 23V down to an output voltage as low
as 0.925V, and supplies up to 3A of load
current.
The MP2307 uses current-mode control to
regulate the output voltage. The output voltage
is measured at FB through a resistive voltage
divider and amplified through the internal
transconductance error amplifier. The voltage at
the COMP pin is compared to the switch current
(measured internally) to control the output
voltage.
MP2307 Rev. 1.7
3/14/2006
COMP 6
EN
SS 8
FB 5
Zener
7V
7
0.925V
TM
MP2307 – 3A, 23V, 340KHz SYNCHRONOUS RECTIFIED STEP-DOWN CONVERTER
1.1V
0.3V
2.5V
1.5V
+
--
+
--
--
+
+
--
+
+
--
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
COMPARATOR
COMPARATOR
SHUTDOWN
AMPLIFIER
LOCKOUT
ERROR
EN OK
Figure 1—Functional Block Diagram
OVP
OSCILLATOR
110/340KHz
© 2006 MPS. All Rights Reserved.
www.MonolithicPower.com
RAMP
CLK
1.2V
+
The
MOSFET switches to step-down the input
voltage to the regulated output voltage. Since
the high side MOSFET requires a gate voltage
greater than the input voltage, a boost capacitor
connected between SW and BS is needed to
drive the high side gate. The boost capacitor is
charged from the internal 5V rail when SW is low.
When the FB pin voltage exceeds 20% of the
nominal regulation value of 0.925V, the over
voltage comparator is tripped and the COMP
pin and the SS pin are discharged to GND,
forcing the high-side switch off.
--
COMPARATOR
CURRENT
converter
S
R
AMPLIFIER
CURRENT
SENSE
Q
Q
uses
REGULATORS
+
--
INTERNAL
internal
IN
OVP
IN < 4.10V
5V
N-Channel
2
1
3
4
MP2307_BD01
IN
BS
SW
GND
6