MB39A132QN-G-ERE1 Fujitsu Semiconductor America Inc, MB39A132QN-G-ERE1 Datasheet - Page 43

• Manufacturer Part Number: MB39A132QN-G-ERE1
• Description: IC CONV DC-DC LI-ION 32QFN
• Manufacturer: Fujitsu Semiconductor America Inc

Specifications of MB39A132QN-G-ERE1

• Function: Charge Management
• Battery Type: Lithium-Ion (Li-Ion)
• Operating Temperature: 25°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 32-QFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 865-1020

DS04–27265–3E
• Design of phase compensation circuit
(1) Constant voltage (CV) mode phase compensation circuit
When a low-ESR capacitor, such as a ceramic capacitor, is used as the output capacitor, it is easier for the
DC/DC converter to oscillate as the phase delay approaches 180 degrees due to the resonance frequency
of LC. In this situation, perform phase compensation by connecting a RC phase lead compensator between
the -INE3 pin (pin 6) and the COMP3 pin (pin 16), and between the -INE3 pin (pin 6) and the BATT pin (pin 17) .
2pole-2zero phase compensation circuit
The constant for the phase lead compensation circuit can be found by the following formula.
As for the crossover frequency (fco) indicating the bandwidth of the control loop of the DC/DC converter,
while a high crossover frequency is good for quick response, it increases the risk of oscillation due to an
insufficient phase margin.
Though this crossover frequency can be freely set, keep the frequency in the range of 1/10-1/5 of the switching
frequency (fosc) whenever possible.
C
R
C
Z1
Z2
CELLS : Number of battery series cells
f
V
f
Z2
LC
CO
: =
IN
: = 8.9 × 10
: =
(2 × CELLS − 1) f
2π × R
: Resonance frequency of inductor and output capacitor [Hz]
: Switching power supply voltage [V]
: Crossover frequency [Hz]
5.1 × 10 −
1
4
Z2
×
× f
V
LC
IN
6
f
CO
× f
LC
BATT
LC
+ 3600
VO
17
C
Z1
Vrefint1
6
Error Amp3
C
Z2
R
Z2
COMP3
16
To PWM Comp.
MB39A132
43