SM3320-BATT-EV/NOPB National Semiconductor, SM3320-BATT-EV/NOPB Datasheet - Page 4

• Manufacturer Part Number: SM3320-BATT-EV/NOPB
• Description: EVAL CHARGE CONTROL BATTERY
• Manufacturer: National Semiconductor
• Series: SolarMagic™r

Specifications of SM3320-BATT-EV/NOPB

• Main Purpose: Power Management, Battery Charger
• Embedded: No
• Utilized Ic / Part: SM72295, SM72442
• Primary Attributes: Lead Acid, Solar Power
• Secondary Attributes: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

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10V Power Supply
The following circuit shown in
power supply rail required to properly bias the SM72295 gate
DC/DC Converter
The DC/DC converter stage is a step up/step down four switch
converter as shown in
er from the PV panel to the load.
C18, R11, and D15 as shown in the system schematic in
Figure
on the “Buck” side of the converter. C19,R14 and D14 form a
snubber circuit to reduce ripple on the switch node of the
“Boost” side of the converter.
When the circuit operates in Buck mode, the Boost switch
node will issue small pulses at a lower frequency in order to
recharge the Bootstrap capacitor of Q2. Likewise, in Boost
mode, the Buck switch node will pulse to recharge the boot-
strap capacitor of Q1.
Specific design guidelines for the DC/DC converter can be
found in the Power Design Guidelines Application Note 2124
for power optimizers.
Specific timings related to the switches can be found in the
SM72442 and SM72295 datasheets. The waveforms in
ure 7
of the DC/DC converter stage.
through
3, form a snubber to reduce ripple on the switch node
Figure 10
Figure
are examples of the switching signals
6. This stage transfers the pow-
Figure 5
will provide a 10V
FIGURE 6. DC/DC Converter Stage
FIGURE 5. 10V Power Supply
Fig-
4
driver. The system can be configured to work with solar pan-
els up to100V (with proper components sizing) and down to
12V Vmp.
If the system is to be used at elevated power levels causing
high temperature increases in MOSFETs Q1, Q2, Q3, and/or
Q4, we recommend the use of a proper heatsink for the MOS-
FETs, especially at higher ambient temperatures. Care must
be taken to prevent electrical contact between the drains of
the MOSFETs in the process of proper heatsinking.
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