AIC1638 AIC [Analog Intergrations Corporation], AIC1638 Datasheet - Page 12

• Manufacturer Part Number: AIC1638
• Description: 3-PIN ONE-CELL STEP-UP DC/DC CONVERTER
• Manufacturer: AIC [Analog Intergrations Corporation]

ANALOG INTEGRATIONS CORPORATION
4F, 9 Industry E. 9th Road, Science-based Industrial Park , Hsinchu, Taiwan, R.O.C.
turn-on time. Switching frequency depends on load,
input voltage, and inductor value, and it can range up
to 100KHz. The SW on-resistance is typically 1 to 1.5
When the output voltage drops, the error comparator
enables 100KHz oscillator that turns on the MOSFET
around 7.5us and 2.5 s off time. Turning on the
MOSFET allows inductor current to ramp up, storing
energy in a magnetic field. When MOSFET turns off
that force inductor current through diode to the output
capacitor and load. As the stored energy is depleted,
the current ramp down until the diode turns off. At this
point, inductor may ring due to residual energy and
stray capacitance. The output capacitor stores charge
when current flowing through the diode is high, and
release it when current is low, thereby maintaining a
steady voltage across the load.
As the load increases, the output capacitor discharges
faster and the error comparator initiates cycles sooner,
increasing the switching frequency. The maximum
duty cycle ensure adequate time for energy transfer to
output during the second half each cycle. Depending
on circuit, PFM controller can operate in either
discontinuous mode or continuous conduction mode.
Continuous conduction mode means that the inductor
current does not ramp to zero during each cycle.
EXT
to minimize switch losses.
VIN
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IN
SW
Isw
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D
Ico
+
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OUT
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OUT
3-PIN ONE-CELL STEP-UP DC/DC CONVERTER
Discontinuous Conduction Mode
Continuous Conduction Mode
www.analog.com.tw
TEL: [phone] FAX:[phone]
V
V
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I
I
V
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V
IN
SW
IN
SW
EXT
SW
EXT
SW
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D
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T
DIS
Charge Co.
Discharge Co.
SPEC NO: DS-1638-00 03/01/00
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PK
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V
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PK
AIC1638
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OUT
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OUT
t
t
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