ARD00386 Microchip Technology, ARD00386 Datasheet - Page 17

• Manufacturer Part Number: ARD00386
• Description: Power Management Modules MCP1640 12V 50mA Boost Converter
• Manufacturer: Microchip Technology

Specifications of ARD00386

• Product: DC-DC Converters / Regulators
• Input Voltage Max: 5 V
• Switching Frequency: 500 kHz
• Output Voltage: 12 V
• Output Current: 50 mA
• Input Voltage Min: 2 V

© 2011 Microchip Technology Inc.
FIGURE 2-5:
Reference Design Test Points (SWH, SWL), Inductor (I
Waveforms for 60 mA Load and 2.4V Input in Continuous mode.
2.2.3
The board was designed to boost low voltage from two alkaline cells or NiCd/NiMH
cells to high voltage. The topology used in this reference design is adapting a
low-voltage boost converter into a high-voltage boost converter using a single inductor,
instead of using a flyback topology that requires a more expensive flyback transformer.
Another advantage is that the switching voltage spikes are kept below the safe value,
6V, for MCP1640 device’s SW pin.
The converter is configured as nonsynchronous; an external diode, D, is connected
between the inductor and the high-voltage output (V
The two sense resistors, R
following equation:
EQUATION 2-1:
Note:
How Does the MCP1640 12V/50 mA Two Cells Input Boost
Converter Reference Design Works?
The reference board is tested up to 24V output with a maximum load of
20 mA. The internal error amplifier is a transconductance type; its gain is
not related to the feedback resistors’ values.
Where:
V
V
V
OUT
R
FB
FB
B
MCP1640 12V/50 mA Two Cells Input Boost Converter
=
=
=
=
T
1.21V
Reference voltage of the FB pin
12.0V
Resistor’s value is selected by the designer
and R
R
T
=
B
Installation and Operation
, set the output (V
R
B
×
⎛
⎝
V
------------ - 1
V
OUT
FB
–
OUT
OUT
⎞
⎠
L
) and Load Current (I
).
) at 12.0V according to the
DS51999A-page 17
OUT
)