Microchip Technology MCP1650, Руководство пользователя

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MCP1650/1/2/3 Evaluation Board User’s Guide
DS51462A-page 6
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2004 Microchip Technology Inc.
- The Under Voltage Lockout (UVLO) feature will prevent the MCP1651 from
starting the converter until the input voltage is above the minimum thresh-
old. Once the input voltage is raised above the UVLO threshold, the
converter will begin to boost the output voltage up to 5V. The output voltage
is fed back to the input so that, once the Boost converter has started, it can
run down to lower input voltages at reduced load currents.
2. Applying the load to the MCP1651 bootstrap application circuit:
- To apply a load to the MCP1651 application circuit, the positive side of the
load (+) should be connected to the +V
OUT
_1 test point (TP2). The negative
side of the load should be connected to the GND test point (TP3). The
maximum load current should not exceed 1A while the input voltage is
within the range specified for this application (2.8V to 4.8V).
3. Using the shutdown feature of the MCP1651 application circuit:
- To shutdown the MCP1651, use a jumper wire to connect the SHDN test
point (TP5) to the GND test point (TP4). By grounding the shutdown pin, the
MCP1651 will enter the shutdown state and minimum quiescent current will
be drawn from the input source. To resume normal operation, remove the
jumper pin from the SHDN test point to ground and the MCP1651 will start.
4. Low Input Status LED:
- The MCP1651 has a low input voltage status indicator that will provide
visual indication (via a LED) when the input voltage is below 3V. This LED
will illuminate to provide a warning that the input voltage is approaching the
minimum 2.8V input voltage.
MCP1653S Application Circuit
1. Powering the MCP1653 non-bootstrap application circuit:
- Apply the input voltage to the surface-mount test points provided. The input
voltage source should be limited to the 3.0V to 3.6V range to regulate the
12V output. The input voltage must not exceed the +5.5V maximum rating
of the MCP165X. The source current necessary to regulate the output
voltage to +12V at 0.4A should be a minimum of approximately 3A.
- Connect the positive side of the input source (+) to the +V
IN
_2 test point
(TP6). Connect the negative, or return side, (–) of the input source to the
GND test point (TP8) located next to +V
IN
_2.
- The UVLO feature will prevent the MCP1653 from starting the converter
until the input voltage is above the minimum threshold. Once the input
voltage is raised above the UVLO threshold, the converter will begin to
boost the output voltage up to 12V. To maintain regulation of the 12V output,
the input voltage range should be between 3.0V and 3.6V.
2. Applying the load to the MCP1653 non-bootstrap application circuit:
- To apply a load to the MCP1653 application circuit, the positive side of the
load (+) should be connected to the +V
OUT
_2 test point (TP7). The negative
side of the load should be connected to the GND test point (TP10). The
maximum load current should not exceed 0.4A while the input voltage is
within the range specified for this application (3.0V to 3.6V).
3. Using the shutdown feature of the MC1653 application circuit:
- To shutdown the MCP1653, use a jumper wire to connect the SHDN test
point (TP9) to the GND test point (TP8). By grounding the shutdown pin, the
MCP1653 will enter the shutdown state and minimum quiescent current will
be drawn from the input source. To resume normal operation, remove the
jumper pin from the SHDN test point to ground and the MCP1653 will start.