Microchip Technology MCP19114, User Manual

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Graphical User Interface (GUI)
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2014 Microchip Technology Inc. DS50002255A-page 21
Users can adjust the Output Current over a range of 0 to 500 mA. The Current Sense
Resistor (R6) value on the MCP19114 - Flyback Stand-Alone Evaluation Board is
200 m
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. Both of these values are used to calculate the set point value written to the
VREFCON register. DO NOT raise the resistor value in the GUI without changing the
resistor on the evaluation board to match. Failure to do so could result in damage to
the evaluation board.
3.2.1.3 OPERATING MODE
This section controls whether the Flyback converter is operated in Fixed-Frequency,
Quasi-Resonant, Synchronous or Asynchronous Modes. When running in Fixed
Frequency mode, the switching frequency parameters are adjustable. The third button
is for Synchronous Operation. When the EN ON button is selected on the GUI, the
Synchronous Operation box is automatically selected by default, putting the evaluation
board in Synchronous mode. If the Synchronous Operation box is unchecked, the
evaluation board is set to Asynchronous operation which disables the secondary driver
(SDRV).
FIGURE 3-3: Operating Mode Options.
3.2.1.4 PROTECTION
The Protection control allows the user to set levels for the three adjustable protection
features. Input Voltage Under Voltage Lockout (VIUVLO), Input Voltage Overvoltage
Lockout (VINOVLO) and Output Voltage Overvoltage (OV) can all be configured in this
section of the GUI.
FIGURE 3-4: Protection Options.
CAUTION
Increasing switching frequency results in increased switching losses in the MOSFETs.
It is the user's responsibility to ensure MOSFETs are operated within their safe
operating range.
Note: Attempting to write a value larger than 0xFF to VREFCON is prohibited by
the GUI.