AN487 APPLICATION NOTE

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Figure 10. Error amplifier circuit

UNDERVOLTAGE LOCKOUT

The chip features a complete built-in under voltage lock out protection, keeps the power output stage off

up to the moment Vcc reaches 11v, with an hysteresis of 1V. After reaching the 11V value the system

starts with the soft start feature.

ERROR AMPLIFIER

The error amplifier is a transconductance Operational Amplifier featuring a current output. The simplified

schematic is represented in fig.10. The basic characteristics of the uncompensated operational amplifier

are the following:

The frequency behavior of the uncompensated amplifier is reported in fig.11.

Figure 11. Open loop gain (error amplifier only).