Design specifications and schematic diagram

AN2528

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Design specifications and schematic diagram

The table below lists the converter specification data and the main parameters fixed for the

demo board.

A schematic diagram of the SMPS is given in Figure 2. The most relevant components are:

1.

HV ESBT main switch and simple driving circuit

2.

L6565 QR PWM driver to get the best efficiency

3.

Special transformer construction with very low parasitic capacitance

Table 1.

Converter specification and preliminary choices

Symbol

Description

Values

Rectified minimum input voltage

150

Rectified maximum input voltage

850

Output voltage

14 V/430 mA

Maximum output power

6 W

η

Converter efficiency @ max load

> 80%

F

Minimum switching frequency

Reflected flyback voltage

250 V

Max over voltage limited by clamping circuit

150 V