AN8031 Ver la hoja de datos (PDF) - Panasonic Corporation

Número de pieza

componentes Descripción

Fabricante

AN8031

Active filter control IC

Panasonic Corporation 

Voltage Regulators

AN8031

s Application Notes (continued)

[2] Operation descriptions (continued)

1. Normal control (continued)

2) Control outline description (Refer to figure 2 and figure 3.)

(1) Input voltage (EIN) detection

The voltage which is divided from the input voltage of chopper circuit (EIN) by using the external

resistor is input to the multiplier input terminal of the AN8031 (MPI terminal).

(2) Output voltage (EOUT) detection

The voltage which is divided from the output voltage of chopper circuit (EOUT) by using the external

resistor is amplified by the error amplifier of the AN8031 (Input to inverted input terminal (EI terminal))

and input to another multiplier input (EO terminal, which also functions as output for error amplifier).

(3) Multiplication of input voltage and output voltage

The signals input to the multiplier are multiplied and outputted from the multiplier. This output is a

signal which monitors both the input voltage and output voltage of the chopper circuit.

MPI

input voltage

0V

EI

input voltage

0V

Approx. 2.5 V typ.

Multiplier output

(MPO) voltage

0V

Enlarged

Time

Time

Time

0V

Transformer reset

voltage detection (VB)

0V

Power MOS turned off

Power MOS turned off

Multiplier output (MPO) voltage

Power MOSFET current detection

(CS) voltage

Time

VB lower limit voltage (regulated inside IC)

Power MOS turned on = bias coil voltage

generated

Reset operation of transformer = bias coil

voltage inversion

VB lower limit voltage (regulated inside IC)

Time

Figure 2. Explanation of normal control operation

7

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