AN8018SA Ver la hoja de datos (PDF) - Panasonic Corporation

Número de pieza

componentes Descripción

Fabricante

AN8018SA

1.8-volt 2-channel step-up, step-down, or inverting DC-DC converter control IC

Panasonic Corporation 

AN8018SA

s Application Notes (continued)

[9] About sequential operation (continued)

V1

V2

DT1

Out1

DT2

Voltage Regulators

Out2

Out1 operation

Out2 operation

Operation when each channel single on/off

[10] Error amplifier phase-compensation setting method

The equivalent circuit of error amplifier is as shown in figure 11.

The transfer function is:

H=

1 / {S (CE1 + CO1)}

RE1 + 1 / {S (CE1 + CO1)}

=

1

SCO1 · RE1 + 1

(from CE1 << CO1)

The cut-off frequency is variable by changing the externally attached phase compensation capacitor CO1 .

Adjust by inserting a resistor RO1 between the FB1 terminal and CO1 in series as shown in figure 12 when it is

required to have a gain on the high frequency side or desired to lead a phase.

The transfer function is:

H=

SCO1 · RO1 + 1

SCO1 (RO1 + RE1) + 1

(from CE1 << CO1)

IN−1

RE1

1 MΩ

57dB

CE1

1.19 V 5 pF

To PWM

CO1

Figure 11. Error amplifier equivalent circuit

IN−1

RE1

1 MΩ

57dB

CE1

1.19 V 5 pF

To PWM

RO1

CO1

Figure 12. Error amplifier equivalent circuit (RO1 inserted)

20

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