MB3788 Просмотр технического описания (PDF) - Fujitsu

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Компоненты Описание

производитель

MB3788

SWITCHING REGULATOR CONTROLLER

Fujitsu 

MB3788

s HOW TO SET OUTPUT CURRENT

The output circuit is configured in a push-pull type as shown in Figure 1. The ON current value of the output current waveform shown in Figure

2 is a constant current and the OFF value set by RE is set by a time constant. Each output current can be calculated from the following expression:

• ON current = 1.5/RE (A) (Output current setting pin voltage: VE ≈ 1.5 V)

• The OFF current time constant is proportional to the value of CB.

CB

OFF current

setting part

Drive Tr

OFF

current

ON current

RE

VE

Output 0

current

ON current

t

OFF current

Fig.1 Output Circuit Diagram

Fig.2 Output Current Waveform

1000 pF

VCC

4

5

1

Iout

MB3788 2

1000 pF

3

150 Ω

-IN1 (C)

22 µH

Vout 10 µF

(5 V)

8.2 k

2.7 k

-IN1 (E)

Fig.3 Output Pin Voltage and Current Waveforms (Channel 1)

Fig.4 Measurement Circuit Diagram

13

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