KA9268D Просмотр технического описания (PDF) - Fairchild Semiconductor

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Компоненты Описание

производитель

KA9268D

4-CH Motor Driver

Fairchild Semiconductor 

Application Information

1. MUTE

Pin #7

Mute circuit

High

Turn-off

Low

Turn-on

7

Open

Turn-on

FAN8000D (KA9268D)

Output driver

bias

• When the pin7 is open or the voltage of the pin7 is below 0.5V, the mute circuit is activated so that the output circuit is

muted.

• When the voltage of the pin7 is above 2V, the mute circuit is deactivated and the output circuit operates normally.

• If the chip temperature rises above 175°C, then the TSD (Thermal Shutdown) circuit is activated and the output circuit is

muted.

2. TSD (THERMAL SHUTDOWN)

VREF BG

R11

Output driver

bias

Q11

R12

• The VREF BG is the output voltage of the band-gap-referenced biasing circuit and acts as the input voltage of the TSD

circuit.

• The base-emitter voltage of the TR, Q11 is designed to turn-on at below voltage.

VBE = VREF BG × R12 / (R11 + R12) = 460mV

• When the chip temperature rises up to 175°C, then the turn-on voltage of the Q11 would drop down to 460mV.

(Hysteresis: 25°C)

Hence, the Q11 would turn on so the output circuit will be muted.

7

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