- 7 -
April. 2002 (Rev.0)
www.interpionsemi.com
AD6392
4-CH MOTOR DRIVE IC
APPLICATION SUMMARY (Continued)
- Mute function through MUTE pin
Mute function is also performed at MUTE pin (pin15). The logic is as followers:
Pin15
Mute
High
off
Low
on
Fig. 2 Mute function
As it can be seen in Fig. 2, If the voltage of the pin15
become low (below 0.5V) or open, Q3 becomes off and
Q4 on, and hence the bias currents for all channel
drivers are shut down and muted. If the voltage of the
pin15 become high (above 2.0V), the channel drivers
operate normally.
- Thermal shutdown (TSD)
The AD6392 has a thermal protection against the abnormal high temperature operation to protect the chip.
Temperature
mute
Above 175
OC
on
Falls below 150
OC
off
Q5 is biased through the resistor string from the
internal bandgap reference voltage so that it
remains in off state at the ranges of the normal
operating temperatures. If the junction tempera-
ture rises above 175
OC, Q5 turns into on state
and hence Q7 turns on, and all channel drivers
are muted as the bias currents are shut down.
When the junction temperature falls below 150
OC, Q5 and Q7 are turned off and the drivers
operate normally. The hysteresis temperature is,
thus, 25
OC
Fig. 3 Thermal shut down
Hysteresis
25
OC