Power supply and control sequencing
STA516B
4
Power supply and control sequencing
To guarantee correct operation and reliability, a correct turn on/off sequence must be
followed. Figure 3 shows the correct power on sequence.
Figure 3.
Correct power-on sequence
Vcc
V
VL
Vcc > VL
t
t
PWRDN
IN
t
Vcc must turn on before V in order to prevent uncontrolled current flowing through an
L
internal protection diode connected between V (logic supply) and Vcc (high power supply).
L
Failure to do so could result in damage to the device.
PWRDN must be released after V is switched on. An input signal can then be sent to the
L
power stage.
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STMICROELECTRONICS [ ST ]
