Si824x
22 Preliminary Rev. 0.3
3.7.3. Undervoltage Lockout (UVLO)
The UVLO circuit unconditionally drives VO low when VDD is below the lockout threshold. Referring to Figures 35
and 36, upon power up, the Si824x is maintained in UVLO until VDD rises above VDD
UV+
. During power down, the
Si824x enters UVLO when VDD falls below the UVLO threshold plus hysteresis (i.e., VDD <
VDD
UV+
– VDD
HYS
).
Figure 35. Si824x UVLO Response (8 V)
Figure 36. Si824x UVLO Response (10 V)
3.7.4. Control Inputs
PWM inputs are high-true, TTL level-compatible logic inputs. VOA is high and VOB is low when the PWM input is
high, and VOA is low and VOB is high when the PWM input is low.
3.7.5. Disable Input
When brought high, the DISABLE input unconditionally drives VOA and VOB low regardless of the states of input.
Device operation terminates within tSD after DISABLE = V
IH
and resumes within tRESTART after DISABLE = V
IL
.
The DISABLE input has no effect if VDDI is below its UVLO level (i.e. VOA, VOB remain low). The DISABLE input
is typically connected to external protection circuitry to unconditionally halt driver operation in the event of a fault.
6.0
10.5
V
DDUV+
(Typ)
Output Voltage (V
O
)
6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0
Supply Voltage (V
DD
- V
SS
) (V)
8.5
10.5
V
DDUV+
(Typ)
Output Voltage (V
O
)
9.0 9.5 10.0 10.5 11.0 11.5 12.0 12.5
Supply Voltage (V
DD
- V
SS
) (V)
