FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
The 33981 has 2 operating modes: Sleep and Normal
depending on EN input.
NORMAL MODE
The 33981 will go to the normal operating mode when the
EN pin is logic [1]. The INHS and INLS commands will be
disabled tON after the EN transitions to logic [1] to enable the
charge of the bootstrap capacitor.
SLEEP MODE
Sleep mode is the state of the 33981 when the EN is
logic [0]. In this mode, OUT, the gate driver for the external
MOSFET, and all unused internal circuitry are off to minimize
current draw.
Table 5. Operating Modes
Condition
Sleep
CONF INHS INLS OUT
GLS
x
FS
H
EN
Comments
Device is in Sleep mode. The OUT and low-side gate are OFF.
x
x
x
x
L
Normal mode. High side and low side are controlled
Normal
L
H
H
H
H
H
H
independently. The high side and the low side are both on.
Normal mode. High side and low side are controlled
independently. The high side and the low side are both off.
Normal
Normal
Normal
Normal
L
L
L
L
L
H
L
L
L
L
H
L
H
H
H
H
H
H
H
H
Normal mode. Half-bridge configuration. The high side is off
and the low side is on.
Normal mode. Half-bridge configuration. The high side is on
and the low side is off.
L
H
H
Normal mode. Cross-conduction management is activated.
Half-bridge configuration.
H
PWM
H
PWM PWM_bar
H = High level
L = Low level
x = Don’t care
PWM_bar = Opposite of pulse-width modulation signal.
PROTECTION AND DIAGNOSTIC FEATURES
offending load is removed. FS pin transition to logic [1] will be
UNDERVOLTAGE
disabled typically tON after to enable the charge of the
bootstrap capacitor.
The 33981 incorporates undervoltage protection. In case
of VPWR<V
(UV), the OUT is switched OFF until the power
PWR
Overtemperature faults force the TEMP pin to 0 V.
supply rises to VPWR(UV)+VPWR(UVHYS). The latched fault are
reset below V
.
PWR(UV)
OVERCURRENT FAULT ON HIGH SIDE
OVERTEMPERATURE FAULT
The OUT pin has an overcurrent high-detection level
called IOCH for maximum device protection. If at any time the
current reaches this level, OUT will stay OFF and the CSNS
pin will go to 0 V. The OUT pin is reset (and the fault is
The 33981 incorporates over temperature detection and
shutdown circuitry on OUT. Overtemperature detection also
protects the low-side gate driver (GLS pin). Overtemperature
detection occurs when OUT is in the ON or OFF state and
GLS is at high or low level.
delatched) by a logic [0] at the INHS pin for at least tRST(diag)
When INHS goes to 0 V, CSNS goes to 5.0 V.
.
In Figure 16, page 19, the OUT pin is short-circuited to 0 V.
When the current reaches IOCH, OUT is turned OFF within
tOCH owing to internal logic circuit.
For OUT, an over temperature fault condition results in
OUT turning OFF until the temperature falls below TSD. This
cycle will continue indefinitely until the offending load is
removed. Figure 12, page 16 and Figure 18, page 20 show an
over temperature on OUT.
OVERLOAD FAULT ON LOW SIDE
An over temperature fault on the low-side gate drive
results in OUT turning OFF and the GLS going to 0 V until the
temperature falls below TSD. This cycle will continue until the
This fault detection is active when INLS is logic [1]. Low-
side overload protection does not measure the current
directly but rather its effects on the low-side MOSFET. When
33981
Analog Integrated Circuit Device Data
Freescale Semiconductor
13
FREESCALE [ Freescale ]
