MC33926 Freescale Semiconductor, MC33926 Datasheet - Page 17

• Manufacturer Part Number: MC33926
• Description: 5.0 A Throttle Control H-Bridge
• Manufacturer: Freescale Semiconductor

SHORT CIRCUIT PROTECTION
outputs tri-state (latch-OFF) independent of the input (IN1
and IN2) states, and the fault status output flag (SF) is SET
to logic LOW. If the D1 input changes from logic HIGH to logic
LOW, or if the D2 input changes from logic LOW to logic
HIGH, the output bridge will become operational again and
the fault status flag will be reset (cleared) to a logic HIGH
state.
by the input pins (IN1, IN2, D1, and D2), provided the device
junction temperature is within the specified operating
temperature range.
INTERNAL PWM CURRENT LIMITING
conditions should be less than 5.0 A. The instantaneous load
currents will be limited to I
limiting circuitry. When the I
reached, the output stages are tri-stated for a fixed time (T
of 20 µs typical. Depending on the time constant associated
with the load characteristics, the output current decreases
during the tri-state duration until the next output ON cycle
occurs.
device junction temperature. When - 40°C < T
between the specified minimum/maximum values. When T
exceeds 160 °C, the I
Shortly above 175 °C the device overtemperature circuit will
detect T
feature implements a graceful degradation of operation
before thermal shutdown occurs, thus allowing for
intermittent unexpected mechanical loads on the motor’s
gear-reduction train to be handled.
permitted only for non-repetitive durations < 30 seconds.
Provision must be made at the system level to prevent
prolonged operation in the current-foldback region.
Analog Integrated Circuit Device Data
Freescale Semiconductor
If an output short circuit condition is detected, the power
The output stage will always switch into the mode defined
The maximum current flow under normal operating
The PWM current limit threshold value is dependent on the
Important Die temperature excursions above 150°C are
LIM
and an overtemperature shutdown will occur. This
LIM
threshold decreases to 4.2 A.
LIM
LIM
via the internal PWM current
threshold current value is
PROTECTION AND DIAGNOSTIC FEATURES
J
< 160°C, I
LIM
A
is
J
)
OVERTEMPERATURE SHUTDOWN AND
HYSTERESIS
are tri-stated (latched-OFF) and the fault status flag (SF) is
SET to logic LOW.
HIGH to logic LOW, or D2 must change from logic LOW to
logic HIGH. When reset, the output stage switches ON again,
provided that the junction temperature is now below the
overtemperature threshold limit minus the hysteresis.
Important Resetting from the fault condition will clear the
fault status flag. Powering down and powering up the device
will also reset the 33926 from the fault condition.
OUTPUT AVALANCHE PROTECTION
would likely tri-state simultaneously due to the disable logic.
This could result in an unclamped inductive discharge. The
VPWR input to the 33926 should not exceed 40 V during this
transient condition, to prevent electrical overstress of the
output drivers.This can be accomplished with a zener clamp
or MOV, and/or an appropriately valued input capacitor with
sufficiently low ESR (see
V PW R
If an overtemperature condition occurs, the power outputs
To reset from this condition, D1 must change from logic
If VPWR were to become an open circuit, the outputs
Low ESR
Figure 13. Avalanche Protection
Cap.
Bulk
PROTECTION AND DIAGNOSTIC FEATURES
100nF
9
Figure
FUNCTIONAL DEVICE OPERATION
VPW R
I/Os
13).
AGND
OUT2
PGND
OUT1
M
33926
17