btn7970 Infineon Technologies Corporation, btn7970 Datasheet - Page 15

• Manufacturer Part Number: btn7970
• Description: High Current Pn Half Bridge Novalithic?
• Manufacturer: Infineon Technologies Corporation

5.3
The device provides integrated protection functions. These are designed to prevent IC destruction under fault
conditions described in the data sheet. Fault conditions are considered as “outside” normal operating range.
Protection functions are not to be used for continuous or repetitive operation, with the exception of the current
limitation
of the connected slew rate resistor. Overvoltage, overtemperature and overcurrent are indicated by a fault current
I
Page 19
In the following the protection functions are listed in order of their priority. Overvoltage lock out overrides all other
error modes.
5.3.1
To assure a high immunity against overvoltages (e.g. load dump conditions) the device shuts the lowside MOSFET
off and turns the highside MOSFET on, if the supply voltage is exceeding the over voltage protection level
The IC operates in normal mode again with a hysteresis
on voltage
during over voltage.
5.3.2
To avoid uncontrolled motion of the driven motor at low voltages the device shuts off (output is tri-state), if the
supply voltage drops below the switch-off voltage
if the supply voltage rises above the switch-on voltage
5.3.3
The BTN7970 is protected against overtemperature by an integrated temperature sensor. Overtemperature leads
to a shut down of both output stages. This state is latched until the device is reset by a low signal with a minimum
length of
meantime.
Repetitive use of the overtemperature protection impacts lifetime.
5.3.4
The current in the bridge is measured in both switches. As soon as the current in forward direction in one switch
(high side or low side) is reaching the limit
During that time all changes at the IN pin are ignored. However, the INH pin can still be used to switch both
MOSFETs off. After
Unintentional triggering of the current limitation by short current spikes (e.g. inflicted by EMI coming from the
motor) is suppressed by internal filter circuitry. Due to thresholds and reaction delay times of the filter circuitry the
effective current limitation level
Data Sheet
IS(LIM)
at the IS pin as described in the paragraph
and
t
(Chapter
reset
V
OV(ON)
Protection Functions
Overvoltage Lock Out
Undervoltage Shut Down
Overtemperature Protection
Current Limitation
Figure
at the INH pin, provided that its temperature has decreased at least the thermal hysteresis Δ
. In H-bridge configuration, this behavior of the BTN7970 will lead to freewheeling in highside
5.3.4). In a fault condition the BTN7970 will apply the highest slew rate possible independent
t
CLS
12.
the switches return to their initial setting. The error signal at the IS pin is reset after 2 *
I
CLx
depends on the slew rate of the load current
I
CLx
, this switch is deactivated and the other switch is activated for
V
“Status Flag Diagnosis With Current Sense Capability” on
UV(OFF)
V
15
V
UV(ON)
. The IC becomes active again with a hysteresis
OV(HY)
.
if the supply voltage decreases below the switch-
Block Description and Characteristics
High Current PN Half Bridge
dI/dt
as shown in
Rev. 1.1, 2007-11-21
Figure
BTN7970
V
T
OV(OFF)
V
10.
in the
UV(HY)
t
t
CLS
CLS
.
.
.