Datasheet TLE6280GP
7 2007-07-19
Shoot through protection / option
As already mentioned, the device has a built-in shoot-through protection, to avoid a simulta-
neous activation of high- and low-side switch in one half-bridge.
In case there is a short circuit in the bridge, the driver will switch off all external Mosfets. If
there is still current flowing in the motor, it is possible for the user to override this shoot
through protection.
By setting the ILx to “high”, the IHx to “low” and MFP to a level above 4.5V, all external Mos-
fets will be turned on simultaneously to blow a well-dimensioned fuse. The application will be
finally disconnected in this way from battery, and thus guarantee that the motor does not ap-
ply any uncontrolled torque.
Undervoltage warning:
If the voltage of a bootstrap capacitor C
Bxx
reaches the undervoltage warning level the error
flag is set and will remain set until the voltage of the bootstrap capacitor has recovered.
The error signal can be seen as awarning that an undervoltage shut-down could occur soon,
and the user can take appropriate measures to avoid this. Such measures could be the
change of the duty cycle to a range of 10-90% or the ramp down of the motor.
Undervoltage shut down:
The TLE6280GP has an integrated undervoltage shut-down, to guarantee that the behavior
of the device is predictable in all voltage ranges.
If the voltage of a bootstrap capacitor C
Bxx
reaches the undervoltage shut-down level, the
Gate-Source voltage of the affected external Mosfet will be actively pulled to low. In this
situation the short circuit detection of this output stage is deactivated to avoid a complete
&
&
NAND
Vmfp x 2
MFP
Shoot
Through
80ns
1.45 /
1.7V
Gate
control
4.5V
IHx
ILx
Levelshifter
Dissable
=
Reset
Fig. 4: Block diagram of internal structure of MFP pin
Datasheet TLE6280GP
8 2007-07-19
shut down of the driver. This allows continued operation of the motor in case of undervoltage
shut-down for a short period of time.
As soon as the bootstrap voltage recovers, the output stage condition will be aligned to the
input patterns by the next changing input signal at the corresponding input pin.
Diagnosis
The ERR pin is an open collector output and has to be pulled up with external pull-up resis-
tors to 5V. In normal conditions the ERR signal is high. In case of an error the ERR pin is
pulled down. There are 3 different causes for an error signal:
1) Short circuit of an external Mosfet – all external Mosfets are switched off. The driver has
to be reset to start again.
2) Undervoltage warning: at least one of the external capacitors connected to Bxx pins has
a voltage below the warning level.
3) Over-temperature warning: The device works normally but is out of the maximum ratings.
Immediate actions have to be taken to reduce the thermal load. The error flag will be re-
moved when the driver reached temperatures below the over temperature warning level.
dI/dt control
In all high current PWM applications, transient overvoltages and electro-magnetic emmisions
are critical items. The dI/dt regulation of the TLE6280GP helps to reduce transient overvolt-
age as well as electro-magnetic emissions.
Each real bridge configuration has stray inductance in each half-bridge. When the Mosfets in
the bridge are switching and load current is flowing, the stray inductance together with the
dI/dt in the halfbridge causies transient overvoltages. These transient overvoltages can be
feed to the DIDT pin of the gate driver by a high pass filter. Voltages exceeding 2 to 5V or –2
to –5V at this pin will strongly reduce the gate current of the actually switched Mosfet, result-
ing in an increased switching time in the Miller plateau of the Mosfet, and reducing the
switching speed exactly and only in the critical area of the switching process. Through this
regulation over-voltages are reduced and a smoother dI/dt in the bridge is obtained.
For more detailed information please refer to application note.
Fig. 5: Block diagram of ERR functionality
OR
ERR
Iscp (VMFP)
3.3µA
0.3µA
10pF
Temperature
Sensor
I undervoltage
τ approx. 1µs
Datasheet TLE6280GP
9 2007-07-19
Estimation of power dissipation within the driver IC
The power dissipation within the driver IC is strongly dependent upon the use of the driver
and the external components. Nevertheless, a rough estimation of the worst case power dis-
sipation is possible.
Worst case calculation is:
P
D
= (Q
gate
*n*const* f
PWM
+ I
VS(open)
) * V
Vs
- P
RGate
With:
P
D
= Power dissipation in the driver IC
f
PWM
= Switching frequency
Q
gate
= Total gate charge of used MOSFET at 10V V
GS
n = number of switched Mosfets
const = constant considering some leakage current in the driver and the power dissipa-
tion caused by the charge pump (nominally = 2)
I
VS(open)
= Current consumption of driver without connected Mosfets during switching
V
VS
= Voltage at Vs
P
RGate
= Power dissipation in the external gate resistors
This value can be reduced dramatically by the use of external gate resistors.
Recommended start up procedure
To assure the driver to be active and functional, a special initialization procedure is required
whenever the gate drive is enabled (V
MFP
is changed from LO to HI). Every time the driver is
enabled, after 10µs or later, positive-going transition signals at all ILx pins are required in or-
der to ensure proper start-up of the output driver. This procedure assures a proper wake up
the device and allowes to fill the bootstrap capacitors. Not filling the bootstrap capacitors
might lead to low Gate-Source voltages mainly in highside and can cause a short circuit de-
tection when the highside switches are activated. Not changing the ILx input signal after
enabling the device may cause the lowside outputs to stay in off conditions.

TLE6280GPNT

Mfr. #:
Manufacturer:
Infineon Technologies
Description:
IC MOTOR DRIVER 8V-20V 36DSO
Lifecycle:
New from this manufacturer.
Delivery:
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